This is how the motor looked when I pulled the heads & Intake off.
bent pushrod
- Thread starter SpeedAddict02
- Start date
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middleagecrisis
Veteran Member
- Oct 22, 2007
- 967
Looks like you've picked up a clean little motor! Was the #7 intake rocker arm nut loose before you disassembled it?
No it wasn't. They were all tight.. I used my cordless impact to take off the rockers and none zipped right off.. Too possibly.. Idk. Hopefully I'll figure it out lol
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body by fisher
Member
was the transmission a manual? downshifting wrong also causes theese problems
I think they guy told me it had a th350.. It was in a 74 el camino..
GearHeadMike
New Member
My First Response
Items to check/verify include - all are influenced by mods, if any, that have been done. Like CAM, SPRINGS, ROCKER ARMS, ETC.
1. Check for valve spring coil bind.
2. Check for proper length of push rod.
3. Check proper clearance of 'slot' on bottom of pushrod. From fully closed to fully open the slot must be long enough not to contact the rocker stud.
4. Check possible interference with block or head near pushrod.
5. Is the pushrod rated as the proper strength for the CAM you are using?
6. Were valves replace/changed? If so, valve stem length needs to be verified. It's been my experience over the years that this results from a CAM change to one with a significant increase in LIFT and the stock pushrod cannot handle the additional stress. Hope this helps. Mike
Items to check/verify include - all are influenced by mods, if any, that have been done. Like CAM, SPRINGS, ROCKER ARMS, ETC.
1. Check for valve spring coil bind.
2. Check for proper length of push rod.
3. Check proper clearance of 'slot' on bottom of pushrod. From fully closed to fully open the slot must be long enough not to contact the rocker stud.
4. Check possible interference with block or head near pushrod.
5. Is the pushrod rated as the proper strength for the CAM you are using?
6. Were valves replace/changed? If so, valve stem length needs to be verified. It's been my experience over the years that this results from a CAM change to one with a significant increase in LIFT and the stock pushrod cannot handle the additional stress. Hope this helps. Mike
Rocker slot too short or coil bind of the valve spring are the two things that will bend a pushrod.
And the retainer hitting the guide is #3.
And the retainer hitting the guide is #3.
GearHeadMike
New Member
So will a VALVE SPRING rated too high for the pushrod - that's why the pushrods are offered in 'thicker than stock' diameters. In this case coil bind, rocker bind or retainers coming in contact with the valve guide are not applicable. Seen plenty of racers suffer this calamity after upgrading springs to match a fairly hot cam and attempting to get by on insufficient stock pushrods.
Damon
Veteran Member
It can, but not usually at "normal" RPMs. Maybe the valves just got floated or something. I'd just put in one stick to replace the bent oner and fire it up if you can't find any obvious reason for it.
Should be back to working on the motor tomorrow.. When I pull the current cam, if it is stock, or damaged, gonna toss it..
I want to replace it with something mild, just a tad better than stock, and budget friendly..
Assuming it's stock bore 400, should I go with the summit K-1102 or 1103?
Again, it's got factory 350 heads, casting #920.. Not touching them with the exception of replacing the valve springs & seals and shimming the springs properly if needed.. Using my "Z28" springs.. Stock rockers, as long as they look OK.. New Comp high energy pushrods.. Stock converter.. 3.42 rear gear & 200-4r trans.. Exhaust is Shorty headers, 2 into 1 Y-pipe (if I can manage to retain it), back to duals after the trans.. performer intake, Stock QJet.
I want to replace it with something mild, just a tad better than stock, and budget friendly..
Assuming it's stock bore 400, should I go with the summit K-1102 or 1103?
Again, it's got factory 350 heads, casting #920.. Not touching them with the exception of replacing the valve springs & seals and shimming the springs properly if needed.. Using my "Z28" springs.. Stock rockers, as long as they look OK.. New Comp high energy pushrods.. Stock converter.. 3.42 rear gear & 200-4r trans.. Exhaust is Shorty headers, 2 into 1 Y-pipe (if I can manage to retain it), back to duals after the trans.. performer intake, Stock QJet.
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