jcorenman

Great work, Scott! We likes shiny parts!

Stan has done a lot more of these that I have, and I respect his opinion greatly. But I think this is worthy of discussion: The purpose of the oil is lubrication, heat transfer and also dampening-- that's what the little check-valve is for, on the part with the o-ring.

Porsche specifies engine oil or gear lube, depending on the reference-- those are about the same viscosity. STP is quite a bit thicker, and while it is true that it will leak out more slowly, I also don't think it will provide the same dampening effect. Having no oil doesn't provide any dampening either, of course.

So my approach is to make a serious effort to make the tensioner not leak (sealer on the boot as you did, clean the gasket surfaces carefully, sealer on the adjuster bolt, etc) and then use the specified oil.

Them's my thoughts, there are no wrong answers, and YMMV.

docmirror

If you didn't remove the bleed nipples and clean the holes in it and the bore they ride in, that needs to be done. The goop tends to clog the bleed nipple at the inside, and the seat. I can't tell from the pics if you did that, but if not, do it before reassembly in the car.

Oh, and I disagree with using STP or another highly viscous fluid in the tensioner. The valve orifice is calibrated for a certain viscosity when warm to provide the correct damping force. STP doesn't have the same thermal coef as gear oil. I used gear oil in the two that I did and they work ok, but I'm in hot TX. I might use straight SAE 40wt or 50wt if I lived in a more genteel climate.

syoo8

Hi Doc and Jim,

Two thoughts:

- Neither bleed screw had rubber boots on them. (!) I cleaned both bleed screws very thoroughly before installing.

- John Kelly's manual cites the higher (i.e. left) bleed screw as the oil "filler" screw, and the lower (i.e. right) bleed screw as the drain. Logic tells me it should be the opposite- to get more oil in there. Am I wrong?

Questions:
- When should I fill the tensioner- now, or when the tensioner is installed?
- Since my bleed screw is missing the rubber boots, do I need to order the Porsche ones, or can I use rubber vacuum caps, of which I have an assortment of colors and sizes?

BTW, here are some of the threads I read on the subject.
Confused: What oil to use in tensioner?
Can a leaking tensioner be the sole reason for loss of timing belt tension?
Tensioner rebuild question
Getting Oil into the TB Tensioner
Gear Oil - T/B Tensioner
Thoughts / methods on filling T-belt tensioner w/ oil?
Filling Tensioner Oil - question

ROG100

Higher one is correct and any good fitting cap will work.
Fill after the tensioner is installed as the oil flows from the tensioner into the cavity in the block and back to the tensioner

jcorenman

Correct (you're wrong), the left-hand (facing engine) bleeder is the fill. If you try to fill it through the right-hand bleeder then the oil can't flow through the little check-valve.

After installing the tensioner, otherwise the oil just goes all over the bench, gasket, etc. The space between the back of the tensioner and the block (sealed by the gasket) is part of the oil reservoir, and there are two little holes on the backside of the tensioner.

As Roger said, anything that fits well enough to keep the major dirt out (also the same size as brake bleeders).

Great list, thanks for posting that !

Cheers, Jim

syoo8

I did a lot of cleaning (two hours) and the left side is looking a bit better.



I pulled the water pump.



I see some radial 'wear' in the cavity, in the path where the impeller would spin. Is this normal?

ROG100

Scott,
Did the pump you removed have a metal impeller?
As long as you do not feel a deep ridge where the impeller was touching the cavity in the block you will be fine.
What was the pump make? Any movement in the bearing? Just interested.
Roger

syoo8

Hi Roger- yes, the pump I removed was a rebuilt Porsche pump with a metal impeller. There was no "play" in the bearing whatsoever- it was solid. However, it makes a slight noise as you turn it- a very faint scraping noise one every three revolutions or so. The noise is similar to scraping your fingernail on a piece of cardboard.

No, there was not a deep ridge. It felt relatively smooth.

AO

That looks normal to me. Looks like machining marks from the factory...

You'll want to take a razor blade to the WP surface to clean off the old gasket - tedious crappy job, but it has to be done.

Great effort. Keep it up.

Bilal928S4

Following up on AO's advice of using a razor blade to clean the mating surface of the block to water pump. Make sure the razor blade is 90 degrees to the mating surface at all times. You will have some material left, do not use the razor blade to try and take that out as you might gouge the surface. Just scrape the surface with the razor blade at 90 degrees.

Avar928

You'll want to replace that washer behind the crank gear. Chances are that gear won't come off easily and you'll need to get an extractor to grip behind that washer to pull off the whole thing.

Took me 3 days to get it off. Mine was rusted onto the crankshaft.

Buy some engine assembly lube (or anti-seize) and apply it to any shaft where a gear is as well as the inside of the gears. Makes pulling them off less of a pain in whatever future.

ROG100

Scott - what amazes me is how competent you have become in your mechanical skills on the 928 and your posts are up there with the likes of Stan (Mr. Merlin), Dwayne and others who give so much back to the 928 community. Your ability to record the process and pose just the right questions to establish a working document for other "newbies" needs special thanks.
I bookmark your threads for the benefit of my "newbie" customers.

Your skills are much wider in scope and without wanting to embarrass you I am sure others would enjoy the following as I and my family do - thank you.

Bertrand Daoust

Take great care of those magician hands while you work on your car.
Would be so sad to even get them dirty!

Wow.
You have all my admiration Sir.

Mrmerlin

Talk about cuttin the rug,
Those are the kind of hands you need to work on a 928.
I suggest to wear blue gloves.


Well done Scott, your supremely talented.
Roger thanks for posting this link.

syoo8

You are all very kind. Thank you for your kind comments about the Tchaikovsky. I am honored to be included in this forum.