AS 5.3 Stg 2's and HS rockers inside please....
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Preload was checked and rechecked. I think its the springs that came on the AS heads but apparently Jay isnt calling/emailing people back so a specific answer is tough to get. Also - remember hearing some complaints regarding the HS rockers but search button isnt helping me out much.
No one else is running the AS S2 heads and HS rockers combo?
No one else is running the AS S2 heads and HS rockers combo?
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this was the original thread I started.....
https://ls1tech.com/forums/pcm-diagnostics-tuning/207047-why-did-i-make-no-power.html
https://ls1tech.com/forums/pcm-diagnostics-tuning/207047-why-did-i-make-no-power.html
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OK after reading your first post on this I would like some additional info.
What Springs?
What lifters?
What length PR?
I had the same issue with mine. Jay set me up with AS 5.3 heads, 977 springs, 7.35 PR, Comp R lifters, and I had stock rockers at the time. Did the tune after the install and made 435 RWHP and 408 TQ but the curve dropped like a rock at 6100. It turned out to be preload on the Comp R lifters. I changed to HS rockers and a .030 SVO shim. Redyno showed 443 RWHP @6500 and the curve was flat as a board to 7K where we ended the test.
HTH
What Springs?
What lifters?
What length PR?
I had the same issue with mine. Jay set me up with AS 5.3 heads, 977 springs, 7.35 PR, Comp R lifters, and I had stock rockers at the time. Did the tune after the install and made 435 RWHP and 408 TQ but the curve dropped like a rock at 6100. It turned out to be preload on the Comp R lifters. I changed to HS rockers and a .030 SVO shim. Redyno showed 443 RWHP @6500 and the curve was flat as a board to 7K where we ended the test.
HTH
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Originally Posted by Steve Burger
OK after reading your first post on this I would like some additional info.
What Springs?
What lifters?
What length PR?
I had the same issue with mine. Jay set me up with AS 5.3 heads, 977 springs, 7.35 PR, Comp R lifters, and I had stock rockers at the time. Did the tune after the install and made 435 RWHP and 408 TQ but the curve dropped like a rock at 6100. It turned out to be preload on the Comp R lifters. I changed to HS rockers and a .030 SVO shim. Redyno showed 443 RWHP @6500 and the curve was flat as a board to 7K where we ended the test.
HTH
What Springs?
What lifters?
What length PR?
I had the same issue with mine. Jay set me up with AS 5.3 heads, 977 springs, 7.35 PR, Comp R lifters, and I had stock rockers at the time. Did the tune after the install and made 435 RWHP and 408 TQ but the curve dropped like a rock at 6100. It turned out to be preload on the Comp R lifters. I changed to HS rockers and a .030 SVO shim. Redyno showed 443 RWHP @6500 and the curve was flat as a board to 7K where we ended the test.
HTH
He has stock length PR's - (7.4) - chromolly hardened.
I believe the lifters are OEM replacements not the Comp R's.
Heads milled to clean the deck (nothing significant).
So nothing should have changed the geometry. No shims were used.
I think he is gonna look at a few things this weekend specific to the rockers and preload. Based on where he is power wise (370-380) against where he should be (415+) - if its the rocker/preload issue - solving it should net him a big gain with the snap of the fingers (should preload/geometry be off) that he should be able to tell as soon as he hits the gas.
Figure its worth the hour or so it will take to figure out.
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Originally Posted by Steve Burger
OK, Jay was using the 977 springs on the 5.3 heads. These required Comp R lifters due to the spring pressure. Just something to check.
Is using Comp R's lifters on his 5.3's standard/required practice? I've never heard that and I know Andy was never informed of that.
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Originally Posted by Steve Burger
Depends on the springs used.
Unfortunately he has found Jay to be completely uncooperative (these are my words and not his). He's made NUMEROUS phone calls and has sent NUMEROUS emails with specific questions in the attempt of solving this lost power issue and he hasnt gotten anything back from Jay. At this point I think he is trying to move forward on his own by using other resources on the board. He has asked for spring info and hasnt gotten it.
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Sorry to hear that. I got my heads about this time last year. Jay was really big on the 977 springs for most 5.3 heads. I have what was a large cam at the time and that was the reason for the 977 springs.
Did you get the lifters from Jay? When did you get the heads? Are they double springs? What size cam? This may help to figure out what is in there.
Did you get the lifters from Jay? When did you get the heads? Are they double springs? What size cam? This may help to figure out what is in there.
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Originally Posted by Steve Burger
Sorry to hear that. I got my heads about this time last year. Jay was really big on the 977 springs for most 5.3 heads. I have what was a large cam at the time and that was the reason for the 977 springs.
Did you get the lifters from Jay? When did you get the heads? Are they double springs? What size cam? This may help to figure out what is in there.
Did you get the lifters from Jay? When did you get the heads? Are they double springs? What size cam? This may help to figure out what is in there.
He has another new set of Crane duals I believe that he bought but never installed. They can be used with the stock lifters so I can think we are gonna swap out the spings (eliminate the possibility of the 977/Comp R lifter issue) and then reinstall the rockers and double check preload, etc.
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Pushrods length should remain stock on that package. Mine stayed 7.4 per Alan himself with that cam and head specs. Andy has basically the same setup (same cam, same deck on the heads). I too think its a preload issue but definately gonna yank the 977's off and put on the Crane Duals which should be OK with the OEM replaceent lifters.
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When I got my 5.3's from Jay mid year, the choices were comp 977's for the big cams (G5X2/3 at the time) or 978's for less aggressive lobes. Comp R's reccomended (anfd shim/preload check) for the 977's.
I have 977's, heads milled .030 (supposedly) and G5X3 with 7.35" pushrods. I had to shim a small amount (.020) to get preload in the .010 range cold.
Also had to slightly clearance the rockers for the spring retainers - not quite touching but way too close for my comfort level.
I have 977's, heads milled .030 (supposedly) and G5X3 with 7.35" pushrods. I had to shim a small amount (.020) to get preload in the .010 range cold.
Also had to slightly clearance the rockers for the spring retainers - not quite touching but way too close for my comfort level.