HELP!! I split all 4 cylinders on one side of my 383 LT1

Drag Bear · 07-20-2002, 08:58 AM

Is this a sign of over powering the block?
I am running around 600hp.
The motor has nevev been over heated. I had the water pump go the week befor but the gage only read 168 and it never boiled.
This is a race only motor and it is all ways around 90 deg. before I make my run and about 140 deg after. I cool it each time in between rounds.

I was turning it over 8000 rpms.

strokedTA · 07-20-2002, 09:16 AM

Rick,

It's a sign of over boosting or spraying it!
Never heard of a motor doing it without a power adder.

As for the temp. I usually have the motor a little more warmed up than that, usually around 160-180 before a run.

Time for an aftermarket block!

Dave

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If a little's good,
More is better,
And too much is just right!!!

Vince · 07-20-2002, 11:04 AM

Was the block filled? When the engine was built was it magnafluxed for cracks? Seems kinda strange to me? Who clearanced the block for the stroker? What size stroke was the block cut for?

Vince

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95 Z28 383 LT1 roller motor. 9.93 @ 135 NA. Nitrious passes coming soon.

Injuneer · 07-20-2002, 10:22 PM

A stock 4-bolt LT1 block, 383, no fill, w/ an under 20# Vortech has been pushed to 1,125crankHP, with no signs of stress on the block. Ran an entire season that way, finishing up at 9.04/155 in a 3900# car. I don't think you overpowered it.

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Fred
94 Formula A3: 381/TH400/N2O

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11.513@115.59 on motor; 11.162@127.67, 1.643 60' on a 125-shot. Going with a 275-shot this year

pink68 · 07-21-2002, 02:22 AM

Thats sucks Drag Bear!! Sorry to hear that but at least you can fix it pretty quickly? I had a similar thing happen Friday at the track but on a smaller scale, I had a lash cap split and only found about a third of it and on the other side of the motor another lash cap looked like a thimble. Of course the Pro Magnum rocker looks a bit bent... On the bright side I managed to drive home 30 miles afterwards and still ran 11.10 at 127 on six cylinders...!

Drag Bear · 07-21-2002, 07:38 AM

I tore it down last night and found all 3 center 4 bolt main caps split. It is cracked from the caps right down through the web between the cylinders.
It looks like the problem started at the crank. Maybe he didn't machine the 4 bolt caps to the block right.
Well I am putting the heads and cam in my stock engine and run that untill I cam come up with a block.
Does any one make a beter LT1 block? Will the LT1 heads and intake fit on an after market block?

rskrause · 07-21-2002, 08:00 AM

Quote:

<font face="Verdana, Arial" size="2">Originally posted by Drag Bear:
I tore it down last night and found all 3 center 4 bolt main caps split. It is cracked from the caps right down through the web between the cylinders.
It looks like the problem started at the crank. Maybe he didn't machine the 4 bolt caps to the block right.
Well I am putting the heads and cam in my stock engine and run that untill I cam come up with a block.
Does any one make a beter LT1 block? Will the LT1 heads and intake fit on an after market block? </font>

There is no aftermaket or Bowtie LT1 block and probably never will be. If I build another LT1 motor I will have a minimal overbore to preserve as much cylinder wall thickness as possible, I think the could of ci this gives up will be only a minor consideration compared to the added blaock strength. I am not an "engine pathologist" so I can't say why yours failed.

As fas as the 600hp range goes, there are plenty of people at this level with no problems. But as far as 1,000+hp, I don't think that one good experience (that Fred alludes to) proves much. There isn't a big enough sample of 1,000+hp LT1 blocks out there to conclude that the block will be reliable at this power level.

Rich Krause

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'95 Z-28 383 with Vortech, nitrous, etc.
"1FASTZ28"

madman69 · 07-22-2002, 08:27 AM

I dont think power broke the block. Either the tuneup.(detonation does weird things) or something in the rotating assembly started the problem. The LT1 block will take 1000hp safely with a proper tuneup and assembled correctly. Baxters motor, 3 out of my shop, Z9s, and a few others have proved this.

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Injuneer · 07-22-2002, 12:50 PM

Rich:

There is a virtual "clone" of that engine in existance... not as much time on it, but that makes at least 2.

Fred

rskrause · 07-22-2002, 06:38 PM

Quote:

<font face="Verdana, Arial" size="2">Originally posted by Injuneer 94FormM6:
Rich:

There is a virtual "clone" of that engine in existance... not as much time on it, but that makes at least 2.

Fred</font>

Well, that doubles the sample size

Rich Krause

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'95 Z-28 383 with Vortech, nitrous, etc.
"1FASTZ28"