Changing Valve Springs

[daren_p]

I'm about to swap out my valve springs, which I haven't done before. I have a valve spring compressor that will work with the head on the car (don't want to take the head off) but was looking for any ideas on how to keep the valves in place? I'm thinking to rig something up that allows me to pressurize the cylinder through the sprarkplug hole. If anyone has made such a thing or has done it another way, let me know. If you have any other pointers on changing valve springs, that would be great.

 

[95blackGsTurbo]

I have done a few different ways. I have personally just taken a broken compression gauge and cut the hose and put a coupler on it to hook to my air compressor so it pressurizes the cylinder. That is the best way IMO. I have tried other ways but they don't work as good. They do make a tool to screw into your spark plug hole specifically for that reason but they are kinda spendy.

 

[daren_p]

^^^ Yes, thats what I was thinking either hacking a compression tester or even better if I can find one that the gauge just screws onto, that I can take off and screw in a coupler for the compressor.

 

[vintagemuscle]

the craftsman compression tester kit comes with a hose for pressurizing the cylinders. i think the kit is around $50.

 

[Maglin]

and it uses a coupler for the gauge. You might also want to make sure that piston is at TDC. That way just in case you drop a valve it won't fall into the cylinder. You can just use a magnet and pull it back up. And I can't see why you wouldn't buy the tool to pressurize the cylinder when you have the OHC valve compressor that costs like 250ish + dollors. I just pull the head and use my $8 compressor that I made. I have the other tool from miller and I actually prefer my tool. That and it never hurts to pull the head and inspect things.

 

[project_tsi]

You can also feed a long single strand of string into the plug hole and have it fill up the chamber. This way, the valve physically couldn't fall down as the string is there taking up the space. Old school guys do this all the time. Best part is, the string pulls right on out. I'd also do this one at a time w/ the appropriate cylinder at TDC so your not wasting miles of string.

 

[daren_p]

I picked up a compression tester, the gauge is a 1/8" npt thread so I got a couple adapters to connect it up to the compressor quick disconnect. As for the spring compressor, I didn't spend $250 on the one that works with the head on the car. I know a guy locally that machined one up that Im using. I heard about the string method as well, but I don't think I should have any issues with the valves dropping with using compressed air. Does anyone know how much pressure I should run? I was thinking it won't take all that much to hold the valves in place, maybe 20 or 30 psi? Maybe I should run abit more?

 

[95blackGsTurbo]

That's more than enough. Once the cylinder fills it shouldn't leak any out.

 

[Lunch_Box]

You can also feed a long single strand of string into the plug hole and have it fill up the chamber. This way, the valve physically couldn't fall down as the string is there taking up the space. Old school guys do this all the time. Best part is, the string pulls right on out. I'd also do this one at a time w/ the appropriate cylinder at TDC so your not wasting miles of string.

That's what I did. It worked great but for the ;ast cylinder the string some how got caught around a valve and was a bit of abitch to get out.

 

[Defiant]

You use soft nylon or polypropelene rope, about ¼" or bigger, so that it's less likely to get stuck behind a valve face.

 

[daren_p]

Well I've got everything taken apart and am going to be changing the springs tonight, I was wondering if I could get some input on what to pressurize the cylinders to? One other thing, I think I have it right but what way does that piece in the CAS go? I believe the longer side is on the bottom?

 

[donmagicjuan]

Well I've got everything taken apart and am going to be changing the springs tonight, I was wondering if I could get some input on what to pressurize the cylinders to? One other thing, I think I have it right but what way does that piece in the CAS go? I believe the longer side is on the bottom?

What's up, Daren? I remembered the positioning of my CAS by the gaps, not the metal, but same difference. With #1 at TDC, the larger gap faces the rear (intake side) of the engine.

 

[daren_p]

What's up, Daren? I remembered the positioning of my CAS by the gaps, not the metal, but same difference. With #1 at TDC, the larger gap faces the rear (intake side) of the engine.

Thanks Don, I'll double check when I get home. I think I put it back right but I had it losened off first, then I remembered there was a difference so I just wanted to be sure.

 

[nightspeed87]

what are some recommended performance valve springs and valves to put in the 4g63t ?
( valves with higher revving features, better air distrubition maybe )

 

[daren_p]

Well the compressed air method worked well. With the tool that I had you could do two valves at the same time so one thing to mention is to take a socket and put it on the retainer and give it a quick hit with a rachet, or hammer, etc. I found out that the keepers liked to stick in place unless they were given a tap first. This could be a problem for some people if they are doing 2 valves at once and you have the keeper removed from the first valve & if the keeper sticks on the second valve while compressing the spring, the valve will open. This will release all the air pressure in the cylinder and the first "lose" valve could drop through.

 

[ZenkaiRacerDsM]

Thread revival! I'm about to do this on my car with a euroexport spring compressor tool (this thing is awesome).

Do you remember the air pressure you used? I'm really nervous about the valves dropping since I've never used air pressure to hold them in place before. I have a compression test with a hose that looks like it was made for this. Already had a male QD on it and everything for the compressor hose.

 

[banishedmunk]

I use 100psi when I use the euroexport tool

 

[My1GLaser]

Just bring the piston to TDC on the cyl you are working on. The valves won't go anywhere...