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Author
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Topic: Q. For those who have split cylinder walls
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Clevo377
Gearhead Posts: 303
From: Blackburn, Victoria, Australia
Registered: Nov 2000
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posted 07-01-2001 06:40 AM
   
Where did they split? was the split verticle or horizontal? Was the block filled at all? Did you have any sharp edges at the bottom of the cylinder radiused?(assuming a split started there). What RPM were you going to?Do you know why it happened??Just curious,
Paul
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Rory McNeil
Gearhead Posts: 1098
From: Surrey, B.C. Canada
Registered: Nov 2000
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posted 07-01-2001 11:52 AM
Several years ago, I had one cylinder wall(#6 or7, I don`t recall)split in my 428 drag car. It was a horozontal split about 2" long
about 3-3 1/2" down from the deck. The block WAS filled, & had been sonic checked prior to boring (at standard bore was .165 at the thinnest spot,making for .150 after .030 overbore.) I can`t recall, but I don`t thick the area where it cracked was the thin spot.
Since it split in the filled portion of the cylinder, there was no water getting inside, the only symptom was it starting to smoke blue, due to the crack pushing inward a bit & gouging the side of the piston & chewing up the rings. It didn`t slow the cars ET`s noticably, though. I never sleeved the block, rather I tossed it & just built another short block. This block was standard bore, & since I was chasing points at the track, never had time to sonic check or fill that block. I just had it bored, did the usual FE oil passage mods, & put it together.
That was in 94, & other than 2 "freshen ups" its still running fine. (10.2 @ almost 131 mph.)By the way, this split cylinder happened with a self imposed 6500 rpm redline, & I don`t know what caused it to occur, I had been running that engine for 2 or 3 seasons before it happened.
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Clevo377
Gearhead Posts: 303
From: Blackburn, Victoria, Australia
Registered: Nov 2000
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posted 07-02-2001 05:26 AM
Thanks for the reply Rory, were you really scratching your head as to why it happened?? I am, especially after 2 seasons. It seems from what I've heard they always split horizontally as well. Interesting...
Paul
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kid vishus
Gearhead Posts: 3894
From: middle of NC
Registered: Oct 2000
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posted 07-02-2001 09:02 AM
I guess with my track record I am required to post on this one  Every time I have cracked a cylinder it has been a verticle crack. Most of them have been on the thrust side of the cylinder, about haflway up (the same place you get the shiny spot from the side load of the piston).Although the first one I split this year was on the opposite side.
(Edit is for this)
That motor was 13.85 to 1 compression. And I was turning it 7800 rpm.
The only time I cracked one with a filed block was when my math for the piston to cylinder head clearnces was off. I had 3 pistons hit the heads hard, and those three cylinders cracked. I believe that when the piston hit the head it tried to cock the piston in the bore resulting in the wall splitting. [This message has been edited by kid vishus (edited 07-02-2001).]
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SG236
Gearhead Posts: 344
From: Jasper, TN, USA
Registered: Dec 2000
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posted 07-02-2001 09:34 AM
Well mine split because the crank broke in the front bending the eagle rods on both sides. Cracks were verticle. I have thought a lot why the crank broke because ALL precautions were taken. All of my bottom end work was done by a professional race engine builder.Something wasn't right but I guess the possibilities are endless. ------------------
Russ Hood
70s Maverick S/Pro
https://mustangsandmore.com/ubb/SG236.html
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Moneymaker
Administrator Posts: 18704
From: Lyons, IL, USA
Registered: May 99
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posted 07-02-2001 10:31 PM
I have never seen a "horizontal" split in a FoMoCo cylinder wall that was not caused by mechanical failure. Spun bearing, rod breakage, etc.  ------------------
Alex Denysenko
Co-Administrator and Moderator
NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00 & '01
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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Rory McNeil
Gearhead Posts: 1098
From: Surrey, B.C. Canada
Registered: Nov 2000
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posted 07-03-2001 12:02 AM
Nope, it was still running fine, & when I took it apart, everything else looked fine. I don`t have any idea what caused it.
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Clevo377
Gearhead Posts: 303
From: Blackburn, Victoria, Australia
Registered: Nov 2000
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posted 07-06-2001 07:05 PM
Sorry  when I said most splits seem to be horizontal, I meant vertical. (remembering Kid's folly). my mistake.Paul
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