Valve spring shim question?
05-21-2009, 09:41 AM
#1
Thread Starter
Join Date: Apr 2009
Location: IL
Posts: 11
Valve spring shim question?
Has anyone ever shimmed there valve springs on 4.6 PI heads. I can't find a shim that will fit the valve guide. Can the shim be ground down on the outside without damaging is strength? I need to get piston to valve clearence out of the way!
Last edited by alloutspeed; 05-21-2009 at 10:06 AM.
05-21-2009, 11:35 AM
#5
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Join Date: Apr 2009
Location: IL
Posts: 11
Just spoke with my machine shop, he said the shim goes under the seal on the head with the shim curve up as to not indent the head, between the seal and spring seat. You won't be able to get a correct height reading otherwise.
05-22-2009, 07:41 AM
#6
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Join Date: Jan 2009
Location: Florida
Posts: 570
He is wrong, even the TFS heads are shipping with the shims between the seal and spring. There is a potential for the seal to not seal to the guide properly with the shim under the seal. The seal also seals the top of the guide otherwise oil will get sucked in from under the seal right down the guide.
05-22-2009, 02:49 PM
#7
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Join Date: Dec 2007
Location: Coral Springs, Florida ~ 33076
Posts: 608
Personally, I'm not a big fan of shimming a spring. For what you're spending for all this shimming, I can't imagine it's THAT much more for the right spring.
The issue with shimming is you're effectively decreasing the amount of travel the spring has. It's in a constant state of partial compression, so they tend to "bottom" out more quickly.
I can't imagine that's going to contribute to longer spring life, which is a whole different issue altogether.
Just my .02, though. IMMV.
The issue with shimming is you're effectively decreasing the amount of travel the spring has. It's in a constant state of partial compression, so they tend to "bottom" out more quickly.
I can't imagine that's going to contribute to longer spring life, which is a whole different issue altogether.
Just my .02, though. IMMV.
05-28-2009, 09:39 AM
#8
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Join Date: Apr 2009
Location: IL
Posts: 11
So I took my micrometer and a piece of wire hanger and measured 1.57" since that is what the beehive spring needs to be set at. Made a mark on the wire. Installed each valve spring without a shim and all of them came out right on the mark between the retainer and top of the spring. So shimming a 4.6 doesn't really need to be done. Thanks for all your input!
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