Re: [DOG mailing list] Limbach engine rebuilds
Update on my last posting. Andrew who works for Qantas has pointed this out. *Limbach hold the type design so are the manufacturer despite not fabricating the part. They hold the design and perform the conformity check before raising the Form 1.* *If you go straight to the “manufacturer” say of the cylinder head you will get one identical to the Limbach one but shouldn’t have the Limbach part number on it nor would it come with a Form 1 if it did it would be considered a bogus part under the regs.* *Limbach provide a licence to manufacturer to a company but as above they must still control the design and conformity to the design* Ah well...It was pleasant getting excited for a brief moment amongst all this dampness here in NSW! regards Rob Rob Thompson 0429 493 828 On Tue, Mar 23, 2021 at 9:28 AM Rob Thompson wrote: > G'day Blokes, > This posting relates to regulations in Australia but there may be some > sort of equivalent regulations in other countries. > > Below is the section on parts replacement from the Australian CASR > https://www.legislation.gov.au/Details/F2011C00973/Html/Volume_1#_Toc311721051 > > Interesting that it says a spare part only requires *"information that > allows the part to be traced to its manufacturer"* > > This says to me that you don't have to purchase a part from Limbach > you can go direct to the manufacturer. Limbach does not manufacture much > stuff. > > 42.445Fitting standard parts > > (1) An individual who is carrying out maintenance on an > aircraft or aeronautical product must not fit a standard part to the > aircraft or aeronautical product unless the fitting of the part is > permitted under: > > (a)regulation 42.450; or *(Rob's note - 42.450 > relates to parts which have been previously removed from the aircraft)* > >(b)subregulation (2). > > (2) For paragraph (1) (b), the standard part may be fitted if: > > (a)the standard part is serviceable; and > >(b)the standard part is accompanied by: > > (i)information that identifies the > specification with which the part complies; and > > (ii)information that allows the part to be > traced to its manufacturer; and > > (c)the standard part is accompanied by evidence that > the standard part complies with the specification; and > >(d)the standard part is eligible to be fitted to the > aircraft or the aeronautical product; and > > (e)if the manufacturer of the standard part has > specified a storage life for the part — the storage life for the part has > not expired. > regards > Rob > > Rob Thompson > 0429 493 828 > > > > On Sat, Mar 20, 2021 at 2:30 PM Ian Mc Phee wrote: > >> My understanding if you have a prop stroke then the bulk strip can be >> done by a LAME organisation (that is qualified) or aviation engine >> rebuilder. There are still some Aviation engine re builders around that >> are good on VWs >> >> A friend 2 or 3 years ago convinced himself the engine had an issue >> (about 800hrs tt) and was pulled down by some VW person in Victoria. I >> explained he had to go to a CASA engine re builder which he did then. >> Platinum 300 in Victoria found no issues but chose to fit new rings and >> bearings like a rebuild (aircraft was bought from an estate so sat around >> for 6 years) . They had to have on file ALL manuals and chose to get the >> heads OH by the old guy here who did lots of aero enterprises machine work. >> >> The reason for the rebuild was faulty mechanical fuel pump! >> >> We in Australia now can go hours "on condition" in most aircraft >> (excluding charter but includes training). Thus as I see it he just keeps >> flying well beyond the 1000hrs subject to oil consumption etc. >> >> During last 200hrs I get oil analysis (I now use ALS), wash out oil >> filter core in blue icecream container and examine with head lens. I place >> a magnet on outside of oil filter and always fit a digital CHT that >> monitors all four cylinders. >> >> If compression is good and oil temps and pressures then keep flying in >> AUSTRALIA. >> >> GFA must mirror CASA requirements I believe. >> >> Personally I am over chasing up genuine parts except where parts are >> critical. >> >> Ian McPhee >> 0428847642 >> Box 657 Byron Bay NSW 2481 >> >> On Sat, 20 Mar 2021, 11:17 Rob Thompson wrote: >> >>> Thanks Tom! >>> >>> A limbach is a very expensive rebranded VW motor. Example... I recently >>> dismantled a L2400 which is based on the Type 25 VW. The main and cam >>> bearings were just "off the shelf" Kolbenschmidt. Limbach is charging you >>> about 300 euros extra to change the boxes they come in. >>> >>> If you can get your aircraft registered as an experimental aircraft, >>> this is the place to buy Aero VW engine parts at reasonable prices >>> https://www.greatplainsas.com/ >>>
Re: [DOG mailing list] Limbach engine rebuilds
G'day Blokes, This posting relates to regulations in Australia but there may be some sort of equivalent regulations in other countries. Below is the section on parts replacement from the Australian CASR https://www.legislation.gov.au/Details/F2011C00973/Html/Volume_1#_Toc311721051 Interesting that it says a spare part only requires *"information that allows the part to be traced to its manufacturer"* This says to me that you don't have to purchase a part from Limbach you can go direct to the manufacturer. Limbach does not manufacture much stuff. 42.445Fitting standard parts (1) An individual who is carrying out maintenance on an aircraft or aeronautical product must not fit a standard part to the aircraft or aeronautical product unless the fitting of the part is permitted under: (a)regulation 42.450; or *(Rob's note - 42.450 relates to parts which have been previously removed from the aircraft)* (b)subregulation (2). (2) For paragraph (1) (b), the standard part may be fitted if: (a)the standard part is serviceable; and (b)the standard part is accompanied by: (i)information that identifies the specification with which the part complies; and (ii)information that allows the part to be traced to its manufacturer; and (c)the standard part is accompanied by evidence that the standard part complies with the specification; and (d)the standard part is eligible to be fitted to the aircraft or the aeronautical product; and (e)if the manufacturer of the standard part has specified a storage life for the part — the storage life for the part has not expired. regards Rob Rob Thompson 0429 493 828 On Sat, Mar 20, 2021 at 2:30 PM Ian Mc Phee wrote: > My understanding if you have a prop stroke then the bulk strip can be done > by a LAME organisation (that is qualified) or aviation engine rebuilder. > There are still some Aviation engine re builders around that are good on VWs > > A friend 2 or 3 years ago convinced himself the engine had an issue (about > 800hrs tt) and was pulled down by some VW person in Victoria. I explained > he had to go to a CASA engine re builder which he did then. Platinum 300 > in Victoria found no issues but chose to fit new rings and bearings like a > rebuild (aircraft was bought from an estate so sat around for 6 years) . > They had to have on file ALL manuals and chose to get the heads OH by the > old guy here who did lots of aero enterprises machine work. > > The reason for the rebuild was faulty mechanical fuel pump! > > We in Australia now can go hours "on condition" in most aircraft > (excluding charter but includes training). Thus as I see it he just keeps > flying well beyond the 1000hrs subject to oil consumption etc. > > During last 200hrs I get oil analysis (I now use ALS), wash out oil filter > core in blue icecream container and examine with head lens. I place a > magnet on outside of oil filter and always fit a digital CHT that monitors > all four cylinders. > > If compression is good and oil temps and pressures then keep flying in > AUSTRALIA. > > GFA must mirror CASA requirements I believe. > > Personally I am over chasing up genuine parts except where parts are > critical. > > Ian McPhee > 0428847642 > Box 657 Byron Bay NSW 2481 > > On Sat, 20 Mar 2021, 11:17 Rob Thompson wrote: > >> Thanks Tom! >> >> A limbach is a very expensive rebranded VW motor. Example... I recently >> dismantled a L2400 which is based on the Type 25 VW. The main and cam >> bearings were just "off the shelf" Kolbenschmidt. Limbach is charging you >> about 300 euros extra to change the boxes they come in. >> >> If you can get your aircraft registered as an experimental aircraft, this >> is the place to buy Aero VW engine parts at reasonable prices >> https://www.greatplainsas.com/ >> >> Profit drivenyes certainly but I also think there are mounting >> liability and insurance issues which has everyone running scared. Including >> me! >> >> regards >> Rob >> >> Rob Thompson >> 0429 493 828 >> >> >> >> On Sat, Mar 20, 2021 at 1:55 AM Tom Preisser wrote: >> >>> Afterthought... I consider you Rob, given your lengthy experience and >>> depth of thought, to be a grandmaster of these motors. You too Ian. >>> >>> On Fri, Mar 19, 2021, 07:51 Tom Preisser wrote: >>> Not yet... They offered a one week "maintenance" course previously that, if I understood correctly, that then qualified one to rebuild. Top end only ? I wonder if this is merely a profit based decision, rather than a technical issue. What would dear Mr Porsche feel, praytell ? I am afraid, however, that they have us by the shorties as far as Limbach manufactured parts are concerned. Case halves are probably the biggest item I can think of. I wonder what
Re: [DOG mailing list] Limbach engine rebuilds
My understanding if you have a prop stroke then the bulk strip can be done by a LAME organisation (that is qualified) or aviation engine rebuilder. There are still some Aviation engine re builders around that are good on VWs A friend 2 or 3 years ago convinced himself the engine had an issue (about 800hrs tt) and was pulled down by some VW person in Victoria. I explained he had to go to a CASA engine re builder which he did then. Platinum 300 in Victoria found no issues but chose to fit new rings and bearings like a rebuild (aircraft was bought from an estate so sat around for 6 years) . They had to have on file ALL manuals and chose to get the heads OH by the old guy here who did lots of aero enterprises machine work. The reason for the rebuild was faulty mechanical fuel pump! We in Australia now can go hours "on condition" in most aircraft (excluding charter but includes training). Thus as I see it he just keeps flying well beyond the 1000hrs subject to oil consumption etc. During last 200hrs I get oil analysis (I now use ALS), wash out oil filter core in blue icecream container and examine with head lens. I place a magnet on outside of oil filter and always fit a digital CHT that monitors all four cylinders. If compression is good and oil temps and pressures then keep flying in AUSTRALIA. GFA must mirror CASA requirements I believe. Personally I am over chasing up genuine parts except where parts are critical. Ian McPhee 0428847642 Box 657 Byron Bay NSW 2481 On Sat, 20 Mar 2021, 11:17 Rob Thompson wrote: > Thanks Tom! > > A limbach is a very expensive rebranded VW motor. Example... I recently > dismantled a L2400 which is based on the Type 25 VW. The main and cam > bearings were just "off the shelf" Kolbenschmidt. Limbach is charging you > about 300 euros extra to change the boxes they come in. > > If you can get your aircraft registered as an experimental aircraft, this > is the place to buy Aero VW engine parts at reasonable prices > https://www.greatplainsas.com/ > > Profit drivenyes certainly but I also think there are mounting > liability and insurance issues which has everyone running scared. Including > me! > > regards > Rob > > Rob Thompson > 0429 493 828 > > > > On Sat, Mar 20, 2021 at 1:55 AM Tom Preisser wrote: > >> Afterthought... I consider you Rob, given your lengthy experience and >> depth of thought, to be a grandmaster of these motors. You too Ian. >> >> On Fri, Mar 19, 2021, 07:51 Tom Preisser wrote: >> >>> Not yet... They offered a one week "maintenance" course previously >>> that, if I understood correctly, that then qualified one to rebuild. Top >>> end only ? I wonder if this is merely a profit based decision, rather than >>> a technical issue. What would dear Mr Porsche feel, praytell ? I am afraid, >>> however, that they have us by the shorties as far as Limbach manufactured >>> parts are concerned. Case halves are probably the biggest item I can think >>> of. >>> I wonder what their authorized service stations are capable of ? >>> >>> >>> >>> On Fri, Mar 19, 2021, 00:02 Ian Williams wrote: >>> Yep Ian W *From:* dog@lists.riverland.net.au *On Behalf Of *Rob Thompson *Sent:* Friday, 19 March 2021 7:51 p.m. *To:* dog@lists.riverland.net.au *Subject:* [DOG mailing list] Limbach engine rebuilds G'day Everyone, I recently had the Limbach factory questioning about me rebuilding their motors. I have Australian qualifications to rebuild 4 stroke motors in motor gliders and recreational aircraft but Limbach seem to be saying that any of their motors requiring a bottom end rebuild need to be shipped back to the factory (at great expense). I am suspicious that they may start refusing to sell parts. Unfortunately we don't have Nigel available to sort out these issues. Currently, in Australia we also have many legal liability difficulties for anyone working on certified aircraft. It really is all getting too hard for anyone like me. Anyone else had issues like this? regards Rob Rob Thompson 0429 493 828 >>>
Re: [DOG mailing list] Limbach engine rebuilds
Thanks Tom! A limbach is a very expensive rebranded VW motor. Example... I recently dismantled a L2400 which is based on the Type 25 VW. The main and cam bearings were just "off the shelf" Kolbenschmidt. Limbach is charging you about 300 euros extra to change the boxes they come in. If you can get your aircraft registered as an experimental aircraft, this is the place to buy Aero VW engine parts at reasonable prices https://www.greatplainsas.com/ Profit drivenyes certainly but I also think there are mounting liability and insurance issues which has everyone running scared. Including me! regards Rob Rob Thompson 0429 493 828 On Sat, Mar 20, 2021 at 1:55 AM Tom Preisser wrote: > Afterthought... I consider you Rob, given your lengthy experience and > depth of thought, to be a grandmaster of these motors. You too Ian. > > On Fri, Mar 19, 2021, 07:51 Tom Preisser wrote: > >> Not yet... They offered a one week "maintenance" course previously >> that, if I understood correctly, that then qualified one to rebuild. Top >> end only ? I wonder if this is merely a profit based decision, rather than >> a technical issue. What would dear Mr Porsche feel, praytell ? I am afraid, >> however, that they have us by the shorties as far as Limbach manufactured >> parts are concerned. Case halves are probably the biggest item I can think >> of. >> I wonder what their authorized service stations are capable of ? >> >> >> >> On Fri, Mar 19, 2021, 00:02 Ian Williams wrote: >> >>> Yep >>> >>> >>> >>> Ian W >>> >>> >>> >>> *From:* dog@lists.riverland.net.au *On Behalf Of *Rob Thompson >>> *Sent:* Friday, 19 March 2021 7:51 p.m. >>> *To:* dog@lists.riverland.net.au >>> *Subject:* [DOG mailing list] Limbach engine rebuilds >>> >>> >>> >>> G'day Everyone, >>> >>> I recently had the Limbach factory questioning about me rebuilding their >>> motors. >>> >>> >>> >>> I have Australian qualifications to rebuild 4 stroke motors in motor >>> gliders and recreational aircraft but Limbach seem to be saying that any of >>> their motors requiring a bottom end rebuild need to be shipped back to the >>> factory (at great expense). >>> >>> >>> >>> I am suspicious that they may start refusing to sell parts. >>> Unfortunately we don't have Nigel available to sort out these issues. >>> >>> >>> >>> Currently, in Australia we also have many legal liability difficulties >>> for anyone working on certified aircraft. It really is all getting too hard >>> for anyone like me. >>> >>> >>> >>> Anyone else had issues like this? >>> >>> >>> >>> regards >>> >>> Rob >>> >>> >>> >>> Rob Thompson >>> >>> 0429 493 828 >>> >>> >>> >>
Re: [DOG mailing list] Limbach engine rebuilds
Afterthought... I consider you Rob, given your lengthy experience and depth of thought, to be a grandmaster of these motors. You too Ian. On Fri, Mar 19, 2021, 07:51 Tom Preisser wrote: > Not yet... They offered a one week "maintenance" course previously > that, if I understood correctly, that then qualified one to rebuild. Top > end only ? I wonder if this is merely a profit based decision, rather than > a technical issue. What would dear Mr Porsche feel, praytell ? I am afraid, > however, that they have us by the shorties as far as Limbach manufactured > parts are concerned. Case halves are probably the biggest item I can think > of. > I wonder what their authorized service stations are capable of ? > > > > On Fri, Mar 19, 2021, 00:02 Ian Williams wrote: > >> Yep >> >> >> >> Ian W >> >> >> >> *From:* dog@lists.riverland.net.au *On Behalf Of *Rob Thompson >> *Sent:* Friday, 19 March 2021 7:51 p.m. >> *To:* dog@lists.riverland.net.au >> *Subject:* [DOG mailing list] Limbach engine rebuilds >> >> >> >> G'day Everyone, >> >> I recently had the Limbach factory questioning about me rebuilding their >> motors. >> >> >> >> I have Australian qualifications to rebuild 4 stroke motors in motor >> gliders and recreational aircraft but Limbach seem to be saying that any of >> their motors requiring a bottom end rebuild need to be shipped back to the >> factory (at great expense). >> >> >> >> I am suspicious that they may start refusing to sell parts. Unfortunately >> we don't have Nigel available to sort out these issues. >> >> >> >> Currently, in Australia we also have many legal liability difficulties >> for anyone working on certified aircraft. It really is all getting too hard >> for anyone like me. >> >> >> >> Anyone else had issues like this? >> >> >> >> regards >> >> Rob >> >> >> >> Rob Thompson >> >> 0429 493 828 >> >> >> >
RE: [DOG mailing list] Limbach engine rebuilds
Yep Ian W From: dog@lists.riverland.net.au On Behalf Of Rob Thompson Sent: Friday, 19 March 2021 7:51 p.m. To: dog@lists.riverland.net.au Subject: [DOG mailing list] Limbach engine rebuilds G'day Everyone, I recently had the Limbach factory questioning about me rebuilding their motors. I have Australian qualifications to rebuild 4 stroke motors in motor gliders and recreational aircraft but Limbach seem to be saying that any of their motors requiring a bottom end rebuild need to be shipped back to the factory (at great expense). I am suspicious that they may start refusing to sell parts. Unfortunately we don't have Nigel available to sort out these issues. Currently, in Australia we also have many legal liability difficulties for anyone working on certified aircraft. It really is all getting too hard for anyone like me. Anyone else had issues like this? regards Rob Rob Thompson 0429 493 828
RE: [DOG mailing list] Limbach engine
Hi Tom, Rob and everybody else, Of interest, the L2400 (ex Stemme S10 engine) I installed in the Grob 109 in Auckland had significant valve seat regression. It powered the Stemme from England to New Zealand in 2004 If you want to check it out, the Stemme Reg was G-OJTAand the pilot was Owen Truelove.. He sadly crashed in Dec 2007 in the South Island of New Zealand. However the little engine did get a hammering but got him the NZ. (and just one magnetoo !!) The valve regression basically is where the seat is driven up into the head because of heat. The result is of course reduced tappet clearances Our fix was to have another set of valve seats made and installed plus new valves and all set up again. With our Dimona L2000 , and referring to the overhaul manual, we reground the valves / seats. And replaced all16 push rod cover seals. There was no sign of any regression but was a little distortion around the exhaust valve side of the inlet seat …. So hoping there will be no more small oil leaks. I am hoping to get it all back together and flying this weekend . So Tom, replacing the heads is a bit radical. It is interesting following the political scene in the US. If it wasn’t so serious it would be real funny. Best regards to all Ian Williams New Zealand From: dog@lists.riverland.net.au On Behalf Of Rob Thompson Sent: Thursday, 3 December 2020 1:56 p.m. To: dog@lists.riverland.net.au Subject: Re: [DOG mailing list] Limbach engine Hi Tom, I am wondering if your valve springs are a little hard and they are beating the seats a little. regards Rob Rob Thompson 0429 493 828 On Wed, Dec 2, 2020 at 1:07 PM Tom Preisser mailto:t...@ecoflight.com> > wrote: I replaced both heads recently (575 hrs) and found significant intake valve "pocketing" on all four intake valves and seats. In other words, the valve face and seat face were no longer flat but rounded, but still mated well enough to give good compression. The wear had gotten to the point where valve sticking could have become an issue. I had wondered why my intake valves always needed a slight loosening every 25 hours or so. I am guessing that abrasives that are present after passing through the air filter are responsible. Any thoughts gentlemen ? Best regards, Slacko On Tue, Dec 1, 2020, 15:34 Ian Williams mailto:i...@agcon.co.nz> > wrote: Yep all understood. I think that realistically looking at the VW head design compared to a Lycoming for example the total cooling surface area is a lot smaller on the VW. So heat removal is a bit more critical But no real drama. It just means good maintenance ... watching tappets clearances and mixture. I wise plug colour as a guide setting the mixture which has been quite OK I reckon that if the engine only needs a valve grind after 500 hrs we are doing real well Best regards Ian W Sent from my iPhone On 2/12/2020, at 10:56 AM, Rob Thompson mailto:amessageto...@gmail.com> > wrote: The exhaust side of the inlet valve seat cops a lot more heat so can be prone to distortion and heat hardening. Nigel was investigating ceramic coatings inside the heads and ports to get the exhaust heat out the pipe not into the metal. Approvals to use ceramic coatings may be a problem. Possibly not for coating the inside of the exhaust ports.If the coating fails it will just get blown out the exhaust pipe. regards Rob Rob Thompson 0429 493 828 (Please note that my new email address is amessageto...@gmail.com <mailto:amessageto...@gmail.com> ) On Wed, Dec 2, 2020 at 8:23 AM Ian Williams mailto:i...@agcon.co.nz> > wrote: Hi Rob.Sorry didn’t. Engine is back together again. What I saw was that as I was lapping in the valves there was a darker area on the inlet valve seat where it passes by the exhaust seat which I couldn’t get rid of by lapping. Ian W Sent from my iPhone On 2/12/2020, at 9:56 AM, Rob Thompson mailto:amessageto...@gmail.com> > wrote: Do you have photos of the distortion/damage to the valves and seats? regards Rob Rob Thompson 0429 493 828 On Tue, Dec 1, 2020 at 6:55 PM Ian Williams mailto:i...@agcon.co.nz> > wrote: Hi All, I thought an interesting situation I have had with these little engines. I “look after” ie the maintenance engineer for 3 limbach powered aircraft … 2 Grob 109’s and our Dimona. One Grob has an L2400 engine originally in a Stemme S10. . The G109 with the L2000 lost compression after about 100 hrs (new heads from Nigel Baker) A leak down rest clearly indicated leaking inlet valves. The fix was to regrind the valves )not just lapped) and all OK. At the time I did think that the reason for the valve seat distortion was overheating as the L2000 in the Grob does run hot (as compared with the Dimona. Hoever I am currently working on the Dimona en
Re: [DOG mailing list] Limbach engine
Hi Tom, I am wondering if your valve springs are a little hard and they are beating the seats a little. regards Rob Rob Thompson 0429 493 828 On Wed, Dec 2, 2020 at 1:07 PM Tom Preisser wrote: > I replaced both heads recently (575 hrs) and found significant intake > valve "pocketing" on all four intake valves and seats. In other words, the > valve face and seat face were no longer flat but rounded, but still mated > well enough to give good compression. The wear had gotten to the point > where valve sticking could have become an issue. I had wondered why my > intake valves always needed a slight loosening every 25 hours or so. I am > guessing that abrasives that are present after passing through the air > filter are responsible. > Any thoughts gentlemen ? > Best regards, > Slacko > > On Tue, Dec 1, 2020, 15:34 Ian Williams wrote: > >> Yep all understood. I think that realistically looking at the VW head >> design compared to a Lycoming for example the total cooling surface area is >> a lot smaller on the VW. So heat removal is a bit more critical >> But no real drama. It just means good maintenance ... watching tappets >> clearances and mixture. I wise plug colour as a guide setting the mixture >> which has been quite OK >> I reckon that if the engine only needs a valve grind after 500 hrs we are >> doing real well >> >> Best regards >> Ian W >> >> >> Sent from my iPhone >> >> On 2/12/2020, at 10:56 AM, Rob Thompson wrote: >> >> The exhaust side of the inlet valve seat cops a lot more heat so can be >> prone to distortion and heat hardening. >> Nigel was investigating ceramic coatings inside the heads and ports to >> get the exhaust heat out the pipe not into the metal. >> Approvals to use ceramic coatings may be a problem. Possibly not for >> coating the inside of the exhaust ports.If the coating fails it will just >> get blown out the exhaust pipe. >> regards >> Rob >> >> Rob Thompson >> 0429 493 828 >> (Please note that my new email address is amessageto...@gmail.com) >> >> >> On Wed, Dec 2, 2020 at 8:23 AM Ian Williams wrote: >> >>> Hi Rob.Sorry didn’t. Engine is back together again. What I saw >>> was that as I was lapping in the valves there was a darker area on the >>> inlet valve seat where it passes by the exhaust seat which I couldn’t get >>> rid of by lapping. >>> >>> Ian W >>> >>> Sent from my iPhone >>> >>> On 2/12/2020, at 9:56 AM, Rob Thompson wrote: >>> >>> Do you have photos of the distortion/damage to the valves and seats? >>> regards >>> Rob >>> >>> Rob Thompson >>> 0429 493 828 >>> >>> >>> >>> On Tue, Dec 1, 2020 at 6:55 PM Ian Williams wrote: >>> Hi All, I thought an interesting situation I have had with these little engines. I “look after” ie the maintenance engineer for 3 limbach powered aircraft … 2 Grob 109’s and our Dimona. One Grob has an L2400 engine originally in a Stemme S10. . The G109 with the L2000 lost compression after about 100 hrs (new heads from Nigel Baker) A leak down rest clearly indicated leaking inlet valves. The fix was to regrind the valves )not just lapped) and all OK. At the time I did think that the reason for the valve seat distortion was overheating as the L2000 in the Grob does run hot (as compared with the Dimona. Hoever I am currently working on the Dimona engine. It has done 500 trouble free hrs (apart from a failed Magneto condenser) It has had a frustrating oil leak so I have replaced the rear oil seal and was planning to lap in the valves. Here is the interesting bit …. There were clear signs that the inlet valve seats were slightly distorted in exactly the same area as the Grob engine. (but at 500 hrs, not 100) However our redesigned baffles etc of the Dimona installation does mean the engine is running very cool (CHT’s around 110 to 140C and oil around 65C) Apart from what I am talking about, I am impressed with the overall condition of the engine. I had the valves reground in an engineering shop as just lapping the valves didn’t totally seal the inlet valves So my conclusion is that there could be an issue that the heat sinking around the exhaust / inlet area is not as good as it could be. This is not serious though but if an L2000 has low compression that could be an area to look at. Best regards Ian Williams ZK-GCB New Zealand >>>
Re: [DOG mailing list] Limbach engine
I replaced both heads recently (575 hrs) and found significant intake valve "pocketing" on all four intake valves and seats. In other words, the valve face and seat face were no longer flat but rounded, but still mated well enough to give good compression. The wear had gotten to the point where valve sticking could have become an issue. I had wondered why my intake valves always needed a slight loosening every 25 hours or so. I am guessing that abrasives that are present after passing through the air filter are responsible. Any thoughts gentlemen ? Best regards, Slacko On Tue, Dec 1, 2020, 15:34 Ian Williams wrote: > Yep all understood. I think that realistically looking at the VW head > design compared to a Lycoming for example the total cooling surface area is > a lot smaller on the VW. So heat removal is a bit more critical > But no real drama. It just means good maintenance ... watching tappets > clearances and mixture. I wise plug colour as a guide setting the mixture > which has been quite OK > I reckon that if the engine only needs a valve grind after 500 hrs we are > doing real well > > Best regards > Ian W > > > Sent from my iPhone > > On 2/12/2020, at 10:56 AM, Rob Thompson wrote: > > The exhaust side of the inlet valve seat cops a lot more heat so can be > prone to distortion and heat hardening. > Nigel was investigating ceramic coatings inside the heads and ports to get > the exhaust heat out the pipe not into the metal. > Approvals to use ceramic coatings may be a problem. Possibly not for > coating the inside of the exhaust ports.If the coating fails it will just > get blown out the exhaust pipe. > regards > Rob > > Rob Thompson > 0429 493 828 > (Please note that my new email address is amessageto...@gmail.com) > > > On Wed, Dec 2, 2020 at 8:23 AM Ian Williams wrote: > >> Hi Rob.Sorry didn’t. Engine is back together again. What I saw was >> that as I was lapping in the valves there was a darker area on the inlet >> valve seat where it passes by the exhaust seat which I couldn’t get rid of >> by lapping. >> >> Ian W >> >> Sent from my iPhone >> >> On 2/12/2020, at 9:56 AM, Rob Thompson wrote: >> >> Do you have photos of the distortion/damage to the valves and seats? >> regards >> Rob >> >> Rob Thompson >> 0429 493 828 >> >> >> >> On Tue, Dec 1, 2020 at 6:55 PM Ian Williams wrote: >> >>> Hi All, >>> >>> >>> >>> I thought an interesting situation I have had with these little engines. >>> >>> >>> >>> I “look after” ie the maintenance engineer for 3 limbach powered >>> aircraft … 2 Grob 109’s and our Dimona. One Grob has an L2400 engine >>> originally in a Stemme S10. >>> >>> . >>> >>> The G109 with the L2000 lost compression after about 100 hrs (new heads >>> from Nigel Baker) A leak down rest clearly indicated leaking inlet >>> valves. The fix was to regrind the valves )not just lapped) and all OK. >>> >>> At the time I did think that the reason for the valve seat distortion >>> was overheating as the L2000 in the Grob does run hot (as compared with the >>> Dimona. >>> >>> >>> >>> Hoever I am currently working on the Dimona engine. It has done 500 >>> trouble free hrs (apart from a failed Magneto condenser) It has had a >>> frustrating oil leak so I have replaced the rear oil seal and was planning >>> to lap in the valves. >>> >>> Here is the interesting bit …. There were clear signs that the inlet >>> valve seats were slightly distorted in exactly the same area as the Grob >>> engine. (but at 500 hrs, not 100) >>> >>> >>> >>> However our redesigned baffles etc of the Dimona installation does mean >>> the engine is running very cool (CHT’s around 110 to 140C and oil around >>> 65C) >>> >>> >>> >>> Apart from what I am talking about, I am impressed with the overall >>> condition of the engine. I had the valves reground in an engineering shop >>> as just lapping the valves didn’t totally seal the inlet valves >>> >>> >>> >>> So my conclusion is that there could be an issue that the heat sinking >>> around the exhaust / inlet area is not as good as it could be. This is not >>> serious though but if an L2000 has low compression that could be an area to >>> look at. >>> >>> >>> >>> Best regards >>> >>> >>> >>> Ian Williams >>> >>> ZK-GCB >>> >>> New Zealand >>> >>> >>> >>
Re: [DOG mailing list] Limbach engine
Yep all understood. I think that realistically looking at the VW head design compared to a Lycoming for example the total cooling surface area is a lot smaller on the VW. So heat removal is a bit more critical But no real drama. It just means good maintenance ... watching tappets clearances and mixture. I wise plug colour as a guide setting the mixture which has been quite OK I reckon that if the engine only needs a valve grind after 500 hrs we are doing real well Best regards Ian W Sent from my iPhone > On 2/12/2020, at 10:56 AM, Rob Thompson wrote: > > The exhaust side of the inlet valve seat cops a lot more heat so can be prone > to distortion and heat hardening. > Nigel was investigating ceramic coatings inside the heads and ports to get > the exhaust heat out the pipe not into the metal. > Approvals to use ceramic coatings may be a problem. Possibly not for coating > the inside of the exhaust ports.If the coating fails it will just get blown > out the exhaust pipe. > regards > Rob > > Rob Thompson > 0429 493 828 > (Please note that my new email address is amessageto...@gmail.com) > > >> On Wed, Dec 2, 2020 at 8:23 AM Ian Williams wrote: >> Hi Rob.Sorry didn’t. Engine is back together again. What I saw was >> that as I was lapping in the valves there was a darker area on the inlet >> valve seat where it passes by the exhaust seat which I couldn’t get rid of >> by lapping. >> >> Ian W >> >> Sent from my iPhone >> >>> On 2/12/2020, at 9:56 AM, Rob Thompson wrote: >>> >>> Do you have photos of the distortion/damage to the valves and seats? >>> regards >>> Rob >>> >>> Rob Thompson >>> 0429 493 828 >>> >>> >>> On Tue, Dec 1, 2020 at 6:55 PM Ian Williams wrote: Hi All, I thought an interesting situation I have had with these little engines. I “look after” ie the maintenance engineer for 3 limbach powered aircraft … 2 Grob 109’s and our Dimona. One Grob has an L2400 engine originally in a Stemme S10. . The G109 with the L2000 lost compression after about 100 hrs (new heads from Nigel Baker) A leak down rest clearly indicated leaking inlet valves. The fix was to regrind the valves )not just lapped) and all OK. At the time I did think that the reason for the valve seat distortion was overheating as the L2000 in the Grob does run hot (as compared with the Dimona. Hoever I am currently working on the Dimona engine. It has done 500 trouble free hrs (apart from a failed Magneto condenser) It has had a frustrating oil leak so I have replaced the rear oil seal and was planning to lap in the valves. Here is the interesting bit …. There were clear signs that the inlet valve seats were slightly distorted in exactly the same area as the Grob engine. (but at 500 hrs, not 100) However our redesigned baffles etc of the Dimona installation does mean the engine is running very cool (CHT’s around 110 to 140C and oil around 65C) Apart from what I am talking about, I am impressed with the overall condition of the engine. I had the valves reground in an engineering shop as just lapping the valves didn’t totally seal the inlet valves So my conclusion is that there could be an issue that the heat sinking around the exhaust / inlet area is not as good as it could be. This is not serious though but if an L2000 has low compression that could be an area to look at. Best regards Ian Williams ZK-GCB New Zealand
Re: [DOG mailing list] Limbach engine
The exhaust side of the inlet valve seat cops a lot more heat so can be prone to distortion and heat hardening. Nigel was investigating ceramic coatings inside the heads and ports to get the exhaust heat out the pipe not into the metal. Approvals to use ceramic coatings may be a problem. Possibly not for coating the inside of the exhaust ports.If the coating fails it will just get blown out the exhaust pipe. regards Rob Rob Thompson 0429 493 828 (Please note that my new email address is amessageto...@gmail.com) On Wed, Dec 2, 2020 at 8:23 AM Ian Williams wrote: > Hi Rob.Sorry didn’t. Engine is back together again. What I saw was > that as I was lapping in the valves there was a darker area on the inlet > valve seat where it passes by the exhaust seat which I couldn’t get rid of > by lapping. > > Ian W > > Sent from my iPhone > > On 2/12/2020, at 9:56 AM, Rob Thompson wrote: > > Do you have photos of the distortion/damage to the valves and seats? > regards > Rob > > Rob Thompson > 0429 493 828 > > > > On Tue, Dec 1, 2020 at 6:55 PM Ian Williams wrote: > >> Hi All, >> >> >> >> I thought an interesting situation I have had with these little engines. >> >> >> >> I “look after” ie the maintenance engineer for 3 limbach powered >> aircraft … 2 Grob 109’s and our Dimona. One Grob has an L2400 engine >> originally in a Stemme S10. >> >> . >> >> The G109 with the L2000 lost compression after about 100 hrs (new heads >> from Nigel Baker) A leak down rest clearly indicated leaking inlet >> valves. The fix was to regrind the valves )not just lapped) and all OK. >> >> At the time I did think that the reason for the valve seat distortion was >> overheating as the L2000 in the Grob does run hot (as compared with the >> Dimona. >> >> >> >> Hoever I am currently working on the Dimona engine. It has done 500 >> trouble free hrs (apart from a failed Magneto condenser) It has had a >> frustrating oil leak so I have replaced the rear oil seal and was planning >> to lap in the valves. >> >> Here is the interesting bit …. There were clear signs that the inlet >> valve seats were slightly distorted in exactly the same area as the Grob >> engine. (but at 500 hrs, not 100) >> >> >> >> However our redesigned baffles etc of the Dimona installation does mean >> the engine is running very cool (CHT’s around 110 to 140C and oil around >> 65C) >> >> >> >> Apart from what I am talking about, I am impressed with the overall >> condition of the engine. I had the valves reground in an engineering shop >> as just lapping the valves didn’t totally seal the inlet valves >> >> >> >> So my conclusion is that there could be an issue that the heat sinking >> around the exhaust / inlet area is not as good as it could be. This is not >> serious though but if an L2000 has low compression that could be an area to >> look at. >> >> >> >> Best regards >> >> >> >> Ian Williams >> >> ZK-GCB >> >> New Zealand >> >> >> >
Re: [DOG mailing list] Limbach engine
Hi Rob.Sorry didn’t. Engine is back together again. What I saw was that as I was lapping in the valves there was a darker area on the inlet valve seat where it passes by the exhaust seat which I couldn’t get rid of by lapping. Ian W Sent from my iPhone > On 2/12/2020, at 9:56 AM, Rob Thompson wrote: > > Do you have photos of the distortion/damage to the valves and seats? > regards > Rob > > Rob Thompson > 0429 493 828 > > > >> On Tue, Dec 1, 2020 at 6:55 PM Ian Williams wrote: >> Hi All, >> >> >> >> I thought an interesting situation I have had with these little engines. >> >> >> >> I “look after” ie the maintenance engineer for 3 limbach powered aircraft >> … 2 Grob 109’s and our Dimona. One Grob has an L2400 engine originally in a >> Stemme S10. >> >> . >> >> The G109 with the L2000 lost compression after about 100 hrs (new heads >> from Nigel Baker) A leak down rest clearly indicated leaking inlet valves. >> The fix was to regrind the valves )not just lapped) and all OK. >> >> At the time I did think that the reason for the valve seat distortion was >> overheating as the L2000 in the Grob does run hot (as compared with the >> Dimona. >> >> >> >> Hoever I am currently working on the Dimona engine. It has done 500 trouble >> free hrs (apart from a failed Magneto condenser) It has had a frustrating >> oil leak so I have replaced the rear oil seal and was planning to lap in the >> valves. >> >> Here is the interesting bit …. There were clear signs that the inlet valve >> seats were slightly distorted in exactly the same area as the Grob engine. >> (but at 500 hrs, not 100) >> >> >> >> However our redesigned baffles etc of the Dimona installation does mean the >> engine is running very cool (CHT’s around 110 to 140C and oil around 65C) >> >> >> >> Apart from what I am talking about, I am impressed with the overall >> condition of the engine. I had the valves reground in an engineering shop as >> just lapping the valves didn’t totally seal the inlet valves >> >> >> >> So my conclusion is that there could be an issue that the heat sinking >> around the exhaust / inlet area is not as good as it could be. This is not >> serious though but if an L2000 has low compression that could be an area to >> look at. >> >> >> >> Best regards >> >> >> >> Ian Williams >> >> ZK-GCB >> >> New Zealand >> >>
Re: [DOG mailing list] Limbach engine
Do you have photos of the distortion/damage to the valves and seats? regards Rob Rob Thompson 0429 493 828 On Tue, Dec 1, 2020 at 6:55 PM Ian Williams wrote: > Hi All, > > > > I thought an interesting situation I have had with these little engines. > > > > I “look after” ie the maintenance engineer for 3 limbach powered > aircraft … 2 Grob 109’s and our Dimona. One Grob has an L2400 engine > originally in a Stemme S10. > > . > > The G109 with the L2000 lost compression after about 100 hrs (new heads > from Nigel Baker) A leak down rest clearly indicated leaking inlet > valves. The fix was to regrind the valves )not just lapped) and all OK. > > At the time I did think that the reason for the valve seat distortion was > overheating as the L2000 in the Grob does run hot (as compared with the > Dimona. > > > > Hoever I am currently working on the Dimona engine. It has done 500 > trouble free hrs (apart from a failed Magneto condenser) It has had a > frustrating oil leak so I have replaced the rear oil seal and was planning > to lap in the valves. > > Here is the interesting bit …. There were clear signs that the inlet valve > seats were slightly distorted in exactly the same area as the Grob engine. > (but at 500 hrs, not 100) > > > > However our redesigned baffles etc of the Dimona installation does mean > the engine is running very cool (CHT’s around 110 to 140C and oil around > 65C) > > > > Apart from what I am talking about, I am impressed with the overall > condition of the engine. I had the valves reground in an engineering shop > as just lapping the valves didn’t totally seal the inlet valves > > > > So my conclusion is that there could be an issue that the heat sinking > around the exhaust / inlet area is not as good as it could be. This is not > serious though but if an L2000 has low compression that could be an area to > look at. > > > > Best regards > > > > Ian Williams > > ZK-GCB > > New Zealand > > >
