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Discussion Starter #1
Has anyone out there ever changed the valve stem seals without removing the head? I am currently away from my shop and am hoping that it is possible to dissasemble the valves without removing the head or camshafts for that matter. Is it possible to compress the valves and get everything out without a complete removal? I know there are tools that will compress the valve and hold the stem, but i dont know if it is possible on our DOHC head. Any help is greatly appreciated!
 

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Actually, this is possible but won't be easy. You will have to make a special tool to compress the valve springs without removing the head. What you will need to do is:

1. Get a steel rod (we'll call it "rod A") about the same diameter as the camshaft journals. Cut it short enough so that it will fit exactly from end to end in 2 of the cam caps. You will tighten the cam caps down on this rod to hold it secure when compressing the springs. This rod is used as a fulcrum.

2. Weld another rod (rod B) perpindicular to rod A approximately 1" long (it will point away from the valve when using the tool). This is used as a lever to get leverage against the spring.

3. Weld another rod (rod C) perpendicular to rod A but on the opposite side of rod B. Rod C and rod B should form a straight line, but rod B should be angled upward so that it sticks up high enough so that it will clear the cyl head when using the tool. The length of this rod must be just short of hitting the valve retainer when rod A is bolted down in the cam caps.

4. At the end of rod C, you need to weld on an adaptor that will compress the spring without getting in the way of the valve itself. It could be in the shape of the fork or a doughnut or whatever, but it needs to be positioned so that when you lift up on the lever (rod B) with rod A secured in the cam caps, the adaptor compresses the spring.

Using this tool, you can remove/install stem seals, springs, and keepers relatively quickly with the head on. Sorry I don't have any pics.
 

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It's definitely possible, but I'm pretty sure you have to remove the cams...It sounds like you're looking for "quick and dirty" so here goes...I take no responsibility for this, it has the potential for bad things to happen...

For starters, this method would require you to take off the timing belt cover (or you must at least be willing to).

If you can get yourself the "tensioner tool" (you know, the 8x1.25 bolt that's about 6" long) you can compress the tensioner, and then remove the camshafts (mark them first) without having to reset the timing...IF you keep pressure on the belt the whole time the cams are out. I think RRE or Buschur or someone has a site about this. The problem with this method is that you have to move the crank to get the pistons where you want them (you could get away with just one move...do cylinders 1 and 4, then rotate the crank then do cylinders 2 and 3). That's why you have to take the timing cover off...because even if you manage to move the belt while you were moving the crank, you would likely not be able to get the motor where it was exactly when you took the cams out, so you'd have to make sure all the timing marks are lined up when you put the cams back on.

If you're a bold man, you could do two cylinders, put the cams back in, make the move (back out the tensioner tool first), reset the tensioner tool, and do the other two cylinders without having to take the timing cover off. It's a lot of work and the danger is if the belt slips, or you think it might have, you'll have to remove the timing cover anyways.

So, if that sounds worth doing, here's how the rest is done:

You start by rotating crank so the piston is all the way up for the cylinder you are working on. You can take the spark plugs out to verify this (but be sure the area around the spark plug holes is cleared out...don't want to get anything in there).

Then, compress the timing tensioner, remove the cams (remember to have a way to keep the belt from going slack), compress the spring, and remove the retainers. It's a pain to get the compressor in there for all of the springs, but it can be done. The piston will keep the valve from dissapearing into your motor. The seals just pull off at that point.

Replace the seals, put the spring back on (you may need to hold the valve up a little, it might slide in some), and repeat for all 4 vaves on that cylinder, and the "sister cylinder" (1 and 4, 2 and 3).

Move to the next cylinder pair (using whatever method you think is best) and start by rotating the piston to the top of the cylinder (if you forget this, you're on your own...at the least it would make for an interesting post topic).

It goes just like that. I've also heard of using compressed air to hold the valves against the head, but guess what happens if you have a leaky valve or accidentally push in the valve when you take the spring off.
 

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drcustom said:
I've also heard of using compressed air to hold the valves against the head
I've heard of that. Also using a coil of rope stuffed in the cylinder from the spark plug hole. Then compressed to hold up that valves.
 

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drcustom said:
It's a pain to get the compressor in there for all of the springs, but it can be done.
Wow, I couldn't get a regular compressor to fit in mine hence the above tool. What spring compressor do you use?
 

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Discussion Starter #7
drcustom said:
remove the camshafts (mark them first) without having to reset the timing...IF you keep pressure on the belt the whole time the cams are out.

Sounds like something i used to do to change heads on Chrysler 2.2 turbos (the original laser!); tie the belt tight to the cam gear, and just hook on a bungee cord to keep it tight, i may try to modify that. Jegs also has a fitting that screws into the spark plug well to hook up to air, its only 10 bucks.... a little apprehensive on that one though.
 

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Discussion Starter #8
Well, here is what i ended up doing. Of course it was neccesary to remove the camshafts, my timing belt ended up being pretty torn up anyway. I made a compression tool out of a piece of angle iron, two half inch bolts, a 18mm socket, and two half inch nuts: I cut the angle iron to fit in between camshaft journals (put them back on, with camshaft removed), i drilled holes to fit on the journals, so it could be bolted down., i then welded the half inch nuts at an angle that was perpendicular to the valves. I cut a six point 18mm socket down and across the 1 an 3 points for a compression tool., from this point it is simple to put the socket on the valve and compress it with the bolt. It worked great!! You just have to be careful on the end four valves where only one bolt holds down the tool.
 
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