Hemi valve failure - Moparts Forums

Register Log In Moparts Forums Unlawfl's Race & Engine Tech Hemi valve failure

Print Thread

Hemi valve failure #1578308 02/13/14 08:44 AM 02/13/14 08:44 AM
Joined: Jan 2005 Posts: 193 Australia T Teamx OP member
Teamx OP member T Joined: Jan 2005 Posts: 193 Australia	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 8037813-photo.JPG (166 downloads)

Re: Hemi valve failure [Re: Teamx] #1578309 02/13/14 08:48 AM 02/13/14 08:48 AM
Joined: Jan 2003 Posts: 1,894 N of Detroit DaveDudek top fuel
DaveDudek top fuel Joined: Jan 2003 Posts: 1,894 N of Detroit	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

Re: Hemi valve failure [Re: DaveDudek] #1578310 02/13/14 10:00 AM 02/13/14 10:00 AM
Joined: Mar 2006 Posts: 9,910 Eighty Four, PA B G Racing master
B G Racing master Joined: Mar 2006 Posts: 9,910 Eighty Four, PA	This type of failure occurs when the retainer is hitting the rocker or the locks are incorrect or lock location is high and possible even with the top of the stem and the rocker or the roller tip is hitting the lock.Anything that creats a movement between the lock and retainer will cause this type of failure.Also look for coil bind and retainer to guide clearences.Look for witness marks at the locks and retainer for movement and at the underside of the retainer and top of seal and guide.Don't rule out valve spring float either. [IMG]http://i430.photobucket.com/albums/qq21/ajcasini/max_zpsdppwd9km.jpg[/IMG]

Re: Hemi valve failure [Re: B G Racing] #1578311 02/13/14 05:07 PM 02/13/14 05:07 PM
Joined: Jan 2005 Posts: 193 Australia T Teamx OP member
Teamx OP member T Joined: Jan 2005 Posts: 193 Australia	Ok, Valve springs are 150 on the seat and 370 on the nose. No coil bind, no lock to guide contact,no roller to lock contact! Will check for rocker arm to retainer contact and cant be sure if valve float was an issue as it seemed to rev through to 6000 ok!

Re: Hemi valve failure [Re: Teamx] #1578312 02/13/14 05:10 PM 02/13/14 05:10 PM
Joined: Aug 2003 Posts: 11,179 Atco NJ DJVCuda I Live Here
DJVCuda I Live Here Joined: Aug 2003 Posts: 11,179 Atco NJ	Since you say you have no coil bind - What amount of travel do you have left after full lift to coil bind? I've seen springs with more then .100 have harmonic issues before.

Re: Hemi valve failure [Re: Teamx] #1578313 02/13/14 06:05 PM 02/13/14 06:05 PM
Joined: Mar 2006 Posts: 9,841 MI, usa dvw master
dvw master Joined: Mar 2006 Posts: 9,841 MI, usa	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

Re: Hemi valve failure [Re: dvw] #1578314 02/13/14 07:53 PM 02/13/14 07:53 PM
Joined: Mar 2006 Posts: 9,910 Eighty Four, PA B G Racing master
B G Racing master Joined: Mar 2006 Posts: 9,910 Eighty Four, PA	Are the locks correct for the retainers?10* locks for 10* retainers and correct for the groove and stem diameter??Is the lash cap depth correct? [IMG]http://i430.photobucket.com/albums/qq21/ajcasini/max_zpsdppwd9km.jpg[/IMG]

Re: Hemi valve failure [Re: Teamx] #1578315 02/13/14 10:34 PM 02/13/14 10:34 PM
Joined: Nov 2009 Posts: 3,410 Belpre,Ohio C CHAPPER master
CHAPPER master C Joined: Nov 2009 Posts: 3,410 Belpre,Ohio	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.

Re: Hemi valve failure [Re: CHAPPER] #1578316 02/14/14 06:11 AM 02/14/14 06:11 AM
Joined: Jan 2005 Posts: 193 Australia T Teamx OP member
Teamx OP member T Joined: Jan 2005 Posts: 193 Australia	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.

Moderated by Al_Alguire, Hotwheelsjr, moparts, not_a_charger, RangerDan440, tboomer

Hop To

Powered by UBB.threads™ PHP Forum Software 7.7.1