I'm building my first motor and am at the point of checking the installed spring height.

Using my valve spring mic, I get a reading of 1.943" installed.

The directions on the Patriot dual golds says they need to be 1.800" installed. The thickest shim I found
on comp's website is .060" With those shims, the installed height is 1.870". Still .070" off from the required
height. My questions is this; is it ok to stack two sets of shims under my spring base or should i be looking for
a thicker base in order to use one shim?

For reference, it's an LS2 402 with PRC stage 3 LS6 heads.

thanks for the help

 

The shims I've found fit best for a factory spring pocket/guides are from CV products

they have a .520" ID / 1.220" OD shim in all thicknesses

yes you can stack shims, i'd rather use 1 if possible

 

Something doesn't sound right unless the heads have long valves in them. It almost sounds like you are measuring from the valve spring retainer to the aluminum on the head, are you using the spring seat when you measure? Photo?

 

Thanks for the tip, I'll check with CV products for some shims.

I thought it was a bad reading too, way too high. But i've measured several times and it keeps coming up the same. The measurement is from the retainer to the spring seat.

I'll pull a spring tonight and re-measure, hopefully will be able to snap a decent pic.

 

Sorry for the delay but I finally got the pics.

This time I decided to measure an intake valve on the same head. The numbers in my first post were off an exhaust valve.

The intake valve in this case read even higher than the exhaust valve. This time I got 1.995"

First pic is of the mic installed on the head, you can clearly see the spring seat between the mic and the head.



This second pic is just the mic showing the measurement. Am i reading it correctly?????

1.995"??????

 

Looks like 1.895" to me as you are right at the 1.900" line and 1.995" would be well beyond it.


However, you need to measure the external height of the micrometer, i.e, the valve spring retainer is sitting down in the micrometer and it should be even with the top to measure correctly. If you have a vernier simply measure the height of the micrometer open to some position and see if it is the same. I believe the fact that the retainer is sitting down in the tool is skewing your measurements, which may lead you to overshim and possibly hit coil bind when the valves open. Kind of hard to explain so if you don't understand I can shoot some photo's. I made some special washers for mine for the small beehive retainers so I could do a direct measurement.

 

I agree, just subtract the difference of where your retainer sits to the top of the tool. Or you could buy the right tool for your size springs. Looks like it's too big for your application, Goodson makes different sizes to match your seat size.

 

So, what you're saying is I can't read a mic and my initial measurement is probably 1.843" not 1.943". I'll check that same valve again.

I have a digital caliper, so I'll measure the spring mic tonight. Can't mess that up, I hope.

Would you mind taking a pic or two of the proper way my mic should be set up on the head?

Thanks for your help.


I'll see if I can get a good depth measurement with my caliper, to see how deep the retainer is sitting. Thanks

 

Here is a link to a set of Darts I have for sale on CF. I have a photo of the valve spring micrometer and if you look you will see the titanium retainer is actually sitting on a brass washer I made to bring the small beehive retainers up to the lip of the micrometer. So as stated above, your micrometer is likely measuring the overall length and you need to account for the depth of the recess that the retainer is sitting in.

Link


The best thing is you are taking the time to do this and ensure a correct setup, most don't bother. These small things can pay off later.

 

I'll have to check the link tonight, the photos are blocked here at work.

 

I have the same problem, that's why I provided the link

 

vettenuts & mebuildit....thanks so much for your help. After teaching me how to correctly read the mic and how to use it, I believe my installed numbers are much closer to what they should be then I originally thought.

The retainer sits 0.14" inside the mic. To double check, I set the mic at 1.80" and measured it with the caliper out to out. It measured exactly 1.80" on the caliper.

So subtracting 0.14" from 1.943" gives me 1.803" for the exhaust valve. (still have to dbl check this spring to make sure I read the mic correctly initially)

And the intake valve from the above pix is 1.754" installed. Much better then my initial attempt at checking these valves.

Time to pull every spring and go through all eight cylinders.

 

It looks like you have 1.895 minus the .150 step would be 1.745 installed height.

99% of the spring installed hight mics have a .150 step in them but yours might be .140 I'd just doubt it!

Also make sure you are using the same ID locator you are going to use or subtract it as well as most are .060 or so.

 

I always double check spring mic with a vernier caliper, double checks the setup that way.

 

Glad you figured it out. Better now than later. Good luck with the rest of the build.