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blown 454

cajunpapa69

cajunpapa69

Well-known member
I blew my engine today, its a 425 hp 454, wondering how much will it cost to replace it, heads,intake and carb are still good.
 
get a shortblock and swap everything over. when you say you blew exactly what happened is there a rod hanging out the side or did you melt a piston? as far as price i dont know.
 
I can get a New 454 425 H.P. about $5,000 NO Carb NO Dist, or pully's

454.jpg
 
motor started tapping and oil and before i could shut it down i had smoke,oil, and water coming out of both exhaust, found 3 pieces of cast iron and what looks like a freeze plug in the boat, no freeze plugs are missing and i cant find where the cast iron broke off from, my block is red and the pieces aren't. the thing that looks like a freeze plug has numbers on it (ps154) and is 2 7/32 and looks chrome plated. no rods thru the block but all the water from the radiator is in the oil pan like i blew a head gasket,or cracked the block, or warped the heads,I'm thanking about getting a 454/425 hp long block,and rebuilding this engine for a spare if the block isn't to messed up.the engine acted like it locked up on me but when i got it home i turned the engine backwards by hand then it would turn the right way(like a rod is broke in side.)
 
airboatcapt2 i would love a price on any options, mark robicheaux's airboat shop is in the next town,i think he can get the motors but i'm not sure, thanks in advance
 
had to go to work and just got back to the boat, pulled the distribitor and intake off today, found that about 6 teeth on the distribitor broke off, and the cam broke in 2.didnt get the heads off yet but i already know both head gaskets are blown. also saw a crack at the bottom fo the slot where the lifters fit in. wondering how much difference in price between a long block and a short one. not the best at mech work and would probaly be smart to get one that i know is put together correctly
 
cajunpapa69":26fgihpw said:
had to go to work and just got back to the boat, pulled the distribitor and intake off today, found that about 6 teeth on the distribitor broke off, and the cam broke in 2.didnt get the heads off yet but i already know both head gaskets are blown. also saw a crack at the bottom fo the slot where the lifters fit in. wondering how much difference in price between a long block and a short one. not the best at mech work and would probaly be smart to get one that i know is put together correctly
Click to expand...

Here ya go

http://www.crateenginedepot.com/sto...zEvE6GrW8bkRyg43dP&SID=1&Category_ID=2&Page=2
 
IMO, the first thing I'd do is figure out what happened and why. For example, what gearbox were you running and what rpm is the operating range? At what rpm did she come from together? I see alot of BBC (and others too) that have a camshaft, intake and gearbox designed for 5500 rpm engines and a 5000 rpm lifter and valvetrain (springs ect.) , which evintually causes a catastrophic engine failure. A blown head gasket can cause it, but so can a valve stem stabbing a bunch of holes in a piston from a dropped valve. Moving parts that hit stationary parts tend to lean toward stuff like 3 pc. cams and junk in the bottom of the sump other than piston top. I say this, not to say what you have is insufficient by any means, but something happened out of the ordinary and could happen again unless a cause is located. Even a small, un noticeable radiator leak will scrap an engine over time if you don't know about it. Once the idiot lights come on and guages go to the red, damage is done already.
 
i pulled one of the heads off and this is what i found so far, cam is broke in 2, 1 piston is in pieces in the oil pan, the barron is spun on the conecting rod that has the broke piston. 2 small holes on the cylinder, and another cylinder scared, head gasket wasn't blown as far as i can see, sounds like the 454 425 hp long block, i was running at 4000 rpm and the temp guage never showed hot, gonna get a long block , use my edobrock performer intake and my holly 750 dp carb. thanks for all the help.
 
Well, sounds like a mess at the very least. One possibility is a rod bearing letting go to the point of causing the piston to hit the deck til it came apart and some of the pieces falling onto the crank, which tossed it into the cam and wadded it up. I guess it'd be hard to hear on an airboat. Just a wild guess though.
 
1st question, is the journal on the crank black and blue if so it's almost always an oiling issue! A ton of people blame rod bolts when the rod breaks but if the crank journal is black or blue it lost the oil layer and the bearing was contacting the journal surface. Then you spun a bearing lost piston to valve clearance then the piston meet mister valve and then you had a CHERNOBYL. If the journal isn’t black then you lost a valve due to valve float or valve failure. Them BBC are notorious for exhaust valve problems all they need to be perfect is a set of sever duty stainless valves that is their Achilles heel in Marine applications. 99% of the time the journal will tell you the story you can read what’s left of your parts like a log book and find out exactly what happened!
 
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