Where can I locate a set of nuts for my 235 rod bearing bolts. Also, is there an updated, say self locking type nut, or the regular nut with the keeper would be sufficient?
Last edited by Peggy M; 04/07/20244:58 PM. Reason: added more info to the title
Ol'55, It would help folks provide helpful info if you let us know what year your 235 is.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
OK I am just gonna think the clue is in the posters name. Pal nuts were used up to and including 1955. Think a light duty lock nut. Available from Classic and others. I am not aware of self "locking" rod nuts. I hope this is helpful.
For more modern locking nuts try HERE. You'll need to measure the diameter and thread pitch to get the right size, of course.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
3/8-24 Grade 8 nut- - - - -don't bother with any sort of locking device. Torque keeps rod nuts tight- - - -not some kind of Mickey Mouse plastic lock ring, Pal Nut, or cotter pin. If you're determined to get obsessive-compulsive about it, use a drop of red LocTite. Heat the nut to 500+ degrees F. if you ever need to take it apart again. That's how we built our 700+ HP small block V8s that ran 7K RPM or more twice a lap. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
So, why did the factory use pal nuts on the dipper engines and drop them on the full pressure engines? They weren't free and each engine needed 12 of them.
1951 3800 1-ton "Earning its keep from the get-go" In the DITY Gallery 1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.
Stupidity and over-engineering everything. Why did they use four different size main bearings on engines producing less than 100 HP at the flywheel? Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
My guess as to why they used pal nuts on dipper engines, but stopped using them on engines with insert connecting rod bearing was due to the possibility to run the engine with babbitt bearings longer before you ran out of bearing material. Seems to me that a well worn, loose babbitt connecting rod is more likely to rattle a connecting rod nut loose if it weren't held fast by a pal nut. Add to the scenario the extra stress on everything caused by a loose dipper constantly having a jet nozzle spraying oil at it. BTW, it has been my experience that GM did not stop using pal nuts when the dipper engines were phased out. They used them for a few years on insert bearing engines.
Last edited by 52Carl; 04/09/20241:30 AM.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
I've found lots of Palnuts in the bottom of oil pans, buried in a layer of sludge. They were notorious for coming unglued- - - -which makes me wonder how effective they were at keeping rod nuts tight. They were also used on MOPAR engines- - - -which were all equipped with insert bearings. Even a slight overtorque of that sheet metal nut would strip it and make it prone to come off. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
The Book says to install new ones and not to reuse them. Those are likely the ones that end up in the sludge receptacle. I have found them there myself a few times. One time I found one, but there weren't any missing on the connecting rods. Goober must not have clean out the oil pan in 1954 when he peeled some shims during a half-hearted overhaul. I don't use them on insert bearing engines even if that came with them, but I won't drive one that has a rod knock either.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
I once had a BMW 320i. On changing the oil one day, on a whim I stuck my finger in the drain hole and felt something move. Got a magnet and fished out a con rod nut.... aaach! What to do? By this time the car had 100,000 + miles and I figured if it was going to come apart it would have already. But I worried the issue for some time, considered pulling the pan to look. But didn't. Sold the car with 250,000 mi. still running well.
1951 3800 1-ton "Earning its keep from the get-go" In the DITY Gallery 1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.
Tommy -- Same experience. But with a backhoe diesel engine. Found the bottom inch of a push rod. Engine ran great.
~ John
A kid raised on Hotwheels, Matchbox and Tonka cannot be reasonably expected to own only one vehicle as an adult.
1949 Chevrolet 3804 In the Legacy Gallery | In the Gallery Forum 1973 IH 1310 Dump 1963 Kaiser M38A1 2001 International/AmTran RE3000 "Skoolie" 2014 Ford E-350 4x4 (Quigley)
PAL nuts, broken adjuster ball from a rocker, the remnants of the O ring seals from valves, all in oil pan sludge. But, they kept going and going and going, lol.
With the new nuts installed what is the torque again?
To get back to your question, see the screen shot below from a 1955 2nd Series Truck Shop Manual for your rod bolt torque specs.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
