Head Nuts - Size difference

[Todd Dykman]

I need some more guidance.
1935 model D
I've got my studs in the block and ready to put the head on.

1. should I spray the head gasket with hi-tac or just put it on raw

2. the nuts that were previously holding the head on are different sizes. I have 5 of the original big ones, and then the rest are just regular smaller 3/4 nuts. my gut says this is not a good way to go.
Do I need to find more of the bigger stock nuts for the other 4 studs?

 

[JRSutton]

I'd spray the head gasket with the copper stuff, not hi-tac.

To be honest, I couldn't tell you exactly why - just always the way I do it.

You definitely want something on the bare gasket.

I think the copper stuff is meant to transfer heat better - not sure how important that really is for a tractor engine, but - again, I've always done it, and I've never had any trouble.

 

[tim s]

Most bolt supply places have what is called heavy duty nut, the difference that could make is a larger area of surface under the nut, and of course making it all look right..but nether would have any difference on the out come...

 

[Mike Aylward]

The head gasket need not have anything on it. Kopper Kote has failed me too many times to recommend it with a clear conscience. I have some cans I would gladly give someone. A clean, flat surface is all that is needed. As for the nuts, your John Deere dealer should have heavy duty nuts in that size. They would be less likely to gall, in my opinion. Mike

 

[JRSutton]

Send em my way!

Actually I think you'll get a different answer from anybody you ask.

I know several people who will support the use of the kopper kote for head gaskets as I do, and I know some who won't.

I've never had it fail me, so I like it. I have however had water leaks when not using it. Especially with older blocks that aren't resurfaced.

So - I think it's really luck of the draw. When you get unlucky one way, you favor the other route.

I do agree on using the larger nuts. Not sure, but I'd guess it's to fully contain and seal against a flattened out lead washer. ?

 

[Mike Aylward]

A good head gasket on a good surface needs no sealer. Only on late A's and 60's and early New Generation tractors (on the right rail) do I use any sealer. Any other time I've used anything I've had leaks. Sorry to burst your bubble. Mike

 

[D-]

I agree. I wouldn't use that stuff if you paid me. Used it once maybe 40 years ago. That was enough.

 

[DONMYEIL]

Been working on the old girls for 45+ yrs.. I use engine oil . The older mechanic that taught me said it was only so the copper side could move when torqued . I have used aluminum paint and quickly put the head and tighten the nuts to squeeze out the excess . Definitely use the larger nuts as they spread out the torque . If the surfaces aren't shiney then its to dirty to assemble . As to COPPER COTE the only place I would use it would be in the garbage can . It causes more leaks than it stops .Just my 2 cents .

 

[D-]

Don't the correct nuts have a machined surface on the head side? They are also larger than regular nuts.

 

[Todd Dykman]

I picked up some heavy hex nuts. they are the right size, but of course they have eased corners on both sides, so yes the originals are machined flat on the contact side for both the block and the head. I'm going to run the ones I have over emery cloth to clear the burrs. and then use the heavy hex nuts in the inconspicuous places.
I've also read about having the head gasket oriented the right way. the one I got is same on both sides, so I'm assuming it can go either way.