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Trying to get through a water pump, front end reseal and OPRV renewal and slightly confused about some things so would love some help from others:
First, my car is an 86 951 but the oil filter/OPRV housing has been replaced with a part stamped with 1988, part # 951 107 151 3R. However, my block has the steel OPRV sleeve which, from what I've read, means the OPRV is the early Type A version. The OPRV does appear to be the Type A so not sure what the 1988 housing is all about.
I'm assuming the newer housing has no bearing on which OPRV I have? Just trying to figure out the correct O rings I need for my car.
Secondly, should I replace the inner O ring on the OPRV? I've read a factory bulletin stating that the OPRV is a non serviceable part and if disassembled , the valve will require replacement but then I thought I've read about people replacing the inner O ring so not sure exactly what is the correct thing to do....
Next, I'm not sure about the guide sleeve or connector tube, the tube that connects the housing to the block, seen below with the green O ring. I'm pretty certain that this tube is removable and has another green O ring inside the block although it doesn't want to move at all, so I just want to be sure before I damage it trying to remove it. Are these tubes removable on all 944's? And are they normally stuck in the block as mine is?
And I've noticed a strange issue on my balance shaft bearing also. The bearing nub has actually been worn down by the balance shaft slightly. The bearings aren't worn excessively and the balance shaft doesn't appear to be damaged but the nub has definitely been worn down. What's the cause of this? Is this acceptable or is there something strange going on? I figured I would just file down the nub and install a new bearing. It seems the nub is soft metal just in case of this situation but please let me know if this is a bad thing waiting to happen.
Looks like that is the right OPRV, the latest one has a full groove for the green oring IIRC.
The sleeve, yes it comes out. And yeah, it'd be a mistake to not replace both o'rings since you are already there.
A flat screwdriver on each side with the tip in the groove 180 deg apart should remove it. You might have to shim the screwdriver with a small piece of wood, etc., to lever against.
The dowel in the balance bearing cap may be able to be driven in further with a punch but it wouldn't hurt to file/dremel it down a little as long as it's not lower than the surface of the new bearing shell.
As mentioned. The oprv is determined by the block 86. Or 87+. If you need to replace the oprv I just had to search and find an 86 unit as well and it was $350 new.
If you choose to replace the bottom o-ring be sure it doesn't tear when you reassemble. I think that is why Porsche says its a non serviceable item,
How difficult is the reassembly of the OPRV without damaging the o-ring? Just wondering if I should order more than 1 o-ring....
Thanks everyone for the helping words, finally on my way to ordering parts and, Humboldtgrin, I already bought the correct tool off eBay for only $12 but thanks for the link. I'm already in for about $800 in parts so I'm going into cost-cutting mode. Always a surprise how much all of the $20 and cheaper parts add up to when doing any engine work on this car; so many seals and o-rings and spacers....and then the car still leaks! All of my other cars get by with a single seal on a shaft with none of the Porsche superfluous extras and they live happy normal lives so not sure why Porsche goes crazy with all these different sealing methods. I guess the spacer sleeves protect the expensive shafts but otherwise, I'm not sure of the reason for this method. Extra expense, complexity, and it sure does make for a long list when putting together a list for ordering parts.
Just don't forget that translucent seal that goes behind the balance shaft sleeve. The camshaft has the same deal. The oil pump gear uses a O-ring behind it. And the sleeves are there for just as you mentioned, to not wear the balance shafts or camshaft. They are much more expensive then the sleeves.
Just don't forget that translucent seal that goes behind the balance shaft sleeve. The camshaft has the same deal. The oil pump gear uses a O-ring behind it. And the sleeves are there for just as you mentioned, to not wear the balance shafts or camshaft. They are much more expensive then the sleeves.
Yup, got the mylar seals as part of my parts order. I also went with genuine Porsche 968 BS seals as they seem to offer an extra lip for dirt protection which I figure can't hurt. Also, any problem with Reinz seals? I thought I saw some people complaining about them not sealing but can't remember exactly. The seals I pulled seem either original or at least older than I've owned the car (20 years old and 120k miles) and they weren't leaking excessively so I know Porsche OEM (Kaco) seals work pretty well.
Anyway, the cam seal I ordered is Reinz so I hope they aren't risky.....God, I don't want to have to do this again for a long, long time!
Oh, also, there was some sealant on various places: the rear cam/distributor cover had sealant on the back where it is attached to the cam housing...does that o-ring not seal well enough?
And what about the rear BS housing cover? I know about Voith's seals but I'm pretty tapped out with the funding right now. But I've heard of just putting RPV on an already leaking rear o-ring taking care of leaks so what is the popular way of ensuring this weak o-ring doesn't leak?
Many thanks for the help and please see my other thread on some strange AFM damage I discovered tonight.
I would not change the bottom O-ring on the OPRV. Porsche says it is a non-serviceable item. I was looking for a used OPRV and Ian at 944 online told me if you pull the bottom out to change the o-ring you will ruin the OPRV.
I would not change the bottom O-ring on the OPRV. Porsche says it is a non-serviceable item. I was looking for a used OPRV and Ian at 944 online told me if you pull the bottom out to change the o-ring you will ruin the OPRV.
Porsche did say it's not serviceable but then they also issued a technical service bulletin describing how to replace the internal o-ring so I think they must have updated their history.
I haven't pulled mine apart yet but I noticed it's slightly crooked and every other o-ring or seal I've removed in this project has been brittle and past its prime.
05-09-2018, 04:08 PM
OPRV and Balance Shaft Questions
