Valve Stem Seals

mjaffe · 12-29-2005, 02:29 PM

Dear Folks:

Suffered a head gasket failure. About to take the head off and do the deed (first time, wish me luck ). Anyway, I have been told to be sure to replace the valve stem seals. According to the manual I have, it says to use special tool #3047. Is there a reasonable facsimile? If not, where do I acquire such a tool? Also, do I need to remove anything else to get to the seals?

Thanks in advance.

Michael

ae1969 · 12-29-2005, 04:31 PM

Nothing special to replacing the valve stem seals....

You will need a spring compressor to remover the valves......

The stem seals can be tapped in with a deep socket..... You should not have any issues.

mjaffe · 12-29-2005, 04:35 PM

Thanks for the reply. I am really raw about all of this. So, do I need to remove the valves to replace the valve seals. I am sure I can buy some sort of spring compressor from Kragen, etc. If I have to remove the springs and valves, is that a job a rookie can tackle?

Thanks agan for your help.

Michael

Granite 944 · 12-29-2005, 07:49 PM

Yep, you do need to remove the valves first, in order to replace the valve seals.

I had hoped to get around to doing this on my '83 this week, but doubt I'll get to it for a little while longer now.

Just be aware that there are TWO different style valve guides. If your early car has not ever had any head work done in the past, you may very well have the earliest style guides which will require you to use an adhesive to bond the seals to the guide. The way to know for sure which you have, is when dismantled, and old seals are off, look for a grove towards the top of the guide. If no grove exists, you need to bond those seals on. If you have the grove, you don't need to use a cement/bond. The "special tool" would make it nicer, but it can be done easily without it.

You really should check and make sure the ID of the guides are still within spec. before putting the seals on anyway. Machine shop time.

I found that a large C-clamp works pretty well, providing you have a pipe or something simular, thats got a cutout on it, to allow down pressure on the springs, and let ya get the valve keepers out once compressed. I have a large C-clamp, and use the lower section of a micro-adjusting depth countersink body as the top part. Yeah, I know, no one will EVER know what that is.
I bought the valve spring compressor from sears, and it won't work unless you modify that top foot on it. C-clamp works much better for me.

mike944 · 12-29-2005, 07:57 PM

It's not too hard a job, especially since you're already going to have the head off.

The valves do not need to actually come out, but removing them will make removal of the old seals easier to remove without damaging the valve stems (which will chew up the new seals quickly) I would reccomeend doing them one at a time, so you don't mix up the valves. They all need to go back into the same holes they came from.

Porsche 944 valves are double-spring'ed. This means you need a heavy-duty compressor, since the double springs are stronger than on many cars. You might get away with a lighter-duty one, but you definitely don't want it to break when you've got a highly-compressed valve spring, and you're fiddling around with the keepers at close range. Safety glasses are a must here. There's a lot of stored energy in compressed valve springs, and they can send all sorts of stuff flying at a very high rate of speed.

one of those really-powerfull small diameter telescoping magnets will help with removal of the keepers. The same magnet, and a little dab of sticky grease on each one will help with their installation.

Good luck!

mjaffe · 12-29-2005, 09:01 PM

Dear Granite944:

Thank you for the reply.

Forgive my ignorance, but would it make sense then to replace the guides with new ones or do you have to replace all of the bits at once (valves, seals, guides, etc)? Going to a machine shop sounds expensive. This project seems like it is growing out of my league.

Thanks for the help.

Michael

yellowline · 12-29-2005, 09:20 PM

Seals are doable with a good spring compressor. The rest of the job, aside from the 2 bolts in the front of the engine that seize up, isn't exceedingly bad. It's a lot of little jobs put together, like removing the intake, then pulling the cam tower, etc...

Did your HG go like mine, where one day it just ran like crap and couldn't move itself in 1st? Or did yours overheat? If the former, you may be able to get away like me and have no machine work done.

FYI, I didn't do guides, but everything in the head seemed fine.

Granite 944 · 12-30-2005, 07:59 PM

First of all, I am NO expert. But, I can tell ya this. For an average cost of about $500.00, you can take your head to a "knowledgeable" PORSCHE machine shop, and get the head completely done over. That should included, regrinding of valves/seats, new valve guides/seals installed, and cleaning of the head (VERY IMPORTANT). ANY other work then above, would add to the above cost, ie, things like replacing valve seats, shaving the head/block mating surface, valve stem height grinding, welding of any corrosion pitting, machining valve spring landings, and of course any replacement of parts like, valve spring sets, or the valves themselfs.

A machine shop in your back pocket, for people like you and me, is a VERY good thing to have. Find one that you can work with, who's familiar with these PORSCHES. I know, a head is a head. I DISSAGREE, for the most part, and DEFINATELY when regarding the block itself!

I'm guessing you have no tools or ability to check the valve guide wear yourself. Take it to a reputable machine shop, they will measure it, and IF, and I mean IF, they are Porsche familiar, they will KNOW ( or at least know where to get the needed info), enough to give you options as to what you can or should do with the head. Or any part of the engine, for that matter. For a nominal fee, they can do a overall check of the head, and then advise you what "should" be done to it. Call around, ask for prices, then go from there.

rudidelange · 12-31-2005, 12:35 AM

Mjaffe
I am in the same position and pulled my head. Quite eazy except for the middle studs that were corroded to the top. Took me some hours to remove the head. Removing the valves is no proble, but you must have a good vlave spring compressor.
My stem seals are rock hard and I cannot remove then from the guides. I will attempt to make a tool (slide hammer - similar to the special tool) to remove them.
A machine shop adviced me to replace the springs, valves and the guides but this sound pretty expensive. I will look for a second opinion in the weeks to come. Let us know about your progress.

Granite 944 · 12-31-2005, 08:20 AM

Quote:

Originally posted by rudidelange
.........My stem seals are rock hard and I cannot remove then from the guides. I will attempt to make a tool (slide hammer - similar to the special tool) to remove them.........

It may not be the proper, or best way, but, I've used just a pair of regular pliers around the outside of seal, and a little heat from a small propane bottle torch, to heat 'em up a little, and soften up the inner rubber, and/or adhesive, then twisted them off. Don't scar up the guides doing it, be careful.

Quote:

Originally posted by rudidelange
A machine shop adviced me to replace the springs, valves and the guides but this sound pretty expensive. I will look for a second opinion in the weeks to come. Let us know about your progress.

Is this because they inspected this head? Or because you were just talking to them over the phone, and it was just a suggestion, as that is what MIGHT need to be done durring a "complete" rebuild, depending on HOW it checks out?

Valve springs are pretty durable, and expensive (about $85.00 per each set.....8 total in the head). And the machine shop can check them. If your valve guides/valve stems are worn very much, it won't do much good to put new seals in (at least for any longevity), not to mention the valve seat leakage issue. The FSM does show how to check valve stem/and or valve guide wear. As a matter of fact, I'll be digging up that info for my sake here in the next day or two myself, as today, I'm pulling the head off my '83 for a gasket R&R. And, I'll be making a decision after removal, as to if this head will be going to the machine shop or not, after I take a looky-peeky at it. It probably will, if I decide to not take the chance on a homestyle overhaul. I'll see later. I should have just taken one of my spare parts car heads down, and got it completely done over. Might still.

Good luck, to us all!

Dark Skies · 12-31-2005, 11:24 AM

Just my 2 pence but if I were going to go through all the hassle of having the head off for the seals I'd bite the bullet and go the extra distance and have everything else checked over in the valve / seating / spring department and fix as appropriate. For the sake of a few extra hundred or so you'll at least have the peace of mind in knowing you're not going to have to revisit the job for another ten years or so.

pm9146 · 01-02-2006, 02:27 PM

I have an 83-85/1 head for sale. Completely reconditioned (see 944 head for sale in classifieds)

Verruckt · 01-02-2006, 06:12 PM

Additionally, you can buy re-manufactured heads from **********.com and 944online. When my head gasket died, and overheated the engine in my 924S, I didn't have access to a Porsche machine shop as I was living in Hawaii. I bought one from 944online and would recommend them to anyone. Replacing the head is a job anyone with basic hand tools, a few "specialty tools" (arrnworx.com), and access to pelicanparts.com and clarks-garage.com can do. Good luck, and keep us posted.

Usmellgass2? · 01-04-2006, 09:45 AM

For some good pics and text check Granetts thread.

http://forums.pelicanparts.com/showthread.php?threadid=257955