[64speed]

This failure didn’t involve fire like my last Chevrolet so I’m still ahead of the game.

[geeteeohguy]

Originally Posted by 64speed

Well I have the heads and the forged rotating assembly. The cam is screwed. Paul Carter picked that cam specifically for my gear,trans,tire height, it was perfect….but it was rowdy. I think a rev limiter and this never would have happened unless it’s was a crack that would have eventually failed regardless. The car is/was outstanding and will be again. Isky is fixing the cam and Wayne will do his thing. Good thing we are friends and I can make payments

Have never seen lifter bosses break off of a block on a stock Pontiac in 45 years of playing with them and other engines. Have never seen a cracked boss on a stock block either.

What about the rest of you guys? My gut tells me that the aftermarket parts are the cause of this failure.

When I was in the auto industry, 99% of the time when something failed, it was the 'upgraded' aftermarket part that caused the failure, not the factory engineered and designed part. This was just as evident when I was in the Model T club as it is here and on the Corvette and Tundra forums.
I see a lot of money being spent on engines and running gear that doesn't even make 1000 miles before it explodes....usually due to poor quality parts.

[64speed]

Originally Posted by geeteeohguy

Have never seen lifter bosses break off of a block on a stock Pontiac in 45 years of playing with them and other engines. Have never seen a cracked boss on a stock block either.

What about the rest of you guys? My gut tells me that the aftermarket parts are the cause of this failure.

When I was in the auto industry, 99% of the time when something failed, it was the 'upgraded' aftermarket part that caused the failure, not the factory engineered and designed part. This was just as evident when I was in the Model T club as it is here and on the Corvette and Tundra forums.
I see a lot of money being spent on engines and running gear that doesn't even make 1000 miles before it explodes....usually due to poor quality parts.

My first Pontiac was a 64 Lemans with a 66 389 and Muncie. The only thing I ever did was put oil and gas in it. I drove it as my only means of conveyance for 4 years. I agree, mild stock parts probably don’t fail as often, but find OE quality stuff now. It’s pillar or post. You can buy 500 roller lifters and hope for the best or you can buy 1200 buck Crowers and still hope for the best. The Chevrolet fire I mentioned was a stock 89 Jimmy that windowed the block for no apparent reason and severed the fuel line onto the exhaust. Freak accident I agree and I was able to save it from total loss but there are no guarantees is my point I guess. I could build it back milder but what’s the fun in that?

[geeteeohguy]

Originally Posted by 64speed

My first Pontiac was a 64 Lemans with a 66 389 and Muncie. The only thing I ever did was put oil and gas in it. I drove it as my only means of conveyance for 4 years. I agree, mild stock parts probably don’t fail as often, but find OE quality stuff now. It’s pillar or post. You can buy 500 roller lifters and hope for the best or you can buy 1200 buck Crowers and still hope for the best. The Chevrolet fire I mentioned was a stock 89 Jimmy that windowed the block for no apparent reason and severed the fuel line onto the exhaust. Freak accident I agree and I was able to save it from total loss but there are no guarantees is my point I guess. I could build it back milder but what’s the fun in that?

You had stated that it was a bit much for the street. I guess you changed your mind since you posted that.

[64speed]

Originally Posted by geeteeohguy

[/B]
You had stated that it was a bit much for the street. I guess you changed your mind since you posted that.

You’re right, I waffled and I’m man enough to admit it. My father in law said it was too “rowdy” but it idled good, pulled 15 pounds of vacuum, got 14 mpg with that overdrive and Ran like a raped ape. I was just getting the kinks out when this happened. The cheapest thing besides a flat tappet is letting Isky fix it for 225. Not a lot of cams I can pick that will do all that and be such an overall package. By the way what happened to GTOFREEK. He’s the one that spec’d it for me

[tom s]

Bores do break when solid roller cam get to 200 lift at 200 duration with out a lifter bore brace.Tom

[grivera]

Are you keeping the BB Chevy rockers for the new build?

[64speed]

Originally Posted by grivera

Are you keeping the BB Chevy rockers for the new build?

I will leave that to Wayne’s discretion because I will reuse everything I can within reason

[grivera]

Originally Posted by 64speed

I will leave that to Wayne’s discretion because I will reuse everything I can within reason

I would recommend Crowers or Harland Sharps for [Pontiac] in case geometry had anything to do with it.

[b-man]

I’m wondering if perhaps a switch to a solid flat tappet cam might be an option for long term durability.

I know they are expensive but maybe some tool steel lifters could be utilized to eliminate what seems to be the hit or miss quality of roller lifters and subsequent failures on street driven vehicles.

[Gach]

If GTOFREEK spec the cam, you can bet it’s a good one and not a lifter bore destroyer. Yeah once you have that power it’s hard to go back. The power is addictive. My advice make sure lifter bore area is cleaned and maged real good, which I’m he will anyway.

[P@blo]

Originally Posted by Gach

If GTOFREEK spec the cam, you can bet it’s a good one and not a lifter bore destroyer. Yeah once you have that power it’s hard to go back. The power is addictive. My advice make sure lifter bore area is cleaned and maged real good, which I’m he will anyway.

I always wondered about claiming X cam has too much side-loading of the lifter bore but wouldn't a thickness measurement be required to make that claim? Just spit balling but I assume not all lifter bores are the same thickness and some blocks might not be up to the task even with a smaller roller.

The suggestion on a SFT cam is a good one. Look up some on the old posts from GTO Karl.

[Dragncar]

Originally Posted by b-man

I’m wondering if perhaps a switch to a solid flat tappet cam might be an option for long term durability.

I know they are expensive but maybe some tool steel lifters could be utilized to eliminate what seems to be the hit or miss quality of roller lifters and subsequent failures on street driven vehicles.

Or solid roller with these. They have a pretty indestructible reputation and with a street cam would last a long time.
Price went up though, I paid 1000$ for mine.

https://vincentperformance.com/shop/bam-b-2030-16-bb1/

[64speed]

How high should my worry level be about valve to piston contact

[Gach]

Not high at all, usually something on a 112 has plenty of piston to valve clearance and most likely it would be on a 112. For street ability

[Gach]

You can run solid rollers on the street guys been doing it for years, with no issues.

[Gach]

They are not nosey yes they require maintenance, but it’s not a big deal. It’s basically checking valve lash, once the initial set up is done. Something to definitely think about, but I definitely wouldn’t go with a bush lifter.

[Gach]

Yeah now you got allot of things floating around in your head.

[64speed]

Originally Posted by Gach

Not high at all, usually something on a 112 has plenty of piston to valve clearance and most likely it would be on a 112. For street ability

It’s on 112

[Gach]

Yeah and no doubt you have plenty of piston to valve clearance. The tight lobes like 108 -106 is were you get into piston to valve clearance.