Reply With Quotethat sux do they know what caused it?
i have seen a couple of those. ( flat brokes motor has had that problem before)
Well after my dissassembly today due to a dead cylinder #7 and 105 psi vice 150 psi like the other cylinders had this is what I found.
No pressure in #7. Massive piston slap with the heads off and once I removed the pan I had #7 rod nearly out of round. Bad bearing....
Trashed the crank, trashed the piston, bore, and rod. Needless to say I'm emotionally getting through this because now I can add a stroker kit possibly blown now.
I had my machinist do the shortblock while I was crunched for time in other areas of the boat build. Now I wonder if I should have just done the assembly myself. One will never know.
http://www.tpcracing.com/images_temp/BBC-BadBearing.jpg http://www.tpcracing.com/images_temp...adBearing1.jpg http://www.tpcracing.com/images_temp...adBearing3.jpg
that sux do they know what caused it?
i have seen a couple of those. ( flat brokes motor has had that problem before)
Looks like something was wrong for quite a while.
Well after I noticed some bronze material in my oil filter and the fact I couldn't get a tune on the motor. I decided to perform a pressure check and a leak down. Soon after I found cylinder seven nearly dead, I took the valve cover off to listen for any crankcase leaking and the basset header for maybe an exhaust valve. Sure enough I had a hiss coming from the crankcase, that's bad!
So after taking off the cylinder head, I found that I could move the piston up and down by grabbing onto the dome with my fingers (not suppose to do that)
Again.....sure enough after the oil pan was taken off it had spun the bearing.
Probable causes:
Milk shake that happened on break-in??
Possible improper warm-up time once off the trailer
Dirty oil??? Not likely
Or faulty assembly by my builder on the shortblock?? Who knows.
Originally posted by Fiat48
Looks like something was wrong for quite a while.
Not even 55 minutes total on this motor and the sad thing was I was troubleshooting a valvetrain issue that I thought was hitting the valve cover. So I take it my ticking sound during that search wasn't the rocker hitting the cover but my bearing causing a massive piston slap on the bore. That's what I sort discovered.
No?
sorry to hear that. But hey, at least you now know that it wasn't a carburetion problem.
Yeah...hahaa....
Jaime thought it was the carburetorsLOL
Nobody will be mad if I go with a blown 460BBF will they
Well, if you want to try and find out what happened, the rest of the motor disassembled and some measuring may give some clues. But sometimes it's just a guess. There's no motor DNA.
The rod journal I see could be any of the following:
Rod cap on backwards.
Improper rod side clearance
Improperly resized rod
improper bearing clearance
Oiling problem
The only lesson I learned from this experience is I should have built it myself. I was in a hurry and had the machinist mock the shortblock up. Who knows if it was him or one of his monkeys who actually assembled it, nonetheless the bearings are gone.
I did notice alot of heat buildup on the rodsides and it makes me wonder if maybe that was the cause.....but then again it could have been the result of the bearing going out.
Oh well....one down many to go.
Posting Permissions