Evolution of installing cylinder heads

Ol' Ron

Ol' Ron

Well-known member
The evolution of installing heads on a flathead is more complex, than a woman's mind. In the "Beginning". We slaped them on torqued them to 60/70 lbs and went racing. When we started using racing cam shafts and milled heads, we found that pistons hit the heads ar reva and the heads leaked, torque then to 80. Learning can be expensive. stripped blocks and Heli coils later?? It took awhile to realize that over torquing the heads was a bad idea, one shop used a torque plate for honing the SBC, so whynot the flatheads. Most of us used Jahnns pistons with .005/6" clearance ( Made from Lead???) Now we used .075/.100 piston clearance. But torquing the heads was still amistory. Back to 50 llbs. Problem solved.. So much for the learning curve, I have no idea who came up with all this?With the low RPM's of the street engines and the light Forged and Egge 3 ring pistons, we can tighten up the piston to head clearance.
THis doesn't address the long term installation of aluminum heads on a cast iron block. When I first started rebuilding Flatheads I began repairing used heads to reduce the price of the builds. I checked the fire ring of the heads, milled them flat. Bead blasted them and filled the corrosion areas with Devcon F and later JB weld. We had an aluminum spray sealant in the beginning, but later versions were just aluminum paint. Since then I use copper coat. However I don't think this will help the long term installation of these heads, but a new method maybe around the corner. Paint the heads with a coat of Latex paint. Install gasket with what ever sealant you want, and bolt the heads down with cadmium coated bolts (with hardened washers) . Torque to 45 lba for 3 or more heat cycles. Until there is no movement. You might wonder if this is enough?? I did. after the hydro engine made a run at over 60mph, a recheck of the head bolts gave little movement. The Evolution continues, tune in next year.
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Ron, A question about re-torqueing; do you break the bolt loose, and re-torque to what ever pds you want,, or, do you just re-torque to what ever pds ?
Thanks,
 
little howard said:
Ron, A question about re-torqueing; do you break the bolt loose, and re-torque to what ever pds you want,, or, do you just re-torque to what ever pds ?
Thanks,
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You do NOT break the bolt loose. that would be counter productive
of re-torqueing.
 
You do nOT brake them Loose. The compression of the clamping force of the new installation. Changes due to the heat of the block and heads in an uneven manner. BY re- torquing the bolt/stud to 45 ft/lbs you even out the total clamping force of the fasteners.You will notice that some bolts move more than others as the gasket and materials come together. Now, with all this said. Back when a torque wrench wasn't available, we just snugged them up, every so often
 
What are your thoughts on bolts vs. studs?

I've had problems with coolant weeping past the studs, so I use a lot of Stinky Brown Permatex on studs (basically gluing them into position). If bolts were used, the sealant would be disturbed on every retorque, right? More weeping.
 
alchemy said:
What are your thoughts on bolts vs. studs?

I've had problems with coolant weeping past the studs, so I use a lot of Stinky Brown Permatex on studs (basically gluing them into position). If bolts were used, the sealant would be disturbed on every retorque, right? More weeping.
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Never had a problem using non hardening Permatex.
It never glued bolts/studs in position and never leaked after re-tightening.
 
Ol' Ron said:
You do nOT brake them Loose. The compression of the clamping force of the new installation. Changes due to the heat of the block and heads in an uneven manner. BY re- torquing the bolt/stud to 45 ft/lbs you even out the total clamping force of the fasteners.You will notice that some bolts move more than others as the gasket and materials come together. Now, with all this said. Back when a torque wrench wasn't available, we just snugged them up, every so often
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Thanks Ron. I was taught as you advise.
And I suppose common sense would dictate that if one were to loosen them, he'd have to start the entire process afresh. And, perhaps ruin any chances of making a permanent and quality seal.

Folks, do NOT loosen the nuts (bolts) prior to (re)torqueing.
 
To seal the threads I use some stuff I had for steam pips. My dad was a plumber and he had this stuff so I used it. Never seems to harden either. Probably the same stuff they make today
 
I haven't dealt with this yet but, when I put my 21 stud engine back together, I had planned on using Teflon tape to seal the stud threads.

Are any reasons why I shouldn't use it?
 
Kube said:
Thanks Ron. I was taught as you advise.
And I suppose common sense would dictate that if one were to loosen them, he'd have to start the entire process afresh. And, perhaps ruin any chances of making a permanent and quality seal.

Folks, do NOT loosen the nuts (bolts) prior to (re)torqueing.
Click to expand...

I can give no empirical data to back up my feelings in the matter, but my gut has always told me; if they move, their loose, if they don't, leave them alone.
 
PTFE is Teflon but that stuff is kinda spendy @ $10 for 1.7 oz. A plumbing supply house, may have it, I'll have to look.

The Teflon tape, used to be spendy but, now is very cheap. It takes a minute to rap it in the threads but, you can put on, what ever thickness you want.

It is a great sealer and the only way you can assure a leak free, pipe thread joint, on air lines.
 
frnkeore said:
PTFE is Teflon but that stuff is kinda spendy @ $10 for 1.7 oz.
Click to expand...

Okay Frank - going to bust your stones here :) In the grand scheme of flathead things, whether the stud sealer costs $10 or $.10 . . . really doesn't matter. ;)

What matters is how well the studs/bolts are sealed in the wet deck!

Just giving you Hell a bit . . . as I've learned that I have attempted to save money on the right things in my life . . . and spent WAY too much on the wrong things! LOL

B&S
 
A lot of us older guys are on a very tight budget. $9.00 saved here and there can make a big difference in how we approach our projects. I know that I am getting by only because I have squirreled away a lot of old parts that I could not even think of purchasing these days. You bet I will be concerned about some big time outfit charging $10 for 1.7 oz. of sealer, especially when if you look hard enough, you can find the same thing a lot cheaper someplace else.

I wish I was rich; I'm not.
 
Hey guys - not trying to be flippant with your money (or mine) . . . the only point was that we tend to worry about saving money on the wrong things. Not only in life, but in our flathead work. I know, a grand statement . . . but one I've had to come to terms with myself over the years. And - I'm not young - I hate to admit it, but I'm an "older guy". :)

Now I know I'm preaching here, but how many times have we seen folks (ourselves included) go 95% of the way through a difficult and time consuming job - spending a lot of money along the way - and then decide to scrimp/save at the very end? I've done this many times! It is almost like I was upset about the 95% of the money I'd already spent (probably 2X what I thought), only to NOT spend the last 5% wisely. I'm not trying to spend anybody's money here -- nor claim to have riches and lack of empathy. The only point is that we tend to worry about the costs that are the least significant at times . . . versus the costs/ramifications if we had not.

I used to worry about costs of things like gasket sealers, assembly lube, oils, etc . . . when if I'd really thought about it, these are the last places I should be worried about spending a few percent more. I'd already spent the big money and spent the big time - so I try to buy the best products I can - and they cost so very little in the grand scheme of these dang car builds.

Also, one hard lesson in life and business that I've learned is that I tend to not value my time enough. If I spend $20 more to save hours of time . . . if that worth it? Maybe - or maybe not - but at my 'young' age, seems that my time is the most valuable thing I don't have enough of.

Okay, enough out of me . . .
B&S
 
Dale,
The main thing about selecting things, is that you use common sense. For instance, if Teflon tape will seal a joint, air tight, then it will seal a water joint, especially if it's under high heat and pressure. I don't like using it but, I have to, if I want my air systems to not leak.

Second, I haven't looked for it yet but, if it's a Teflon past, it's probably used for sealing pipe fitting, maybe even designed for that purpose and if so, can be purchased at a plumbing supply house for $3 or less.
 
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