Motor goes boom
04-09-2007, 09:48 AM
#1
Motor goes boom I guess the MS4 was a little more than my 120k mile short block was willing to handle. It was freshened up w/ new rings, bearings, and ARP rod bolts. I put about 400 miles on it and the oil pressure was steady at 40-60 psi, depending on RPM. Took a couple of friends for a ride Saturday at their request, and needless to say we all got a little more than we bargained for. I shifted 1st, 2nd, and 3rd at 7k and was WOT in 4th when clack-bam-boom-smoke screen. It let go at about 6k. I looked under the car and oil is dripping from both sides of the block, so it is well perforated. I'll be tearing down in the next couple days to see what exactly let go and what, if anything, is salvagable. Time for a forged short 
04-09-2007, 09:52 AM
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Originally Posted by 5.3LJimmy
Or a piston let go
04-09-2007, 09:59 AM
#7
111 LSA
I hope my heads made it. Its likely the cam took a beating from the rod also, so I won't get my hopes up about it.
No, I did not check PTV. My heads aren't milled any and it's supposed to clear. I'll let yall know if the valves made their own reliefs after the tear down.
I hope my heads made it. Its likely the cam took a beating from the rod also, so I won't get my hopes up about it.
No, I did not check PTV. My heads aren't milled any and it's supposed to clear. I'll let yall know if the valves made their own reliefs after the tear down.
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04-09-2007, 10:00 AM
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Originally Posted by 5.3LJimmy
111 LSA
I hope my heads made it. Its likely the cam took a beating from the rod also, so I won't get my hopes up about it.
I hope my heads made it. Its likely the cam took a beating from the rod also, so I won't get my hopes up about it.
Are you surprised or were just looking for a reason to forge it. Good luck on the rebuild.
04-09-2007, 10:01 AM
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Originally Posted by brad8266
I had the same thing happen, snapped the rod. The oil from both sides is the sign of the snapped rod. It snaps in half, hits one side of the block and makes the hole then goes back the other way and puts a hole in the other side of the block too. Oil then comes out of those holes.
Many people doing it with no problem although ARP rod bolts are cheap insurance.
04-09-2007, 10:04 AM
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Originally Posted by bluecamaroz28
Is it too much for continuously spinning the stock rods to 7000RPM?
Many people doing it with no problem although ARP rod bolts are cheap insurance.
Many people doing it with no problem although ARP rod bolts are cheap insurance.
04-09-2007, 10:09 AM
#12
Nope I'm not surprised, just a little dissappointed. Its all part of the game, stuff is gonna break. Especially pushing the limits of stock components. I shift my Jimmy at 6800 w/ stock everything(including rod bolts) and I won't be surprised if it goes too. But its been taking it for 4 years and 100k miles.
04-09-2007, 10:19 AM
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Originally Posted by brad8266
7K on stock rods and bolts is not good. Its just a matter of time till it pops.
I know some people are getting away with spinning to 7000RPM a cam only motor with stock rods and bolts. But, what defines the safety limits?
04-09-2007, 11:43 AM
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Originally Posted by bluecamaroz28
Will ARP rod bolts be safe enough with stock rods and 7000?
I know some people are getting away with spinning to 7000RPM a cam only motor with stock rods and bolts. But, what defines the safety limits?
I know some people are getting away with spinning to 7000RPM a cam only motor with stock rods and bolts. But, what defines the safety limits?
04-09-2007, 04:50 PM
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Originally Posted by slow95z
my car shifts right around 6400 but thats when the cam starts to die out. i would NEVER spin one to 7K even with ARP bolts. thats just asking for trouble.
Why would they make camshafts for cam only motors, that has 7200 RPM range label.
04-09-2007, 08:18 PM
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Originally Posted by TeEnAgE pHeNoM
I turned mine to 7000 on the kit plenty of times and it held up fine. This was running 13.0-15.0 air to fuel ratio.
