Head gasket thickness

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dartlove

dartlove

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So started mocking up and checking clearances. Noticed my domed piston are .024 out of the hole. Not sure if I am accurately figuring out my gasket thickness. So my question is if the piston is .024 out of the hole would I just add ,keeping the ideal .040 quench just add .040 to the .024 and start from there? Then maybe I can start checking piston to valve clearance. Any useful help is appreciated.
 
If you had a zero deck height flat top slugs and closed chambered Edelbrock heads and want .040 clearance, well, that would be to easy. It would be a .040 thick gasket. With the positive deck height of your pistons, add that positive height to the gasket thickness.
 
dartlove said:
So started mocking up and checking clearances. Noticed my domed piston are .024 out of the hole. Not sure if I am accurately figuring out my gasket thickness. So my question is if the piston is .024 out of the hole would I just add ,keeping the ideal .040 quench just add .040 to the .024 and start from there? Then maybe I can start checking piston to valve clearance. Any useful help is appreciated.
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What are You working on, and what kind of heads, is it a closed chamber with the quench/squish area flat at the gasket/deck surface? If the pistons were at -0- deck & the
heads are as the example I chose, then add .024", You'd pretty much have to come up with a gasket .060-.065" compressed. It would be better to have the pistons topped in
that instance, to remove the .024", but not cheaper!!
 
Use a felpro 519sd head gaskets, they're roughly .054 compressed.
.030 quench is tight but it works.

Still, always clay check everything
 
383/496. Trick flow 270 heads. Not sure if open or closed chamber. How could I tell? I will look now. 13 :1 compression. Dome I believe is 6.5cc. Machinist says he can cnc the pistons to .005 out of hole. That is his preference . But he wants to put gasket and head on and check valve to piston clearance first. Feeling a little confused
 
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dartlove said:
383/496. Trick flow 270 heads. Not sure if open or closed chamber. How could I tell? I will look now. 13 :1 compression. Dome I believe is 6.5cc. Machinist says he can cnc the pistons to .005 out of hole. That is his preference . But he wants to put gasket and head on and check valve to piston clearance first. Feeling a little confused
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I would let Your machinist do His job, and if the quote for scalping the pistons is reasonable, that's less mass to reciprocate & You get the squish You're shooting for.
 
Yep mill the Pistons down. It's simple to do. You have to calculate the CR as it will be higher as you raised the dome by the amount the deck is positive.
 
If these are domed pistons, you need to clarify if only the dome is above the deck or is the flat quench area also above the deck. Maybe also post a picture at TDC. If it's a small dome and is intended for closed chamber heads like TFS 270s, and only the dome is protruding above the deck, then you'll have to mock up the head, without a gasket, turn it upside down, roll it over to TDC, loosen rod bolts, and measure how far the piston and rod can be moved toward the head. Once it stops, rock the piston back and forth, pivoting on the pin, and look for smallest reading. That's the piston to head clearance before gaskets are factored in. If the flat quench area of the piston is above the deck surface, mill the pistons as others have suggested.
 
They are domed pistons
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15094629078751043239960.jpg
made specifically for the TF 270's. The flat of the piston as well as obviously the dome are out of the hole.
 
I have checked every hole. All the same. This block had so much taken off on the decks that all identification #'s are gone
 
Then you can just machine the flats on the Pistons. But, like I've said...now you've raised the dome by the amount you have to machine off.

You are technically rising the dome by that amount.
 
before cutting pistons what gasket do u want to use? how thick is it? grab a gasket and throw a head on and rotate the assembly and make sure domes are not hitting heads. do not cut the pistons .005" . pick a gasket and then cut the pistons the amount needed to get the quench u want-like .040"
 
I am doing some piston to valve checking with a .040 std 440 head gasket. With clay. I am pretty positive there will be interference, but it's a starting point.
 
On an engine like this I would forget the clay. Degree the cam where you want it, install light checking springs on both valves in cylinder number one, install head on block with a spare gasket of known compressed thickness or leave gasket out completely, and install lifters, pushrods, and rockers. With degree wheel showing true TDC, turn engine to 10 degrees BTDC and measure clearance with a dial indicator by pushing the valve open further until it touches piston or retainer hits guide. Repeat this at 10 degrees ATDC. Been using this method for years and I always check it to 20 degrees both ways just be sure and never had an engine with less clearance away from the 10 degree positions. This was from the Reher-Morrison engine book. I forget if intake or exhaust is closer at BTDC or ATDC so I am not specifying, just check both since it's easy. Also, double check every cylinder this way, especially since you know you have a heavily decked block.
 
aching needed. Cometic will make any thing a guy needs, so I`ve neen told .
Bobzilla said:
On an engine like this I would forget the clay. Degree the cam where you want it, install light checking springs on both valves in cylinder number one, install head on block with a spare gasket of known compressed thickness or leave gasket out completely, and install lifters, pushrods, and rockers. With degree wheel showing true TDC, turn engine to 10 degrees BTDC and measure clearance with a dial indicator by pushing the valve open further until it touches piston or retainer hits guide. Repeat this at 10 degrees ATDC. Been using this method for years and I always check it to 20 degrees both ways just be sure and never had an engine with less clearance away from the 10 degree positions. This was from the Reher-Morrison engine book. I forget if intake or exhaust is closer at BTDC or ATDC so I am not specifying, just check both since it's easy. Also, double check every cylinder this way, especially since you know you have a heavily decked block.
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rolling a full turn w/ clay is fool proof no rocking back and forth. Just cut the clay cleanly w/ a razor blade , measure w/ a dial caliper , hard to mess up if u oil the head to keep it from sticking. done all my engines that way for 50 plus yrs. , hemi`s, sbc, 440/505 wedge. If ur heads are done, u don`t have to mess w/ breaking them down.------jmo
 
famous bob said:
Can he not run a .065 thick headgasket to get .040 quench , and have head clearance ? Then clay check for sure ? Cometic will make anything a guy needs .
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He sure can, they will make anything. I was told up to .140 thou. They made a .085 for me once.
I just happen to like .038 quench with the already made .062 cometic.
 
MOPAROFFICIAL said:
He sure can, they will make anything. I was told up to .140 thou. They made a .085 for me once.
I just happen to like .038 quench with the already made .062 cometic.
Click to expand...
Got .039 on mine w/ a .040 cometic. (STEEL RODS)
 
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