Calling all flathead guys !! some of you may have remembered I was having problems with my studs sealing coolant and now I think I have a problem with the head gaskets sealing out the coolant. First of all, I will bring you up to speed. I am just starting up a brand new rebuilt 8BA. I had all the machine work done so everything should be flat and straight. I am using a new set of Edelbrock heads, new studs and Best brand "graphtite" head gaskets. The first time I started the engine I filled the engine with coolant and capped it. Then I started the engine, ran it up to temp and then torqued the heads. did this 4-5 times. The studs leaked. After working with the HAMB, decided I was using the wrong sealant and method. I tore the heads, gaskets and studs out, cleaned up everything and started over with new gaskets and with ARP stud sealer. This time I put 4 out of 5 gallons of antifreeze in the engine and did not cap the radiator. Nothing leaked out of the studs before I started the engine (the 1st time it did). After I started it up, gradually about 8-10 studs on each side began to leak again. The ARP sealant is pretty thick and I cannot believe it is that bad that it would leak that quickly with no pressure. I retorqued the heads about 3 times and the leaking is not going away. I did not seal the head gaskets with anything because I was told be several people that Best Graphtite head gaskets work great without any sealant. Question is: should i just keep running the engine thru hot/cold/retorque cycles till it seals? Does anyone have experience with sealing Graphtite gaskets using aluminum heads? Also what are all the tricks you experienced guys use to get heads to seal up tight. I would prefer not to use an overall coolant system sealer unless I absolutely have to. I will take the heads and everything off again if I need to, I just need some more tricks to try so I do not have to do this a 3rd time. Any help or ideas are appreciated -Dave
I use Fel-Pro head gaskets with copper crush rings and spray both sides of the gasket with copper gasket spray (made specially for heads). The studs I generally snug up with a stud socket and a drop or two of red loctite (yes I know it is considered permanent but you shouldn't have to remove them, and if you do a heat gun goes a long way). You must install the heads relatively quickly though as most sealing compounds (especially loctite) are anaerobic and harden in the absence of oxygen, meaning they will harden then "break free" when you tighten down the nut and rotate the stud slightly, allowing them to leak. I have seen seepage in the past but only slightly and it generally stops after a good amount of heat/torque cycles, i.e. drive the car 20-30 miles, let cool, re-torque, drive it back, let cool, re-torque, etc. Hope this helps Mike
You didn't re-use the head gaskets, did you? An 8BA with studs? Was the block decked during the rebuild? Did they retap the headbolt holes? Try the SilverSeal I suggested. Supposedly it only hardens up at the leak spots, and doesn't coat the rest of the surfaces. The car I did cools really well, so I know it didn't gunk up the waterjackets.
Quick thought, how soon after installing the heads did you try to fill/start? If the sealants require a cure time, which most do, you must wait the appropriate time before subjecting the sealant to any liquid or pressure.
I cannot help you any other than saying that I did as you did an no problem. Graphite gasket, high-temp teflan thread sealant on head bolts, re-torqued about four times. Seems odd you are having that much problem. Block sealant may not be that bad of a option. What do you have to lose? Neal
No, I got new graphtite gaskets. I also made sure all surfaces were clean again and did not have any old gasket stuck to them The block was not "decked" it was just dusted off to make sure it was flat. I do not know if the headbolt holes were tapped when it was cleaned and machined, but after I took the studs out I ran a tap to clean out the old sealant. However, the tap did not remove any metal, just the old sealant. Is there a problem with an 8BA with studs? I thought they all can use studs. I will keep the silver seal in mind. I suppose it would not be bad if i just used enought to seal the engine up and then flushed it out. It just seems like a band aid approach on a new engine.
I filled it on the same day that I sealed the studs. The ARP instructions say that it never hardens and will seal something crazy like 1000 psi. All I need it to seal is 13 PSI
This may be the key to your problem. Did the studs seem "wiggly" at all before you put the head and nuts on? Maybe the block was over-tapped before you ever got it. Bruce says they have a funky-tight thread from the factory, and the sealing ability is ruined if they get tapped with a regular tap.
Amen...regular taps take off the "roll' from rolled threads. I have no idea what the hell you're gonna do now except maybe remove all the studs and load 'em up with red loctite before re-installing them. They'll never come back out so don't break one off but I've had great luck using it [red loctite] as a sealant...maybe somebody else has a better idea for a good thread sealant that may be less "permanent" and still as effective.
I use Permatex #2 & Fel Pro gaskets with bolts on my Merc Blown motor. No problems with leaks or seepers.
Flathead Jack swears by some stuff he sells called Snake Oil. It's a silica mixture that you put in the radiator and run for about 30 minutes and then drain it. I think you are suppose to do that twice then discard it. It's specifically for sealing up leaky flatties. Give him a call and see if he thinks it will work in your case. I think I'd at least try it before I tore the engine down again. Doc.
Yes there was some movement here but not sloppy by any means. I read Bruces comments about this before but this is the way I got my block, too late to turn back now. I know this would make it a little harder to seal but I can't believe this would make it impossible. I also cannot believe that starting the engine 3 times with no pressure in the coolant would push past 1/2" plus of very thick ARP sealant in 1/3 of the studs Doesn't it make more sense that the head gasket is just not sealing off the water jacket yet? I did not use any sealant on the head and since the heads have to be re-torqued several times to get the pressure ring compressed all the way, it would make sense that maybe the head gasket is not seeing full pressure around the water jacket yet. I noticed last time I took the head off, the gasket stuck to the block but not to the head at all. Would it make sense to take the head off put some hi temp silicone sealant around the water holes and put it back on? Comments about resealing the head gasket around the water holes?
Thanks, I will give him a call. I also have the stuff Speedway recommended that works just like that. It is Moroso ceramic seal and the instructions say the same thing. Run it in the system long enough to take care of the leak and then drain and flush everything out.
i've always heard to spray the head gasket lightly on each side with copper paint and to put them on while they are still tacky when using alluminum heads.
Back in the 60s with my 296 ran copper head gaskets coated with Coppercoat. Used stock bolts torqued cold ,fired up engine got it up to temp. Let it cool back to room temp and re-torque ,re-torque in a hundred miles or so cold. Never had any leakage problems. Did not have much luck with the black fibre style gaskets.
I did the same as John Evans. Used copper head gaskets sprayed with copper gasket sealer,used my old head bolts with a little permatex on the lower section of the threads and tightend down the bolts, fired er up let it get good and warm and retightened the bolts again and that was 4 years ago and not a sign of leakage. Old set of Edelbrocks that a guy said he thought was milled to much,i had a guy flycut the heads and they work great. My 3 cents on the subject. 8-Ball
13 pounds of pressure? Stock only had to seal to 4# or 7#. I seem to remember some guys using small O rings on the studs to keep the coolant in. Or did I imagine it?
Do not use any silicone based sealant on the head gasket! Use the copper paint and a good gasket, if it will not seal there is another issue, but adding more goop to the equation will not fix a head gasket. If you have excessive corrosion in the area surrounding the coolant passages, there is a possibility that coolant is seeping under and around the crush rings, but you would have noticed such extensive corrosion before assembly I would think. And the pressure does seem a bit high to me as well, even a non pressure system should work just fine if you have a proper cooling system. My 8BA in my '37 ran a '37 radiator and cap - no pressure - and I could sit in rush hour traffic in the summer and never once overheated. Just a thought Mike
I think the name is sodium silicate and you can buy it at most drug stores by the quart. Put 1/2 in the radiator and fill with water. Run motor until operating temp is reached. Drain it all out. Wait 24 hours and refill with water then start it up; get to operating temp and shut down. Next day after cool re-torque in sequence to 55#'s. Repeat until the nuts stop moving.
How bad of a leak are you talking about? I used FelPro gaskets and non hardening Permatex #2 and still get a few dribbles out of 2 or 3 studs when the engine is hot (zero pressure Model A radiator). Nothing that affects coolant level, it's just another drip on the floor so I've been ignoring it. They tell me it will eventually seal.
Thanks for all the feedback. Even though the studs were leaking without any pressure on them, I will have to keep that in mind later when I do get it sealed up. The guy that built the radiator put a 13 lb cap on it and I didn't give it a second thought. Sounds like its pretty common to use some kind of spray sealant on the head gaskets. I am also hearing that it might work better to assemble everything, start the engine DRY and go thru the re-torque cycles before putting any coolant in. This would give everything a chance to seal up nice and tight before adding coolant. Question is it dangerous to start a new engine dry and possibly overheat in spots? If not, then maybe this is the best way. Also is there some reason why studs should not be used on an 8BA? The leak is pretty bad in my book. It is coming out of 10 studs per side and it adds up to quite a mess on the floor after just a short time running. However, I am not done with the re-torquing and that may make a big difference. I would like to have no leakage at all and it looks like if I do enough of these tricks it should be fine. I am going to re-torque the heads and start it up today. Then I am going to let it cool and re-torque again. If I do this until no more re-torquing is needed and the leaks are still there, then I think I will take the heads off and start over with all the new ideas. Thanks again -Dave
Don't run it dry!! Torque the heads to final value cold , fill with coolant. Then run to operating temp,thermostats open,let cool to room temp re-torque. Re-torque after 100 miles or so,if there is not some problem with heads,block etc. should not have any further problems. You do have good washers under the nuts right?
back in 50`s while racing flatheads ,we would use alumilium paint on copper gaskets. we had no autozones. used with what we had . my 2 cents
Just thought of something...you do know the gaskets are different right & left? I know it sounds dumb but thought I'd mention it. Keyholes go to the rear on both sides, right side has a tab that sticks out the front by the dizzy. Jim
What happens if you run it dry? I agree it is not a good idea, but I do not know what happens if you do, maybe you have a few horror stories about this. Yes I do have good washers under the nuts.
Not a dumb question, ya never know. Yes I do know there is a difference and I have them on the way describe. I think with this engine there is only one way they will actually go on.
When I worked on forklifts, I came upon Loctite 515. It's a purple color gel, used it to seal the trans case and the bolts. This stuff seals hot oil without gaskets and regular bolt threads. I used this on my Merc flathead with new studs, copper gaskets sprayed with copper gasket. It works.
There is something that we are missing here. It isn't that hard to seal up the threads on the studs. If I understand right, you have several leaking with just water in it and not running. I would think that the thread sealant is working so that would put the fault on the heads. Seems like a long shot but doesn't make sense that almost half of the studs are leaking. Out of cuiousity, the next time a head is off, I would stick on a cast iron head and see if it leaks. It would just be a check and I would probably use the old gasket just because I am cheap. Are these heads new or do they have some corrosion on them? Just grabbing straws here. The higher psi radiator cap should not be the problem. Specially if it is leaking just setting there. I ran a 13 psi cap for a while and my concern was the radiator, not the motor. Neal
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