When doing a hot adjustment on valve lash on my engine, I had an adjuster where the jam nut wouldn't turn. Seems the threads on the harder than the hinges to the gates of hell adjuster had started chipping off and had jammed the nut. It wouldn't turn even 1/6 turn with a hand screwdriver. Fortunately I have another rocker assembly I was able to rob an adjuster off and replaced the bad one. I ran into a couple of others that had the same issue back when I was assembling the engine and doing a cold valve lash adjustment. If I didn't have spares, I would have been dead in the water waiting for a replacement. Just something to look out for.
Here's a pic of the adjuster after I used a 1/4-inch impact driver to get the jam nut off.
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.
That looks like someone in the past has overtorqued the locknut and stretched the thread. Mr. Bad Pliers probably used a long box end wrench or a breaker bar on the locknuts to be sure the next guy would have a rough time adjusting the valve lash!
Here's a novel idea- - - -a spring loaded ball bearing in the adjuster screw that keeps a little pressure on the rocker arm tip all the time- - - - -The "Q-T" adjusting screw! I've got a couple of sets of them stashed away.
"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!
Those adjusters look pretty cool. I just bought that set. Considering that Chevy's of the 40's wants $15 each (with nut), that's a bargain.
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.
Be sure to keep a FIRM down pressure on the adjuster screw during a valve adjustment to compress the spring so you get an accurate clearance adjustment. Now that you've got your set, I'm tempted to buy the rest of his stock. 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!
I just bought the seller's remaining 4 sets of adjuster screws, and 25 7/16-20 stainless steel jam nuts to complete the assembly. PM me with a snail mail address, and I'll send you some new lock nuts. 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!
I bought a set from another seller for a bit more $ after Jerry bought out the other seller, but still at a great price compared to Chev's of the 40's. For anyone else interested in some of these, here's the other seller offering now 3 remaining sets:
Edit Note: As of about 8:00pm CDT 5/24/2026 there are only 3 sets still available from this seller.
Last edited by Gdads51; 05/25/20261:08 AM. Reason: add edit note
~ 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)
Thank you both for this information. So, these will work for a 235 engine ?
Ron - - Dusty53 1954 Chevy 3604 In the Gallery Forum "You can't dance with the Devil and then wonder why you're still in Hell." "They will forget what you've said, and they will forget what you have done but they will never forget the way you made them feel."
Ron - The original valve adjuster screws GM# 837385 are listed for all Chevy 6 cylinder engines 1934-62, so these should work to replace any original pieces.
~ 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)
Rocker arm adjusting screws for a 1954-65 Ford 239/272/292/312 V8 engine will also work on stovebolt rocker arms, if you prefer the regular ball tips instead of the spring loaded Q-T ones. Any half thickness (jam) nuts in 7/16-20 thread will work as lock nuts. The ones I bought on Ebay are Grade 8 stainless steel items. Use a little Never-Seez on assembly to prevent the stainless threads from galling.
Here's an interesting item- - - -it combines a screwdriver and a 1/2" square drive to hold a socket during valve adjustments. I've got part of a similar tool stashed away, one that I'm about to fabricate the missing bits and pieces and put it back int service.
"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!
About 5 minutes on a belt sander reduces the outside diameter of all 12 adjusters enough to make the difference in radius a moot point. Panic just likes to stir the proverbial pot a lot. 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!
Attended a local swap meet today. I thought I might find some of those Ford adjusters to try them out. Didn't find any Ford adjusters but I did find a 235 head. I didn't want the head, but there was some other parts hidden under it. The guy sold me the rockers, push rods and adjusters for $10. Threw in the valve cover to carry all of it home. Looks like one of the adjusters is messed up just like the picture in Kevin's post above, but the rest seem good.
Sounds like a great score there Gord! Lots of "spares" for future needs.
~ 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)
