Tom M'Guinn

Outside o-ring? What motor is this for?

triscadek

87 S, the OPRV has 2 O-rings. Didn't mean to sound confusing, both are inside the motor, I meant the outermost of the 2.

Tom M'Guinn

According to the Tech Bulletin #3 at the back of the spare parts book, the 87 944S used the same one-piece OPRV as the 8 valve motors (944 107 035 01). That valve, as best I can tell from the literature, only uses one o-ring and one aluminum washer -- just like the earlier one-piece retrofit valves on my car.

p.s. I assume you are referring to the 944S and not the 924S. The 924S changed OPRV styles mid-year. Both OPRV's used only one O-ring, but the O-rings are different on the early and late 924S cars -- according to the tech bulletin.

KuHL 951

This had me confused also, all the 1-piece valves I've seen were a single o-ring at the tip only. Pet also shows 2 different o-rings based upon MY.

triscadek

The dealer looked it up and sold me 2, showed me from his PET ( I assume) where 2 went. I found a grooved area towards the back of it where it looked like one could go. So now I have one there too.

Wouldn't surprise me if he looked up the wrong thing.

Tom M'Guinn

It is very easy to mis-read the PET diagram. Do you have the part numbers of the o-rings he sold you. I bet he sold you one for the early OPRV and one for the late (i.e. your) OPRV. One is slightly thicker than the other, right?

KuHL 951

Paul,
I think the PET numbers are showing 2 different o-rings for two different 1-piece valve styles(i.e 45 and 45a). If you put an o-ring in that upper groove the piston won't be able to travel as designed. Ad far as I know there is only one external o-ring at the tip of the 1-piece valve. I could be wrong but the 2nd o-ring isn't shown on Paragon either. Have you already installed it?

triscadek

It's in and nothing changed with my oil psi.

Thinking about it, it seems that the first O-ring forces the oil through the valve and the second keeps it from leaking out of the end, even though it didn't leak before without one there..

Tom M'Guinn

Based on the tech bulletin, it seems pretty clear that there is only one o-ring by design, which goes on the tip. (Was there an update I missed?) Did you get the part numbers for the o-rings you installed? Were they the same or was one thicker?

(I have an oil seal article on my rennlist site, and just want to make sure I have the latest info listed. )

Kevin Baker

Lets see if this link works.http://boards.rennlist.com/upload/op...aceo-rings.gif
If so, this was posted to a thread that I started when I was having problems with my oil pressure at start up.

triscadek

I threw away the receipt but both of the O-rings were the identical, pale green in color.

If you look at Kevins link, just inside of where the threads end on the OPRV there is an area that looks like a groove where an O-ring goes, that's where I put the 2nd O-ring (there wasn't one there when I removed it) but going off of the word of the dealership parts man, I assumed that he was correct when he said that I needed 2 O-rings.

I go back to work tomorrow and most likely won't be online again 'til next weekend, so I won't be able to respond again 'til then. But if anyone has anymore questions PM me and I will go by the dealeshipr and have him print the page from his PET that shows 2 O- rings with part #'s and get them to you.

There's still more of a story as to why I resealed the OPRV.

Tom M'Guinn

Ok, I went back and looked at all of Porsche's TSB's and found TSB 19017 (Oct. 9, 1990). It clears up the confusion. The one piece OPRV's (both types) do indeed have two o-rings. However, only the o-ring on the tip can be replaced without disassembling the OPRV. The other o-ring seals the body (tube) part of the OPRV to the 24mm screw-head. The TSB says that you can disassemble the OPRV by putting the screw-head in a vice and pulling the body (tube) out by hand. Doing so, however, destroys the internal o-ring sealing those two parts. You then need to replace that internal o-ring (oiled) and press the body back into the screw-head with a "handpress or vice."

So, if you just pull out the OPRV and then reinstall it, without disassembling it, you should only replace the one o-ring on the tip (since the other o-ring is still installed inside the assembled OPRV). When it goes into the block, you will only see the one o-ring. I can supply additional info from the TSB upon request. The chart below shows the part numbers of the o-rings. The upshot is that you want to use 999 107 145 40 on the end of the 86 retrofit valve, and 999 107 144 40 on the end of the 87 and later valves. If you take the OPRV apart and need to also replace the inner o-ring, use 999 107 146 40 for the 86 retrofit valve and a second 999 107 144 40 on the 87 and later valves.

KuHL 951

Thanks Tom-That should clear up the 1 or 2 o-ring question. Do you feel it's worthwhile to replace the inner one at the same time? I've soaked the 1-piece OPRV in solvent so I guess I need to get that inner one also. Thanks again for the TSB post, that's a new one for me.
Steve

Tom M'Guinn

It seems to be the only soft part inside. Looking at the cut away picture posted below, it appears that the inside o-ring seals the tube/body in the cap and therefore would seem to function to prevent the cap from leaking, rather than affecting the operation of the OPRV. So, if it is not leaking, and your oil pressuire is correct, I'd probably leave it rather than pull apart a $300 valve.

triscadek

I found the PET page I had printed from the dealer.

Header at the top of the page:


Model Year MG SG Illustration Update
: 944 2 87 1 04 104-00 184