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Volvo B20 oil leak Timing cover

M

Mvicente

New member
Hi guys.
New here.

My name is Miguel and I was wondering if you could help me out on this issue.
I have a Penta Volvo b20 engine connected to an aq100. It has been in a warehouse for the last 30 years with no maintenance whatsoever. Since February I’ve been working on it.

Had tow stuck exhaust valves, replaced everything and the head was all worked out perfectly. Installed a Weber 32/36 to replace the old stromberg it had. Cleaned every water passage.

Right now it’s working really smooth but made a big error by putting an oil that was too thin (5w30) by complete ignorance. Let it run for 30 interrupted minutes with that oil and started to notice oil leaks where there were none before restoration started.

First leak appeared at the bottom of the timing cover through a hole (see picture) when the engine started to warm. After 20 minutes noticed oil coming out from oil dipstick and valve cover cap.

So my first thought was that I had a blow by but then started studying the matter and realized the main issue was the wrong oil and I was having a lot of pressure inside the engine.

I immediately changed the oil for a 15w40 with LiquiMoly Molybdenum additive to try to correct the leaks and help the engine.

After changing the oil all the leaks disappeared except for the one on the timing cover and it’s leaking a drop every 30 seconds I’d say. A lot less than before changing the oil.

Is that hole important or can I cap it with some sealer? My question comes from watching other engines that lack these holes and can’t understand their purpose.

I’m obviously planning to change the gasket but right now I would like to hear from you because I have no mechanics willing to work on old engines for miles around me.

Thank you.
 
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looking at your pic, the timing cover casting (where the leak flows from) looks like it should have a fastener thru it...

very possible it wasn't there when you started...

I'd check the block, under the cover,where the leak flows, to see if there is a threaded hole and if so, add the fastener.

If you have the service manual, there should be a discussion on reinstalling the timing cover and most likely a diagram...see if a fastener goes thru that hole.
 
makomark said:
looking at your pic, the timing cover casting (where the leak flows from) looks like it should have a fastener thru it...

very possible it wasn't there when you started...

I'd check the block, under the cover,where the leak flows, to see if there is a threaded hole and if so, add the fastener.

If you have the service manual, there should be a discussion on reinstalling the timing cover and most likely a diagram...see if a fastener goes thru that hole.
Click to expand...
Watching videos and pics of other engines I realized it’s literally just a hole on these covers (that are different comparing to the original car timing cover. The marine kind has an additional hole for the water pump and two holes like the one leaking. One on the top and one on the bottom). Behind the cover hole you’ll find the wall where the gasket meets the engine. Two days ago I realized I had the engine air circulation mounted the opposite way. Instead of having the air being sucked by the flame trap and being expelled by the valve cover cap, it was the other way around. And this was creating positive pressure inside the engine. I swapped the tubes coming from those structures and linking to the carburetor and corrected it. The leaking became almost insignificant now but there is still a very small leak when the engine passes +\-4000 rpm. I now believe that I still have a leak because the gasket got damaged by the positive pressure that was pushing oil out of the engine. Do you think my theory makes sense?
 
not sure what "engine air circulation" is...or how it works being reversed...

The engine won't last very long, in a boat, running at 4000 RPM...so it may not be relavent...

The gasket seals a flange (on the block) to what I believe is a cast cover...and likely wouldn't be damaged by modest positive crankcase pressure if installed correctly. This is all based on my assumptions about the materials so take it as just an opinion.

It wouldn't hurt anything the change the gasket...
 
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