Compstar rods?

Old 03-02-2008, 09:41 PM
  #1  
altune
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Default Compstar rods?

I have a buddy of mine that just had a pretty bad engine break on his 434 cid sbc. He had just had it rebuilt with compstar rods and crank.
This car is a pro street 3500 lbs. It never runs over 7000 rpm, he had made a burnout, ( with rev limiter AT 6800) and made a 1/4 mile pass. the 6th one of the day.
right after the 1/8 mile it went. #2 rod came apart, #4 rod got colateral damage from #2
these are the new Compstar forged sbc rods 6" with the arp L9000 bolts.
I have the same product in my short block and don't want to run the engine of this is a known problem. Anybody ever hear of these coming apart?
Thanks
Al
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Old 03-03-2008, 03:13 AM
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hammertime
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I've seen/heard nothing but good about the Callies Compstar stuff.
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Old 03-03-2008, 05:29 AM
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tyster
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Altune, what do you mean came apart? Not tyring to sound elementary but there's usually more to the story. Even bone stock rods dont normally just come apart. Any signs of heat or oil starvation? How about clearance? Just cause one rod cleared doesnt mean another one will. Just a little food for thought. More info is needed.
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Old 03-03-2008, 06:39 AM
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engineaction
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I'm think in a 434 application my guess is that there wasn't enough rod to cam lobe clearance. I think the guy that assembled it didn't clearance the rods. # 2 I believe is one of the problem holes when it comes to cam lobe to rod clearance on stroker engines. It might have turned over on the stand but probably just cleared. You need .045-.060" clearance or your situation occurs.
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Old 03-03-2008, 02:23 PM
  #5  
altune
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found out.
Spun a bearing.
He had been doing burnouts w/o rev limiter
did the run with spun bearing, heat welded the rod to the crank and boom!
yep not pretty.
How do you know you have spun a bearing before you grenade an engine? theis one is loud, so listening is not the option
he claims oil pressure at 90 psi when it occured.
would hold true if the bearing swung over the top hole and blocked it.
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Old 03-03-2008, 03:23 PM
  #6  
tyster
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Originally Posted by altune
found out.
How do you know you have spun a bearing before you grenade an engine? theis one is loud, so listening is not the option
he claims oil pressure at 90 psi when it occured.
would hold true if the bearing swung over the top hole and blocked it.
-Performance, he should've felt the car laying over somewhat.
-Should've made some sort of noise.
-Sometimes the Temperature will rise.
-If this was only the 6th pass he should've been checking the dipstick for particals in the oil at sometime during the day.
-E.T. & MPH should've been getting slower.

......................Tyster
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Old 03-03-2008, 03:29 PM
  #7  
tyster
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Default Re: Compstar rods?

Originally Posted by altune
I have the same product in my short block and don't want to run the engine of this is a known problem. Anybody ever hear of these coming apart?
Thanks
Al
Al they cant be any worst than the Chinese stuff in motors now-a-days.
Make a few passes then cut the filter open and have a look inside. :wink:
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Old 03-04-2008, 08:34 PM
  #8  
a13badazztoys
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He did his burnout at 6800 rpm..
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