| cracked crossover retaining strap on head [message #86382] |
Fri, 28 May 2010 04:52  |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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Senior Member |
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I took off the left valve cover, It lookes remarkably clean but one of the crossover retaining straps is broken allowing the pushrods to be slightly askew.
Is this a commone failure or is it indicative of a more serious problem.?
Thanks
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: [GMCnet] cracked crossover retaining strap on head [message #86406 is a reply to message #86403] |
Fri, 28 May 2010 09:26  |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Dave,
If I understand -- you have a rocker pivot broken. This can happen easily if you loosen one of the two mounting bolts while one valve is in an open position. Otherwise I do not consider it as a common occurence. You may have a bent pushrod or two after this event. Keep all the parts carefully noted as to original location -- I use a piece of cardboard wiht punched holes and cylinder numbers to stay organized.
Dennis
Dennis Sexton
73 GMC
Germantown, TN
USA
-----Original Message-----
From: Rob Mueller <robmueller@iinet.net.au>
To: gmclist@temp.gmcnet.org
Sent: Fri, May 28, 2010 9:16 am
Subject: Re: [GMCnet] cracked crossover retaining strap on head
Dave,
Picture please!
Regards,
ob Mueller
ydney, Australia
US '75 Avion-The Blue Streak TZE365V100428
SA '75 Avion-Double Trouble TZE365V100426
----Original Message-----
rom: dave silva
I took off the left valve cover, It lookes remarkably clean but one of the
rossover retaining straps is broken allowing the pushrods to be slightly
skew.
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List Information and Subscription Options:
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: cracked crossover retaining strap on head [message #86414 is a reply to message #86382] |
Fri, 28 May 2010 10:47 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| hertfordnc wrote on Fri, 28 May 2010 05:52 |
I took off the left valve cover, It looks remarkably clean but one of the crossover retaining straps is broken allowing the pushrods to be slightly askew.
Is this a common failure or is it indicative of a more serious problem.?
Thanks
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Dave,
I can not tell you how common a failure this is, but it is not likely to be critical and not an indicator of another issue. Most likely the screw that clamps the rocker pivot was not effectively tensioned. The function of that strap is just to position the rocker arm pivot during assembly.
The only thing you should be careful to do is inspect the pushrod for wear as it appears to be contacting the cylinder head casting. If it has worn much at all, replace that while you have the heads off. The working face of the rocker arm may also be worn to a less than advantageous surface.
Good Picture - by the way....
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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