Home Menu

Menu


Pontiac - Race The next Level

          
PY Online Forums - Bringing the Pontiac Hobby Together > General Classic PONTIAC TECH > Pontiac - Race > Max rpm 3" vs 3.25" Mains
Reply
Page 2 of 2 1 2
 
Thread Tools Display Modes
  #21  
Old 01-21-2009, 05:11 PM
Polar-Pontiac's Avatar
Polar-Pontiac Polar-Pontiac is offline
Suspended
  
Join Date: Jan 2002
Location: Northern Canada
Posts: 1,592
Default
Quote:
Originally Posted by Jagtec1 View Post
I run a factory 455 crank cut down to 3", in a 400 block. 455CI trapping at 6400. Has gone 9's. I will be pulling it apart this winter (only because it will be freshened and sold, had no issues, and good oil pressure) and will report on findings.
What did you find out.




Thanks Mark

Reply With QuoteReply With Quote
  #22  
Old 01-21-2009, 08:49 PM
Jagtec1's Avatar
Jagtec1 Jagtec1 is offline
Ultimate Warrior
  
Join Date: Mar 2003
Location: Bryn Athyn, PA
Posts: 4,815
Default
Quote:
Originally Posted by Polar-Pontiac View Post
What did you find out.




Thanks Mark

I found out it's too stinkin' cold to go out to the garage yet. Or maybe I am too lazy this year! I am not racing next year, so there is no rush...If I were, my new motor would already be done. I hope to get it torn down within the next month. I expect I may see some fretting on the #2 cap...maybe not.

__________________
Darin
'64 Bonneville Wagon (sold)
69 Lemans-All motor (sold)
9.81 @ 136.39MPH
Reply With QuoteReply With Quote
  #23  
Old 01-23-2009, 10:58 PM
Junkyard Dog's Avatar
Junkyard Dog Junkyard Dog is offline
Ultimate Warrior
  
Join Date: Oct 2003
Location: Senoia, Georgia
Posts: 2,629
Default
Quote:
Originally Posted by BILTIT View Post
I believe all 3.25'' cranks were cross drilled, all 3'' were not.
Is this true?

__________________
Badder than old King Kong
And meaner than a junkyard dog
-Jim Croce
Reply With QuoteReply With Quote
  #24  
Old 01-24-2009, 09:36 AM
Cliff R's Avatar
Cliff R Cliff R is offline
Ultimate Warrior
  
Join Date: Nov 2000
Location: Mount Vernon, Ohio 43050
Posts: 18,153
Default
Good information. The "weak" link here when going to 3" mains is the construction of the crankshaft. We've seen enough cast steel Eagle cranks fail to avoid them in 3" or 3.25" mains. One of our customers in particular, broke one in 4 peices at 730hp, and another one in two peices about a year later. He finally went to forgings, no more troubles. One of the cast steel cranks was raced for two seasons, nearly every weekend, in the high 9's/low 10's, then, without warning it gave up, windowed the block and oiled down the entire top end of the track. About a year later, the back-up engine did the same thing.

The 3" main cast steel cranks have their limitations, as we've seen them in 500hp engines last for many years without problems.

FWIW, with the forgings currently available, I wouldn't even look at a cast crank at any power level.

As far as rpm potential, I don't see the larger main 3.25" journals as a big trouble area here. If you are building from scratch, you should be looking at 3" main blocks. Easier to obtain, and plenty of good cranks readily available in just about any stroke you would want to set them up with.....Cliff

__________________
If you can read this, thank a teacher. If you can read this in English, thank a Veteran!
https://cliffshighperformance.com/
73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile),
Reply With QuoteReply With Quote
  #25  
Old 01-24-2009, 10:44 AM
Tom Vaught's Avatar
Tom Vaught Tom Vaught is offline
Boost Engineer
  
Join Date: Dec 2001
Location: The United States of America
Posts: 31,302
Default
Cross drilling is not necessarily a good thing. Most crankshafts from Moldex are not cross-drilled. The best cranks in my opinion are center drilled cranks like the race 303 Pontiac crank was. Ford's best cranks are center drilled presently.

Tom Vaught

__________________
"Engineers do stuff for reasons" Tom Vaught

Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward.
Reply With QuoteReply With Quote
  #26  
Old 01-24-2009, 12:09 PM
Polar-Pontiac's Avatar
Polar-Pontiac Polar-Pontiac is offline
Suspended
  
Join Date: Jan 2002
Location: Northern Canada
Posts: 1,592
Default
That's good info Cliff & Tom ....Thanks

Reply With QuoteReply With Quote
  #27  
Old 01-25-2009, 03:30 AM
Jack Gifford's Avatar
Jack Gifford Jack Gifford is offline
formerly 'Pontiac Jack'
  
Join Date: Dec 2004
Location: Phelps, NY 14532
Posts: 10,341
Default
Tom V- I haven't seen "center drilled" cranks. Can you please post a sketch or picture?

__________________
Anybody else on this planet campaign a M/T hemi Pontiac for eleven seasons?
... or has built a record breaking DOHC hemi four cylinder Pontiac?
... or has driven a couple laps of Nuerburgring with Tri-Power Pontiac power?(back in 1967)
... or has a Pontiac born the same year as Jim Wangers? (1926}
Reply With QuoteReply With Quote
  #28  
Old 01-25-2009, 07:30 PM
Polar-Pontiac's Avatar
Polar-Pontiac Polar-Pontiac is offline
Suspended
  
Join Date: Jan 2002
Location: Northern Canada
Posts: 1,592
Default
Quote:
Originally Posted by pontiac jack View Post
Tom V- I haven't seen "center drilled" cranks. Can you please post a sketch or picture?
Jack I would like to see that also.

Reply With QuoteReply With Quote
  #29  
Old 01-26-2009, 03:53 PM
Polar-Pontiac's Avatar
Polar-Pontiac Polar-Pontiac is offline
Suspended
  
Join Date: Jan 2002
Location: Northern Canada
Posts: 1,592
Default
I think this is a centre oil crank. Maybe Tom could chime it.

Last edited by Polar-Pontiac; 04-09-2010 at 06:48 PM.
Reply With QuoteReply With Quote
  #30  
Old 01-26-2009, 09:52 PM
440GP69's Avatar
440GP69 440GP69 is offline
Ultimate Warrior
  
Join Date: Feb 2008
Location: Tigard Or.
Posts: 2,681
Default
535 here with AP/Scat Ultra Light 4.5 forged crank, BME Alum 396 series 6.7 rods, BRC Custom Pistons, At first i will probably leave it under 6500 But After a while I'll Probably put in a Big Roller and Springs then stick it to the wood to see what 8000+rpm Sounds Like! YeeHaw!

__________________
D.S.R.E. Your NW Pontiac Street/Strip Engine Builder, Specializing in Cylinder Head,Intake Manifold,and Exhaust Manifold Porting services and Building the Most Efficient stock rebuilds to Hi HP Pump Gas and Race Combinations for Pontiac,Buicks,Olds,FE Fords,385 Series and HP Gen 3 and 4 LS engines!
2006 silvy Z71 4X4,383 LS 600+hp NA
Shared Toy-66 Lemans 470cid by me 537hp 580tq-manifolds, 570hp 590tq-2"headers,custom cam,rpm intake, mild e-heads, Looks stock ;-}
Reply With QuoteReply With Quote
  #31  
Old 01-26-2009, 10:21 PM
PunchT37's Avatar
PunchT37 PunchT37 is offline
Ultimate Warrior
  
Join Date: Dec 2002
Location: Lafayette,LA
Posts: 3,349
Default
Quote:
Originally Posted by 440GP69 View Post
535 here with AP/Scat Ultra Light 4.5 forged crank, BME Alum 396 series 6.7 rods, BRC Custom Pistons, At first i will probably leave it under 6500 But After a while I'll Probably put in a Big Roller and Springs then stick it to the wood to see what 8000+rpm Sounds Like! YeeHaw!
You know you need help, don`t you?

Reply With QuoteReply With Quote
  #32  
Old 01-26-2009, 10:34 PM
440GP69's Avatar
440GP69 440GP69 is offline
Ultimate Warrior
  
Join Date: Feb 2008
Location: Tigard Or.
Posts: 2,681
Default
LOL Yes I do!!!

__________________
D.S.R.E. Your NW Pontiac Street/Strip Engine Builder, Specializing in Cylinder Head,Intake Manifold,and Exhaust Manifold Porting services and Building the Most Efficient stock rebuilds to Hi HP Pump Gas and Race Combinations for Pontiac,Buicks,Olds,FE Fords,385 Series and HP Gen 3 and 4 LS engines!
2006 silvy Z71 4X4,383 LS 600+hp NA
Shared Toy-66 Lemans 470cid by me 537hp 580tq-manifolds, 570hp 590tq-2"headers,custom cam,rpm intake, mild e-heads, Looks stock ;-}
Reply With QuoteReply With Quote
  #33  
Old 01-29-2009, 11:08 AM
OINK 1's Avatar
OINK 1 OINK 1 is offline
Ultimate Warrior
  
Join Date: Jan 2002
Location: Colorado
Posts: 1,060
Default
Well. Wifes new motor will see 8400.

__________________
Greg Merrick
Reply With QuoteReply With Quote
  #34  
Old 02-19-2009, 02:14 PM
Junkyard Dog's Avatar
Junkyard Dog Junkyard Dog is offline
Ultimate Warrior
  
Join Date: Oct 2003
Location: Senoia, Georgia
Posts: 2,629
Exclamation
Quote:
Originally Posted by Cliff R View Post
If you are building from scratch, you should be looking at 3" main blocks. Easier to obtain, and plenty of good cranks readily available in just about any stroke you would want to set them up with.....Cliff
Hmmm . . .

Since I just discovered that my (former) machine shop misinformed me when it told me my 1973 455 block had to go .040 over, and now it turns out I must go .060 over, but I already have .040 over pistons (that I ordered after relying upon my -former- machine shop, groan) . . . .

Can a 400 block go to a 455 .040 over?

__________________
Badder than old King Kong
And meaner than a junkyard dog
-Jim Croce
Reply With QuoteReply With Quote
  #35  
Old 02-19-2009, 02:35 PM
Junkyard Dog's Avatar
Junkyard Dog Junkyard Dog is offline
Ultimate Warrior
  
Join Date: Oct 2003
Location: Senoia, Georgia
Posts: 2,629
Default
4.19" ??? I guess that is .070 over, so I will have to go find another 455 block or get new pistons. Oh, well. It was an idea.

__________________
Badder than old King Kong
And meaner than a junkyard dog
-Jim Croce
Reply With QuoteReply With Quote
Reply
Page 2 of 2 1 2

« Previous Thread | Next Thread »
Thread Tools
Display Modes
Linear Mode Linear Mode

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 03:56 PM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Contact Us Home
Copyright © 2017