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Valve Spring Height Micrometer

Posted By: cuda_tim

Valve Spring Height Micrometer - 06/23/08 06:49 PM

Anybody ever use one to set the spring height? They seem easy to use. Simply (??) remove the spring and install the micrometer in its place.

So here is my question.

Then what?

I'm guessing that the reading you get must be subtracted from the spring height you are trying to achieve. This difference is the thickness of the shim you need to place under the bottom retainer.

Correct?

Thanks,
Tim...
Posted By: JohnRR

Re: Valve Spring Height Micrometer - 06/23/08 06:54 PM

yep or you get a taller height retainer if you don't have enough height .
Posted By: moper

Re: Valve Spring Height Micrometer - 06/23/08 08:53 PM

Shims or cups go under the spring. there is no lower retainer...
Posted By: JohnRR

Re: Valve Spring Height Micrometer - 06/23/08 08:58 PM

Quote:

Shims or cups go under the spring. there is no lower retainer...



who said anything about a lower retainer ? they make valve spring retianer that go on top of the valve spring to ADD installed height because you can't move the notch in the valve higher

Posted By: Challenger 1

Re: Valve Spring Height Micrometer - 06/23/08 09:41 PM

Quote:

Quote:

Shims or cups go under the spring. there is no lower retainer...



who said anything about a lower retainer ? they make valve spring retianer that go on top of the valve spring to ADD installed height because you can't move the notch in the valve higher






Cuda-Tim did.

A spring height mic will tell you the springs installed height on each valve. If it's too much then you would put the shim under the spring or spring cup.
Posted By: 451Mopar

Re: Valve Spring Height Micrometer - 06/23/08 11:25 PM

yep, pretty simple.

Attached picture 4507208-IMG_1272.jpg
Posted By: cuda_tim

Re: Valve Spring Height Micrometer - 06/25/08 04:39 PM

Quote:


Cuda-Tim did.

A spring height mic will tell you the springs installed height on each valve. If it's too much then you would put the shim under the spring or spring cup.



Yes, I mentioned a lower retainer...

My mistake...

But here is a another question. So I just put a shim UNDER the spring, if I need less height? Won't that cause "undue wear" to the shim?
Posted By: Challenger 1

Re: Valve Spring Height Micrometer - 06/25/08 05:02 PM

Quote:

Quote:


Cuda-Tim did.

A spring height mic will tell you the springs installed height on each valve. If it's too much then you would put the shim under the spring or spring cup.



Yes, I mentioned a lower retainer...

My mistake...

But here is a another question. So I just put a shim UNDER the spring, if I need less height? Won't that cause "undue wear" to the shim?



Really the reason your checking height is so you know how much spring pressure you have.( If you have a spring tester) Even if you don't, at least your know the height and you can take the springs somewhere that does have a spring tester. Hope this helps. If you have enough spring pressure, there's no reason to shim. If not then use some shims but you have to make sure your not getting into coil bind, and by knowing the installed height you know how much room you have till spring bind. very important.
Posted By: JohnRR

Re: Valve Spring Height Micrometer - 06/25/08 05:04 PM

Quote:

Quote:


Cuda-Tim did.

A spring height mic will tell you the springs installed height on each valve. If it's too much then you would put the shim under the spring or spring cup.



Yes, I mentioned a lower retainer...

My mistake...

But here is a another question. So I just put a shim UNDER the spring, if I need less height? Won't that cause "undue wear" to the shim?



i just assumed you called it the wrong item , i thought you meant a spring cup which is used to locate a spring on a head thats not machined to keep the spring from moving around or keep the spring from eating up an alum head .
Posted By: Challenger 1

Re: Valve Spring Height Micrometer - 06/25/08 05:14 PM

Quote:





But here is a another question. So I just put a shim UNDER the spring, if I need less height? Won't that cause "undue wear" to the shim?



No, especially if it's steel.The only kind I will use.
Posted By: cuda_tim

Re: Valve Spring Height Micrometer - 06/25/08 07:01 PM

Quote:

Quote:

Quote:


Cuda-Tim did.

A spring height mic will tell you the springs installed height on each valve. If it's too much then you would put the shim under the spring or spring cup.



Yes, I mentioned a lower retainer...

My mistake...

But here is a another question. So I just put a shim UNDER the spring, if I need less height? Won't that cause "undue wear" to the shim?



I just assumed you called it the wrong item, i thought you meant a spring cup which is used to locate a spring on a head thats not machined to keep the spring from moving around or keep the spring from eating up an alum head .



Well, my main reason for wanting to check the spring height is because I don't believe that it was set properly when I had the valve job done.

When I picked up the heads from the shop, I asked whether any of the springs needed to be shimmed. And I got a blank "look", and a "No, they were fine" response. I was in a hurry at the time, and I figured I'd check it out later.

Well, later has come and gone and I think I have valve "float".
Posted By: Challenger 1

Re: Valve Spring Height Micrometer - 06/25/08 07:05 PM

Well get a spring tester that you can use on the motor. What kind of motor? I'll post a picture of a spring tester if you tell me the motor and cam. Who's springs do have, part#?
Posted By: cuda_tim

Re: Valve Spring Height Micrometer - 06/25/08 07:17 PM

Quote:

Well get a spring tester that you can use on the motor. What kind of motor? I'll post a picture of a spring tester if you tell me the motor and cam. Who's springs do have, part#?



Well, I have a 1969 340 with a Lunati Voodoo 60402 Cam, with the MP P4120249 valve springs already installed on (pretty much stock) 'X' heads. Just new valves and seats.

But I also have a new set of 73949's (in a kit) from Lunati on the shelf, that I've been considering going with.

I figured that if I took off the P4120249's and the height was way off, I'd probably swap in the new ones anywho...

Got any advice on what height I should be aiming at? I'm kinda thinking 1.65 with the new springs.

Tim...
Posted By: RobX4406

Re: Valve Spring Height Micrometer - 06/25/08 07:49 PM

MP springs, nuf said.

They don't have the greatest rep for quality or maintaining spring rate.

You're right at the upper limits of those springs. Aggressive ramp designs makes it even tougher.

How hard were you turning it when valve float occurred?
Posted By: Challenger 1

Re: Valve Spring Height Micrometer - 06/25/08 08:29 PM

Quote:

MP springs, nuf said.

They don't have the greatest rep for quality or maintaining spring rate.

You're right at the upper limits of those springs. Aggressive ramp designs makes it even tougher.

How hard were you turning it when valve float occurred?






How hard was it turning?
Posted By: cuda_tim

Re: Valve Spring Height Micrometer - 06/26/08 06:55 PM

Quote:

MP springs, nuf said.

They don't have the greatest rep for quality or maintaining spring rate.

You're right at the upper limits of those springs. Aggressive ramp designs makes it even tougher.

How hard were you turning it when valve float occurred?



Well, the issue is that I can't get it to Rev more than 4800, since day one. Sometimes better, but most of the time worse.

Again, I really think that the problem is that the springs were never installed correctly. That is, "incorrect spring height".

I could be wrong, but until I check it myself, that is my theory.

Tim...
Posted By: RobX4406

Re: Valve Spring Height Micrometer - 06/26/08 07:47 PM

Quote:

Quote:

MP springs, nuf said.

They don't have the greatest rep for quality or maintaining spring rate.

You're right at the upper limits of those springs. Aggressive ramp designs makes it even tougher.

How hard were you turning it when valve float occurred?



Well, the issue is that I can't get it to Rev more than 4800, since day one. Sometimes better, but most of the time worse.

Again, I really think that the problem is that the springs were never installed correctly. That is, "incorrect spring height".

I could be wrong, but until I check it myself, that is my theory.

Tim...



MP springs pretty much suck IMO. Whether they are installed correctly or not. Having them incorrectly installed sure doesn't help. That's a pretty aggressive ramp on those cams.

If they aren't installed to spec, have too much installed height, you're losing seat and pressure along the lift range. That cam should have something in the 130-140 on the seat and probably 330-350 over the nose. If you have stock style rockers, they tend to have issues at rates much over 300.

Get a couple of them off and test them on a Rimac. Find out the height they get 130# and coil bind. Do some math to figure out whether coil bind is an issue and spring rate at max lift.

Good luck. I bet they are all over the map as far as installed height based in the assemblers answer. Only takes one to cause an issue. Get them where they should be and let it fly.
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