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Thread: Cant stop dropping valves
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01-23-2020 #1Registered User
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- Jan 2020
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Cant stop dropping valves
I have an LQ9 in my 02 silverado. My intitial problem resulted after the planetary gear in the transmission went out. seemed to have over revved and mushed the valve. Perhaps it didn't close in time, or it just went haywire at the higher rpm range.
I had Richard Godly rebuild it out of Moultrie, Ga as he had built it previously. However, 500 miles, and two days later it all but locked up on me.(dropped valve). I found another OEM head and sent it to Bill and Jeff Ford to have them put it on the flow bench to match the original build.
After the reassembly it went about 5,000 miles being babied. and I mean babied. for it to drop another valve...
Where Am I going wrong here? too much lift from the cam?
I ran this truck hard for 2 years with no problem until the transmission went out causing the first valve to drop. and now it seems like an uphill battle.
Considering going to Trickflow Specialty heads this time around...but can anyone shed any light on what else might be happening?
Any help is appreciated.
sincerely,
a man tired of pouring out money
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01-24-2020 #2Registered User
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- Jan 2020
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UPDATE: I have been talking with texas speed. and thinking my lift is 0.606. perhaps even most of the heads you purchase aftermarket are maxed at 0.550. maybe the valve spring seat wasn't milled out with enough clearance? could this explain why it took so long for it to drop another valve??
Does anyone have a recommendation on a set of heads that can support this kind of lift without going on the bench? Or am I stuck to have even the Trickflow Specialty heads sent off to be milled out for clearance??
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01-28-2020 #3
.606" lift is honestly not much. The lift definitely isnt your issue. Now if you are running into coil bind, thats an issue. The main reason I have seen valves drop is cause the clearance to the guide is too small.
1970 VW Bug - Just your average mid engine Bug
Track toy - 06 Evo - E85 and lots of boost
Newest track toy - 2021 Supra
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08-05-2020 #4