I realized a couple days ago that I had a blown head gasket, so I pulled the head (stock 8ba) off and sent it to the machine shop to have it surfaced 8 thoundths. I put a felpro gasket along with copper spray and tightened everything down the way its supposed to be done, and to my suprise I can still see it leaking in the same spot. I am confused as to what to do next, any help or advice would be greatly appriciated . Thanks (Also I checked the block for cracks and there where none visible)
How about a photo or description of where its leaking, hate to say it, but the head isn't cracked is it? I had a stock 8BA head do that to me once. never seen it before or since. Also one of your head bolts isn't just leaking is it? When you pulled the motor down did you see the tell tale signs of a blown head gasket?
Choices are a crack in the block ( not normal to the outside and visible) or warped block deck surface due to overheating ! Are you sure all studs are sealing 100 %. And have you tried some "seal well" sealant kind of like a small block of rat bait that you add to coolant? A radiator coolant pressure check may help pinpoint leak.
I am confused to how you can see a blown head gasket or did you take the head back off again. I would need more information. Neal
It is leaking from the driverside rear of the head, and I can see it trickling down the back of the head. I am not to familiar with flatheads so what is the best way to have the head bolts seal, and if the block is warped is the only fix to deck it? Also the head was checked for cracks to when it was surfaced. I have to say I am completely dumb founded. (I can take pics tomorrow when I pull the head off again). Thanks for the reply's brothers.
It sounds like you have a head gasket leaking water vs. a blown head gasket leaking from the combustion chamber. When I have had the studs or bolts leaking, the water came out by the bolt/stud and not the back of the head. Have you gone through and retorqued the head bolts? Maybe that is all it needs. Neal
I have retorqued them a 3 times after heating up and cooling off, I am startng to wonder if maybe the copper spray that I used is not thick enough to seal everything as opposed to a brush on type which is alot thicker. Could this possibly be an issue? Also what do people use if the bolts don't seal, is the some kind of special sealant for the bolts?
Flatmotor heads need retorque after the first warm up... and it doesn't hurt to do it a cpl more times, for good measure. A "warped deck" is highly unlikely. 4TTRUK
Bolts / studs leaking....I find the best fix for that is the "hardening" type Permatex brand sealant. I use the "stock type" head gaskets, they seem to work best. 4TTRUK
Just re read your post,....You said "trickling down the back of the head ? Give a hard look at the nearest head bolts..... It may be as easy as resealing that bolt. What heads are you using ? originals, or aftermarket ? 4TTRU
Flatheads with studs that you can seal are hard enough to make leak-proof. I can't imagine the patience it takes to seal up the threads on head bolts that need to remain "tightenable". What sealant is best for this guy that won't glue the head bolt in too tightly? On our flathead (with studs glued in with Permatex) we used two small containers of Silverseal to stop the small trickles. It's a silver flakey powder that will find the leaks from the inside and magically plug them. Wait til these guys can give you an answer for the leaky head bolt before you go taking the whole head off again. Why waste money on another gasket when that's probably not the problem?
The only time I've had this issue is when I turned a head gasket end-for-end. They will leak when installed that way and no amount of re-torque will stop them.
On the flatties with head BOLTS many times the bottom of the threaded hole has rust build up that prevents the headbolts from fully seating on the head giving false torque readings. Cure = wire wheel the threads on all of the bolts and run a tap down each bolt hole. Iron heads torque cold then re-torque at operating temp.
But don't run a tap down the block if you can't see rust for sure. The original threads are supposed to be a tighter tolerance, and running a regular tap through them will make matters worse.
When I replaced head gaskets on my 8BA flattie, here is what I did: Made damn sure the head and block surface were completely clean and free of any and all old gasket residue, put a good straight edge on the block and head and used a feeler gauge to make sure none of the surfaces were warped, cleaned all 48 bolt threads with a wire wheel and used non-hardening Permatex #2 on all of the bolts. I torqued and retorqued probably 3 or 4 times and four thousand miles later all is well. I used the Graphtite gaskets with the copper spray, if your surfaces are clean and warp free I don't see the need for a ton of copper spray on the gaskets, just enough for a good light coating, I would personally not use any thick, brush on gasket shit on there. As somebody else mentioned, are you sure the gasket is blown or just leaking? When mine was blown I knew it and so did everybody else around me Best of luck, leaks can be a real bitch.
Thanks for all the advice and info! I know the head gasket was blown before I took the head off the first time, and once it was off I saw that it was completely blown out on the bottom rear of the driverside head (stock 8ba), where it still seems to be leaking with the new gasket. I made sure that the block was perfectly clean, and the head was perfect from the machine shop. As much as I hate to say it, I think I might just take the head off again, get a new gasket, clean the bolts and use permatex, and then do a once over on the block again to make sure everything looks hunky doory. I will keep everyone posted, and keep my finger crossed.
Be sure to lay the gasket on the block and make sure the holes line up before you coat it. If it is flipped end for end it will be noticable - but just barely. That's why it's easy to get them reversed.
I had my machine shop assemble my 8ba and that's what they did to one of my heads. It lasted for half an hour until it blew. Luckily I had a huge hole in my firewall so I knew it went right away based on the hot coolant spraying on my foot.
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