Run a Chevy piston with a SBF "N" Head ??

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Run a Chevy piston with a SBF "N" Head ??

Post  QtrWarrior on July 20th 2013, 9:38 pm

Anybody out there done this ??

Looking at pistons for the new dirt buster, trying to use off the shelf parts..
Need a comp height between 1.525 and 1.515..
Diamond has a Chevy piston, but I wonder about the valve reliefs....
I know the "N" heads require little if any valve relief....hmmmm

What say the masses ???
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Re: Run a Chevy piston with a SBF "N" Head ??

Post  rmcomprandy on July 20th 2013, 9:48 pm

QtrWarrior wrote:Anybody out there done this  ??

Looking at pistons for the new dirt buster, trying to use off the shelf parts..
Need a comp height between 1.525  and 1.515..
Diamond has a Chevy piston, but I wonder about the valve reliefs....
I know the "N" heads require little if any valve relief....hmmmm

What say the masses ???

KB used to, (maybe they still do), make a flat-top piston with NO reliefs at all.
I can't remember if it was listed as a Chevy or a Ford.

EDIT: A 1986 302 Ford forged OEM Flat-top piston had NO reliefs.

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Re: Run a Chevy piston with a SBF "N" Head ??

Post  c.evans on July 20th 2013, 10:15 pm

The typical SBC has a 23* valve angle, and the N-351 has a 15* valve angle. I wouldn't do it. You would have too much valve relief depth in the wrong place and be wasting some compression ratio.

Charlie

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Re: Run a Chevy piston with a SBF "N" Head ??

Post  slurm on July 20th 2013, 10:25 pm

Have a 347 N heads with a set of probes 230 domes and have shallow reliefs. Runs best with 30 degrees of timing. The piston tops have good color with little fuel wash. Running E85
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Re: Run a Chevy piston with a SBF "N" Head ??

Post  QtrWarrior on July 20th 2013, 10:32 pm

Actually.. The N head is 10*...

The 5cc volume of the valve relief isn't going to kill much compression..
Especially when they will be .005 to .010 out of the hole..
I can tuneup the location of the reliefs , if I need to..

I've heard that some on the board had done this before..
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Re: Run a Chevy piston with a SBF "N" Head ??

Post  c.evans on July 21st 2013, 12:13 am

My mistake, I had a brain fart. Yes, they are a 10* head. If you don't think the compression thing is a problem, then go for it.

Charlie

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Re: Run a Chevy piston with a SBF "N" Head ??

Post  LivermoreDave on July 21st 2013, 12:41 pm

If memory serves me correctly, a local, famed engine builder explained to me he has incorporated the SBC piston into a SBF/N head combination. The piston does not incorporate valve reliefs and piston pin offset may be an issue that need addressing.

Dave.

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Re: Run a Chevy piston with a SBF "N" Head ??

Post  rmcomprandy on July 21st 2013, 12:51 pm

c.evans wrote:The typical SBC has a 23* valve angle, and the N-351 has a 15* valve angle.  I wouldn't do it.  You would have too much valve relief depth in the wrong place and be wasting some compression ratio.

Charlie

Charlie ... the "N" head is 10 degrees.
MIKE ... what size engine is this, (actually what compression distance are you looking for), and what pin diameter do you need

EDIT: OOPS ... I should have read the following posts.


Last edited by rmcomprandy on July 21st 2013, 12:55 pm; edited 1 time in total

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Re: Run a Chevy piston with a SBF "N" Head ??

Post  LivermoreDave on July 21st 2013, 12:53 pm

Good morning Randy or good afternoon to you! How are things North of Motor City, wish you are well.

Dave.

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Re: Run a Chevy piston with a SBF "N" Head ??

Post  QtrWarrior on July 21st 2013, 12:57 pm

rmcomprandy wrote:
c.evans wrote:The typical SBC has a 23* valve angle, and the N-351 has a 15* valve angle.  I wouldn't do it.  You would have too much valve relief depth in the wrong place and be wasting some compression ratio.

Charlie

Charlie ... the "N" head is 10 degrees.
MIKE ... what size engine is this, (actually what compression distance are you looking for), and what pin diameter do you need

EDIT: OOPS ... I should have read the following posts.

Randy,

It is a 358, a 3.500" stroke and a 6.200" rod, 9.465" deck...
I need a 1.515" to 1.525" comp height, because the block has been decked before.
That would give me 0 deck to .010" out...
Needs to be a .927" pin
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Re: Run a Chevy piston with a SBF "N" Head ??

Post  rmcomprandy on July 21st 2013, 12:58 pm

LivermoreDave wrote:Good morning Randy or good afternoon to you! How are things North of Motor City, wish you are well.

Dave.

Well, actually Dave; I got woken up this morning with a phone call telling me that a friend of mine, Jeff Kobylski owner of Modern Cylinder Head, died overnight from the cancer he was fighting.
Other than that, everything is pretty normal.

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Re: Run a Chevy piston with a SBF "N" Head ??

Post  rmcomprandy on July 21st 2013, 1:03 pm

QtrWarrior wrote:
rmcomprandy wrote:
c.evans wrote:The typical SBC has a 23* valve angle, and the N-351 has a 15* valve angle.  I wouldn't do it.  You would have too much valve relief depth in the wrong place and be wasting some compression ratio.

Charlie

Charlie ... the "N" head is 10 degrees.
MIKE ... what size engine is this, (actually what compression distance are you looking for), and what pin diameter do you need

EDIT: OOPS ... I should have read the following posts.

Randy,

It is a 358, a 3.500" stroke and a 6.200" rod, 9.465" deck...
I need a 1.515" to 1.525" comp height, because the block has been decked before.
That would give me 0 deck to .010" out...
Needs to be a .927" pin

What ring pack are you looking to get...?

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Re: Run a Chevy piston with a SBF "N" Head ??

Post  QtrWarrior on July 21st 2013, 1:05 pm

Most pistons I've been looking at are 1/16, 1/16 , 3/16 so that would work for me...

You got something in mind ??
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Re: Run a Chevy piston with a SBF "N" Head ??

Post  rmcomprandy on July 21st 2013, 1:19 pm

QtrWarrior wrote:Most pistons I've been looking at are 1/16, 1/16 , 3/16 so that would work for me...

You got something in mind ??

Well, I have used a Federal Mogul forged replacement piston for a Chevrolet in that application but, it had 5/64" compression rings and a 3/16" oil ring.

It is #L2417F and it has NO pin offset with one "trough" type valve relief; Available STD., .030" or .060".
It has a 1.560" compression height but, is really thick so machining .040" from the top would be nothing.

I will keep looking through past builds and see what else I find.

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Re: Run a Chevy piston with a SBF "N" Head ??

Post  rmcomprandy on July 21st 2013, 1:34 pm

QtrWarrior wrote:Most pistons I've been looking at are 1/16, 1/16 , 3/16 so that would work for me...

You got something in mind ??

I came across another number Mike. It is a Federal Mogul, Speed/Pro and not a production replacement.
We machined one valve relief to accept the stock type E7TE heads.
It also has a thick crown and a compression distance of 1.565" so machining .045" would be necessary.
It has NO pin offset and has 2 valve reliefs with a 1/16", 1/16", 3/16" ring pack ... #L2490F.

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Re: Run a Chevy piston with a SBF "N" Head ??

Post  QtrWarrior on July 21st 2013, 2:09 pm

Thanks Randy , I'll check them out !!!
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Re: Run a Chevy piston with a SBF "N" Head ??

Post  schmitty on July 21st 2013, 3:57 pm

rmcomprandy wrote:
LivermoreDave wrote:Good morning Randy or good afternoon to you! How are things North of Motor City, wish you are well.

Dave.

Well, actually Dave; I got woken up this morning with a phone call telling me that a friend of mine, Jeff Kobylski owner of Modern Cylinder Head, died overnight from the cancer he was fighting.
Other than that, everything is pretty normal.
Is this the gentleman we met when we brought my engine up there? If so, that is too bad, and my condolences to the family.
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Re: Run a Chevy piston with a SBF "N" Head ??

Post  zrob90sc on July 21st 2013, 4:49 pm

Tim Meyer's site shows a dome piston for a 347 on his what's new page.  He has some odd piston combinations for other engines, might be worth checking into.

Link:

http://www.tmeyerinc.com/what%27snew.html
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Re: Run a Chevy piston with a SBF "N" Head ??

Post  rmcomprandy on July 21st 2013, 7:04 pm

schmitty wrote:
rmcomprandy wrote:
LivermoreDave wrote:Good morning Randy or good afternoon to you! How are things North of Motor City, wish you are well.

Dave.

Well, actually Dave; I got woken up this morning with a phone call telling me that a friend of mine, Jeff Kobylski owner of Modern Cylinder Head, died overnight from the cancer he was fighting.
Other than that, everything is pretty normal.

Is this the gentleman we met when we brought my engine up there?  If so, that is too bad, and my condolences to the family.

YES ... Schmitty, you met him; the tall thin guy. Not even 40 years old yet.

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Re: Run a Chevy piston with a SBF "N" Head ??

Post  schmitty on July 21st 2013, 7:24 pm

Truly sad Randy, he was a very gifted young man with a very bright future.
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Re: Run a Chevy piston with a SBF "N" Head ??

Post  dfree383 on July 22nd 2013, 1:15 am

rmcomprandy wrote:
LivermoreDave wrote:Good morning Randy or good afternoon to you! How are things North of Motor City, wish you are well.

Dave.

Well, actually Dave; I got woken up this morning with a phone call telling me that a friend of mine, Jeff Kobylski owner of Modern Cylinder Head, died overnight from the cancer he was fighting.
Other than that, everything is pretty normal.
damn Randy that sucks to hear.
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