Fragged a 455

J-(Chicago) · October 13th, 2008, 11:00 AM

Fragged my 455 at Cordova this weekend. Checked Oil pressure with a portable gauge before racing and it was great. 4 passes later the engine was cranking slow. Thought the starter or battery cable got fried. When I pulled a plug and turned it over with a breaker bar it was a horrifying feeling. Slower than dirt, with a 3 ft breaker bar. After the motor cooled it wouldn't turn at all

.
I tore it down and even with all the caps off the mains and rods it STILL wouldn't turn.

Turns out the #3 rod bearings slipped underneath one another and welded themselves together. Then welded the #4s to it as well. I just had 1 solid 1.5'' ring welded around and to the crank. It was a total loss. Rods, crank, everything... JUNK. The block seems ok but you can't eyeball machinist tolerances.

It was running 14.6 in the 1/4 with a stock g headed motor, th350 and 7.5 3.08s Shifting at 5100. Oh well, At least it wasn't my 350.

Weirdest thing ever. No knocks, noises, rpm fluctuations, nothing. Ran strong every pass till it started cooling down.

Going back to 307 power this winter

Run to Rund · October 13th, 2008, 11:42 AM

#3 and 6 rod oil feeds come out at the wrong angle. At some rpm vs. oil pressure, the oil doesn't flow out. For at least 35 years people have chamferred the oil holes heavily and run a trough about 1/8" wide and deep in the direction of rotation at those journals. Run heavy wire through the oil feed holes and you will see what I mean, and what direction to run the troughs.

J-(Chicago) · January 30th, 2009, 12:41 PM

I put another big block in. It's a wimpy 72 motor though. I'm gonna have to do a decent amount of work on the heads to make it un-slow.

The 307 only had 75 psi compression in the # 6 cylinder, so It's in the junk pile now too.

Oldsguy · January 30th, 2009, 12:45 PM

You know the same thing happened to the 455 in my '76 Regency, except I wasn't racing it. Those big blocks seem to go without warning, even though they go forever, and ever, and ever....

f-85 · January 30th, 2009, 12:52 PM

Quote:

Originally Posted by J-(Chicago)

Going back to 307 power this winter

Not in my garage! NO MORE 307S! Did you pick up that 69 455? Now thats something we can work with!

Lady72nRob71 · January 30th, 2009, 01:44 PM

OUCH!

That is a painful story indeed... Do the 350's have any known weaknesses like that??

Quote:

Ran strong every pass till it started cooling down

What might have happened if you hadn't shut it down??

Hope you get it running again, only better than before!

citcapp · January 30th, 2009, 02:20 PM

Ouch that hurts even from here in Bothell. Crazy that there was no warning. Do you have an oil guage at the dash as well and what was the reading during the cool down between passes

f-85 · January 30th, 2009, 02:36 PM

Quote:

Originally Posted by citcapp

Ouch that hurts even from here in Bothell. Crazy that there was no warning. Do you have an oil guage at the dash as well and what was the reading during the cool down between passes

No he didnt.

now he does

88 coupe · January 31st, 2009, 11:14 PM

Quote:

Originally Posted by J-(Chicago)

I put another big block in ........

Shift this one at 4500 RPM.

Norm

Techmaven · February 4th, 2009, 01:54 PM

Quote:

Originally Posted by 88 coupe

Shift this one at 4500 RPM.

Norm

Agreed. I don't know what cam you were running, but a basically stock 455 is all done before 5100.

My stock 69 442 400/325 auto/3.23 ran best left in drive 14.5 at 96 shifting at about 4700rpm.

smcurro · February 8th, 2009, 06:29 PM

Quote:

Originally Posted by Run to Rund

#3 and 6 rod oil feeds come out at the wrong angle. At some rpm vs. oil pressure, the oil doesn't flow out. For at least 35 years people have chamferred the oil holes heavily and run a trough about 1/8" wide and deep in the direction of rotation at those journals. Run heavy wire through the oil feed holes and you will see what I mean, and what direction to run the troughs.

Does this problem exist for 425 crankshafts as well? How about 330/350 cranks?

wolfman98 · February 9th, 2009, 05:27 AM

Quote:

Originally Posted by J-(Chicago)

Fragged my 455 at Cordova this weekend. Checked Oil pressure with a portable gauge before racing and it was great. 4 passes later the engine was cranking slow. Thought the starter or battery cable got fried. When I pulled a plug and turned it over with a breaker bar it was a horrifying feeling. Slower than dirt, with a 3 ft breaker bar. After the motor cooled it wouldn't turn at all

.
I tore it down and even with all the caps off the mains and rods it STILL wouldn't turn.

Turns out the #3 rod bearings slipped underneath one another and welded themselves together. Then welded the #4s to it as well. I just had 1 solid 1.5'' ring welded around and to the crank. It was a total loss. Rods, crank, everything... JUNK. The block seems ok but you can't eyeball machinist tolerances.

It was running 14.6 in the 1/4 with a stock g headed motor, th350 and 7.5 3.08s Shifting at 5100. Oh well, At least it wasn't my 350.

Weirdest thing ever. No knocks, noises, rpm fluctuations, nothing. Ran strong every pass till it started cooling down.

Going back to 307 power this winter

My first good car was a 66 Chev Impala SS 2 door hardtop with a 283 and the bullet proof two speed glide tranny. I was running it on the highway about 70 miles per hour and stepped on it . When it hit 90 everything just stopped. It was like the motor shut it self off and I ended up coasting to a stop on the side of the road. turned out that one of the crank bearings slipped in behind the other and jammed up to stop the motor dead in it's tracks.Ended up that was only damage and just had to turn the crank and get new bearings. Then I sold it and put in a stock 325 horse 327.

J-(Chicago) · February 9th, 2009, 12:39 PM

Quote:

Originally Posted by wolfman98

My first good car was a 66 Chev Impala SS 2 door hardtop with a 283 and the bullet proof two speed glide tranny. I was running it on the highway about 70 miles per hour and stepped on it . When it hit 90 everything just stopped. It was like the motor shut it self off and I ended up coasting to a stop on the side of the road. turned out that one of the crank bearings slipped in behind the other and jammed up to stop the motor dead in it's tracks.Ended up that was only damage and just had to turn the crank and get new bearings. Then I sold it and put in a stock 325 horse 327.

Yeah, that's pretty much what happened to me as well. Except there was no saving that crank.

October 13th, 2008, 11:00 AM	#1 (permalink)
J-(Chicago) Seasoned beater pilot. Join Date: Jan 2007 Location: Chicago Posts: 2,696	Fragged a 455 Fragged my 455 at Cordova this weekend. Checked Oil pressure with a portable gauge before racing and it was great. 4 passes later the engine was cranking slow. Thought the starter or battery cable got fried. When I pulled a plug and turned it over with a breaker bar it was a horrifying feeling. Slower than dirt, with a 3 ft breaker bar. After the motor cooled it wouldn't turn at all. I tore it down and even with all the caps off the mains and rods it STILL wouldn't turn. Turns out the #3 rod bearings slipped underneath one another and welded themselves together. Then welded the #4s to it as well. I just had 1 solid 1.5'' ring welded around and to the crank. It was a total loss. Rods, crank, everything... JUNK. The block seems ok but you can't eyeball machinist tolerances. It was running 14.6 in the 1/4 with a stock g headed motor, th350 and 7.5 3.08s Shifting at 5100. Oh well, At least it wasn't my 350. Weirdest thing ever. No knocks, noises, rpm fluctuations, nothing. Ran strong every pass till it started cooling down. Going back to 307 power this winter __________________ I'd rather have a numbers matching poker hand. Last edited by J-(Chicago); October 13th, 2008 at 11:03 AM..

January 30th, 2009, 12:41 PM	#3 (permalink)
J-(Chicago) Seasoned beater pilot. Join Date: Jan 2007 Location: Chicago Posts: 2,696	I put another big block in. It's a wimpy 72 motor though. I'm gonna have to do a decent amount of work on the heads to make it un-slow. The 307 only had 75 psi compression in the # 6 cylinder, so It's in the junk pile now too. __________________ I'd rather have a numbers matching poker hand.

January 30th, 2009, 12:45 PM	#4 (permalink)
Oldsguy Hot Rodder at heart Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 5,360	You know the same thing happened to the 455 in my '76 Regency, except I wasn't racing it. Those big blocks seem to go without warning, even though they go forever, and ever, and ever.... __________________ Dan '77 Cutlass Supreme '46 2 door "The rocket 455.....it's a sledgehammer approach to a thumbtack world" LuxBlue of HAMB.

January 30th, 2009, 02:20 PM	#7 (permalink)
citcapp Super Moderator Join Date: Nov 2007 Location: Bothell, WA Posts: 3,445	Ouch that hurts even from here in Bothell. Crazy that there was no warning. Do you have an oil guage at the dash as well and what was the reading during the cool down between passes __________________ Pat 1957 Super 88 with a 455 1948 2dr series 76 with a 455

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October 13th, 2008, 11:42 AM	#2 (permalink)
Run to Rund Registered User Join Date: Mar 2008 Posts: 337	#3 and 6 rod oil feeds come out at the wrong angle. At some rpm vs. oil pressure, the oil doesn't flow out. For at least 35 years people have chamferred the oil holes heavily and run a trough about 1/8" wide and deep in the direction of rotation at those journals. Run heavy wire through the oil feed holes and you will see what I mean, and what direction to run the troughs.