2 replies to this topic

[lambretta]

Hello all.

 

I recently installed a 350 Holley on the 202 and during that process noticed that there was a fair amount of oil in the inlet runners.  Mulling over that with idle hands lead me to start thinking that, as well as the head being a bit noisy from time to time (see my other post on this forum about that) I thought, well, perhaps the valve guides/stems are worn and letting in oil because I didn't replace them when I rebuilt the motor 10,000km ago.

 

Compression is still good across all 6 pistons so that led me down a fairy deep rabbit hole and a popped up with a new to me and recently worked on Yella Terra head that I fitted over Christmas. 

 

I had reason to remove the inlet manifold after I fitted the new head and found that, lo and behold, there was still oil in the inlet runners.  This has led me to ponder the fact that I may have in fact wasted some money and a fair amount of time changing the head when perhaps it wasn't the valves after all but just the rocker cover breathing its oily mist via the PCV valve (back of engine) into the inlet manifold where the oil is collecting and burning; this I understand is by design but we have noticed that the engine oil does need toping up every month or so I guess it's pushing a bit of oil in there.  Fresh with the sickening realisation that I have walked the wrong path I have started thinking I just need a way of preventing the oil getting from the rocker cover and that will solve some/all my problems.

 

I have attached a picture of the rocker cover in the old girl - how have you knowledgeable folk solved this type of problem on your engines?  Any advise will be appreciated.

Attached Files

•  PXL_20260106_092424210.jpg   193.64K   5 downloads

[I'm a Red Motor fiend]

Its not breathing properly.
The centre hole that is plugged should be plumbed to an enclosed air filter housing.
Failing that, at least fit a vented oil filler cap.
You could also look at better baffling in the rocker cover.
Or delete the valve and fit a road draught tube, leave the middle hole plugged and fit a vented filler cap.
Then it wont suck any oil.

Edited by I'm a Red Motor fiend, 28 January 2026 - 06:22 PM.

[yel327]

Agree, fit the PCV breather hose back in. You might need a different air cleaner or you might be able to put a source on the air cleaner base. Originally they had a small filter on the source too. Originally fit a vented cap, but the first solution is better.