RE: L20b oil

[Terry Rudd]

Not necessarily although the max engine speed (i.e. piston feet per minute) does come into play with a modified engine. The magic number some years ago was 2800 ft/min which was the old oil sheer SE rating. Now that's been upgraded, something like SF today so oil has improved along with most things and the PFM will be something staggeringly high, like 30 years ago you would have thought it possible. The viscosity ratings of the different oil types is the main problem with using newer oils in older design engines, no matter what state of modification it's in. The valve guide design and tolerances will have difficulty keeping newer type oils out of the combustion chamber once impurities get into the oil, especially with mutli carby engines, as opposed to EFI engines which run much cleaner as there is very little "washing of the cylinder bores with excess petrol" like webers etc were renown for. This is not a problem until the oil goes off, thins out etc and it will happen at a fairly short interval when used in an older engine, then you've got a problem. Oils such as Penrite 30 have additives which combat this very well and will all things equal will last up until the service interval and it is achieved more easily in a single grade oil - motor racing technology at work again.   There is a lot of good reading on the net about oils and much better written than i can do here - worth looking up a few.   regards terry (who said "oils aint oils?") -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Rick Parker Sent: Friday, 28 March 2003 11:39 AM To: [EMAIL PROTECTED] Subject: Re: L20b oil My engine is pretty worked, 3/4 cam, bored 2.3mm, machined & balanced L28 pistons. high compression. would this change what i should use? ----- Original Message ----- From: Terry Rudd To: [EMAIL PROTECTED] Sent: Thursday, 27 March 2003 7:31 PM Subject: RE: L20b oil Dang it, I missed a critical "not" in this sentence,  it should have read: Synthetic oils are "not" all that suitable for the L series -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Terry Rudd Sent: Thursday, 27 March 2003 7:16 PM To: [EMAIL PROTECTED] Subject: RE: L20b oil Rick,   If it's only used on the street and the occasional trip in the country and it's a bog stock to medium warm L20B and/or it's a high mileage unit with worn valve guides but good seals then in my humble opinion you can't go past Castrol GTX (i.e. the original blend). GTX2, Valvoline XLD etc are OK but they thin out and break down in the second half of the change cycle. GTX will stay good up till around 80% cycle in a warn L series engine. If some of my conditions don't apply eg you hill climb or autox etc then you're looking at a different grade and quality of oil, probably a single grade would be more suitable eg Penrite 30. Synthetic oils are [Terry Rudd] not  all that suitable for the L series, although some ppl have good results from Shell Helix.   Heath mentioned BP Coarse + - good oil that and also very suitable for the L20B, in fact it's one of the few "petrol vending company" type oil products I've ever used in 30+ years of motoring that's done the job to my satisfaction. --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[EMAIL PROTECTED]/ --------------------------------------------------------------------- --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[EMAIL PROTECTED]/ --------------------------------------------------------------------- --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[EMAIL PROTECTED]/ ---------------------------------------------------------------------