M30 oil pressure relief valve

[myles]

Happy new year guys...

Has anyone come across this problem before? Is it common only to older m30s? or all m30s?

I hear from a mechanic here that there is a common fault with the design of the oil pressure relief valve in the m30 engines. The valve gets stuck half open because the lower edge of the valve piston is sharp and will dig into the bore of the valve after a while. The solution is to chamfer the lower edge of the valve to prevent it from sticking. I got a full demo of the problem from a m30 engine from an 82 528i.

It was very nasty as it causes the oil pressure to always be bled off at a slow rate. Meaning that low pressure is lower than it is meant to be and high pressure is higher than it is meant to be.

Any one hear about or seen this problem on a 535i?

Thanks guys.
Myles

[winfred]

the pre 87 m30 had a crappy oil pump and a good oil filter housing (from the standpoint of drain back) the post 88 m30 has a good oil pump and a shitty oil filter housing, when it's working right it pukes oil over the motor mount when you change the oil, and the rest of the time all of the oil drains out of it, and it takes around 15 seconds to fill the canister before the motor gets oil

[myles]

Thanks winfred

Have you seen any m30 oil pumps with a damaged bore inside the relief valve?

I had a look at the etk, and the e34 oil pump itself is only common to m30 powered e32 and e34 cars, but the e34 oil pressure relief valve is common to all m30 powered cars. Maybe they improved the hardening inside the bore of the valve on the post 87 m30 oil pump

Thanks for your thoughts.