LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

valve spring change

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Old 01-23-2003, 02:19 PM
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valve spring change

I was told not too long ago that you can't change your valve springs without taking off the heads to hold the valves in place. Would someone with some experience let me know?

I want to get some dual-coil springs and 1.6 rockers for my lt1, but if I have to break the car down to the heads, I might as well save up for a cam, rev-kit, head-work etc........ that's alot of work for only 10-25 horsepower!
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Old 01-23-2003, 03:01 PM
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You don't have to, but once you get to where You're ready to do the valvesprings, you might as well take off the heads, it's only a few bolts... I didn't think of it when i was doing it.. I have an installation guide in my sig. click on Install page.
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Old 01-23-2003, 03:12 PM
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When I did my Hotcam, I used a compression check tool, and just hooked it up to an air compressor to charge the cyclinder and hold the valves up. If I do it again, I'll take the heads off. It was a major hassle doing it the way I did. Take plug out, fight to get tool threaded right, charge cyclinder, fight to get spring compressor under cowl, fight to get pliers on valve seal, put back together, fight spring compressor again, fight to re-install plug. Add that I'm 6'4", my hood hits right about where my knees are. Thats alot of distance to stoop down. It was hard pratically laying across the motor to get the back springs. My knee were hurting for a week after. Just take the dang heads off.
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Old 01-23-2003, 03:20 PM
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swingrr, i know what you mean about that air tool thingie... we tried using that but couldn't get that tool in 6 of the 8 cylinders, so we just did the crank rotation method. Jacking the car up, or putting it on ramps helps with the back/bending problem.
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Old 01-23-2003, 03:26 PM
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Of course, you should go with the appropriate springs if you go with RRs or a cam. The strength of the spring should be compatible with the requirements of the proposed lift as recommended in the Cam Card.

There are single springs that will work with small cams and 1.6RRs, in which case you needn't remove the heads.

If you go with large springs, double springs, etc. (which require larger than stock spring seats) you will need to remove the heads to have the seats machined to accommodate the larger dia. springs.

If, however, you don't require machining, you can install the springs with the heads on.

There are at least 3 ways to keep the valves from dropping during the process. You mentioned the introduction of compressed air as one.

I've also heard of stuffing cord into the cylinder through the plug hole.

Have also, heard of several people just bringing the pistion to TDC and finding that the valve only drops about a quarter of an inch and doesn't disappear into the block.

Don't know what my mech. did on my springs, but somehow doubt that he compressed the the cylinder. JMHO.
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Old 01-23-2003, 03:31 PM
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jkayner, it was on ramps, still painfull. What is the crank rotation method?
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Old 01-23-2003, 03:35 PM
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Just do it by using the top dead center method. the valve will only drop about 1/4-1/2" and it will rest on the piston. And if you think removing the heads is only a few bolts after you've got the rockers off, you're crazy. Try unbolting the manifolds, removing the intake, draining the block plugs and coolant, and then maybe a few more bolts. No way, I'd take off the heads just to install some RR's and valve springs. The only way I'd take off the head is if you're trying to remove some dual coil valve springs.
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Old 01-23-2003, 03:42 PM
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:loll True that. I thought he was replacing the cam and would have the intake and all the stuff you said already off.
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Old 01-23-2003, 05:22 PM
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Originally posted by SWINGRRR
jkayner, it was on ramps, still painfull. What is the crank rotation method?
I think he mentioned it above, but the process is in the install guide if stil interested.
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Old 01-23-2003, 05:34 PM
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Use this bad boy to change springs...makes it a lot easier:
http://moroso.com/catalog/categorydi...?catcode=27035

You can disassemble the tool to get at the back springs.
I used the TDC method to bring the piston up to hold the valve while I changed the springs. Much easier this way and using this tool(kind of expensive). I tried one of those cheapy 19.99 spring compressors which sucked.
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Old 01-23-2003, 06:40 PM
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Originally posted by bad95z28
Just do it by using the top dead center method. the valve will only drop about 1/4-1/2" and it will rest on the piston. And if you think removing the heads is only a few bolts after you've got the rockers off, you're crazy. Try unbolting the manifolds, removing the intake, draining the block plugs and coolant, and then maybe a few more bolts. No way, I'd take off the heads just to install some RR's and valve springs. The only way I'd take off the head is if you're trying to remove some dual coil valve springs.
I agree. Additionally you'll blow about $60 worth of gaskets upon reinstallation of the heads and intake. Using the compressed air method of holding the valve up is an option...but a sorry one for an f-body with limited space in which to work, as one guy that posted above found out.

The TDC method is by far the easiest and quickest method for a 4th gen f-body.

Also, only an masochist would want to change springs with one of those wimpy hand twist spring compressors. THey are slow, difficult to operate, and don't work well with dual springs. I know I own two of them before I bought a Moroso stud mount compressor. The Moroso cost about $60 at Summit and they can reach all the springs!!!! Yes, even the ones on the back with some careful installation of the tool. Last fall I installed a set of Crane dual springs on my car. The Moroso was worth it's weight in gold. I'll never use the other two compressors ( Lysle and K-D) again.
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Old 01-23-2003, 07:04 PM
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Thanks alot! I thought about the TDC idea, but my friend
(crust-ang owner) insisted that I'd HAVE to take off the heads.

I want the 1.6 roller rockers, but I'd like to change the springs while I'm at it...... but I know I can't overdo it. Would the LT4 springs be an appropriate upgrade? Where can I get them?
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Old 01-23-2003, 07:59 PM
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I just did the swap last night. I changed over to LT-4 spring and 1.6 rockers. I also used the compression tester hose to inject air into the cylinder. With the Lt-4 springs the twist spring compressor was't so bad. Mine was a bluepoint. I'm sure its just like the others I just took the twist handle off and used a ratchet. Luckily I had my headers off so reaching the plug holes was easy. It was also easier once I figured out a few shortcuts.
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