My dads 455 pontiac spun a rod bearing again, this block, formerly a 428 engine has done this twice before! It has aftermarket rods, pistons, and a medium sized hydraulic cam.
The 455 made approx ten 1/4 mile runs and blew up
again. Max RPMs at finish was between 5700-6000.
Is there some inherent oiling issues with this engine? This engine has had three different people rebuild it, machined, everything ground up, with same end results. It was aligned bored.
What is going on here??? And if its simply the rpms, what does everyone else do different that runs 12's, 11's, 10's and doesnt blow up? Thanks!

My dads 455 pontiac spun a rod bearing again, this block, formerly a 428 engine has done this twice before! It has aftermarket rods, pistons, and a medium sized hydraulic cam.
The 455 made approx ten 1/4 mile runs and blew up
again. Max RPMs at finish was between 5700-6000.
Is there some inherent oiling issues with this engine? This engine has had three different people rebuild it, machined, everything ground up, with same end results. It was aligned bored.
What is going on here??? And if its simply the rpms, what does everyone else do different that runs 12's, 11's, 10's and doesnt blow up? Thanks!

That rpm seems high going thru the traps. What rear gears are you using? My 67 goes thru the traps at 5500rpm, turns 12.6, that's with a 3.73 rear. My engine is a 455+.030 over with trw pistons, and SD rods, 4 bolt mains with studs. Same engine since 1991 and before I bought it, it was a drag only car with the same shortblock.

What are your clearences on the bearings? Are you using studs for the mains? What is your oil pressure at idle?, at speed? Mine at idle is 25lbs, cruising 60lbs, and when drag racing 80lbs.

I'm no expert, but it seems to me that your bearing clearances may be to loose, or your just spinning it to high. 455's don't need much rpm to get them moving down the track.

We remember it being about 20lbs a idle, in gear, when warmed up. I guess my dad didn't run it enough times to think about checking it "down track". LOL It also has 3.73 gears, and was using 28x9 m/t slicks; sounds like the converter is slipping WAY too much, huh? Do you think 5800-6000 alone is what got it, or some other issues here?

When I lost my motor in August, we discovered that one of the mains was egg shaped, due to a poor line bore job. When assembled, everything was within tolerances, as the bearing was still round. Under running pressure, the bearing moved out, blocking the oil supply off. I would check that.

I don't that your RPM is excessive for the parts you have in the short block.

"Do you love me? Do you hate me? Ready or not....Here....I......come....."

Ja Rule

I don’t think your RPMs are out of line at all. Too many of us are seeing 6000-6500+ with out incident.

with out questions there can be no answers

1969 Grand Prix
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If you don't already have one get a RPM limiter.

You'd be surprised at what rpm's you turn doing a burnout.

Also at the end of a pass make sure you don't slam the brakes too hard forcing the oil away from the pickup.

Make sure the oil galleys are clean.A lot of shops around here don't bother cleaning them out.
They figure hot tanking them will work.

johnta1
Pontiac Power RULES !!!
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Hmmm, some fundametals Best PRactices followed by me:

I re-affirm hand-picking the 428/455 block to be free from need for line-bore.

I re-affirm keeping stock hard-parts in-place until there is strong concern for failure in the application.

I re-affirm that I will run low 11's or high 10s (10.5sec) while keeping the Revs under 5200RPM.

yea, It's just metal...with a pedigree.

H.I. Stud

"11.00/123MPH/1.50 60foot/29.5"/4.10:1/10"/472 #48/Flat HYD/DualQuad/Wenzler/3250Lbs
12.00/112MPH/1.61 60foot/26"/3.31:1/10"/472 #48/FlatHYD/Q-Jet/Torker/3650Lbs"

was it the same bearing?? maybe #7 or #8.

Seen a problem once where a guy would consistently wipe out the rear main, #7 or #8. He had a high RPM stall converter. When driving on the street the conveter would heat-up transfering the heat to the rear main, wiping out the rear main, #7 or #8. That was our theory anyway! After changing the converter, never had a problem.

PHS Documented "REAL JUDGE"
12.53 @ 110.68 on street tires, through the mufflers and a 4 speed!!

So much on the theory of the defective OEM Pontiac timing chain covers causing the engine failures. [img]/infopop/emoticons/icon_wink.gif[/img]

http://kurtspontiac.homestead.com/files/77canam.jpg

Still haven't found that piece of aluminum............

"Do you love me? Do you hate me? Ready or not....Here....I......come....."

Ja Rule

[QUOTE]Originally posted by Goatman:
Still haven't found that piece of aluminum............

Is this true or false? Or Multiple choice. [img]/infopop/emoticons/icon_biggrin.gif[/img]

How about...........Cause it wasn't in there to begin with? [img]/infopop/emoticons/icon_rolleyes.gif[/img] [img]/infopop/emoticons/icon_biggrin.gif[/img] [img]/infopop/emoticons/icon_biggrin.gif[/img]

Q-16 Norwalk Qualifying [email protected]
2nd Round, [email protected] ...Radials... hard on the brakes, Ray. LOL.
http://PontiacDude.cc

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Rick Lightfoot:
So much on the theory of the defective OEM Pontiac timing chain covers causing the engine failures. [img]/infopop/emoticons/icon_wink.gif[/img]<HR></BLOCKQUOTE>

Oh yea', here we go! Let's get it spun up good! [img]/infopop/emoticons/icon_razz.gif[/img]

http://kurtsplates.homestead.com/files/badta.jpg

SECOND AMENDMENT: AMERICA'S ORIGINAL HOMELAND SECURITY.
I Misus Rash'!

Ken, the cover was intact when installed......

"Do you love me? Do you hate me? Ready or not....Here....I......come....."

Ja Rule

Paul Spotts sells several versions of aftermarket timing covers.

Starting with original Moon stuff for $150 and all the way up to pretty but unnecessary billet covers.

Paul's prices on billet covers are the best deal around.

www.spottsperformance.com

[img]/infopop/emoticons/icon_wink.gif[/img]

Not really, but they are nice and they are a damn site better than the factory ones, for several reasons. Have one on my engine already. If anyone wants to see a pic of a really nice, quality billet timing cover, drop me a line. Already have it installed on a mock up motor.



"Do you love me? Do you hate me? Ready or not....Here....I......come....."

Ja Rule

[This message was edited by Goatman on October 19, 2002 at 07:17 PM.]

We heard that High PRESSURE oil pump would help the 455's "high bearing speed" and oil that area better under higher RPM's, what do you guys think of this?

Bandaid on a shot gun wound...........

"Do you love me? Do you hate me? Ready or not....Here....I......come....."

Ja Rule

Rip it back out and find out whats wrong. If you can't, take it somewhere that can. Too many failures to keep screwing with it.

http://kurtsplates.homestead.com/files/budgto.jpg

My Rig's a little old, but that don't mean she's slow.

[This message was edited by Bud Lyons on October 26, 2002 at 12:22 AM.]

was it a main bearing or a rod. clearance must be checked as crank or rods are bolted together , as well as with bearings only installed .,6000 rpm is not to much . some one is missing something during assy.