odurandina

i hope you get years of pleasure out of your new motor. i hate to detract from the thread, but given all the catastrophes with these engines over the years, they're just not the kindest of rebuild candidates in the first place, so, i just don't see how the reward outweighs the risks here, when there are so many competent engine guys out there that would have put this back together with ease for less than the price of a new RIDING LAWNMOWER engine, especially when you've already spent time and good money doing things right. and i hope you're not re-using the original connecting rods. you need the late rods.... sorry for being such an ***. all the best.

RajDatta

Alan, the man is looking for help in putting his engine together. Not sure how your comments help.
Regards.

Cloud9...68

Thanks, Raj. You took the words right out of my mouth (and believe me, it has taken a lot of willpower to bite my tongue). I view this as a project, a learning experience, along with a way to save a lot of money. Many people have rebuilt these engines with good results. I had expected challenges to present themselves along the way, and they have.

Now, does anybody have any experience with re-assembling their OPRV? My engine was leaking from practically every seal, so one of my major goals is to replace each and every one of them, but this particular one is quite literally in a tight spot. The part that has me scratching my head is that the manual states that the old o-ring will be destroyed when the OPRV is pulled apart. So how exactly is the new o-ring supposed to survive the re-assembly process? Should I try twisting it as I tighten? Thanks.

odurandina

i just wanted to keep the conversation lively by playing the devils advocate.

and having read about so many horror stories.

Cloud9...68

Still biting my tongue...

dougs968

Cloud, I'm sitting here looking at page 17-5 in the workshop manual. It looks to me like the o-ring is maybe slightly oversize by design. Altho I have never done what you are doing yet to my engine, I think that I would try to coax the o-ring back into the groove with something like a feeler gage, small screwdriver, or whatever. That is if the o-ring is shearing on the outside diameter of the o-ring. I would also inspect the o-ring groove on the slide valve housing for any damage or very sharp edges that would start to bite the o-ring on re-assembly. If found, I would VERY carefully dress the groove with a stone or 600 grit wet/dry sand paper. About .005 radius or angle should be plenty unless there is a bigger one to start with.
If you run out of o-rings, I bet that somewhere in Austin there is a hydraulics supply shop. They might have the right size.
I wish we were closer. I'd like to help.
Good luck

Doug

Cloud9...68

Doug,

Thanks for the suggestions. I'll take a close look at the condition of the inner o-ring groove. Also, I was thinking I should put some oil on the inside of the plug, using a q-tip. And next time, I'll try pushing the slide valve housing into the plug by hand with the spring removed, to get a better feel for what's happening when I press these pieces together.

By the way, have you ever R & R'd your cams? If so, did you use the tool the girl in your avatar is holding? The manual says to use it, but I've heard people putting the cams on without it, by just carefully tighting the cam bearing cap bolts very gradually. Thanks again for the well thought-out response.

fortysixandtwo

I've installed cams, a few times, without the factory tool. In addition to tightening each cap a little at a time, you have to pull the cams apart (by hand) so they line up with the bearing surface, while tightening. Otherwise the cam journal gets pinched between the head and cap bearing surfaces.

Edit*
I should add that I also do the cam alignment by eye.

Cloud9...68

Has anybody who's done this gotten away with installing the oil filter mount casing without using the OPRV alignment tool? If not, does anybody have a tool they could lend me? Thanks.

dougs968

Cloud, yes I have done my cams, all the front seals, cam chain, pads, water pump, water pump studs, belts, hoses, and probably a few other things I'm forgetting. Oh yea, and rebuilt the magnesium toothed belt covers that enclose the exhaust cam gear, and reset the engine timing. At my slow pace it took me over a year, but it is done exactly right.
When you get to the point that it is time to do your cams I would highly recommend that you read the write up on that procedure that Raj and Arash did. It helped me greatly. Thanks again guys. Other good sources of information are of course are the factory workshop manual, which you may already have. Porsche Club of America also has a pretty good question and answer section on their website, but I think you have to be a member to access it. I found it useful when I was trying to set my timing. When Porsche translated German to English sometimes they would use phrases like "sense of rotation". Ok. Do they mean clock-wise or counter clock-wise? Stuff like that causes me to seek more info. Anyway, good source. All text no pics.
About that cam saddle tool. I made those myself and that is my daughter. I am a machinist by trade mostly, so it helps when I need a special tool, I can usually make it.
I hope this helps.

Doug

Cloud9...68

Yes, I can see how being a machinist can be very valuable when working on these cars. I wish I knew so much as how to weld! The cam saddle tool looks great, and I'm sure it significantly simplifies and de-stresses the cam install procedure. Cool avatar, too. I also have a pair of teenage daughters, but neither of them has the slightest interest in cars - at least not the 968, although my older daughter (17 years old) has expressed some interest in going to the track with me. Speaking of special tools, did you use (or make, and then use, in your case) the special alignment pin Porsche specifies (No. 9262/1) for aligning the oil filter mount casing to the block prior to inserting the oil pressure relief valve, or did you get away with just using the OPRV itself to do the alignment? I've heard it can be tricky, even with the special pin. Thanks.

Edit: I just realized it doesn't appear that you've yet had the "pleasure" of R & R'ing your oil filter mount casing (doing this with the engine in the car can't be fun!), so never mind. Anybody else have any comments about the need for the alignment tool? I'm leaning toward biting the bullet and buying it, given the risk of putting the OPRV back in imperfectly aligned. I'll need it again in a few years when I build my turbo conversion

And thanks so much for pointing me to Arash and Raj's cam R & R DIY - a beautifully written DIY which has already answered several of my questions.

RajDatta

This is where you need to be careful and make sure your oil filter housing does not make the OPRV bind. I have the tool but you should be able to do it without the tool.
Don't tighten the body, keep it hand tight and then put the OPRV in to align the hole. Once you have the OPRV aligned, then tighten the oil filter housing.
Regards.
Raj

Cloud9...68

Thanks, Raj. I understand, but I'm concerned that the OPRV flexes where the slide valve body intersects the plug, so it doesn't make the ideal alignment tool. But I do understand that I might be able to make it work. Still debating on this one...

RajDatta

If it helps, I can lend you the tool. Let me know.

Cloud9...68

Ack! Thanks, Raj, but I just ordered one from Paragon. Decided to maximize my chances of success, and that using the tool would help ensure a perfect alignment. Thanks for the offer.