just curious for anyone out there that has heads with rocker studs which protrude into the intake runner. what, if anything, do you use to seal the threads to prevent the motor from sucking air and oil through the threads into the chamber? do AFR heads have the rocker stud hole protruding into the intake runner?

 

far as i know they're all blind holes

 

The intake rocker studs go into the intake port roof.
The exhaust rocker stud goes into water on some heads.
Just put some gasket sealer or silicon RTV on the threads when you install the studs.

 

Factory LT1 heads have the same thing. I prefer PST on the threads to seal them. The factory used nothing except what appears to be LocTite on the pressed studs on iron LT1s.

 

Use Liquid Teflon Pipe thread sealant. I use the GM version. Also works well on things like water pump bolts, head bolts, and pipe fitting threads - go figure!

 

When my AFR 190's were stock they didn't open up into the intake port. Now that they are ported, they all do. I just use RTV on all the studs.

 

thanks for all the input. I used the ARP white thread sealant, which i don't understand how it seals because it doesn't harden. Anyhow, i'm going to give silicone a try.

Does the liquid teflon stuff harden up? Or is that the same as the ARP white stuff.

 

DON'T USE SILICONE!!!! Being an intake manifold, there's gasoline there, and gasoline dissolves silicone.

 

RB is right ( duh )

Use TFE past, it dosent harden, but I assure you it still Seals )

 

- - - - - - - - - - - - - - - - - -
Later,
Vader
- - - - - - - - - - - - - - - - - -
All my life I've been searching for something. Something never comes - never leads to
nothing...

 

vader -
does that stuff harden? bort mentioned that it may not. I have already used the ARP thread sealer (white gunky stuff) and it did not harden and it did not work. I suppose I could yank it all apart and use a lot more, but it seems like engine vacuum will just suck it on through just like it's doing with the oil. grr.

 

Dunno about the stuff Vader posted or the ARP stuff, but the GM stuff is an anaerobic style sealant and hardens in the absence of oxygen.... So the stuff you can see will still be tacky forever but the stuff sealing the threads will harden. But it doesn't really turn into a rock either.... The bottom line is that I used the GM stuff on my TFS heads (as well as countless other applications when I was a tech) and in that exact application for the rocker studs when I put the engine together and it uses virtually 0 oil and never emits any smoke. How certain are you that your oil consumption issues are from the rocker studs?

 

well, i tried both the teflon sealant stuff, and a non-teflon "oem specified" thread sealant that had a chemical smell. both came from the local autozone and were from permatex i think. anyhow, neither worked, neither hardened, and they both let oil past the studs. After removing the studs and seeing the oil on the bottom of them, and all through the threads it's pretty evident that the oil is going through them. Neither sealant appeared to harden at all and the sealant and oil were actually semi mixed together in a gray mess that kind of resembled moly lube, almost like the sealant was soluable in oil.

One of them was so bad that I could visibly see more smoke in the exhaust as I used an oil squirter to flood the stud in oil.

so out with that, in with the silicone....i'll keep everyone informed how that works.

87gta, do you have a part number or anything for the GM anaerobic stuff?

 

Sure do:

12346004

I always thought the Permatex stuff would be comperable but have never used it. Did you clean the threads out before installing the studs? I have had good results even without making the threads spotless in other applications, but if you are having issues with it, it wouldn't hurt to use some brake cleaner or something on the threads that will leave them oil-free and provide a better surface for the sealant to adhere to.

HTH - Matt

 

The stuff vader has up there should seal , I've been using pipe sealer on by small block head bolts for years and they are always rock hard after removal. The aerobic sealer matt's talking about should also be a fine choice though I've never tried it in thid type situation.. I bet even lock tight would work

 

thanks everyone for the help.

every time i've yanked it apart to re-seal it, i have indeed cleaned the threads and studs with carb cleaner to get them oil and dirt free.

anyhow, the silicone seems to have resolved the problem. I won't be 100% sure until I run it during the day, but the problem seems to be gone based on what I could see with a 500W halogen flood.

I think if the white stuff had hardened it might have also sealed, so probably the anaerobic stuff would have worked.

 

Hey 91L98Z28, I don't know if you or anyone else is still following this thread, but incase anyone is... I also have blue smoke coming out the exaust.

I seem to recall my AFR 190 heads having heli coil threads for the rocker studs. Do your heads have a heli coil thread for your Rocker studs? Could the oil be getting passed by the outside wall of the helli coil and not the stud itself?

 

It certainly could.

 

I use teflon tape. No issues here after 10K miles.

 

I suppose that it's possible that it could.

My fastburns do have helicoil rocker studs, yes. i still have a tiny, tiny bit of smoke (one tiny puff about every 30 seconds) but I'm pretty sure it's because I turned one of the rocker studs when setting my lash (mechanical cam) so i have one stud dripping a drop every once in a while and it needs to be redone.

Try using silicone or another sealant perhaps?

ARe you sure the problem is in the heads?

 

I am confident that my problem is with the AFR heads. The engine was rebuilt and have no more than 3000K miles on the rebuild. I have good even compression as one should expect with a fresh rebuild.

I am thinking on doing machine work as seen in these pics on the corvette forum. http://forums.corvetteforum.com/show....php?t=1118974

I'm just worried about hitting a water jacket. I am going to get in touch with the people at AFR and ask for their opinion.

 

Don't rule out anything or assume the problem must be with the heads, etc. There is another thread floating around on here where I posted about my problems, and my end solution turned out to be in the lower end after all - fresh rebuild, but total seal supplied the wrong rings for my pistons. My pistons have 5/64 top and middle lands, but for one of the lands (i think the middle - can't remember anymore) they supplied 1/16 rings. this was not caught during assembly, and lead to the smoking and 50 miles per quart oil consumption. it passed compression tests and everything just great/fine.

Just something to keep in mind - just because it's rebuilt doesn't mean you can rule it out, unless you rebuilt the entire thing, AND it smoked the same way before, AND the only thing you didn't touch was the AFR heads - and even then, it's not an ironclad deal! There is so much that can go wrong in a lower end - broken ring on install, rings skating on the cylinder walls, improper hone, ring flutter, ring tension issues, so on and so on.

you can of course also get oil through the intake runners if they dont mate right with the heads (block decked? heads milled?) and any number of other areas.

just check carefully and don't rule anything out!