kev951

Ok. I have an early 86 block, with an updated early 1 piece oprv . (this OPRV was not originally on this engine , but another early 86 block.)

Simply put, the metal bushing or dowel or guide sleeve for the OPRV that is in the block will not allow the 1 piece valve to go in. ..... Am I missing something here? I tried to genty install and drop in the early 1 piece OPRV in the guide sleeve to see how well it fits without even with the actual housing in place ! Only the very first lip of the OPRV goes in and thats it. Do I need to update the metal bushing guide sleeve or something? What am I missing here? Nothing looks to be out of the ordinary as far as burs or marrs

Thanks in advance!

I did search for all the info I could find. I only found one post where a RLister mentioned something of a smaller bushing but it was very vague and from 6 or 7 years ago..

KuHL 951

Are you absolutely sure you have the early style 1-piece OPRV and the donor block was indeed from an 86? The later OPRV's are larger diameter and will not fit in a sleeved early style block. Sounds like you have the wrong one. Look where the O-ring is at and the base of the mounting threads

Early Style


Late Style

kev951

thanks steve,
my oprv looks exactly the same as the early one on top , not the later one
and the stamp on the engine block is: M44/07 48G01217

anyone else?

kev951

-according to clarks garage, my block is a later 87-88 NA block. I guess I should try the later valve and see what happens? I can try to borrow one from parts heaven to see if this is the fix, and get a new one if that is what is going on.

M758

You need to use the right OPRV to match the block. Don't put the "retrofit" style OPRV in late block that came with later style OPRV. I have used 3 blocks in my 944 race car. 84 block, 86 block, and 88 block. The 84 and 86 both used the uncaptured o-ring replacement OPRV. The 88 use the capurted O-ring style "late" OPRV. Never swap between them. The oil filter housing is also sligly different for each style of OPRV, but I believe it is only critical if you are using 3 piece spring type. The reason is the pistong needs to slide in the oil filter housing and needs the right bore. The later oil filter housings did not use close tolerance bore because both 1 piece styles did not need it.

I am currently usng a 86 oil filter housing on my 88 block and later Oring style OPRV.

kev951

well from the looks of things , the housing should be ok, or atleast the early oprv will thread into the housing when holding the housing in your hand and not mating it to the block. I will take the housing and oprv to parts heaven with my digital calipers to see whats up. The real funny thing is that on my old block which had the the same stamp m44/07 took this oprv and the new donor block which was rebuilt also has the same stamp m44/07 and both blocks use a timing belt stud not an auto tensioner. Maybe my new block is on the cusp of 86-87 and that's why this is happening??

Thanks Joe!

M758

The OPRV was a mid year update. My 87 924S used the "retfit" style OPRV. However it was an early 87 build using alot 86 parts. That is why I called it an "86" Most 87's had late OPRV, but not all. Just make sure it matches the block and you will be fine. If you must use the wrong oil filter housing like me pay attention to the way OPRV fits in there to be on the safe side. I did a little grinding in the bore on my 86 turbo housing to ensure it worked for late OPRV. For me I have many NA housings, but only 1 Turbo housing. I use the one turbo housing so I can use the turbo oil cooler on my NA.

kev951

ahh , si si !

Thanks again Joe!

kev951

Fluke of the century. There is no way the later one piece valve will fit in the oprv sleeve in the block. The later valve has a slightly larger diameter to it. The only conclusion I have come to is that the sleeve insert is oblonged right at the beginning or right at the top . It's very hard to tell, but I think I hit the nail on this one. What a crappy day.

kev951

has anyone else had the same problem with their oprv not going in the guide sleeve ?
ttt

KuHL 951

I'm still a bit confused. Have you ever ran this engine or are you rebuilding? Do you have the old 3 piece OPRV to see if it binds up also? The sleeve can be replaced and it's covered in the FSM but the old one will be ruined when you remove it so make sure you have the parts on hand, the driver tool, and Loctite for sealing the bottom edge of the sleeve in the block. It's possible that someone tried to remove the oil filter housing with a 1-piece OPRV still in there. Maybe they pried the housing sideways or something and deformed the sleeve but it sounds unlikely. I've heard of them coming loose at the bottom but never deforming like you suspect. Can you take the o-ring off the bottom and see if it still doesn't fit in the sleeve? If it doesn't then yes your sleeve is toast. Maybe you have the larger o-ring for the 87+ on a 86 OPRV?

kev951

Hey Kuhl,
to clarify, I am finishing a rebuild and have never ran this motor. I got this block bare as bare can be, just the block. it was a clean low mileage na block with a sleeve for the oil filter housing in the block. So from my memory, right off the bat, any block I have seen with this sleeve is for the "early style" one peice update. The valve goes in but only a the first portion where the lip and green o ring goes, and right past the port holes, then, it stops at the beginning of the "shank" . I got a plunger from an early 3 piece oprv which has the same diamter as the shank on my 1 piece valve. This plunger or slug, if you would call it does exactly the same thing, except there is no lip on this older piece , so it doesnt even go in, unless i carefully change the angle of the slug and put it in diagonaly, then it binds of course. So I think just the very beginning of the sleeve has become 'distorted'. Maybe i will try something to round out the beginning of the sleave itself only , or have a machinist kiss off a few thousanths of an inch from the actaual shank of the oprv. woahs. I also have to pull the pan back off, now that is torqued, with my ishihara teflon knife edged scaper, there is a bind. which was not there with the oil pan off,, ARGHHHH!@! I have to get this engine in my car fast because I am moving to San Diego in 3 weeks!! the more complete the car is on the move, the less 'dead weight' she will be..

xschop

I have a spare 3-piece OPRV kept from my V8 swap that someone is welcome to, just pay the shipping. I've always thought the OPRV was a strange design as the alloy block expands and binds the steel valve. I always wondered if Porsche made it one piece to be able to remove it. A few thousandths off the line bore of that valve diameter and it will bind no matter 1-piece or 3....

Tom M'Guinn

You know you have to loosen the housing and line it up with an alignment tool for the OPRV to slide in, right?

If you don't have the tool but are using a one-piece valve, you can just loosen the housing, put the valve in, then tighten the housing down -- essentially using the OPRV as the alignment tool.

Have you tried both an early and late style valve?

kev951

Tom,
the housing is not the issue here, what is happening is the guide sleeve in the engine block for the oil pressure reliefe valve is not a true circle anymore just at the opening or the top and that section is now oblonged conflicting with initial fitmant. I am going to carefully tap the sleeve with a tapered plunger from an early 3 piece valve which is the same diameter as my 1 piece valve . Since I will make it tapered, it might work. to see if i can correct the trueness @ the beginning of the sleeve. Understand? Or Thinking of something else? Sorry for any confusion , I just haven't seen this happen or become an occurance on these engines before.
Thanks