Replacing Valve stem seals!
 

Hi guys!...I'm just about to start replacing my valve seals on my 1977 Porsche 2.7 ltre !...and i just need to clarify some info before proceeding!

What would be the ideal PSI air pressure to hold the valves in the cylinders at TDC!

also after reading all the posts from others here at pelican forums on replacing valve seals, is it ok to release the air pressure in the cylinder once the valve spring has been removed to check for any play or movement in the guides!

Some say that they have done this because its a good idea while you have the valve spring off or removed to check your guide for wear!

one Porsche owner stated that when he checked his guides the valve with the piston on that particular cylinder would move down the guides about an inch or 2.5 cms

Is this correct!..in releasing the air out of the cylinder or is there another method!

any info from experienced Porsche 911 owners who have replaced their valve seals would be greatly appreciated!:)

I replaced an exhaust spring at the track once. With the piston down some I shoved a bunch of string into the chamber through the spark plug hole (of course keeping an end out), and then ran the piston back up until all was tight. No worries about air supply or pressure. You could back off a bit to check stem play, then move the valve back up.

Also, you might consider doing this only on the intakes. There really is no pressure differential around the exhausts to suck oil up hill. And what might get in there isn't going to get into the combustion chamber, is it?

seals
 

The exhaust seals are pretty easy in the car.60-100 psi will keep the valve in place.The older white nylon seals are the best replacement with the engine in.Why ? Because when you tap them on they bottom and the seal is square to the valve.The red Viton seals are way tougher to get square.To see if they are square you need to get the piston towards BDC bottom dead center then release the air and push the valve up until the 3 keeper grooves are at the top edge of the seal.Then look to see if the top edge of seal is level with the groove.Now you can wiggle the valve up & down to check for play.The Viton seals are tougher to remove as well.Then you have to scrape off what is stuck to the top of the guide.Other than that it is Easy Peasy.Ciao Fred

Thanks guys for your quick reply's!...

Walt!..
Interesting with the rope method!..i did try this method to see if i could get rope down into a cylinder but i could only get a few inches of rope in there and no more as the cam towers where a pain in the ass to try and feed any rope down there!...i do like the rope method but trying to get the rope down there is a mission and a half!....how did you get your string or rope down there!..i even twisted the rope as i was feeding it down into the spark plug hole but the rope would only go so far and not much at all!...also with the air pressure method!..so it is OK to let some pressure off the cylinder to check for valve play and because the piston is at TDC you can move the valve back up to its closed position and then apply air pressure again to replace the stem seal!

faapgar!...interesting about what type of valve stem seals there are!..i have the black rubber victor reinz seals!...but if the white Teflon type seals are better i would rather the white ones if they last longer and are a more versatile seal!...i read somewhere also that the white Teflon type seal are so good in stopping oil from leaking past the valve that some make a little slit inside the seal itself for some oil to lub up the guide!... whats your thoughts on that and the seals and what would be the best named brand white seals to get!...cheers guys much appreciated :)

seals
 

Wrightwood Racing use to have them.Maybe check with Supertec.

here at pelican they have the white Teflon seals!...When i search for stem seals on the internet the Teflon seems to be the same product!..just hope they are the same quality!

https://www.pelicanparts.com/catalog/SuperCat/911M/POR_911M_ENGCYL_pg4.htm

Fred, what seal do you recommend if the engine is apart with full access to the heads?

seals
 

Those are the right white seals for in the car.For the engine stand I like the new ones,I use a piston pin for install because it has a beveled edge on the inside.Tap the seal down gently and check with the valve keeper groove to ensure it is square to the groove and not cocked.

Good advice faapgar on how to install valve seals!...i also read somewhere that when installing the seals that you place some tape around the keeper grooves on the valve stem so that the valve seal lip doesn't get chaffed when pushing onto the valve stem!....

What would be the benefits of the white seals!..would they last longer than the rubber type?...some guys in the past have experienced their rubber type valve stem seals have cooked or hardened up because of heat very quickly of time!..hence the leaking of oil into the camber problems

does anyone know how to correctly undo and slide out the rocker pin?...

HOLD the 8mm side, TURN the 5mm side. If you do it backward you could crack the rocker shaft. Push it out by hand (after backing off valve lash adjuster and verifying the cam lobe is down). If it's stuck, spray some carb spray or brake cleaner around the shaft then GENTLY tap out.

When reinstalling, keep the shaft flush with the skinny side boss on the cam housing and HOLD the 8mm side, TURN the 5mm side. Use the RSR seals to prevent leaks. Torque to 18 ft lbs if used shafts. The 5mm side should go toward the inside of the engine (doesn't matter on the middle shaft). If you reverse it, the next guy will have trouble removing the shaft if the engine is still assembled in the car. Don't be THAT guy.

white teflon seals
 

Main benefit of the white seal is the ease of installation with motor assembled in the car.You just tap down gently until it stops.Very little chance of the seal not being square to the valve.As far as not letting enough oil to the guide do not worry.Your guide will have play so the valve will be rocking the seal and opening it up and some oil will pass.O n race motors I would use a seal on the intake but none on the exhaust.In the 80,s in IMSA we would make a tower where the breather cap is and run a vacuum line to the collector point of the header.That would pull crankcase vacuum and help the motor rev.If you had worn guides it could smoke like crazy so we used an exhaust seal and drilled a 1mm hole from valve spring retainer to the center of the guide for lube.This was copied from a 935 engine.Those guys were smart.Ciao Fred

Thanks Guys!...your info is so much appreciated!

dannobee!... i'm guessing when you say to turn or undo the 5mm side of the rocker pin!..is undoing it in anti-clock wise direction as in the normal way to undo a bolt and nut or is the rocker pin bolt and nut assembly left-hand thread!..I'm assuming the correct method of undoing or loosening the rocker pin is the normal way which is anti-clock direct!...

faapgar!....I know you mentioned earlier in post #9 that you use a piston pin to tap down the seals...some say they have used a 10mm long socket to tap the seals down without any issues!...what are your thoughts on this!...cheers

tool for install
 

10mm socket could work.Just set the seal up to it and see how it fits.If you use it make sure it is clean inside.Ciao

OK!..thanks for that faapgar!..i have a brand new 10mm socket!..i have a few cars parts yards in my area and i will take a valve seal with me and see if they have an piston pin with a bevel edge that will fit to the seal...cheers and thanks for all your help!..you guys have given me a lot more confidence in doing the seals...cheers!

just a quick question on the rope method!...once you get the rope or string down the cylinder, and compress the rope with the valves!...whats a safe way to get the rope out again once you finish holding the valve!...I heard that its not a good idea to turn the engine anti-clock wise as this can damage the tensioners in the timing chains!...or is it OK to turn the crank just a little or enough to pull rope out!...

To me, the business about never turning the engine counter clockwise is just an old wives tale. I've turned 911s backward many times, especially with the chain cover off. It certainly won't damage the tensioners - they are very stout. For sure, the pressure fed tensioners are unaffected by any of this.

For the older style, maybe this would force some of the oil in the tensioner out, though it should refill soon enough. But with the spark plugs removed there isn't all that much force on the tensioners while turning backward.

Cheers!..Walt!..that is good news!...i guess if you are going to turn the engine anti-clock wise your'll do it to a minimum anyway!...

Is it OK to tap the top of the valve spring retainers before decompressing the springs to loosen the keepers?...and is it OK to tap the retainers with a hammer after the spring has been depressed to make sure that the keepers have settled back in their proper place with the valve stem!

I think you meant "before compressing the spring to loosen the keepers". I use a socket to contact only the retainer.

Yes on tapping the valve tip after installing the locks. Again, a socket. A slight to moderate tap should be enough to ensure proper retainer lock seating, but cover the target area with a shop cloth, block any black hole engine openings (e.g. oil drain tubes) and wear eye protection, just in case.

Sherwood

I have recently replaced the intake valve seal for #5 and most recently, I replaced all from passenger side exhaust seals, due to the previous wrench using too much force installing them and ruining them. I will also be replacing the driver exhaust seals, as I can still smell oil being burnt, which is why I began replacing them.

I used the Brown Viton seals as I have read that the Teflon seals use a stiffer material and thus starve the valve stem.

Note: I replaced the seals while the engine was in the car.

Thanks guys your tips they are most grateful! and very helpful is this area of maintenance!..I am up to the stage of removing the seal from cylinder 1 and i have dropped the stem down just enough so the keeper lines on the stem are level with the seal!..does the stem seal pliers that you can buy either from amazon or any auto store work with these type of seals?..or is there any alternatives to remove the seals!...i do have the black rubber type seal so they are tight and hard to move!..has anyone found ways to loosen these seals either by pliers or other tools to ease the seals off!.

The old trick that I used was a pair of spark plug boot pliers. Keep wiggling until the seal pulls off.

thanks dannobee!..i just ordered some spark plug boot pliers so they are on the way!..i know i will need some patience to get them off!..I'm so glad that you can have the ability to low the stem to remove the seal in 2 ways!..

1) so you will not scratch the stem itself when removing the seal and

2)you have more room to get to the seal!...oh and one other thing!..i am using the rope method to hold the valves!...One trick i learnt is to get a plastic tube and wedge it into the spark plug hole so you can feed the rope down into the hole !..so much easier than trying to feed the rope down because of the cam towers!...I hope this helps anyone!.....:)

hi guys!..I hope you are all well and enjoying life!..well after my first replacment of the intake valve seal all went good and now i am up to the second seal which ofcoarse is the exhaust seal!

After draining the oil and removing the exhaust cover i checked the rocker pin hex keys to see where the 8mm and 5mm hex's are positioned on cylinder #1,#2,and #3!....

After checking #1 the 8mm is facing towards the front of car or gearbox!..and as you guessed it ,the 5mm hex is on the timing chain cover end!...

does this mean that i can't get the rocker off because the 5mm hex is the head bolt of the rocker pin?....or is the exhaust rocker pin hex the bolt head!...

Or can i get around this by loosening the 8mm side removing the 8mm hex round nut..then sliding the rocker pin back towards the timing cover so there is room to get a tool to pull the rocker pin out towards the front of car or gearbox!....Basically is there any tips to remove the pin without removing the timing chain cover to get the rocker pin out!...cheers!

You deal with this by shortening the end of your L shaped Allen to use on the 5mm end. You might be able to use an Allen socket after shortening its protruding end - a 1/4" socket type would be a bit smaller. And have a shortened 8mm L shaped Allen, too.

How the fasteners are installed doesn't affect the ability to push the rocker into one of the center spaces so it can be removed (though for what you are doing, you don't need to remove the shaft, just the rocker).

Thanks Walt for your reply much appreciated!....I had the idea of shortening the allen hex "L" 5mm to fit into the space on the right-side of the rocker!..so i will shorten the 5mm! and 8mm...cheers!

With the rocker pin are you saying that once you loosen and remove the 8mm collar round nut from the left-side of the rocker pin, all you have to do is push the pin to the right of the shaft to remove rocker!....cheers!...:)

I'm assuming that the shaft is the rocker pin!

The standard advice is to install/remove the rocker shafts (pin??) with all their hardware (three pieces) removed. I suppose this prevents spreading the end of the shaft you are pushing on - the purpose of the tapered pieces is to spread the ends of the shaft. So it makes moving the shafts easier and less likely to score the hole in the cam carrier these shafts reside in.

But necessity sometimes dictates ignoring this to get a shaft out. It is sort of a fine point. And you can reinstall the "right" way.

Sockets of suitable diameters are helpful in pushing a shaft out after it has been pushed part way in. Having a suitable magnet is useful in placing these, and retrieving them.

Thanks Walt this really helped me in removing shaft!..

I did noticed the shaft nut 8 mm was a little burred but OK!..so i just ordered 2 more as a spare!..
i did notice also that the intake and exhaust shafts don't have any rubber seals sitting in the grooves of the shaft and i don't get any leaks into the spark plug chamber areas!...strange!..is this normal?..or would it be a good idea to order some seals!..

one other thing i would like to ask!...Does it matter where the 5 mm rocker arm shaft bolt go into on each end weather it is left side or right!...The reason why i ask is that it was a real challenge loosing the 5 mm end because of the timing cover area which as you know is the back part of the engine with minimal space to work in!...if i install the 5 mm in reverse meaning placing the rocker shaft bolt 5 mm in the front of engine this will give a lot more room to loosen if i need to uninstall later in future

anyway thanks you guys for all your help!....cheers!

According to Bentley, the 5mm bolt for the outer cylinders should face #2 and #5, which
makes is easy to tighten. #2 and #5 can go either way.

I just removed my rocker shafts (and put RSR seals) while in there.

Serge

Thanks Serge!...my 5mm rocker shaft bolt was facing the timing case!..i will install the 5mm bolt facing cylinder #2 for future uninstalls if it comes to that!...cheers!

Anyone know how to remove the outer valve exhaust spring!..seems that the spring is to big in diameter to slide out from the head!...I've uncompressed the spring with the special Wayne Dempsey spring compressor!..inner spring and keepers are out!..the spring sits loose when its flush with the guide!..Has anyone come across this situation with their exhaust spring!..There is no damage to the spring and this is exhaust cylinder #1.... the engine is a 1977 2.7 ltre

When I did this at the track once, I had the same problem. Maybe I could get it out, but not back in? In any case, a mechanic there took pity on me and did it. So I can't tell you how, but can assure you it can be done.

Thanks Walt!..I have a pair of special pliers that i recently purchased for removing the valve stem seals!..These work perfectly in removing the seals!.. The pliers are thin also making it good to fit on the seal while the outer spring is still in the head!..these pliers are the best i could find for removing valve stem seals! and they are a MUST if you want to remove the exhaust stem seals..as for removing exhaust springs maybe you unwine the spring over the head part to remove it!

Here is a link for these good pliers!
https://www.amazon.com/Removal-Pulling-Cylinder-Insulated-Handles/dp/B07XXLM664/ref=sr_1_16?keywords=Car+Spark+Plug+Wire+Removal+P liers&qid=1569317559&s=gateway&sr=8-16

Try some needle-nose pliers to pull the spring out.

Hi nene!...how would you pull the spring out !...one idea i had was to get some descent cable ties thread them though the spring on each side and leave then loose or untied for the moment then get your valve spring compressor with the shim cap that sits on top of the spring and compress the spring down then do up the cable ties on each side and see if that will come out!..if it comes out you can leave the spring under tension for the time you remove old valve seal and replace with new seal!..then add spring back in compress a little more so the cable ties are a little loose and then cut ties remove and then uncompressed again!...Not sure if this would work though but if its possible to remove spring with pointy nose pliers how would you do it!...cheers!

Needle nosed pliers and twist the spring while pulling.

Thanks dannobee you are right it was easier than i thought!..all though cylinder #1 exhaust is more tighter in head room but cylinder #2 was a lot easier i just angled the spring to the right and didn't need the pliers but that was for #2!...one question though the chrome like disk plate that sits flush in the seated guide where the inner and outer springs sit seem to be a bit loose in there, there's no damage or bits of metal anywhere!...Thank God!..is this normal?...i mean does these inner disk-like plates have a clip to hold them or do they just sit there with the spring to hold them once tensioned!

The spring shims just sit in there, under the spring, held in by the spring tension. There should be a spring cup, too.