Stock rods..Pistons..and Crank..??

Buix893

Buick = $$$
Joined
Jul 2, 2009
How far can one go safely with the stock connecting rods? And what about the crank shaft and Pistons? Would Low 11's on a stock motor be safe ya think?? Of course if the tune was rite, I have gone 11.67 on my car, all that is done to the motor is ported heads, timing chain and valve springs.
 
How far can one go safely with the stock connecting rods? And what about the crank shaft and Pistons? Would Low 11's on a stock motor be safe ya think?? Of course if the tune was rite, I have gone 11.67 on my car, all that is done to the motor is ported heads, timing chain and valve springs.

Thats a hard question to answer IMOP. I have seen stock internal motors turn some great #. However i have also seen some slow 13's motors gernade all over the track.

im running a stock crank and rods and lets just say i have been 11.00 ;)
 
That's good to know....Also the motor has 37K original miles, so I am hoping to get Loooots of 11 sec runs outta it with a safe tune...:biggrin:
 
My tune is nothing special, but I always tune the car rich when I start playing with it then try to equalize it as I get settled. I know the motor has pretty low miles, and The only time I beat on it is at the track, but I know a few guys with stock unopened motors that run low 11's and beat the snot out of it and because the tune is great the car holds together perfectly fine..and that's with motors with 120K+ miles..lol

My concern is how long on the stock internals can one run low 11's...guess I will find out? I am also guessing everything has a breaking point, or does it come down to wear and tear?
 
problem i see is the stock crank. since its cast who knows how well the mold was. Air pockets weak areas etc.
 
I will bet you will see the 2nd & 3rd main crank bearings wear quickly due to crank flex
 
I will bet you will see the 2nd & 3rd main crank bearings wear quickly due to crank flex

X2

From what I've seen. When you start going low elevens with one of these sleds, your flexing the stock crank pretty good. I have known people (including myself) to put hundreds of low eleven second runs on a stock bottom end and have it live quite a while. Even with a "safe" tune, you'll be loading the bearings in ways that they weren't ment to be loaded. The engine can't last forever doing this. IMO, your on borrowed time. You just need to be all over the tune, like a fat lady on a jelly donut.;)

Happy spooling.

Mike Barnard
 
problem i see is the stock crank. since its cast who knows how well the mold was. Air pockets weak areas etc.
Thats cast nodular iron which is a lot different than plain old brittle cast iron. Several in the last couple years have cracked pistons running over 700hp.
 
Anything I can do to prevent the crank from taking a poop? If running low 11's is a issue then I will keep it at mid elevens like I have it now.
 
Thats cast nodular iron which is a lot different than plain old brittle cast iron. Several in the last couple years have cracked pistons running over 700hp.

so in your opinion whats the weekest link?

figured the crank is a un-known for the most part
 
so in your opinion whats the weekest link?

figured the crank is a un-known for the most part

The block holding the crank.The two bolt main design with the pretty thin webbing tying it to the thin skirt wall will cause a lot of movement under higher HP levels. that is why guys use billet caps, and some go even further with a girdle.
Look at the 3800 series blocks those were built with vast improvements and for the ultimate the TA aluminum block with 6 bolt mains.
Nodular iron cranks are what most OEM manufacturers use for crank material and they are very reliable and durable.
 
so your saying the block is the weakest link first before the crank,rods, and pistons?
 
Yes.
The Buick 2 dot rods are great beefy pieces compared to what other factory camps (including GM) churned out.
The stock Pistons were also great for a cast piston with the steel top ring insert and steel reinforcements under the pin bosses. Many of cars went very fast in the early days with these.
The crank is in last place of the above two but that is because of the offset rod journals made for the even fire v6.
But it still is in cars that run 9 seconds.
It is the side to side, up and down, and front to back movement that causes an early death.
Put that same crank in a sturdy block saddle and cap assembly end and it lives much longer. That's not just Buick that is any engine.
The 109's block's crank area is no different than the early NA versions.
 
Hmmm...so ya think I should install billet Caps? I don't think it would hurt anything, but if anything help me
 
Have gone 10.17 134mph with stock crank, rods and block did put 30over trw pistons with a great set of IRON heads and a 212/212 bilet roller, was hoping for 9,s with the combo but had Drive shaft problems at last race!!!
with a crappy 60fts!!!

the tune is the MOST important part!!!

JD
 
Hmmm...so ya think I should install billet Caps? I don't think it would hurt anything, but if anything help me

I'd say do the caps and studs when you go to a forged crank. Until then...no knock...have fun.
 
Thanks guys for the answers...I should be ok then with my mid-low 11 sec goal for now till I upgrade the internals... sounds good....:cool:
 
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Have gone 10.17 134mph with stock crank, rods and block did put 30over trw pistons with a great set of IRON heads and a 212/212 bilet roller, was hoping for 9,s with the combo but had Drive shaft problems at last race!!!
with a crappy 60fts!!!




How many times? have you looked at your bearings
 
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