Chevy & GMC Vans

I've heard that the 4.3 V6 has a weak crankshaft...never saw a broken one until now. This one is from a 1988 Astro.



Can't say that this is a real problem to the vast majority of 4.3 engines, though. This crankshaft is from an engine that was dropped off at Bryan Engine Rebuilding and the business owner said that it's the first broken crank he's seen from a 4.3.

Hmm, that's the first time I've heard of one. Given the 4.3s running around with 150-200K+ miles, I guess it is a 'problem' we can live with!

I like the earthen backdrop contrasted nicely with the man made destruction, nice effect

I've never heard of the problem either....

Zam: it is a nice pic i'd use it as a background for my work computer

I'd like to know some history on that 4.3. You just don't see broken cranks these days. :-k

I like the earthen backdrop contrasted nicely with the man made destruction, nice effect

Is very picturesque isn't it ?
Obviously a Fall crank event.

astrozam wrote:I like the earthen backdrop contrasted nicely with the man made destruction, nice effect

Keith, you got me laughing out loud with that reply. Larry, you made me continue with the laughter!

All I know about this crank is that the guy who owned the van, which had high miles, was just out driving it normally and suddenly there was a lot of noise and the engine quit. That much I was told, but I'm sure he tried to start it. The starter gear would still engage the ring gear, but I bet the racket made while cranking told him that something was very, very wrong.
A couple of the main bearings were spun and one of the main bearing caps was gouged up pretty bad, but the block was okay. In fact, the block, heads and manifolds were used to build an engine that found its way into a 91 Chevy pickup truck.

I've heard that the 4.3 V6 has a weak crankshaft...never saw a broken one until now. This one is from a 1988 Astro.



Can't say that this is a real problem to the vast majority of 4.3 engines, though. This crankshaft is from an engine that was dropped off at Bryan Engine Rebuilding and the business owner said that it's the first broken crank he's seen from a 4.3.

_________________
Rob Shaver
1989 Astro 305 with an MSD 6A ignition and a dash-mounted MSD timing control, a 4160 Holley 465 cfm four barrel carb, and an HEI distributor.
Moog 625 front springs and Energy Suspension poly bushings. Rear OEM sway bar. Edelbrock shocks.




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Rob,,so now that's over with,,,what's going on in the far north. You up to another transplant bud or is this really someone elses tragedy ?

Larry,

No, that crank has nothing to do with me, I just had to get a photo and post it cuz I'd never seen one broken before and figured that you guys might not have, either. Like I mentioned, the owner of Bryan Engine had never seen a broken 4.3 crank before this one.
I'm still working slowly on the Chevy 350 rebuild for my 82 Olds Delta 88. Really put the emphasis on the word 'slowly' when you read that last line...There isn't much left to do on the 350, but it's a matter of making the time to do it. Finding the proper pushrod length is next on the agenda for the engine. Can't run the stock length as I'm using full roller rockers (steel ones from Comp Cams).
Replacing the engine is phase 1 for the Olds; phase 2 will be the installation of a 5 speed manual transmission. Just last Saturday I bought a 1984 305 Camaro Borg Warner T5 transmission and bell housing off of craigslist for the Olds. I had my heart set on a Tremec TKO 500 transmission but sure didn't have the $2000 plus for it. So spending $200 for the T5 appealed to me. The transmission seems fine, I just hope it'll slip into the Olds with minimum fuss.

By the way, the shift lever measures about 22.5 inches back from the bell housing lip. A quick and dirty measurement in the Astro tells me that this Camaro T5 would have its shift lever poking through the floor about even with the rear of the driver's seat if I were to install the transmission in the van. I've read that a T5 from an S-10 has the shift lever much closer to the front of the transmission. That would be a big plus in an Astro.
If you want to read my long, rambling postings concerning my Olds, you can go to CD Smalley's website, B-body.org, by clicking here.

Wait a minute! Did I just violate some forum rule?! Yikes! I beg mercy, O, Zammer!

Smiliesafari wrote:I'd like to know some history on that 4.3. You just don't see broken cranks these days. :-k

Something else happened here, it looks like an oil stavation problem and spun a main journal bearing where the crank broke. Look how black that main journal is compared to the other silver ones, it got real hot.

I agree with you, Darren, about oil starvation. But it broke at a rod journal, not at the main. Very unusual to say the least.

good observation socali!

it is discolored.. may have (most probably) spun the bearing first then heated up and snapped. it is also the weak spot in all offset journaled crankshafts. V8s included.

I used to do R&D for Buick Special Products Division, we tested for crankshaft flex/twist Ive seen cranks snap and engine blocks divide into peices right infront of me.. it was a cool gig. we made progress... dominated. then Buick was outlawed.

yes, nice backdrop for the photo ;-)