Catalina 34

General Activities => Main Message Board => Topic started by: KeelsonGraham on July 23, 2022, 12:40:16 AM

Title: Sooty Intake Manifold on M35B
Post by: KeelsonGraham on July 23, 2022, 12:40:16 AM
Recently, after taking off the air filter to clean it, I ran my finger around the inside of the manifold and picked up a very thin film of oily soot. I'm experienced with auto petrol engines - not with diesels, but I assume this is abnormal?

The engine starts immediately first time, every time and runs sweetly (albeit a little hot) so I'm reluctant to fix it if it ain't broke.

I assume this could be due to back flow from one or more inlet valves, either because the tappet clearance is too small or because a valve isn't seating correctly?.

Has anyone else seen this?
Title: Re: Sooty Intake Manifold on M35B
Post by: KWKloeber on July 23, 2022, 01:33:47 AM
When The B engines go out the factory door they have the crankcase breather hose run to the air intake.  Does yours?
Title: Re: Sooty Intake Manifold on M35B
Post by: KeelsonGraham on July 23, 2022, 10:17:32 AM
i'll check!
Title: Re: Sooty Intake Manifold on M35B
Post by: Ron Hill on July 23, 2022, 01:33:00 PM
Keel : I don't believe that you have a problem.  As Ken said the newer Universal M35B and XM25 XPB engines all have their oil pan breather vented in to the intake manifold.

A thought
Title: Re: Sooty Intake Manifold on M35B
Post by: KeelsonGraham on July 24, 2022, 12:25:37 AM
Thank you Ron. The oil breather would certainly explain it.