lost my motor

yup my merely 6 month motor broke today[img]/phpBB/images/smiles/icon_frown.gif[/img]. i went to the gas station down the road today to get a quart of oil, i was a 1/2 quart low. on my way back i got on it, went to about 6500 rpm then let off, shifted and then cruised home. i heard faint noises of something rattling during this. when i got home i threw it in park it idled for maybe 5 secs then i heard the rattling noise and it went clunk and seized. it wont turn over and i pulled the v/cs and looked for bent pushrods, nothing. must be bottem end related. as i remember i had the crank cut .010"/.010". i had my rods pressed with arp rod bolts,torqued to 28 ft lbs, checked for roundness/straightness. i used stock main bolts, stock vol oil pump, .002"-.0022" oil clearance on main & rods. within spec on crank endplay and rod side clearance, my rods are a set of C8OE 302 rods with the rail style caps, crank is the original piece from 68. this sucks!! but i guess i'll tear into her and reveal the bitter truth.[img]/phpBB/images/smiles/icon_cry.gif[/img]
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did yu have it balanced??
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Holy smokes, you just scared the sh!t out of me! I built almost the exact same motor this summer and my redline is 6,300 rpm. I am affraid to put it there now! [img]/phpBB/images/smiles/icon_eek.gif[/img] That really sucks man, let us know what happened I really want to know. I also am running the same rods, with the same rod caps, the same heads, only smaller cam and stealth intake. Which kb pistons are you running, are they the kb-116 pistons? That is what I have in my motor, let me know what ones your running, i'd like to know. Didn't you have some kind of oil leak problems with it when you first got it done to? [img]/phpBB/images/smiles/icon_confused.gif[/img]
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no i never had it balanced[img]/phpBB/images/smiles/icon_frown.gif[/img] i was using the stock crank and rods and close to same weight as originals pistons. so i figured i would dare to go without doing it[img]/phpBB/images/smiles/icon_evil.gif[/img]. BLstangin, i have the kb116 pistons although i dont think they are the culprit. i have put about 20 passes on it at the strip shifting at 6400 rpm and never had any problems. i feel that this is a fatigue issue considering the life span of my rods but i will find out this week and inform you. the oil leak i had trouble with was a simple fix, i had used a rubber gromet with no hole in it in my v/c. it didnt allow the egr system to work properly and caused it to leak out of every gasker and seal.
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Hey James, how many miles were on your rods? Did you have them reconditioned? Also what brand of bearings did you run in it? I ran clevite77, I think that the part number was cb-634-p on the rods, and like 520 or something on the mains. I would like to see what the bearings look like when you get it apart. Might help to predict the future of my motor. Maybe the stock oil pan didn't hold enough oil, and it got run dry a couple of times? I put a 8 quart plus filter pan on mine along with a high volume pump. Did you start to loose oil pressure before it went? My motor also had arp bolts, the rods were reconditioned and shotpeened, and the whole assembly was balanced.
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broken crank maybe? That's about the only thing I can think of off hand. Normally, if a rod "comes loose" it will destroy the block, leave an inspection hole in the pan, and bend valves. Just my thoughts on the subject, FWIW.

Didi you pull dizzy to see if the oil pump rod snapped or twisted???? If you did not use a good arp or FPRP could be an issue een them wimpy originals come like pretzels....
Later......
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#4 cylinder sucked a valve. piston is junk, block is fine, head is fine. BLstangin, i had about 100,000+ miles on my rods and i had them reconditioned while the shop was pressing the arps. i used clevitte 77 bearings on main/rods. i have had great oil pressure since day 1. 1Badmav, i have a ford racing hardened oil pump drive shaft. i have a set of 1.94"/1.60" street flos that will be taking the place of the 1.84/1.54s. cause i will have to do a valve job now anyway. by the way, stock 2 piece valves do have their limits[img]/phpBB/images/smiles/icon_rolleyes.gif[/img]
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Valve Spring pressure can yank the heads right off a two piece valve the Street Flows are nice liteweight valves I think they will take up to 300#s open