I have a 1991 TA with SLP headers. I was going to have the valve springs changed as part of some modification work. But from what I understand, a compressed air fitting needs to go to the spark plug hole to allow air into the chamber. This keeps the valve from falling in when the spring is removed.

I don't believe that there will be sufficient room to get a fitting and hose around my header pipes. And removing the headers is out of the question.

Are there any special fittings or tools that will allow a spring change on an engine with headers?

Thanks.

 

If you plan on changing the valve springs you have two options, take the heads off, or fill up the cylinders with air like you're suggesting. Unless you can find a tapered 90 degree fitting for the spark plug hole, and you still might have clearence problems, those headers have to come off.

 

You don't have to remove the heads or use compressed air to change the springs on the heads.
What you need is about 3 feet of 3/8" nylon rope. Tie a knot in one end of the rope, remove a spark plug and rotate the engine until that piston is about to come up on compression. Now, feed the rope in through the spark plug hole (the end without the knot). Once you have as much rope in the cylinder as you can get, rotate the engine on around until the piston just pinches the rope hanging out of the hole. You can now compress the springs on that cylinder and remove the locks/keepers and spring without loosing the valve. After finishing the spring change on that cylinder, back the engine off so the rope will pull out and move on to the next cylinder.

~M~

Note: Rotate the engine by hand for this, don't use the starter.

 

My tool for compression is shorter than most spark plugs, so I don't see that it would be a problem either way. (Yeah, I know, I know. I said my tool is shorter than a spark plug. Ha, ha....really funny.)

The rope trick has been around for decades, and it works very well, too.

 

simple, but also true....

 

Thanks Guys.

But I'll have to put the spring change off. Don't think my mechanic will be up to the compression fitting on my SLP heads or the rope trick.

He thinks with 70,000 miles on the engine they should be OK.

Oh well.

Money talks and I am whispering.

 

I tried that compressed air trick on my 305, I have Heddman long tubes headers, I think that it's an ole wives tale. I started off at 90 psi and it would'nt hold the valve, went up to 125 psi and same thing, valve kept wanting to silde down. Luckily there was soo much varnish on the step that it would only go down so far. Once you put put the new seals on the valves that will hold the valves up while you put the new valve spring on. Mine had 120,000mi. though.

 

Then call me an old wife. It works, but you have to be on TDC, if not the piston will travel downward.

 

The compressed air does work - at least it did for me.

For an air compressor fitting, I gutted an old spark plug.

I then went to the local hydraulic shop and picked up a 90 degree brass fitting with a quick connect for 1/4" plastic tubing, a straight fitting with the same quick connect that would accept a connector to the air supply, and 2-3 feet of tubing.

http://www.globalfluid.com/TOC/prestolok.htm

I epoxied the 90 degree fitting to the spark plug shell. This screws into the head (used a box wrench) with plenty of header clearance.

I then plugged the tubing into the 90 degree fitting and plugged the remaining fitting into the other end of the tubing.

Connected the air, did the springs and seals, disassembled the fittngs and tubing and moved onto the next cylinder.

 

A friend of mine recommended this procedure. Anyone done it this way??


All you need is a
timing tape on your harmonic balancer. It's a black piece of tape with
markings for your timing (360 degrees) and is available at any speed shop or
Summit/Jegs for less than $10. You might want to mention to your mechanic
that if the piston is at or very near TDC (top dead center), the valves will
only "drop" slightly, i.e. less than 3/4" inch (approximation). You will
NEVER "lose" a valve this way.

The procedure goes like this: Rotate the crank until the #1 cylinder is at
TDC (confirmed by your timing marks on the balancer). Remove the #1 valve
springs and replace. Once completed, rotate the crank 90 degrees. Verify
this on the timing tape. Remove the #8 valve springs and replace. Every
time you're done replacing the springs, rotate another 90 degrees and
following the firing order, i.e. 1,8,4,3,6,5,7,2.

 

Most of the air pressure was probably blowing past your rings.

 

Oh, NO! Not Parker Presto-Leaks! (I used to work for Parker Hannifin.) Some of their fittings are very nice, especially in the HP hydraulics. The Presto-Leak, unbfortunately, isn't one of them. Imperial Eastman has a solid brass push-lock fitting that is much more reliable. I'd hate to see you lose a valve...

 

Thanks for the warning, Vader.

I had no problems with the fittings I used.

It might not have been Presto-Leak fittings that I used. I recall the locking rings being gray and not green (if this matters at all). They might have even been a different brand.