[Fot] [TR] Timing cover crank seal oil leak

[van.mulders.marcel at telenet.be]

Hi Mark,
I forgot about the cause. Indeed there was a broken chain tensioner. These tensioners are so flimsy, I wonder if they do much of a job.
If the chain is running quiet, the surface of the tensioner remains smooth. A broken tensioner, but also deep ridges, sometimes in a short time, are proof that the chain was slapping on it. This happens when the sprockets are not perfectly in line as is often the case when a billet steel crankshaft is fitted. A wobbling chain means also that the ignition advance is not stable with some loss of power. It shows with a stroboscope light. But this is  starting to look like a lesson, sorry!
Marcel

----- Oorspronkelijk bericht -----
Van: "fot" <fot at autox.team.net>
Aan: "fot" <fot at autox.team.net>
Verzonden: Vrijdag 25 december 2020 18:50:59
Onderwerp: Re: [Fot] [TR] Timing cover crank seal oil leak

On 12/25/20 7:37 AM, van.mulders.marcel--- via Fot wrote:
> On  2 occasions I had a leaking timing because of a small hole in the 
> cover itself : once the hole had the shape of a thin line and was 
> located near the rivets or spotwelds of the chain tensioner.


If the timing chain tensioner breaks so that you have a rough edge 
riding against the cover, rather than a smooth curve, it will eventually 
machine a slot into the cover.  I've had it happen on some Spitfire engines.

mjb.


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