Ian Maybe contact John Godfrey. <john.glid...@hotmail.com> as has g109 with dual plug heads and is newish engine. He received the engine as single plugs but later changed them to dual plugs with heads from Limbach (via Nigel). Thus he may know. John owned Moura engine reconditioning in past life so knows stuff
We recently got new heads from limbach for grob 109 and there were clearly a new casting with extra shaping under heads. The plug thread was only slightly longer by say 1½threads more thus solving the the need for 2 washers. (Should say the guy that removed plugs in old heads think removed plugs while hot and helicoils came out. Then somebody sent heads away for time serts next up from helucouls. These are not allowed in GA in Australia, following an accident out of Bankstown late 80s where they came out. - needless to say that guy does not work on engines with us and before he gad issue fitting a slick 4330 requiring huge expense) I do know Sauer use long reach plugs in both top and bottom plugs but is who new casting with much increased finning to help cooling and it does help. VWV think had heads done by Aero power in WA in years gone by as it was in Tasmania for a long time. Personally I like car plugs and gave no issue, with noise. Std car ones NGK have a life of 150hrs and the 3 prong Limbach plugs have 500hr life. Notice Limbach now have 2 prong plugs now and do not know about their life. Aviation plugs are too expensive and you tent to be reluctant to discard them. Also people tend to persist with old harness wires with aviation plugs. A good exercise is to run engine at night and you may be surprised to see arcing sparks as those harness can fail. If old then replace. Think now you can't buy the wire only as can now only buy complete harnesses. I do not think resistive plug caps or spark plugs are required. I want a good spark and resistive caps as limback supplied give poor spark. It is a Europe requirement to reduce interference as some old German or Swiss near airport complained about the radio noise. WVW may need extra mag service as think old magneto. At least the Slick 4330 life is 500hrs if you have dual ignition. I always, use one copper washer as well as the CHT pick up washer. I monitor all 4 cylinders and could recommend same Ian McPhee +61 428847642 Box 657 Byron Bay NSW 2481 Australia On Wed, 19 May 2021, 07:27 Ian Williams <i...@agcon.co.nz> wrote: > Hi All, > > > > I have an interesting situation I am currently involved with breathing > life into a H36 Dimona (prev VH-GNW) in New Zealand. I also have what > remains of VH-WVW which I am using as a spare parts source. > > > > The engine that was installed in GNW was a L2000 and a standard > configuration …. Ie a Slick mag and used the non shielded plugs marked as > Limbach LB-N41.0. The thread length the same as the shielded plugs I > currently use for the other Limbach powered TMG’s I look after. > > > > The L2000 from VH-WVW was fitted with a secondary electronic ignition > system …. 2 plugs per pot. Removing the plugs from this engine , the > thread length was a lot longer and marked Limbach LB-L41.0 > > > > I am a bit anal about plugs and ensure the installed torque is as per the > Limbach data to avoid head thread damage. However the long reach plugs > are a real problem because of the number of threads exposed to combustion > damage. Removing the plugs and pulling damaged threads thru the head is a > quick way to destroy the thread integrity > > > > Both top and bottom plugs were the long reach ones. > > > > I would be interested in any comments. > > > > Best regards > > > > Ian Williams > > ZK-GCB > > Bew Zealand > > > > >
