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10-27-2017, 03:12 PM | #1 |
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Brattons pistons
Anyone use brattons pistons, and do the listed .002”/.003” clearances work. The machine shop has a tight .002, and I’m nervous. Anyone know who makes them?
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10-27-2017, 03:36 PM | #2 | |
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Re: Brattons pistons
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I would hone them to at least .0035 |
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10-27-2017, 04:42 PM | #3 |
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Re: Brattons pistons
Right on, George.
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10-27-2017, 05:11 PM | #4 |
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Re: Brattons pistons
call Brattons, they are helpful people.
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10-27-2017, 06:44 PM | #5 |
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Re: Brattons pistons
.003 is too tight. My engine shop bored my cylinders to piston factory specs, which were .003. The engine seized up whenever it got warm. I pulled it apart and had it honed to .0045. No more seizing.
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10-27-2017, 06:47 PM | #6 |
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Re: Brattons pistons
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10-27-2017, 07:43 PM | #7 |
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Re: Brattons pistons
I've always used Brattons pistons. I order one size larger if I'm having the block bored, and get the rings too
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10-27-2017, 09:25 PM | #8 | |
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Re: Brattons pistons
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The weird thing is I know a guy with 75 engines with brattons pistons with .002” clearance, and no problems. Yet others have seizures. There has to be something that’s different. |
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10-28-2017, 10:32 AM | #9 |
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Re: Brattons pistons
Some newer pistons are---- Hypereutectic pistons are made of an aluminum alloy which has much more silicon present than is soluble in aluminum at the operating temperature. Hypereutectic aluminum has a lower coefficient of thermal expansion, which allows engine designers to specify much tighter tolerances.
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10-28-2017, 11:25 AM | #10 |
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Re: Brattons pistons
It maters how you check the clearance. Piston size and bore size will not give you a true reading. You need to have final check with feeler gauge, on the piston skirt.
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10-28-2017, 11:42 AM | #11 |
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Re: Brattons pistons
Using inside a micrometer and double checking the measurement with a outside micrometer works good enough for engine rebuilders. Outside micrometer are checked against a standard. I like my Intrimik mics for checking the bore but you can't use them while boring the cylinder.
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10-29-2017, 10:49 AM | #12 |
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Re: Brattons pistons
I agree with George, use a feeler ga. I bore to .003, then hone another .0005, much more on a racing engine.
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10-29-2017, 02:06 PM | #13 |
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Re: Brattons pistons
A good machinist will bore the cylinders to fit the new pistons...this will solve any issues of piston manufacturing tolerance variations. My machinist even makes sure to mark which piston goes to which cylinder.
If the clearance is too small on your motor after rebuilding it, it sounds like the machinist didn't do a good job.
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10-29-2017, 03:04 PM | #14 | |
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Re: Brattons pistons
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10-29-2017, 05:26 PM | #15 |
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Re: Brattons pistons
The problem may not be the clearance. It may be the pistons.
A couple years ago I took some new pistons and a block to a machine shop for fitting. The machinist looked at the pistons and noticed the skirt of the piston was rather thin. He measured the piston, held it hot tap water for a few minutes and measured the piston again. The piston skirt had expanded over two thousands of an inch under hot tap water. He refused to use them. I bought some Silver-o-lite pistons, bored the cylinders 3 thousands over and have not had a problem.
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10-29-2017, 10:53 PM | #16 |
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Re: Brattons pistons
Snyder's. BTW, George gave me the good advice about honing out to .0045. Thanks again, George!
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