Quote:
Originally Posted by qualicas
Got another head the other day. I pulled it apart to do a valve job. I found that the 3 intake cam caps that were really scored on my head show signs of scoring already. This head was from a running engine. Looks like my theory holds water.
ie Long oil changes cause sludge, sludge causes lack of oil to the oil pump, resulting low oil pressure staves the intake cam bearing caps. The caps score making the intake cam harder to turn. When really hard to turn chain stretches and rides up on sprocket teeth breaking the chain guides. Replacing the chain with a stronger chain does not eliminate the problem.
If you have one of these engines, my advice would be to change oil often and make sure it gets a long highway drive often so sludge does not build up, And if you have the stop and go engine, turn that feature OFF! As sooner than later it will stop and not go any longer.
This my humble opinion.
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Yep, that theory actually seems like the best explanation for the timing chain issues that I have read so far. I'm glad that my car has been, and still is, driven mainly on highways / motorways and only occasionally in city. Of course there is some city driving every day but anyway the engine gots to warm up properly almost every day.
Now I'm wondering if it would be advisable to drop the oil pan every let's say 100k miles and clean up oil pickup thoroughly. I don't know if there is some sludge that wont self clean up even if oil is changed. So even if the car is driven usually for long distances can there still be some sludge there? It would be also nice if there would be some upgrade available to oil pan that would have improved oil pickup. What I have understood the oil pump has hard time to get oil during heavy breaking and heavy cornering. If the car is tracked it might be a problem.
I'm also wondering if it would make any difference if I would do ceramic coating treatment to the engine? Something like this:
https://www.rvs.fi/en/technology/
That product is claimed to help to reduce the friction between moving parts and at least some user reports says that the engine runs "smoother" after the treatment. Hard to say really if it works or not?
Anyway I haven't seen any reports of the BMW users, let alone N20 users, if that kind of treatment is helpful or not.
Edit. Actually that RVS company has tested the product on E90 328i and the dyno results improved which means that internal engine friction is reduced. Of course the result must be taken with a grain of salt as the result is provided by the company selling the product.
https://www.rvs.fi/wp-content/upload...estimonial.pdf