Frank@Work

I am replacing my '87 951 shortblock with a '86 NA shortblock. In many threads on Rennlist I've found that the OPVRs are not interchangeable. However, I noticed part no 944.101.181.01 Guide Sleeve (no. 26 in the picture below) which is only on the '86 shortblocks.

Has someone tried to remove the guide sleeve and fitted an '87 OPVR?

Douglas Sorrells

My good friend Cyrus just recently replaced his 951 block with an NA block and had issue with that guide sleeve. You may want to shoot him a PM about it, because he knows all about it now. His screen name is CJB3. I don't believe you replace it with the OPRV but he could definatly help you out. If it's not reassembled correctly you will have to pull the engine again. It will let water into the oil system.

Dal Heger

You'll have to get an updated OPRV for the 86 block. The end is different than the 87+ OPRV's they will not fit into the block on an 86 or earlier. The sleeve that you are pointing to is only for the old 3 piece OPRV (the one with the spring and the ball bearing).

You HAVE to get a new OPRV made for the 86 and earlier blocks.

Dal.

KuHL 951

There was a lengthy discussion on this just recently. Tom McGuinn corrected me and researched this. 9fitty1 just the same swap and used the 87 oil cooler housing and used the 86 OPRV installed on the 86 block with no problems. That block and 86 OPRV together you should be fine with either housing. Having to purchase a new retrofit 86 1-piece OPRV isn't cheap. Do not remove the 86 sleeve and try to fit the 87 OPRV it will not work. Confusing isn't it?

https://rennlist.com/forums/showthre...highlight=OPRV
86 and earlier retrofit 1-piece OPRV

87 and later 1-piece OPRV

Frank@Work

OK thanks!

I hope my '86 924S engine has the correct OPVR. That engine will be replaced with an S2 engine so I won't be needing that OPVR in the 924S.

xsboost90

Ok so if im putting an s2 oil cooler on my 86 turbo- i cant use the late one piece OPRV correct? How much is the 86 updated one piece OPRV? i would really like to go to the one piece while im updating stuff. I have a late s2 OPRV and housing and i sourced a cooler and lines, so i can ditch the crappy turbo cooler.

Jeremy Himsel

They're like $225 new. What's wrong with the OPRV you have in your 86 now? Whay are you swapping the 86 951 housing for an S2? You're better off finding a used OPRV, having it cleaned and put a new o-ring on it.

KuHL 951

I'ts my understanding that if you use the S2 cooler housing and late OPRV you should be fine. It's when you try to use a later 1-piece OPRV in an 86 housing that causes the problem.

xsboost90

im swapping the housing because the s2 uses a one piece line design where the lines just plug in and have one bolt that holds them in - instead of the big retaining nut style- and the cooler is larger. So if i use the s2 housing i can leave the one piece unit in there and roll with it? that would rock!

do i need to remove that sleeve or leave it in there?

KuHL 951

After re-reading what you are trying to do I misunderstood. The later OPRV will not fit in an 86 block no matter what housing you use, sorry my bad. You will either need to buy the updated early conversion 1-piece OPRV or use the 3-piece that's on there now. It has to do with the placement of the o-rings on each version of the one-piece; the pics above show it well.

Frank@Work

Correct! The shortblock determines which OPVR to use.

Duke

I have an old N/A eninge in pieces and it has was seems to be a completely different OPRV. Instead of the usual style it seems to be a large spring and guide sleeve and stuff? Anyone know what I'm talking about?

Frank@Work

That's the 3 piece OPVR. When I replaced my 951 '87 shortblock with a '86 NA shortblock I had to replace the 1 piece OPVR with the 3 piece OPVR that came out of my 924S.

KuHL 951

That's the standard 3-piece OPRV used up until 87 in all 944/951

xsboost90

damnit- or i can get a real expensive one piece conversion- well looks like three piece it is for now.