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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Looking for some advice on sealing my rocker stud. I put this vortec engine in about six weeks ago and it started missing this morning. After work I checked it out and found one of my rocker studs backed out. I pulled it all the way out to check if the threads were ok and put some lock tight on and had coolant come out. Now I'm not sure what will seal and keep it in for good. Thanks to anyone with advice.
Thanks, I appreciate the quick response. If one more comes out I'll probably redo the rest. I hope the machine shop didn't put them in hand tight and rely on the sealer to hold them since they didn't have a hex on them for torquing.
yea, that's odd. usually you see a hex for tightening them down. i guess you could run a nut down them to the head for some clamping force if you have room?
Quick update. Doing the one loose stud worked for a few days. Lost another one and it took the pushrod with it. So I spent my Saturday doing the rest. Used a old poly lock to tighten them all with new sealer. Took way longer than I ever thought but good thing I did all of them. More than half the studs came out when I tried to take off the rockers.
NEVER EVER EVER EVER use Indian Head shellac on an engine anymore. That's one of those old obsolete materials that they used to use back in the World War 2 days, that's been completely replaced in the last 75 years or so by better stuff. It's one of the main reasons that cars from the 50s and 60s hardly ever went more than 100,000 miles without engine rebuilds: they got to where they leaked EVERYTHING from EVERYWHERE, directly attributable to using sealing materials and methods like cork, natural rubber, and shellac, all of which turn to dust and disappear under long-term engine operating conditions.
We can do MUCH better than that today.
My personal preference for rocker studs is the Permatex/Loctite (same company, 2 brand names) "automotive high-temp thread sealer with Teflon". (which what y ou are using, looks like it might be that) The #3, which looks similar to the old shellac museum article in spite of being a FAR SUPERIOR material, is good for various other things, and while it will "work" for threads, isn't really the "best" choice for that application IMO.
I used the permatex. I called around for the 569 but no one could get it till the next day and I wanted the first stud fixed that night. I think they must have never been tight enough the moter was only running a few weeks when they backed out. I'll keep checking my oil cap for moisture for a while. And to think I told them to do the threaded studs so I wouldn't have any trouble.
I use locktite blue on flywheel bolts that protrude into the crankcase on some motors. It works to seal the threads and prevent backing out. The key is to be sure the treads are clean and dry and don't be conservative with the liquid. Make sure the treads are well coated. Never had one leak. I haven't tried it on screw in studs but seems like it should work. My only concern with the teflon is that it is a non hardening lubricant. Should be fine though as long as you got the studs tightened securely. The teflon isn't going to help keep them in.
I also still use Permatex #2 on alot of threaded fittings where retention could be an issue. It hardens and keeps things in place better than teflon.
Funny to see a photo of Indian Head. I think I have an old bottle, long since dried up I'm sure, collecting dust on a shelf somewhere. Went hand in hand with cork gaskets. Lol. The Permatex #3 Aviation is good stuff though for sticking gaskets on valve covers and such.
The GM white Teflon sealant does harden and seal threads. The intake studs are usually the ones to pass coolant. If its the exhaust then you have a problem. If not have heads machined down for screw in studs (with hex nut) and or forpush rod guides also.
Joe
Well it’s been a few months, but I have more rocker stud trouble. This time one of them broke. It has a almost stock cam in it I can’t imagine why it broke. The exhaust stub broke but does anyone have any theories why the intake pushrod bent all to hell. I checked the intake valve and it moves easily. I need to check if ARP makes this style stud, really not interested in pulling the heads and getting them machined for hex style studs.
I'm not sure if it's just me but those rockers look really close to the stud bosses, and there are allot of threads sticking out of the poly-lock set screws, mine are almost flush ...did you check the valve train geometry, your pushrods might be too short putting a side load on the rocker studs and possibly letting the rocker come in contact with the stud boss....just an observation based on the pic...
I noticed this as well. Looks like your push rods are too short. Also it looks like a push rods is missing for the #7 cylinder intake side. Pull a pushrod and measure the length.
The engine is a 98 vortec. The pushrods are the original for it. The bent one in the picture is from the intake. When the exhaust stud broke the pushrod came out unharmed.
The rocker probably looks extra low because the pushrod is out. Maybe the threads poke out further because they are aftermarket threaded studs. Just got a new set of studs from Speedway today. I’m going to just replace the broken stud, if one more goes I’ll do the rest all together.
When you grow up you'll learn to do em all the first time, given that a SUBSTANTIAL portion of the w .... w ... wo .... {throw up a little in the back of my mouth...} ... wooor ... {hurl} ... {worship ralph the porcelain god at length} {totally empty my guts in reverse} ... work .... {flush my mouth with a fire hose and a bottle of Dawn} ... sorry, I have real trouble typing filthy 4-letter words like that without my moral filter kicking in... is in the process of GETTING THERE. Once you're there, finishing them ALL is a piece o cake.
Just do it. Get it over with. Never have to go back and do it AGAIN. (assuming of course, there isn't something ELSE wrong causing all this... but at least you can sleep better at night knowing your rocker studs are as solid as they can be)
The only reason I don’t want to do all of them now is the new studs may be the same as old ones. The machine shop that did the work closed down and I can’t ask them if they remember what they used on them but the new ones look identical. If I could have bought ARPs in that style I would definitely swap them all.
05-30-2017, 06:28 PM
