Scotts94z28

Whats involved, what will I need regarding special tooling? I will be off for four days over thanksgiving, and I am planning on replacing the intake gaskets, and valve guide seals. The car is a 94 Z28 with 238,000 orginal miles. Ive actually had the valve covers off only once on this car, and bought car new.

Just to go ahead and give as much info as possible up front regarding the seals. The car is hard to crank after sitting for awhile, and smokes gray for a moment once started. Now if I start it after sitting at work all day, and I drive a mile or so to a gas station, when I come back out turn the key and boom it fires right up with no smoke. Ive been told by a compatent(sp im sure) mechanic thats its my valve seals that are bad.

I almost hate to do anything to the engine at this point short of rebuilding it, its getting tired, I just cant afford a complete rebuild at this time.

I also have many tools, and the mechanical ability to do the job, although not looking forward to it.

Any help or advice will be greatly appreciated.

evilundisguised

Basic tools to remove alternator/valve covers/rocker arms. Large wrench to take belt off/spin the crank (to keep from dropping valves into the cylinders), a valve spring compressor is a must, a magnet to snag the retainers is greatly helpful, needlenose pliers to twist off the old seals. That's all I can think of, it's relatively straightforward.

StephenDeli22

I was reading about high milage motors and replacing valve seals and how it can possibly blow out the bottom end? I was thinking of doing 1.6 RR on my car and replacing valve seals while I was at it but, there is a chance of blowing the bottom end? Can someone else chime in about this becasue it wasnt really explained well.

shoebox

The seals only keep oil from migrating down the valves and into the combustion chamber. There is no pressure involved. Blowing out the bottom end? Someone will have to explain the logic of that to me.

If you are going to do 1.6 rockers, you are going to want to replace the springs (if they are stock). Might as well as replace the valve seals at the same time as the spring has to be off to do it.

StephenDeli22

Is there a disadvantage/possibility of damage that can be done to the motor? ie. cam bearings, ect. I have 164k on the clock and think I have a loose rocker and would rather just replace them with something higher performance than just fix them.

shoebox

You mean damage by installing 1.6 rockers? Sure. Spring failure will generally cause a dropped valve and catastrophic failure. On a 164k mile engine, I would not even consider putting 1.6 rockers on without new springs (actually, not even on any LT1 engine, no matter what the miles).

StephenDeli22

Oh yes, springs, locks, keepers, arp studs all the supporting mods.

MachinistOne

You got mixed up somehow or the article was wrong. That kind of situation refers to doing a valve job on a high mileage motor, buy all of a sudden having no blowby at the valves you can ruin the ring seal and cause an oil-consumption problem.

96 TA

Im about to do the same thing on my camaro (1.6rr,and complete new valve train, minus valves )

Will we need to compress the cylinders with air to keep the valves up or can we just rotate the crank to TDC on the cylinder we are working on and be safe? My car has 194,000

MachinistOne

Put air in the cylinder, with the piston at TDC the valve will not drop, but you will have a hard time getting the retainer to separate from the valve without the help of the air pushing up on the valve...

shoebox

If you rap the retainer before you compress the spring, the locks will usualy come off with the TDC method. I had no problem this way. A difficult as plug access is, it's hard to get air into the cylinder.

Javier97Z28

Agreed, never had an issue just moving the cylinder to TDC.. and with decent valve seals they usually hold up high enough to do the trick. Done it oh, 3 or 4 times now, no issues.

wrd1972

Forget about the air fitting in the spark plug hole due to terrible plug access. The compressed air is the best way but you can put the piston at top dead center as well. The valve will not fall through unless you have holey pistons. Perfectly safe to do this, you can still do two at a time.

Once you have the spring compressed just lightly wack the retainer with a dead blow hammer and the locks will snap loose and come out with a magnetic retriever.

The valve seals come out with pliers or vice grips, just grab a hold and twist while you lift. They come of very easy. Make damn sure you use the plastic sleeve that comes with the new seals, this sleeve slips of the valve shaft to prevent the lock groove from cutting the o-ring when reinstalling. Failure to do this will result in leaky seals.

Go to shoeboxes site for instructions on putting the pistons at TDC.

96 TA

thats good info, thanks!

Scotts94z28

thanks for all the info guys, I'm sure I'll be back when I get into it over the thanksgiving holidays for additional help. Once again thanks.