I'm Installing LT4 Valve Springs. Checked my heights and I get 1.98" for intake and 2.08 for exhaust.

Do they make 0.20 and 0.30 shims...Or do I need to get shorter valves? ...to achieve the 1.78" installed height.

 

If I remember right, .10, .20, .30 are the common sizes. Comp cams makes a complete shim kit for pretty cheap, you can get it thru summet or jegs or the like.

 

.015, .030, and .060 are the shim thicknesses.

 

http://www.gmpartsdirect.com/perform...CATID=734.html

I haven't measured thicknesses, but I have these. Machine shop I WAS using told me these are only for aluminum heads.
True?

That's what I thought. My machine shop cut these seats too deep?
Marvelous, just marvelous.
What's the best solution here???

 

Whoah, whoah, whoah. You have measured your valve spring installed height at 1.98 and 2.08???

That's a LONG damned way from stock (~1.75"). Are you using longer than stock valves?? What are you running for retainers and locks?

You are .200" and .300" from your desired 1.78" installed height. If you've got stock length valves your machinist would almost certainly have struck water before he got the seats sunk OVER A QUARTER INCH to achieve those heights.

Typical valve spring shims are like .030-.060 thickness, which is going to take a HUGE stack to shave off .200-.300". Most aftermarket valves are either stock length or +.100".

Something's not adding up here.

 

i'd guess a misplaced zero or something like that. i never read it that close but .2 is way off, like said above.

 

So possibly measuring wrong...ok

I put my stock size (I'll verify part number) manley valve in. I'm using LT4 springs, retainers, and keepers that come in the kit. Have those shims, too.
I'm using a valve sring mic...the 2" circular thing that basically replaces the valve spring. I put the retainer and keepers on. The measurement starts at 1.6"...and I open it up till its snug and the valve is seated. I get the measurements above.

Machine shop cut for these LT4 springs.

I'd take a picture and show...but my computer at home has crashed.

The retainer fits inside the top portion of the mic...should it sit across the top? That would make a big difference.

I'll play with it some tonight with a 6" dial gauge.

Thanks

 

way faster and easier to use a snap gauge and a dial caliper to check the height with

 

I believe in those valve spring height checkers
they are designed for multi sized retainers.
The larger retainers 1.46" and 1.50"+ sit outside on top of the height mic, and read directly. The smaller stock size retainers sit down in the recessed part of the top of the height mic.
Because of this you have to Subtract the thickness of the recess in the top of the height mic to the spec you get from measuring to achieve the final height.

 

.....

 

I measured the recess @ 0.15" with a digital dial caliper that has dead batteries. Close enough I think.

1.98-.15 = 1.83" intake installed height.
2.08-.15= 1.93" exhaust installed height

An 0.03 shim should work fine then for intakes (stock cam).
Comp Cams makes a 0.15" shim...maybe it will work for exhaust.

The LT4 shims I have will not fit over my guide boss by the way, so can't use those.

I plan to call Comp Cams and see what they can offer.

 

k line sells shims in box of 100 for around 20 dollars, cheapest i've seen. thicknesses is in .015, .030, and .060.
800-241-0936

 

Thanks ede,

What about the weird 1.32" LT4 valve spring seat diameter? How does that play into it, and buying bulk like that?

I don't forsee going LT4 springs again anytime soon...

Edit: I could use (2) 0.060 shims on the exhaust and have 1.81" installed height. What if the shims' top come up over the "lip" of the valve spring seat? Wouldn't want my spring sliding around...

 

if you go to jegs or comp for a skin pack of shims 16 will cost you 20 dollars