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-   -   H-I-J '76 Nova re-fit. (https://classracer.com/classforum/showthread.php?t=67661)

Mark Yacavone 07-27-2019 06:47 PM

Re: H-I-J '76 Nova re-fit.
 
It usually takes a spun bearing and a half of rod to bust up a cam.
I think I see the latter, only.
At least they were light. :-(

Nmbr1GMfan 07-27-2019 06:59 PM

Re: H-I-J '76 Nova re-fit.
 
Quote:

Originally Posted by Mark Yacavone (Post 593285)
It usually takes a spun bearing and a half of rod to bust up a cam.
I think I see the latter, only.
At least they were light. :-(

Good news is the oiling issues were fixed, all the bearings look perfect and it had 75psi when it exploded. The bad news... the rod came off the piston and was swinging like a steel baseball bat. Total destruction!

Rich Biebel 07-27-2019 07:48 PM

Re: H-I-J '76 Nova re-fit.
 
The block you chose to use had a cam hole that appeared to indicate the block had a lot of core shift and the cam and crank centerline were offset to one side. Pictures were not real clear but it looked like that block was offset at the cam hole.....

Combine a block with this issue and some aftermarket rods with much larger big ends than stock and you may have had something hitting in the bottom end.

I built a 383 for a street car and ran into this problem. Had to use different rods to get comfortable clearance. Rods hit block on one side badly and cleared no problem on the other bank....Grinding the block may have hit water...

A 383 with even a stock rod will hit the cam on 2 cylinders every other rotation....I built a lot of them....

I always checked them with cardboard strips where the rods would nearly hit the cam on those 2 cylinders. Always Ground the rods at the inner bolt for clearance.....and that was with stock 5.7 rods...

Don't know if that had anything to do with your blow up but I thought I'd mention it since I saw the cam hole issue way back....

Nmbr1GMfan 07-27-2019 08:22 PM

Re: H-I-J '76 Nova re-fit.
 
Quote:

Originally Posted by Rich Biebel (Post 593293)
The block you chose to use had a cam hole that appeared to indicate the block had a lot of core shift and the cam and crank centerline were offset to one side. Pictures were not real clear but it looked like that block was offset at the cam hole.....

Combine a block with this issue and some aftermarket rods with much larger big ends than stock and you may have had something hitting in the bottom end.

I built a 383 for a street car and ran into this problem. Had to use different rods to get comfortable clearance. Rods hit block on one side badly and cleared no problem on the other bank....Grinding the block may have hit water...

A 383 with even a stock rod will hit the cam on 2 cylinders every other rotation....I built a lot of them....

I always checked them with cardboard strips where the rods would nearly hit the cam on those 2 cylinders. Always Ground the rods at the inner bolt for clearance.....and that was with stock 5.7 rods...

Don't know if that had anything to do with your blow up but I thought I'd mention it since I saw the cam hole issue way back....

I can see where this might happen (and was checked in this case). It's clear what happened here and it was a part failure. I won't be able to address my concerns till Monday when I start ordering new parts.

Nmbr1GMfan 07-27-2019 11:51 PM

Re: H-I-J '76 Nova re-fit.
 
Quote:

Originally Posted by J&S Racing (Post 593283)
Ouch...
Like many others I was rooting for you guys.

Your not the only one, my new 565 for the dragster ran wicked for 10 passes before it broke a valve.

Was this the cam from the other motor?? Possibly part of you oiling issue?

That's a bummer. Sucks because this was a nice little piece till it broke, not a record setter but I feel like it was strong and safe. Cam was the same, luckily without me knowing, the cyl head guy here sent the cam to be checked the first time we had issues, now at least we can have a duplicate made.

fredjohnston 07-28-2019 11:05 AM

Re: H-I-J '76 Nova re-fit.
 
might be time to call one of the well known engine builders and get a complete motor or at least send your parts to them. then you could rebuild it when time comes to learn a few things. At least you may get on the track this year.

Nmbr1GMfan 07-28-2019 11:45 AM

Re: H-I-J '76 Nova re-fit.
 
Quote:

Originally Posted by fredjohnston (Post 593322)
might be time to call one of the well known engine builders and get a complete motor or at least send your parts to them. then you could rebuild it when time comes to learn a few things. At least you may get on the track this year.

A well known engine builder or a guy building outside in a tent can't do anything about a defective part.

Glenn Hayes 07-28-2019 03:32 PM

Re: H-I-J '76 Nova re-fit.
 
So sorry to read and see the news Todd.

I am a bit perplexed as to why a quality aftermarket rod(s)? would fail … we always are in hopes that using better/stronger components will avoid these issues.

How did the block, crank, and heads fair in this?

I continue to wish the best for your families adventure,
God Bless
Glenn

Nmbr1GMfan 07-28-2019 05:43 PM

Re: H-I-J '76 Nova re-fit.
 
Quote:

Originally Posted by Glenn Hayes (Post 593335)
So sorry to read and see the news Todd.

I am a bit perplexed as to why a quality aftermarket rod(s)? would fail … we always are in hopes that using better/stronger components will avoid these issues.

How did the block, crank, and heads fair in this?

I continue to wish the best for your families adventure,
God Bless
Glenn

Glenn, I know it may appear the rod failed but that is not the case. I'm sending some parts off to be checked and I would like to not throw a manufacturer under the bus until I've had everything looked at. I'll tell you I believe it was kind of a freak thing and I will lay it out there when I know for sure, even if it were my fault I'll tell everyone exactly that and I will own it. One head was hit and has 2 bent valves but we think it's fine. The timing cover is salvageable but everything else is destroyed, the block is broken internally as well as both outer sides. It made equal power with 1.3 rockers to either engine did prior with 1.5 rockers so I know it was going to be a pretty good one and honestly I feel terrible about it because it's tough to watch tears hit your kids cheeks after all her hard work literally hit the dyno room floor... but life is exactly like this some times. We've already dusted ourselves off and once again have a plan. After I make some phone calls tomorrow I'll post up our intentions. Thanks for your continued interest and well wishes Glenn.

HP HUNTER 07-29-2019 08:56 AM

Re: H-I-J '76 Nova re-fit.
 
Quote:

Originally Posted by fredjohnston (Post 593322)
might be time to call one of the well known engine builders and get a complete motor or at least send your parts to them. then you could rebuild it when time comes to learn a few things. At least you may get on the track this year.


Its about time some one said it


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