Interesting article in March mag, on cam wear in VW engines leading to on-going power loss.
While some wear is inevitable in old engines, I wonder if use of the wrong oil might be a cause?
Limbach are emphatic about oils, they warn of dire consequences if aircraft oils are used in their engines.
Only the best car type oils should be used in VW engines, such as Castrol GTX or equivalent. Also oil changes at 25 hours or one year max, are recommended.
VW engine cam wear.
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MikeGodsell
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Nigel Ramsay
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Steve at Great Planes puts a lot of emphasis on the use of new cam followers when fitting a new cam. Cam follower wear is always a problem with any engine and with race car engines where cams are changed every few races as perormance can drop noticeably with just a little wear, obviously the cam followers are changed at the same time.
Somewhere in my research of VW Aero engines I have seen mods for followers which improve lubrication of the mating faces between lobe and follower. Anything which improves lubrication in this area must be a good thing, and of course the use of correct oils (as stated in the previous post).
Unfortunately it means a cranck case split to change followers in the VW or I'd be inclined to change them as a preventative measure.
One last thing; If you are building a new engine or reconning where a new cam and followers are fitted, it would be worth measuring the actual lift of each lobe and recording it (using a dial guage), and then perhaps at annual or a specific number of hours, re-check. Wear basically reduces lift and thus effects the valve overlap causing an imbalance in combustion etc.
Somewhere in my research of VW Aero engines I have seen mods for followers which improve lubrication of the mating faces between lobe and follower. Anything which improves lubrication in this area must be a good thing, and of course the use of correct oils (as stated in the previous post).
Unfortunately it means a cranck case split to change followers in the VW or I'd be inclined to change them as a preventative measure.
One last thing; If you are building a new engine or reconning where a new cam and followers are fitted, it would be worth measuring the actual lift of each lobe and recording it (using a dial guage), and then perhaps at annual or a specific number of hours, re-check. Wear basically reduces lift and thus effects the valve overlap causing an imbalance in combustion etc.
Bob (R S) Hoover has his mods documented for improving VW lubrication.
http://bobhooversblog.blogspot.com/2007 ... -mods.html
http://bobhooversblog.blogspot.com/2007 ... -mods.html
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Nigel Ramsay
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Mike Millar
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Cam wear and oils
I'm now using Brad Penn 20W-50 racing oil in our Fournier VW's. It's not cheap but James Calvert at Stateside Tuning, our supplier, says it's one of the few oils that does not contain Zinc, which is implicated in cam wear on VW's. Limbach certainly exclude non-dispersant oils. I wonder if this is because VW's generally have no oil filter, only a course mesh strainer so it's better if the metal particles DO fall out of suspension.