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Re: Hemi valve failure
[Re: Teamx]
#1578309
02/13/14 08:48 AM
02/13/14 08:48 AM
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Joined: Jan 2003
Posts: 1,894 N of Detroit
DaveDudek
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,894
N of Detroit
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What kind of valve spring pressures are you using?
Dave Dudek 1st Factory Stock legal car in the 10`s!!! [/b] FAST & Factory Stock Rules: www.fastraces.org FAST 69 Hemi RR 9.98@139
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Re: Hemi valve failure
[Re: Teamx]
#1578313
02/13/14 06:05 PM
02/13/14 06:05 PM
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Joined: Mar 2006
Posts: 9,861 MI, usa
dvw
master
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master
Joined: Mar 2006
Posts: 9,861
MI, usa
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Quote:
Anyone like to put forward a theory as to why this valve failed?
Some backgronnd:
Hemi Mopar/Edelbrock heads. Comp Cams 925 springs,10 degree retainers, 10 degree locks and Hemi lash caps. Comp 230/238 hyd roller cam and Comp hyd roller lifters.
The failure happened after about 2 1/2 hrs dyno run time. After removing the valve covers we found a lash cap had come out and the roller wheel was running on the collet. At first we thought the lash caps had been bottoming out on the collet but after examaning other valves (which all have some degree of lock groove failure) we discovered that the lock groove was getting eaten away allowing the collet to ride up the valve stem and push up the lash cap. We were lucky to catch this before a valve dropped!
Any help would be apreciated!
Tim
Odd thing, Maybe related maybe not. This weekend when they talked to about Capps explosion to Rahn Tobler he said there was a problem with the machining of the valve locks. Your's looks to be starting to out the same way. Doug
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Re: Hemi valve failure
[Re: Teamx]
#1578315
02/13/14 10:34 PM
02/13/14 10:34 PM
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Joined: Nov 2009
Posts: 3,410 Belpre,Ohio
CHAPPER
master
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master
Joined: Nov 2009
Posts: 3,410
Belpre,Ohio
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I have had some trouble in the past with Comp Cams locs. My 'decision' was that some of the locs were missing the heat treat process. I had some that would wear the locating tange away and allow the valve stem to pass through. I saw it on about 3 motors in a year's time. Not ALL the locs did this, just a couple/three at each time. Also, both locs on the same valve did not fail, just one wore severely. Even this wearing of the tange did not wear the groove in the valve as your pic shows. All of these were caught at valve adjustment time, except one....my personal motor!! I found it after a valve pulled through at around 6300 RPM as I shifted in to high gear. These were all 10* locs/retainers from Comp. All square/single groove.
If you like drag racing, support your local track.
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Re: Hemi valve failure
[Re: CHAPPER]
#1578316
02/14/14 06:11 AM
02/14/14 06:11 AM
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Joined: Jan 2005
Posts: 193 Australia
Teamx
OP
member
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OP
member
Joined: Jan 2005
Posts: 193
Australia
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They were the 5/16 10 degree locks and 10 degree retainers also the short Hemi lash caps.
Travel left before coil bind was aprox .100 thou Going to go with some beadloc valves and slightly stronger springs!
Last edited by Teamx; 02/14/14 06:16 AM.
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