Cylinder base o-ring

·         Kai Lyche

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Doug,

I have an elderly 2200A engine on my hands with what must be shorter barrel length cylinders, as they all have 1,0mm thick cylinder base shims. It came back with these from a Jab distributor shop after an overhaul a little more than one year ago. Recently the owner noticed oil leaks leaks (I would be more inclined to call it sweating) from the #3 cylinder base.

So just to be nice I tried to help when he decided to replace the cylinder base o-ring. Without the shim this is a piece of cake, but with the shim the o-ring does not seem to want to seal properly. The overhaul manual has of course been consulted, and Locktite 518 has been applied as instructed. But nogo! And the motor continues to run like the proverbial sewing machine.

The cylinder base o-ring does not seem capable of sealing off both the barrel and the shim, L518 notwithstanding.

Is there a trick somewhere?

Thanks
Kai

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·         Doug Smith

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Hi Kai,
I'm not aware of any particular tricks to that one... I know you have to be very fastidious on cleaning all the oil off everything (i.e. remove all the old sealant and give everything a good clean with a non-residue cleaner like Aerostart) before the 518 goes on but that's standard practice... Obviously new O-Rings would be recommended too.

Did you check how well the shim lined up with the cylinder base while you had it apart? I'm wondering if the shim might have distorted a little at some point (wouldn't take much in the areas between the bolts where there's not much sealing surface). It's not unheard-of to get oil leakage up past the bolts too... does it look like the oil is coming from a bolt or from the cylinder base?

If it's convenient that might be one of those jobs that it'd be worth calling Mark or someone in the engine shop to talk over ideas and see if there are any inside secrets they're not sharing with the engineers!

Regards,
Doug.