Oil pressure relief valve

[Pete]

#3389

My 36 hp seems to have an issue with too much case pressure, forcing oil out from the pulley.  No other leaks I notice; rest of case is sealed up well.  I decided to pull the oil pressure relief plug to see if the valve spring was broken or if the valve was stuck.  To my surprise the case has neither the spring or the plug; I can insert a wire rifle brush almost 7″ into the oil passage (and it’s surprisingly clean).

Could the lack of a relief valve/spring be causing the pressure problem?

[John Jones]

#3402

interesting….  a 36 with too much oil pressure??

Been a wild ride, but it got me here 😎

[Pete]

#3418

I guess so?  Or maybe with the lack of a valve it’s limiting oil getting to the cooler when warm, so the crank is churning in excess oil and forcing it out of the pulley?    Not so much from pressure but maybe from too much volume of oil.  I get a lot of oil vapor from the draft tube when the motor is warm which I always assumed was a pressure problem, but maybe it’s a cooling problem.

[JWDII]

#3419

Pete do you have a an extra oil sump on your 36? Just asking because my 1915 cc has a deep sump and if I fill it to the full line it would puke oil behind the pulley and put oil in the vent box. I dropped the level in mine and it has been fine. Also had that problem with synthetic. it blew that stuff out everywhere.

[Pete]

#3423

No extra sump, all stock.  2.5 quarts of 10w/30.

• This reply was modified 6 years ago by Pete.

[Franz]

#3425

I don’t think you would have any oil pressure without the control piston and spring. I bet someone drilled and tapped the relief hole(in the side of the bore) and took the piston out so that there is not pressure regulation. Whatever oil it pump goes to the bearings.

 

Oil pressure shouldn’t cause your problem with oil coming out from behind the crank pulley. That is usually too much case pressure. aka worn rings/cylinders. Pushing air and oil out any vent. You could run a compression test to confirm.

[Pete]

#3427

Franz wrote:

I don’t think you would have any oil pressure without the control piston and spring. I bet someone drilled and tapped the relief hole(in the side of the bore) and took the piston out so that there is not pressure regulation. Whatever oil it pump goes to the bearings. Oil pressure shouldn’t cause your problem with oil coming out from behind the crank pulley. That is usually too much case pressure. aka worn rings/cylinders. Pushing air and oil out any vent. You could run a compression test to confirm.

That makes sense, thanks.  I’ll leave it like I found it, put it back together for now and not worry about it since it’s been running ok, appearances aside.  I guess I just need to get off my ass and order a long-block from Ruiz to ship you.  😉

[Jb]

#3439

Well that’s a new one?!? I never lay a finger on the bottom end ? didn’t have a reason to pull the relief. (Or lack there of haha) if was missing all together would it just bypass the cooler or dump bearing pressure into the sump? I’m not versed on mouse motor oil paths. Sounds like blow by past rings….we had an oe set of jugs honed and re ringed it…..was mint? u been caining on the poor little Ghia Pete? Big burnouts or what??

[Pete]

#3440

I know the pressure relief was never opened by you guys; it was still dimpled….had to address that before the plug would unscrew.  I’m easy on this old car….RPM’s never over 3k.

Pretty sure most oil is bypassing the cooler so I’m running 20w-50 now, thinking the heavier weight may hold up better under the circumstance.  Changed oil pump gasket while down there in case that’s any of the leak.  I’ll check compression but I’m doubting that’s it.  It’s not going through much oil st all; it’s more just my OCD wanting to stop every sign of a drop.  I should just leave it alone.

[Jb]

#3448

Hahaha stop every drop? Good luck my friend…..you do drive a vintage vw?

[Pete]

#3450

The oil that hits the pulley is the worst; that sh*t gets flung everywhere.  I can live with the rest. 🙂

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