Is it necessary to resurface head when doing headgasket?
 

Hey guys. its been a while since Ive been on here. Been pretty much enjoying the car up until a month ago when I blew my headgasket.

Just got around to tearing it apart today and it was definitely the gasket (i tried snyders no leak gasket on this motor) which aparently didnt work since it broke in several spots.

This round I am going with the traditional copper gasket, copper spraying both sides. New head studs as well.

I am wondering if I should get the head cleaned/resurfaced while Im at it. I dont want to have any problems in the future with this.

Thanks
theo

Re: Is it necessary to resurface head when doing headgasket?
 

Do you have a high compression head? It was my understanding that they had to use a special gasket and the traditional copper ones would not work properly. I don't know, but I am sure someone who does will chime in here shortly.

Re: Is it necessary to resurface head when doing headgasket?
 

It is not necessary to have it surfaced. Very advisable to have it checked to make sure it is still flat and have it surfaced only if needed. Rod

Re: Is it necessary to resurface head when doing headgasket?
 

If I remember correctly the spec for flatness is .003. Rod

Re: Is it necessary to resurface head when doing headgasket?
 

Get a straight edge like a 24" carpenters square and check it 15 ways from Sunday! Only if it is out have it resurfaced.

Re: Is it necessary to resurface head when doing headgasket?
 

I have experienced friends (over 30 years in the hobby) that have used a wide variety of head gaskets over the years with high compression heads. also torqued at the standard 55 lbs and the 65 lbs recommendation. It didn't really make any difference the gaskets blew eventually, not all the time but they failed every once in a while. They drive their cars a lot and I don't really know if that makes a difference....just my observation. I am about to put a Snyder 5.5 head on a re-build I am working on and will probably will use a copper sandwiched gasket torqued to 60 lbs. to split the difference. I will see how that holds up.

Re: Is it necessary to resurface head when doing headgasket?
 

As long if you have the head off, you should have it surfaced this will save you the trouble of having to do the job over again. Also have it checked for cracks.

Re: Is it necessary to resurface head when doing headgasket?
 

First, you need to make sure both gasket surfaces are flat.
This needs to be done with a precision straight edge, not a carpenters square or a yard stick.
Next is to check what almost NO ONE ever checks and that is the gasket for "hangover" of the chamber and cylinder edges. Different gaskets of the same manufacture will vary on the same engine.
The fire ring must ABSOLUTELY be captured between BOTH the block and head surfaces.
If it hangs out on either, it will not last very long.

Re: Is it necessary to resurface head when doing headgasket?
 

As Pete said, you need to lay the copper gasket on the head to make sure all of the fire ring is covered by head metal, then lay the gasket on the block and make sure all of the other side of the fire ring is covered by block metal.

I have a carpenter square that I only use for heads, but I first took it to the shop and checked it against a precision straight edge. It was dead on. If in doubt let the shop check the head while you watch. If work is slow they might grind it just for something to do, even if it's within specs.

Re: Is it necessary to resurface head when doing headgasket?
 

Unless you have a problem with a stud, I wouldnt screw with them. Trying to remove the old ones sometimes creates more problems than it fixes.
If you had the motor out and were doing a full-on rebuild , then I might feel differently about it.
Good Luck!:)

Re: Is it necessary to resurface head when doing headgasket?
 

i would compare it to doing a brake job CORRECTLY ..

its always a good idea to make sure the rotors and drums are TRUE and giving them a new surface.

its also a goo idea to check it for cracks.

or then there are those that just slap pads and shoes on and go....
its off do it right

Re: Is it necessary to resurface head when doing headgasket?
 

Theo,
You mentioned that your "modern" thin head gasket, with the silicone seal rings, fell apart.
I feel that they should ONLY be used, IF you have a perfectly flat head & a perfectly flat block surface!!!
Bill W.

Re: Is it necessary to resurface head when doing headgasket?
 

There is a phenomenon sometimes encountered where the studs will slightly pull up the top thread of the block above the block surface which prevents the head from completely compressing the gasket in that area.

I usually use a 90 degree countersink in a hand drill to slightly recess the metal around the stud hole. This also removes the feathered edge of the thread and prevents it from breaking off during installation.

Disclaimer: I've built up a lot of engines, but no Model As, so take this as a general hint.

Also, be sure and get all the old gasket compound off both surfaces and be very careful to keep bits of old carbon from getting in the cylinder bores and other recesses. It is very abrasive stuff.

When it comes to assembling engines, cleanliness is way ahead of godliness.

John