The Stovebolt Site Forums The Shop Area Engine Shop 235 Rods

My 235 with 40K on a rebuild sounded like it threw a rod about a week ago. I towed it home, took it apart and was hard pressed to find the source of the noise. Finally figured out it was the small end of #1 rod. The bolt looks like it was backed out 3/16 resulting in an oval small end. I don't see any marks indicating the threads tore out. How common is this failure? Should those bolts be lock tighted in or did they use lock washers? I did find a peice of what looks like a lock whasher in the oil pan. Don't have my shop manual with me so not sure how they went together. Was assembled by the machine shop.

Good news is this will be a cheap fix, new rod and perhaps wrist pin. Bad news I don't have an excuse to build a 261.

Also wonder if anyone has tried using non copper head gasket? Ordered a headset from Napa (Victor with Napa name) and it wasn't copper like the one I got from Patrick's. Think I may order from Patrick, also cheaper.

Thanks

This is a good question. My '54 rods had lockwashers. I bought 6 reconditioned rods for my 235 build. 1 had a lockwasher and 5 did not. Should these rods have lockwashers, or is locktite the way to go?

Chip

Charlie Baker's "Building the Really Right Inline" states that the 216/235 rod design, specifically the small end "pinch bolt" style, is a weak link for a motor turning high RPM on a regular basis. He speaks more of the pinch bolt or wristpin journal itself being prone to breaking under stress and notes that the 261 rod was beefed up considerably. Supposedly the 235 Corvette rods had this improvement too.

So much for my two-stage nitrous....

I'm more worried about the wrist pin coming loose and digging a trench in my fresh block.

Are the vette rods being repop-ed?
Will 235 and 261 rods interchange?
Why do we build these motors when they fly apart like cheap chinese coo-coo clocks?

I've never been able to confirm the Corvette 235 story, there were many differences in the Corvette versions - different heads, block castings etc, even running changes between '53 & '54 versions but it seems the factory didn't publicize or document what went into these engines, or at least I haven't been able to dig it up. The Vette 235's were tuned for higher RPM - they definitely used dual-wound valve springs, solid lifters, and a different camshaft - so beefed up rods would make sense.

The 261 rods are the same length and the big ends are the same, but the wristpin bores are larger than the 235. GMC rods can be modified to work - big ends have to be narrowed - but require cu$tom pi$ton$ due to different compression height. So it seems there are no easy alternatives, at least affordable ones.

Hey Sixpack where can I find Charlie Baker's Building the Really Right Inline? Is it a book or article?
Thanks.

Chiphead, These rods should have lockwashers. I'm pretty sure that my rod failure was due to a lockwasher breaking allowing the small end to open up the thickness of the lockwasher. I talked with Leo Santuci, the 292 turbo guru. He used to race 216's, 235's and 261's and says he believes my engine woes is a freak occurance. He never had a rod or crank failure, never replaced the lockwashers or bolts with new ones. He is allways trying to convince me to put a turbo or at least nitrous on my 235, so he believes the 235 will take it. Now if I can just find out what to torque the pinch bolts to.

"Building the Really Right Inline" was a series of articles in the Inliners "12 Port News" back in the late 1980's. Very detailed info using a 261 hot sreet engine. Most of these issues are out of print now. But there are at least two new books in the works on the 235/261. The Inliners web site will probably have an announcement when they are avaialable.