5.3 Heads on an 99 T/A
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5.3 Heads on an 99 T/A I can't believe I haven't already posted here....Got a problem and I need some specs if anyone can help. Bent a couple of valves on the stock head <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> and replaced em' with a set of 2000 5.3L heads. While they are milled about .05 that shouldn't make a difference, but when I tighten the valves down I am getting 0 compression in #6. I can back off the valves and it puts out about 210 psi in each cylinder. However I have to back off all of the rockers.
Now, my question. Are the Valve boss' shorter on the 5.3L head? Valves?
I bought the factory replacement gasket kit with the head bolts, so everything should be fine...but...
I spoke to the shop that did the heads, and he suggested a .040 shim. I would have to shim ALL of the valves though. Those who are familiar with the valve train setup on an LS1 will understand why. Am I missing something? Should I use a shorter pushrod? I am confused.
Thanks in advance!
Now, my question. Are the Valve boss' shorter on the 5.3L head? Valves?
I bought the factory replacement gasket kit with the head bolts, so everything should be fine...but...
I spoke to the shop that did the heads, and he suggested a .040 shim. I would have to shim ALL of the valves though. Those who are familiar with the valve train setup on an LS1 will understand why. Am I missing something? Should I use a shorter pushrod? I am confused.
Thanks in advance!
Re: 5.3 Heads on an 99 T/A The psi sounds about right. I am at 215psi per cylinder.. If the heads are milled that much I would think the stock pushrods would not work, but do not quote me. I am no mechanic. I am sure some of the other guys will chime in.. .050 is quite a bit. I am running I think 7.350's. My heads are milled .060 according to Flow Technics.. I found this out after the fact..
<small>[ July 10, 2002, 07:48 PM: Message edited by: VINCE ]</small>
<small>[ July 10, 2002, 07:48 PM: Message edited by: VINCE ]</small>
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Re: 5.3 Heads on an 99 T/A oops...did I say .050...what I meant was .005! And I really wouldn't think that would matter unless the valves are a little longer or the pushrods on a 5.3 are shorter, or the rockers are 1:6.1's....like I said I'm confused.
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Re: 5.3 Heads on an 99 T/A ****....nevermind....just read your post and started thinking. Cylinder pressure just doesn't make sense at .005. I'm running just about where you are and if you do the math that ='s way more than .005. My heads must have been milled more than that before I bought them. I miked the pushrods and they are just under 7.5 inches which would be about .040. I have the valve train shims I am going to use. I believe this will alleviate the problem. I will post and let everyone know tomorrow!
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Re: 5.3 Heads on an 99 T/A ok..I know its not tomorrow yet, but here it goes...
1. Its only one cylinder giving me problems. All the others are pretty much there without the shims.
2. I know the valves are right, as well as no problems with the valve seats. Valves are all the same height, and they wouldn't be if there were any probs.
3. Heads aren't warped. Besides there aluminum and they would correct to a degree anyway....its still just one cylinder were talking about.
4. The only thing I can't see or check is the lifter. The plunger could be f#$@ed up and/or stuck in the hole. I bent another pushrod....bad! I haven't revved it above about 2500 sitting in the driveway, so I'm not sure how it suddenly became bent. This may be what I need to fix. I was hoping otherwise at a cool $250 bucks a set for head gaskets...not to mention the 2 pints of blood and enough skin loss to actually weigh....
I'm still not 100% sure this is what it is.
1. Its only one cylinder giving me problems. All the others are pretty much there without the shims.
2. I know the valves are right, as well as no problems with the valve seats. Valves are all the same height, and they wouldn't be if there were any probs.
3. Heads aren't warped. Besides there aluminum and they would correct to a degree anyway....its still just one cylinder were talking about.
4. The only thing I can't see or check is the lifter. The plunger could be f#$@ed up and/or stuck in the hole. I bent another pushrod....bad! I haven't revved it above about 2500 sitting in the driveway, so I'm not sure how it suddenly became bent. This may be what I need to fix. I was hoping otherwise at a cool $250 bucks a set for head gaskets...not to mention the 2 pints of blood and enough skin loss to actually weigh....
I'm still not 100% sure this is what it is.
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