#1  
Old 02-27-2005, 10:40 PM
shaggy69gradprix's Avatar
shaggy69gradprix shaggy69gradprix is offline
Member
 
Join Date: Feb 2005
Location: SPRING TX
Posts: 95
Default

anyone ever weld up cracks in the mains and have any luck with it?

  #2  
Old 02-27-2005, 10:40 PM
shaggy69gradprix's Avatar
shaggy69gradprix shaggy69gradprix is offline
Member
 
Join Date: Feb 2005
Location: SPRING TX
Posts: 95
Default

anyone ever weld up cracks in the mains and have any luck with it?

  #3  
Old 02-28-2005, 06:22 AM
shaggy69gradprix's Avatar
shaggy69gradprix shaggy69gradprix is offline
Member
 
Join Date: Feb 2005
Location: SPRING TX
Posts: 95
Default

ive been spraying 2 plate systems on the car. a69 gp street car 10 inch tire.I welded mine up and im curently putting it back together.the block is o-ringed filled steel 4-bolt caps scat 6.800 rods cast crank not a N crank 4.25 stroke.car runs 10's on motor 6.o's on the dope.any info would be great.

  #4  
Old 02-28-2005, 07:15 AM
Mr. P-Body Mr. P-Body is offline
Ultimate Warrior
 
Join Date: Aug 2004
Posts: 3,690
Default

The mains in the block (bulkheads) or mains on the crank?
Crank? NEVER!!! It WILL break...
The block? Iffy. Welding cast iron is an art. In most places, a crap-shoot. "Spray" welding will fill the holes, but won't add any strength lost to the crack. Arc-welding (nickel rod, low energy) MAY work, but has been known to extend cracks ("spider webbing").
Best of luck. We would rather machine up another block to be safe, unless you simply have SO MUCH money in the block, it's worth the risk.

  #5  
Old 02-28-2005, 07:18 AM
Robert C.'s Avatar
Robert C. Robert C. is offline
Ultimate Warrior
 
Join Date: Feb 2003
Location: Midlothian Va.
Posts: 1,419
Default

Welding cast iron is tuff to do. I would never weld up any block that has main webs cracked. If it is thru the oil galley it will never have the correct pressure. The block broke for a reason. Welding it will not make it stronger. Welding cast iron make it more brittle and will brake faster than the not welded area.

__________________
Bob C.

Quickest, Fastest, Best selling Pontiac Aftermarket Block IA II and Tiger Heads

Boss Bird Funny Car
Best pass to date 08/06/2016 6.027@231.64
Allpontiac Big Chief Aluminum Engine Block

http://www.AllPontiac.com
  #6  
Old 02-28-2005, 10:50 AM
ErikW's Avatar
ErikW ErikW is offline
Ultimate Warrior
 
Join Date: Apr 2003
Location: White Plains, MD USA
Posts: 1,378
Default

I often wonder what impact it would have to run the block regardless of the cracks. I have cracked a couple in the past, but only knew of the cracks after end of season tear downs. Car never slowed and never showed oil pressure variances. Who knows how long the were cracked.
Just wondering.

Erik

__________________
1964 GTO
501, Edelbrock Heads NA, 3460 lbs.
9.76 @ 137mph
1971 Trans Am Lucy Blue, 11.56 @ 115
1966 LeMans. 462, SD prepped Kaufman D ports. 11.90 @ 112
1976 Trans Am twin turbo 462, SD Edelbrock heads 8.50@159
2009 G8 GT
  #7  
Old 02-28-2005, 11:48 AM
Half-Inch Stud's Avatar
Half-Inch Stud Half-Inch Stud is offline
Ultimate Warrior
 
Join Date: Jul 2000
Location: BlueBell, PA or AL U.S.A.
Posts: 18,457
Default

I agree.

__________________
12.24/111.6MPH/1.76 60'/28"/3.54:1/SP-TH400/469 R96A/236-244-112LC/1050&TorkerI//3850Lbs//15MPG/89oct

Sold 2003: 12.00/112MPH/1.61 60'/26"x3.31:1/10"/469 #48/245-255-110LSA/Q-Jet-Torker/3650Lbs//18MPG 94oct
Sold 1994: 11.00/123MPH/1.50 60'/29.5"x4.10:1/10"/469 #48/245-255-110LSA/Dual600s-Wenzler/3250Lbs//94oct
  #8  
Old 02-28-2005, 04:38 PM
74t/a 74t/a is offline
Ultimate Warrior
 
Join Date: Oct 2004
Location: Maloof Racing Engines Clarkesville, Ga.
Posts: 1,146
Default

For me......cracked mains = throw the block in the garbage. I will not try and repair a cracked block. I will very rarely even sleeve a block unless it is a rare restoration engine that is hard to replace. I just threw away a 66 corvette 425HP 427 4-bolt block because it was cracked up through a main web up towards the cam tunnel. I cost me $1900 to replace the block if that tells you anything.

  #9  
Old 02-28-2005, 07:40 PM
Badbird69's Avatar
Badbird69 Badbird69 is offline
Senior Chief
 
Join Date: Jun 2004
Location: Minneapolis, MN
Posts: 344
Default

Had a nice back-up 474 that went 9.55 in a 3100 pound car, 8.70's w/250 shot. While freshening, discovered crack in #2 and #4 main webbing. Made the decision to spend $1000 to get it "fixed". They ground material out of the cracks, heated the block up in a huge oven, brazed the cracks. Then machined the bottom of the block flat, bored the mains, bored and sleeved the cam bores.
Ran the motor last half of the season. Ran great, no oil pressure or performance issues (were running a titan pump).
Recently disassembled for inspection: #4 main web cracked up through lifter valley, #4 cam bearing spun - scored cam journal, #3 main bearing and crank journal scored, crank cracked at #3 main journal, #5 & 6 rod bearings wiped. Surprisingly, crank end play was only .010 and #4 thrust bearing looked pretty good, considering. Block AND crank are now both junk.
Was it worth the gamble? In hindsight, no. The block repair company routinely does these kinds of repairs, but those blocks probably aren't subject to this kind of abuse. One more weekend on the racetrack and we would have been picking up pieces.
Now I need a good block that can bore .060.

  #10  
Old 02-28-2005, 07:46 PM
Brinson Pachar Brinson Pachar is offline
Senior Member
 
Join Date: Dec 1999
Location: Orange, Tx.
Posts: 188
Default

Shaggy, if you decide you need a block, I'm just right down the road from you in Orange. I've got a few that might work.

__________________
77 Formula
8.47@ 158
70 GTO-11.37 @ 117.7
  #11  
Old 02-28-2005, 08:22 PM
punisher#1's Avatar
punisher#1 punisher#1 is offline
Chief Ponti-yacker
 
Join Date: Sep 2004
Location: Austin, Texas
Posts: 776
Default

shaggy, this is john in austin with the fairmont. we were running steve's motor last year with the stock block and when we tore it down for inspection we found no problems. if you want to talk to me about block prep or if you need to find another block call me at 512-771-5257 and i'll hook you up. but please don't try to weld up the block and think it will hold with what you're running. it wont work.

__________________
'78 Ford Fairmont 526ci pontiac; true 10.5 tires and stock suspension.
5.14 @140.5 w/nos; 8.86@151 all motor.8.17@172 1/4 mile w/nos
  #12  
Old 02-28-2005, 08:39 PM
shaggy69gradprix's Avatar
shaggy69gradprix shaggy69gradprix is offline
Member
 
Join Date: Feb 2005
Location: SPRING TX
Posts: 95
Default

the block has been cracked for awhile probly..i never lost oil presure.im guessing the motor makes 600HP because of the weight of the car and what it runs on motor.i've sprayed 275 bigshot plate off the line and added a 175 shot midway through 2nd gear on top of it for a total
of 450 im pretty sure it was the 275 out the gate that has cracked it and the weight of the car.thanks for the info.

  #13  
Old 02-28-2005, 09:40 PM
Robert C.'s Avatar
Robert C. Robert C. is offline
Ultimate Warrior
 
Join Date: Feb 2003
Location: Midlothian Va.
Posts: 1,419
Default

That is why we built the IA II. Save the stock block for restoring a nice car. The time and money that you spend on building a stock block, you have spent over 2k to make a block that will take 700hp for a while, but in time it will not last. For the dollar per run IA II is the only way to go. Add the resale value of an IA II motor to this equation, and you have an even better return to the investment. We added more meat in the main webs of our IA II motor and remove all of the stress risers in inside the water jackets that were in the old IA motor. It is the things that you can't see that made our block the strongest and only after market block made.

__________________
Bob C.

Quickest, Fastest, Best selling Pontiac Aftermarket Block IA II and Tiger Heads

Boss Bird Funny Car
Best pass to date 08/06/2016 6.027@231.64
Allpontiac Big Chief Aluminum Engine Block

http://www.AllPontiac.com
  #14  
Old 02-28-2005, 09:48 PM
shaggy69gradprix's Avatar
shaggy69gradprix shaggy69gradprix is offline
Member
 
Join Date: Feb 2005
Location: SPRING TX
Posts: 95
Default

ive got plans to build a new combo in september when i get my bonus.will go with the new IA-II block but trying to get buy for a couple months with my curent stuff.

  #15  
Old 02-28-2005, 11:21 PM
KEN CROCIE KEN CROCIE is offline
Pontiac Performance Author
 
Join Date: Mar 2000
Location: Rancho Cucamonga Ca.
Posts: 1,522
Default

Had a formerly reputably machine shop line bore a block and install four bolt mains.He made the thrust .023" too narrow.Had the block brazed up @ the best shop in town. Block split #4 web and was losing HP on the Dyno.Was making 588HP@5800 & 603 #s @ 4300.Then it was all downhill power wise.was losing a little oil pressure and each sucessive run was down 20 or so.pulled valve covers and saw metalflake. I would never braze or weld on a structural cast iron part again.

__________________
GOOD IDEAS ARE OFTEN FOUND ABANDONED IN THE DUST OF PROCRASTINATION
  #16  
Old 03-01-2005, 08:16 AM
Half-Inch Stud's Avatar
Half-Inch Stud Half-Inch Stud is offline
Ultimate Warrior
 
Join Date: Jul 2000
Location: BlueBell, PA or AL U.S.A.
Posts: 18,457
Default

I suspect Rear and front engine plates will ELIMINATE cracked mains webs.

Do a Force-Balance Diagram on the Block with Factory engine mounts and see where all the distortion-inducing Force concentrates...

__________________
12.24/111.6MPH/1.76 60'/28"/3.54:1/SP-TH400/469 R96A/236-244-112LC/1050&TorkerI//3850Lbs//15MPG/89oct

Sold 2003: 12.00/112MPH/1.61 60'/26"x3.31:1/10"/469 #48/245-255-110LSA/Q-Jet-Torker/3650Lbs//18MPG 94oct
Sold 1994: 11.00/123MPH/1.50 60'/29.5"x4.10:1/10"/469 #48/245-255-110LSA/Dual600s-Wenzler/3250Lbs//94oct
  #17  
Old 03-01-2005, 08:41 AM
Rob Rob is offline
Ultimate Warrior
 
Join Date: Dec 1999
Location: Loudonville, OH 44842
Posts: 1,331
Default

Cracked block is a cracked block and a cracked head is a cracked head.

If I was trying to save a RAV head or something, I'd try the stitch plugging stuff. Drill, tap, plug, grind and repeat...

I tried to torch weld a crack once. Drilled a hole at the end of the crack, ground a groove along the crack, heated up with the torch and started welding. Everything was going fine till I noticed a crack was chasing my welding.

All the effort of block fill, steel main caps, align honing mains, and you can still only max bore to 4.250. Then praying you don't find rust pinholes in 30 year old castings with .040 or less wall thickness to concrete in places.

Motor Plate better but not the cure.

Get an IAII.

-Rob

  #18  
Old 03-01-2005, 08:57 AM
PONTIAC DUDE's Avatar
PONTIAC DUDE PONTIAC DUDE is offline
Ultimate Warrior
 
Join Date: Dec 1999
Location: West Central Florida
Posts: 14,756
Default

Repairing cracked parts (I.E. Iron Heads, Iron blocks) is for <span class="ev_code_RED">Very Rare</span> or #'s matching <span class="ev_code_RED">Very rare</span> collector items.

  #19  
Old 03-01-2005, 10:45 AM
Blowing hot air Blowing hot air is offline
Member
 
Join Date: Feb 2005
Location: Plainfield, IL. (Suburban Chicago)
Posts: 30
Default

Maybe a dumb ? But does the IAII block come machine or do you have to have everything machined?
Thanks Tom

  #20  
Old 03-01-2005, 11:42 AM
Larry Navarro's Avatar
Larry Navarro Larry Navarro is offline
Ultimate Warrior
 
Join Date: Dec 1999
Location: Spring(Houston) Tx. USA
Posts: 6,369
Default

Hey Shay.....glad to see you are finally here!
Took you long enough!

__________________
Home of WFO Hyperformance Shaker induction.
Reply

Thread Tools
Display Modes

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 06:04 AM.

 

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.

 




Copyright © 2017