Pistons above the block Questions?

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Pistons above the block Questions?

Post  Mustang-junky on September 15th 2014, 10:08 pm

I'm putting my 545 together now, the pistons are above the deck. I know this is not a big deal, I just need a bit thicker head gaskets.

My question is how do you measure how far above the deck the pistons are? Do you measure in the middle of the piston, near where the pin would be? Or at the top and bottom(intake side or exhaust side)? I can push the piston down on one side and get the opposite side of the piston to go up a bit. I'm seeing about .012" with a feeler gauge and a straight edge.

I am using 6.8" rods and Probe 10671 pistons. Piston to wall clearance was supposed to be set up using Probe's instructions.

I bought the M-6003-A429 gasket kit. The Fel-Pro 1018 head gaskets in the kit are only .041" thick. I have run SBF's at .030" quench without issue, but they were more of a street motor. Smaller bore, longer piston skirts, at a lower RPM than I plan on running with this motor.

Thanks.

Jess
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Re: Pistons above the block Questions?

Post  TRUKPULR on September 15th 2014, 10:16 pm

Are your pistons Flat top or do they have a bump.

Check your pistons on the Pin side of the pistons .
The rocking your seeing is the piston side wall clearance.
.012 sounds like a lot I know my JE pistons call for .005


Dan
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Re: Pistons above the block Questions?

Post  Mustang-junky on September 15th 2014, 11:01 pm

They are flat tops.

Jess
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Re: Pistons above the block Questions?

Post  cool40 on September 15th 2014, 11:44 pm

i would check the highest point the piston could get.rock the piston and check the high side becouse it will sure rock when its running.some say quench is an important thing but i can tell you when the clearance aint enough the rod bearings become more important. Embarassed
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Re: Pistons above the block Questions?

Post  gt350hr on September 16th 2014, 10:41 am

You could also cut the piston .012. There should still be plenty of deck thickness there for safe operation. I'm sure Mark would agree.

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Re: Pistons above the block Questions?

Post  cool40 on September 16th 2014, 11:18 am

gt350hr wrote:   You could also cut the piston .012. There should still be plenty of deck thickness there for safe operation. I'm sure Mark would agree.
x2 Cool
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Re: Pistons above the block Questions?

Post  dfree383 on September 16th 2014, 4:21 pm

Easier to get a set of gaskets.....
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Re: Pistons above the block Questions?

Post  cool40 on September 16th 2014, 6:16 pm

dfree383 wrote:Easier to get a set of gaskets.....
unless you wanted to use standard shelf gaskets. Pistons being flat tops would be a breeze on a mill. Wink
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Re: Pistons above the block Questions?

Post  dfree383 on September 16th 2014, 6:30 pm

cool40 wrote:
dfree383 wrote:Easier to get a set of gaskets.....
unless you wanted to use standard shelf gaskets. Pistons being flat tops would be a breeze on a mill. Wink

If you have a mill and a piston vise...... Most people don't.
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Re: Pistons above the block Questions?

Post  Mustang-junky on September 16th 2014, 7:09 pm

I have the shortblock assembled now. So, Cutting the pistons is out for now.

I checked the pistons across the pin area, I got about .006" out of the hole. I think I will get a set of .050" or .055" thick gaskets for now.

SCE makes a .059" thick gasket. I will probably go that way.

Jess
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Re: Pistons above the block Questions?

Post  cool40 on September 16th 2014, 8:31 pm

dfree383 wrote:
cool40 wrote:
dfree383 wrote:Easier to get a set of gaskets.....
unless you wanted to use standard shelf gaskets. Pistons being flat tops would be a breeze on a mill. Wink

If you have a mill and a piston vise...... Most people don't.
no need for a piston vise but I can see your point.I always look at things how i would do it and having some machinery can spoil you. Cool
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