Valve seals, how hard to replace?

[Tipsysmile]

Well i got my recently purchase quest in the garage and Finally got the exhaust header off. After pulling it off I noticed that ports 1, 3, and 4, (from front to back of motor) all had oil in them. While number 2 was dry.. So im kinda figuring my valve seals are bad.

 

Now im trying to look through the FSM, but Ive checked the engine section and tried searching for Valve seals, but yet nothing comes up..

 

What is all involved in replacing them? I vaguely remember reading a post about them on here, something about not having to remove the head was the part i remembered.

 

 

I have my valve cover off, and set everything to TDC. Removed the distributor, and thats where im at now..

 

Any help would greatly be appreciated.

[Edde]

Several things. One you may be able to look thru the valve springs when they're fully closed and see. If you have new ones to look at the old ones will have cracks in the rubber ring and be hardened looking. Those will also have enlarged holes from the heat and age. Exhaust side first since it's hottest.

 

You need to:

 

Remove rocker shafts - keep the cam caps in place. Careful not to strip the bolts when re-installing and/or have a heli-coil of the right size ready.

 

Get an "on the car" valve spring compressor. Pretty cheap and works.

 

* Figure a way to keep valves from falling into the chamber once a spring is removed. Any common sense method will do. Some push air into the cyl.

 

Compress a spring. Remove the keepers and don't lose them. Remove the retainer and spring.

 

Grab the old seal with pliars and carefully work it off. It'll be tight to get going.

 

You'll need something that fits real well to use as a "press" to tap the new one on without distorting it. Oil things a bit of course, especially the rubber.

 

I think that's the gist of it.

[Tipsysmile]

Thanks alot edde, I also found it in the FSM when i searched for "valve seats" instead of "valve seals"... Stoopid me..

[Edde]

A compression test would also be able to tell you where to focus - rings, valves, whatever.

 

 

[AutoBodyGod]

Jamming nylon rope down the cylinder will work as well.

[h3r3tic]

So I did a compression test yesterday and it was 141-142 across the board. So Im assuming there is no seals needing to be replaced internally on my motor correct? valve seals, rings, etc..?

[Shelby]

once your all set up you can replace all valve seals with in an hour,, great time by the way to install heavy duty springs if you haven't already,, Dad has them in stock i beleave

 

useing air pressure to hold valves close'd is the best way,, also you want to loosen the valve spring keepers before starting to remove the springs

Edited July 13, 2010 by Shelby

[Edde]

So I did a compression test yesterday and it was 141-142 across the board. So Im assuming there is no seals needing to be replaced internally on my motor correct? valve seals, rings, etc..?

 

 

If you're not burning oil, no. Don't fix it if it ain't broke!

[vbrad511]

Valve seals have nothing to do with compression. Your seals may still be bad. I prefer the nylon rope stuffed in the cylinder through the plug hole (pull the plug, get the cyl at the bottom of the stroke, feed a fair amount of rope in the hole, rotate the motor up until the piston wedges the rope against the bottom of the valves. When you're done with that cyl spin the motor back EVER SO SLIGHTLY, just enough to get the rope out, move on to the next cyl). If you use compressed air with the piston down, and you break the seal of the valve to the seat, the valve will fall into the cylinder. If you start with the piston up, the air may force the piston down and move the vehicle while you're working on it. It'll scare the bejesus out of you. Rent/buy the spring compressor from AZ. Knock the retainer on each valve lightly with a deadblow hammer to jar loose the keepers. Install the compressor and when you start tightening it to compress, put one of the telescoping little magnet jobbers on top of the retainer to catch the keepers. A pair of pliers or channel locks will remove the old seals. A 1/4" drive, 12 point deep socket on a small extension will aid in the install of the new ones, but you've gotta make sure you get one that fits over the seal correctly and lets you drive it down without damage.

[Tim_C.]

Using compressed air is best. With the cylinder all the way down, the valve will not come out with air in the cylinder. Even if the valve comes off the seat, the air will push it back on. I have never seen one fall perfectly past the groove on the valve and into the cylinder. That just doesn't happen, especially with air on it. You do need the air to hold the valve in place when tapping the new stem seal on. Pay very close attention to when the seat is all the way on. Do not tap on it after it is all the way down. That is where most people damage it. Look at how much of a gap there is between the bottom of old seat, and head. Use that as a gauge for where to put the new one. Just remember the new ones may not be the same type, so that gap may be a little different. Key is to be careful and pay attention. You might want to buy two sets of seals since you are not an expert, and will probably ruin a couple. That's okay because you are saving much more by doing it yourself. Otherwise, you will need to stop the job, go back to the parts house and order another box. Use a small air regulator to slowly turn it up when the cylinder is up. That will rotate the engine slowly. Keep it in neutral as you don't need to hold the car with the engine.

You may want to put the rear cam cap back on so it holds the rear of the cam when turning the engine.

Be sure to use the plastic guide that goes over the valve so the seal will not tear on the valve groove. Lubricate the guide too.

[Shelby]

or if the car is std trans,, simply place it in gear with parking brake on,,that way the engine can not turn,, you can do 2 cyls at a time,,turn engine and do it again

[h3r3tic]

Ill have to do a leak down test then.

[Edde]

Ill have to do a leak down test then.

 

 

Are you having an oil problem then? Your comp numbers are really good.

[Shelby]

comp numbers can lie to you esp if theres a lot of oil already arround the rings

[h3r3tic]

Well Im not sure if its just my pcv or it was leaking from somewhere. I have a new pcv on the way from dad. My car doesnt smoke what so ever but I thought I kept having oil disappear. Past 3 days though the oil level really hasnt changed so Illl change the pcv out and see how that goes. From what I understood the 141 across the board is like perfect, correct? I was told it had a rebuild about 5k ago, All the gaskets looked new, head gasket, waterpump, oil pan, valve cover etc. Idk Ill see what happens.

[Shelby]

what cam are you useing,, a high lift cam can hit and distroy the valve stem seals

 

normaly valve stem seals will last well over 125k miles

Edited July 15, 2010 by Shelby

[Edde]

I wouldn't go tearing into it until I knew I had trouble. I gather you haven't had it too long. A bad pvc can blow oil all over and make the dipstick tube pop out of the oil pan tube. It's said to wipe the oil stick and give a few seconds for oil to even out in the tube before reading again or else it can be off. All the tests are fine though. It never hurts to know. Dad's got the correct pcv so it should be fine. Changing contaminated oil can reduce burning too.

[Shelby]

you can see most of the valve stem seals with a good light and a little tlc ,,

like was said don't jump before you know why and where your jumping to

another way for oil to get into the cyls is from the jet valve seals or the jet valve elim stud seals ,,i'd look at them if the head was a j valve head odds of that being your problem is very good

[norcalstar1]

So I ve been putting off trying to get my 87 back on the road, but have some time now. Was trying to replace valve stem seals, but having some troubles knowing how to properly install the valve stem seals. I tries to use the old one, but it looks like I messed up and lightly gouged the top of the first seal. I was looking for the correct stem seal install tool and how far or how much to use it to tap it down, It seems to be an interference fit but I'm not sure from the description i the factory service manual if it is supposed to be a t a certain height or all the way down. Thanks in advance.

[psu_Crash]

It's very easy to mess up a seal when installing them. If yours has visible damage then take it back off, it's junk.

Like said, make sure you use the install tool to get the seal over the groove in your valve stem. OIL EVERYTHING!

Then press them on my hand. After that I use a socket that fits the outside rim of the seal and very lightly tap them the rest of the way on. I have screwed them up more than once using this method so be careful, but it does work.

 

P.S. I'm a fan of the compressed air method to hold the valves up. If you have a compression tester then use that fitting/hose to screw into the head. Then put a quick disconnect on the other end of the hose and hook to your compressor line.

Edited January 5, 2015 by psu_Crash

[93 GSX TURBO]

I know this kind of late, but just to add to what psu_Crash said, purchase a wheel valve stem removal tool so that you can take the stem off your compression tester hose. Also set your compressor to about 80 to 100psi.

 

This is the keeper removal/install tool I used:

 

http://buy1.snapon.c...group_ID=675633

 

Like everyone said, just take your time and make sure to cover up any timing chain area or drain back slots with paper towels, the last thing you is something dropping in there. I also used engine assembly lube when installing new seals and on the tip of the valve stem where to keepers lock into. For peace of mind I always lightly tap the top of the valve spring once everything is assembled just to make sure everything locked in correctly. And definitly install a JET Valve Delete Kit while your in there.

 

I've used the above tools/methods several times on Honda, Mitsusbishi and a couple of Conquest engines.

Edited January 11, 2015 by 93 GSX TURBO

[twojayzeestarion]

Screw using air. I don't trust that. I always jam my cylinders full pinkie sized cotten rope then compress it by turning the crank a little

[93 GSX TURBO]

I've used air around 6 times and it never failed, even with small compressors.