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Author Topic:   main caps
richard mcright
Dirt Roller

Total posts: 9
posted April 01, 2003 10:05 AM
I HAVE A 383 LONG ROD MOTOR JUST WENT TO JESEL SET UP AND NOW MY CRANK CAPS BUSTED ON ME. EVERY THING IN ENGINE IS AFTERMARKET BUT I DID NOT CHANGE CAPS ON MAINS. After pulling pan with hole in it i found three of my caps broke any suggestions on what could have cause this. track was hooking hard. 560hp and 509 torque on dyno are my #;s. thanks for the help. running ump.

CrackedHead
Dirt Newbie

Total posts: 2
posted April 01, 2003 10:45 AM
Sounds like some hard core detonation to me.

sdhnc29
Dirt Freak

Total posts: 467
posted April 01, 2003 06:53 PM
This is very common in higher horse power engines , especially if your center three cap's are 3412 cap's . The 3412 cap's are standard cast iron main cap's , and will not handle the load of higher horse power and higher compression engines , especially when they are run on hooked up race track's . Severe detonation can be ruled out for the simple fact that this would be show up from destroyed spark plug's , burned piston's , head gasket problem's , or rod bearing failure . The solution to this problem is after market cap's . The 350 block's with three center cap's numbered 2482 , tends to hold up a little better than the 3412 cap's . The 2482 cap's are nodular iron .

if your planning to use this block again , be sure to mag your main web's , they are probably cranked . I would also mag your crank , they will usually be cracked after breaking the center three main cap's .

Steve

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

dirtracer50
Dirt Full Roller

Total posts: 42
posted April 01, 2003 10:13 PM
sdhnc29 do you have any suggestions on what years the 2482 caps can be found? I've been looking at several blocks and haven't found one with these main caps yet. Thanks for any help.

sdhnc29
Dirt Freak

Total posts: 467
posted April 01, 2003 11:14 PM
To the best of my knowledge , and from what I've found them in over the year's , 1969 up to about 1973 or so truck's , Blazers , and a few HP car's . This is based on what we used to find they came in , in California . Since I've been in North Carolina , they are rare to come across . Someone who is a GM part number buff could probably get you a lot closer than I can .

Steve

------------------
Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

richard mcright
Dirt Roller

Total posts: 9
posted April 02, 2003 08:17 AM
thanks steve for the info i had plans for the checking of crank and block for i figured to break the caps it had to stress other rotating equip,

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