Rob Edwards

I am continuing with the demolition of the '91 GT motor I bought and have a dumb newb question. I thought I'd show some pics first for other newbs, tho.

Here's the setup to disassemble the valvetrain on S4 heads. First, the head's gotta be up off the bench. Second, it needs to be clamped so it doesn't tip over when you use the spring compressor:





The tool itself is a Schley products 91400A, bought straight offa Ebay:



Somewhat annoyingly, the 928 head is longer than the cross-bar that comes with the tool, so you will have to move it around multiple times to get all the valves out.

The 87+ cam towers have these little sleeves around the bolt holes, which necessitates using some M12 washers to get the tool's towers to sit on the surface of the head:




Below: Note the 3/8" drive socket hole in the compressor handle- I used a 1/2" drive ratchet (with a 1/2-3/8 reducer) to increase the leverage while compressing the valve spring- makes it easier to use your free hand to get the collets out.



So once the tool is bolted down, you set up the arm so that it pushes straight down on the valve spring concave washer and remove the collets with a magnet:




Then valve just drops out the bottom, and you remove the concave washer, the springs, the lower washer, and a shim (1mm in this case)



The valve was in pretty good shape:






All this leaves the valve stem seal:









Ok- now the retard question: I pulled on the seal and managed to dislodge the spring in the seal, but it's not budging. I'm hesitatnt to really torque on this thing, how hard should it be to remove? How do I pull this thing off without hurting the valve guide, and without scratching the lifter bore? I have this pair of valve seal pliers, they're narrow enough to reach, no problem:

BC

They are really on there. Quite a bit of force is needed.

GregBBRD

That's the tool. Grab on, wiggle and twist. They'll come off. Think "Anaconda" on the end of those pliers.

Just don't hit the lifter bore with the pliers.

RyanPerrella

Rob,

I think your seal pullers are less than IDEAL, they will work but i used the long mouth ones and as Greg said, you need to twist and just pull up. The come out and i cant see you risking damage to any part of the guide (you would likely replace those anyway) but as Greg said, be very careful not to damage or gouge the lifter bore.

BC

But just in case you do, in fact, nick the lifter bore, you can use those rubber disks that are for dremels to round down any scratches. Not that I have personal experience on that or anything.

Rob Edwards

Got them off last night- Brendan and Greg are (of course) right- they're tight. But grabbing the seal with the pliers and turning it will sort of loosen its grip o n the valve guide. Continued rotating the seal and pulling upwards and wiggling side to side a bit will eventually get them off. I didn't hurt any lifter bores, but I do wonder how this bore made it past Porsche QC at the factory ~20 years ago:

It's intake, cylinder #1 - The corresponding lifter looks fine...

fraggle

Timely pics and advice on the tools and tips.

thanks!

BC

find those rubber wheels for the dremel. If you can't find any, I can lend you mine.

GregBBRD

Porsche QC.....Military Intelligence. Might be located in the same office...for sure, in the same building.

David L. Lutz

Rob,

Great pic's, good information here. Thanks.

ptuomov

(1) When using that valve spring compressor tool, there's an essential accessory for it: 5/8" by 36" zinc plated round steel rod, available from Home Depot for less than $10. This will allow one to remove all valves without moving the flange towers or whatnot.

(2) The best way that I have been able to come up with for getting the locks out is with a magnet. The bottom washer also wants to come out much easier with a magnet.

blown 87

I have some old lifters that I can modify so just the outside shell is left with a lip to help with removal out of the lifter bores.

I might have to do some welding, IE weld two together and maybe a weld ring to shrink them.

It would sure help to protect the lifter bores when doing the seal removal.

What do you think?

AO

Wouldn't it just be easier to find a hunk of heater hose or similar that is slightly oversized, slit it, and then trim just enough material so it fits the lifter bore? Cheap and "cusioney" (if that's even a word).

blown 87

Yes, as a matter of fact it would be better and cheaper.

123quattro

+1