so, i've noticed alot of guys using gotha adjustable rocker arms have issues with them not staying in adjustment. is there any way to aleviate the adjustment problems? possibly changing the adjuster or putting a very thin coat of say loctite on the threads just to keep them from backing out? anyhow, this has been bugging me and i want to know what could be done to fix the issue.
Sounds kinda stupid but on some things where the nut seems a bit loose ill tap on the threads with a hammer, not killer hard, just enough to flatten the threads a bit. kinda like how a metal lock nut is kinda smooshed a bit. but lock tite should work too. JEFF
I've seen guys upgrade them to use a slim locknut. In all out competition they were going for as light as possible, but there's way better hardware out there for that now - so I assume your not near as worried about the weight of a locknut. I've used loctite on mine, but honesty am not sure I trust it.
That problem is inherent in all adjustable rocker arms not just Gotha. Adjusting screw jam nuts need to be torqued rather than snugged to keep them from loosening. I torque mine to 35 lb/ft.
Due to the fact that Gotha rockers don't use a jamb nut, but rather a tapered bolt (like a pipe thread) you have a few options. First would be to 'stake' the threads on the bolt lightly. This means you can use a hammer or hammer and punch to SLIGHTLY flatten the threads. This will create an interference fit and should help hold them. Using Loctite is perfectly fine if you don't need to do constant adjusting. The Gotha rockers I ran on my Nailhead really didn't need much adjustment for the ten years I ran them. I think I only adjusted them about 3 times and mever more than .001-.002" out on a couple of them. Installing locking nuts can be done but you will have to make sure the ones you get will work with the tapered threads on the existing bolts. or finally you can purchase the more common style bolt/nut set up and likely have to open up the holes in the rockers to accept them.
very interesting. i've heard some guys saying they were constantly screwing with them. well considering i'm not really building an all out competition motor here, just a healthy street motor, im sure tracking down a jamnut to fit and use would be a safe bet. interesting stuff.
I am pretty sure once they have been turned in far enough to 'open' the holes some, anytime you try to get them to stay at a lesser adjustment, they will back off. Think of them as pipe plugs.
Actually if my Gotha's are anything like yours they are not really tapered at all. They are almost "standard" (but not quite) - and most definitely straight. What they use is a special thread form with a flat valley that is meant to interfere with the mating thread. As they get adjusted several times they simply wear out and loosen up. The jamb nut is an addition and you may want to closely inspect the register where the nut will bottom as it will most likely NOT be flat and perpendicular as you would want it. It might require some massaging to get it optimal.
good to know. i never took mine apart enough to chech the thread pitch, so i assumed they were more like a tapered thread. we all know what happens when we assume...
the screw threads are sharp and quite hard, I had a set on an Olds 394 many years ago that had a couple rockers that would not stay in adjustment. it was the rockers that would wear. in the end I went back to the stock rockers and used adjustable pushrods
While looking for something else I ran across a spare Gotha Adjuster screw.....I snapped a pic and while it's not a great pic - I think you can see the FLAT VALLEY I spoke of earlier. It is this flat that interferes with the mating thread. It is similar to a KEENSERT in which you drill a LARGER than normal tap drill and then tap it with a standard thread - the result is a thread form with a FLAT on the tip of the INTERNAL thread - bigger the tap drill - the bigger the flat. In this case the tap drill is STILL smaller than the diameter of the flat on the adjuster screw - resulting in an interference. That interference is what "locks" it into position. And of course it also wears out. So a regular jam nut can be used but it will of course INTERFERE with the nut threads so you may want to drill it out slightly.
These were built in the "60s and have probably been adjusted hundreds of times and are worn out. Had the same problem with Flstheadlifters years ago.
Man I guess I have been very fortunate to have a set that is not used up yet. I pulled them off a few years ago to run Telesco Roller-tip rockers, that was quite an improvement! Still keep the Gothas on the shelf for the next project.
Go to fastenal and get some grade 8 locknutsto fir.....if not, get each individual adjuster stud and dimple the threads on a anvile slightly....works every time.......
Tom Telesco had 100 sets made for Nailhead Buicks. He is occasionally on this site, more commonly on v8buick.com and goes by TelRiv on both sites. He is located here in CT and is not only an excellent source of Buick parts and knowledge, but a really good guy as well. I have his contact info somewhere, but you can find it easy enough on the v8buick site. By the way, the rockers work awesome. He also has high torque mini starters for Nailheads as well.
Tom Telesco C/O Classic & MUscle Automotive 465 Glenbrook Rd. Stamford, Ct. 06906-1820 203-324-6045 Great guy....
Hi Paul, who makes adjustable push rods nowadays? I have a set of Gotha rockers, that I'm trying to use on a 324, and someone has apparently replaced some of the push rod cups with some that are too small for the push rods to seat into. It would be great to find some "right size" cups but I'm getting desperate
I'm considering going to stock rockers and adjustable push rods. Sorry for the 2 part post but something is flaky this morning.
Yes, what Rich said, I have used Smith Brothers Pushrods too, not just for adjustables but any odd length or end rod
I've used adjusting screws made from long fine thread Allen set screws with machined 5/16" balls on the end. Also check and see if you can rethread the rockers for a bigger size. I now use 3/8" Titan adjusters in my home made rockers on my GMC 6. They were longer and came with thin pal nuts.
There are helicoils that are wave lock thread for when you want a self locking internal thread. They may even have the thin wire style so you don't need to drill and tap as much.
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