34 Terraplane head gasket issues

dhutzn

I am restoring a 34 Terraplane and thanks to some of you folks she is running. The issue my mechanic is having is getting the head gasket to seal. I have bought 3 NOS gaskets from HET venders and each has leaked in a different location. He has followed recommended steps of torqueing and retorqueing after getting the engine warmed up. Has used spray copper sealant each time. With the seeping occurring in a different spot each time it doesn't seem to me that the head would be warped. He thinks that because the gaskets are NOS that the fiber between the metal is the culprit. Does anyone know if there is a better gasket sealant for this application and whether I have any options for gaskets rather than 85 year old NOS.

Thanks to all!!!

Geoff

Generally, the NOS gaskets tend to be better, as they contain asbestos, which is more compressible.  What you probably need to is counter bore the head holes with a large drill bit so that there is a slight chamfer to allow for  distortion around the cylinder  block studs.   Do be very careful that you do not tighten more than 40 lbs, or you will distort or even crack the block.  

dhutzn

Thank you Geoff! What sealant have you had the best results? How deep counter bore? Do you recommend new head bolts?

Geoff

Ordinary Aluminium paint is best in my experience.   Put a good thick coat on and allow to dry, but not harden, (a few hours probably).   Then install the gasket and head and tighten down in  a star pattern working from the centre outwards,   tighten first to 30 lbs, then to 40, and do it once again  when the engine is thoroughly hot. You will see the paint squeeze out as you tighten.  The 212 engines used studs, not bolts, and no need to renew them if the threads are good.  Countersink so that there is a bit of relief around the base of the studs, probably about .030" all round.

dhutzn

Oil based aluminum paint on the head, block and both sides of gasket? Right? Thanks again. I will stay in touch to let you know my progress and further questions.

Geoff

Just on the gasket.  Both sides. 

dhutzn

I realized that after I replied. Obviously I am NOT a mechanic. Thank you for your patience.

dhutzn

I think that I am going to replace the head studs on my Terraplane since I' be taking them out to chamfer the holes as Geoff recommended. Does anyone know where I can get a set? I know one of the holes is sort of striped. what is the recommended solution for that? Helicoil? As you all can see from my postings my Terraplane has some issues or probably I have issues! Thank you all!

Geoff

No, no, No  YOU CHAMFER THE HOLES IN THE HEAD, NOT THE BLOCK!

dhutzn

OMG! Thank you Geoff for following  up my mistake. Luckily we are probably a month from redoing the head gasket. Thank you!

Old Fogey UK

Geoff said:

Generally, the NOS gaskets tend to be better, as they contain asbestos, which is more compressible.  What you probably need to is counter bore the head holes with a large drill bit so that there is a slight chamfer to allow for  distortion around the cylinder  block studs.   Do be very careful that you do not tighten more than 40 lbs, or you will distort or even crack the block.  

I have a problem with a little bit of water weeping at a couple of points between the left side of the head and the block that's torqued down 45 pounds (as per Geoff) and sealed with Copper Seal. My gasket is a newly manufactured one from the ROC (who say to torque the head down to 55 pounds) and I suspect it may be the culprit as both the head and the block have been skimmed.
I'm going to take the head off and have a look. I hope it's just a sealant problem as another gasket is £120 here in the UK !

Geoff

Again, if you have the head off, chamfer the holes.   This allows for relief around the studs and gasket holes, and slight distortion of the block when the nuts are tightened. 

dhutzn

Please  see my post regarding  Top Speed. Thank you all!!!!