1994 MTX - Changing valve stem seals

[boat]

Doing my homework and reading up on changing valve stem seals on my 94.
I have a couple of questions...

I have been reading this:
http://web.archive.org/web/20110505225621/http://www.shophoenixproject.com/stemseals/stemseals.htm

It talks about pressurizing the cylinders with an air hose, through the spark plug threaded hole.
"1. Remove your spark plugs. You can remove one at a time, or you can remove them all at once. Just be sure that you do not drop anything in the cylinder.

2. Next, hook up your air compressor, hose and adapter in the plug well to pressurize the cylinder."

Q1
Is there an air hose fitting with a thread pitch of M14 x 1.25? Is there another adapter being spoken of?

Before I dive into this, I am going to check compression to verify the piston rings. I have noticed in the past that I have oil coming out the exhaust (noticed on oil spatters on a white box behind the tailpipe and oil spatters on the garage floor) and I have heard that it could be the piston rings or it could be the valve stem seals. I've also seen a blue-ish cloud a few times on start up.

Q2
Maybe to put this debate to rest, can any of the SHO veterans speak to this?

 

[SHOtimer]

1. I don't think an adapter is necessary - no different that what is used for a compression check - except you are sending air in, instead of measuring it.

2. Oil coming out of the exhaust does not sound like valve stem seals. Typically the oil leaked past the valve stem seals is burned up in the combustion and you get blue smoke. If you have actual oil getting all the way through the exhaust (if that is in fact what it is) I think you have bigger problems.

Doug

 

[Irish Pride]

I don't think oil would make it past the Cats. What you see might just be carbon build up coming out the exhaust. If it is oil you have a serious engine problem as already stated.

As far as the valve seals, you could do it with soft rope. You shove soft rope into the plug hole with the piston on the down stroke. Once you have the rope crammed into the cylinder you rotate the crank to compress the rope and hold the valve in place.

 

[LOUDSHO92]

You can use a compression checker with the needle removed.

We actually have all of the needed parts at SHO Source from the rotunda kit and some of the other pieces if you are interested.

 

[kevinspann]

Step 1: Rethink it

Step 2: Quit

 

[msteiny]

When I did my stem seals I used the hose adaptor from my compression check kit. the threads were 1/4 inch so I just put a ****** on it for my compressor. You don't need much pressure to do this I think I was at 10psi, its been awhile. Just be careful!!!

After my rebuild I too get the occasional blue smoke from the tail pipes, however I have concluded that it mostly happens when I move the car around in my yard and don't let it warm up, say like I only run it for a couple minutes. Then the next day I go to start it I get blue smoke, but its just a little.

When did you notice the "Oil splatters"?

 

[rubydist]

you will get oil smoke out the tailpipe at startup from bad valve stem seals - if the car has sat overnight or longer.

you will get oil smoke out the tailpipe when you quickly close the throttle (lift off the gas with engine at speed) from bad rings.

typically, the SHO engine will have problems with both.

Whenever I have changed valve seals, I have also removed pistons and cleaned up the rings. All 3 engines I did this to were 120-180k mile engines, and the exhaust valve stem seals were mainly missing, the intakes were halfway decent, and the rings were mostly stuck. Also, I noted that after all those miles the valve keepers were very tight and did not want to come loose - I am not confident that some air pressure in the cylinder would have held the valve in place well enough to get the keepers loose (although guys who have done that have not raised that issue).

I would pull the pistons too, and clean up (or replace) the rings.

 

[zak]

Boat it seems you are planning on doing this in the car. If so will you be removing the hood?

In trying to determine rings vs seals on mine, I used a leakdown tester which could be used to hold the valves up.

Might be easier to just rebuild a spare rear head and then r&r in the car.

 

[yamahaSHO]

In that write-up, I used the extension and fittings that came with my compression tester.

If you plan on doing this, I highly suggest you get the punch tool over what I have described in that write-up. It will save you HOURS over that route.

 

[kevinspann]

Also, if you do buy the tool as suggested by Jason, buy the smaller of the two. It was pretty effective in removing, but I couldn't get it to work for reinstallation. I had A LOT of air escaping past the valves though, the valve wouldn't stay up when compressing the spring.

 

[boat]

Thank you for all the info and tips, guys.

We actually have all of the needed parts at SHO Source from the rotunda kit and some of the other pieces if you are interested.

Thanks, Matt. I was fortunate enough to get a barely used Rotunda kit for Christmas.

When did you notice the "Oil splatters"?

Several times over the last couple of summers. But it may be like Irish said, that it may be carbon coming out the exhaust.

you will get oil smoke out the tailpipe at startup from bad valve stem seals - if the car has sat overnight or longer.

you will get oil smoke out the tailpipe when you quickly close the throttle (lift off the gas with engine at speed) from bad rings.

typically, the SHO engine will have problems with both.

Whenever I have changed valve seals, I have also removed pistons and cleaned up the rings. All 3 engines I did this to were 120-180k mile engines, and the exhaust valve stem seals were mainly missing, the intakes were halfway decent, and the rings were mostly stuck. Also, I noted that after all those miles the valve keepers were very tight and did not want to come loose - I am not confident that some air pressure in the cylinder would have held the valve in place well enough to get the keepers loose (although guys who have done that have not raised that issue).

I would pull the pistons too, and clean up (or replace) the rings.

Fred, I was thinking about replacing rings, but wondering how necessary it really is.

I was already considering pulling the motor with a laundry list of things to do. Having it out may be easier to do rod bearings, replace rear main, replacing p/s pump, and valve stem seals.

Boat it seems you are planning on doing this in the car. If so will you be removing the hood?

In trying to determine rings vs seals on mine, I used a leakdown tester which could be used to hold the valves up.

Might be easier to just rebuild a spare rear head and then r&r in the car.

Zak, Well leaving it in the car depends on how far I go as far as if I do piston rings or not like Fred (rubydist) was suggesting.

Don't have any more spare heads, gave, sold, and junked all of them.

If you plan on doing this, I highly suggest you get the punch tool over what I have described in that write-up. It will save you HOURS over that route.

Punch tool? Please forgive my ignorance.

 

[TimboSHO]

I was already considering pulling the motor with a laundry list of things to do. Having it out may be easier to do rod bearings, replace rear main, replacing p/s pump, and valve stem seals.

I would pull it out. It will save a lot of headache over doing it in the car. You might as well do a complete refresh and get all new gaskets, rings and bearings. Then you know everything is good, and you shouldn't have to worry about anything for a long time!

 

[rubydist]

the last 2 I rebuilt, I just re-used the factory rings after cleaning them all up. you have to be careful to get them out without breaking one or more, but the end gaps were only slightly over the high side of the spec, and I plan to boost at least the one I have in the RX7, so I wanted a little larger gap anyway. you just want to be very careful to keep the right side up, and put the same rings on the same piston into the same cylinder.

on the other hand, in my collection of stuff I probably still have a set of new 3.2 rings (I don't recall if I have them listed in the for-sale thread or not) but if I still have them you can get a real deal...

 

[jimtash]

If you plan on keeping the car and maintaining it, buy the Rotunda tool kit for it. It has all the tools necessary, minus a valve holder for air, to remove and install the seals.

 

[Irish Pride]

If you plan on keeping the car and maintaining it, buy the Rotunda tool kit for it. It has all the tools necessary, minus a valve holder for air, to remove and install the seals.

Thanks, Matt. I was fortunate enough to get a barely used Rotunda kit for Christmas.

:sun:.....

 

[kevinspann]

Mike these are the tools Jason is referring to:

http://www.amazon.com/Lisle-36050-Keeper-Remover-Installer/dp/B0012S61IO/ref=pd_sim_auto_2

 

[msteiny]

Boat, I would say its carbon. Mine leaves black puddles in the garage if I let it idle for a long time. How old is your exhaust?

 

[boat]

Yeah, that's kinda what I was thinking, but it seems like a lot of work to pull it out. I was/am kinda in limbo about pulling it. I knew if I pulled it out, I'd want to refresh it while I have it out on a stand. Car monies budget is tight. I need to see what it costs given the time between now and the convention. The wife and I decided to go to a reasonably strict budget so we can start knocking out debt.

I would pull it out. It will save a lot of headache over doing it in the car. You might as well do a complete refresh and get all new gaskets, rings and bearings. Then you know everything is good, and you shouldn't have to worry about anything for a long time!

I am definitely interested in those new 3.2 rings. Just gotta see how my budget plays out.

on the other hand, in my collection of stuff I probably still have a set of new 3.2 rings (I don't recall if I have them listed in the for-sale thread or not) but if I still have them you can get a real deal...

Not sure. It was on the car when I got it. Could be original. Car spent most of it's life on the west coast, Washington, northern California. The mufflers are borla, not sure when those made it on the car. About 2 summers ago, I installed a SHOSource y-pipe, it has a leak where the intermediate pipe and exhaust meet. That might cause some excess carbon?

Boat, I would say its carbon. Mine leaves black puddles in the garage if I let it idle for a long time. How old is your exhaust?

 

[zak]

Maybe try auto-rx first?

Didn't do a thing for my 85 Fox 5.0 main seal leak, but on the SHO 700 miles with two bottles was enough to stem the oil burning smell I was getting enough to attend an open track event without embaressment. I did drain/refill/change filter right before the event (a cleaner is not a lubricant), and a few thousand miles after that the oil burning smell began to return.

Based on the leakdown testing I did I think its the valve seals/guides on the left bank (front) left cylinder (#4).

Post 11 here:

http://www.shoforum.com/showthread.php?t=117087

 

[rubydist]

Zak, cylinder compression leakdown has nothing to do with valve stem seals. It has to do with rings, ring gaps, and if valves seat properly.

Boat, a little exhaust leak at the end of the y-pipe will not be a cause of excess carbon in your rings. Rings carbon up due to collecting the remains of unburned hydro-carbons from the cylinder - both oil and fuel. Eventually, the stuff cokes to the point where its almost all carbon. The ring stickiness is compounded in the newer, low tension ring engines (which are used to reduce friction, yielding higher mpg) and since the SHO engine is in that group, it often gets sticky rings. Frequent oil changes definitely help, and extended oil change intervals with regular oil definitely make it worse.