Re: Deck and head surface finish.
[Re: Stanton]
#686700
05/02/10 06:03 PM
05/02/10 06:03 PM
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Joined: Feb 2010
Posts: 18,493 Granite Bay CA
Kern Dog
Striving for excellence
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Striving for excellence
Joined: Feb 2010
Posts: 18,493
Granite Bay CA
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I just used a red Scotch Brite and some Lacquer thinner. Zero problems. I am not a hillbilly.
Last edited by Frankenduster; 05/02/10 11:56 PM.
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Re: Deck and head surface finish.
[Re: Stanton]
#686702
05/02/10 07:23 PM
05/02/10 07:23 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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Is 50 on the smooth side or the rough end of the scale?
live every 24 hour block of time like it's your last day on earth
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Re: Deck and head surface finish.
[Re: RapidRobert]
#686703
05/02/10 07:32 PM
05/02/10 07:32 PM
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Joined: Dec 2007
Posts: 18,157 Mass
DAYCLONA
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I Live Here
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Posts: 18,157
Mass
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Quote:
Is 50 on the smooth side or the rough end of the scale?
50 is on the "smooth" side,...generaly most heads are finished at 70 micro inches, that's just enough to barely grab your fingernail as you drag it across the head
Mike
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Re: Deck and head surface finish.
[Re: moparman89]
#686706
05/02/10 07:48 PM
05/02/10 07:48 PM
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Joined: Dec 2007
Posts: 18,157 Mass
DAYCLONA
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I Live Here
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Posts: 18,157
Mass
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Quote:
A 0 would be perfect, 4 is basically a mirror finish. I dont know if there is a scale per say, the higher number, the rougher it is.
but keep in mind the smoother the micro finish, the more chance of blowing a head gasket, esp. if the gasket compression is in the .020-.030 thickness range, the RA fiqure required by some gasket manufacturers, is what they find offers the best "bite" at retaining the gasket..
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Re: Deck and head surface finish.
[Re: Stanton]
#686707
05/02/10 07:53 PM
05/02/10 07:53 PM
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Joined: Jan 2003
Posts: 10,730 North Dakota
6PakBee
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I Live Here
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North Dakota
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The only MLS head gasket I've ever worked with is the 2.0 Neon engine. On these Chrysler has a sealer they want you to coat the gasket with, both sides. On the Cometic, I thought they could custom build almost any thickness you wanted?
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: Deck and head surface finish.
[Re: Stanton]
#686708
05/02/10 07:59 PM
05/02/10 07:59 PM
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Joined: Dec 2007
Posts: 18,157 Mass
DAYCLONA
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 18,157
Mass
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Quote:
The shop I'm using uses a machine with cutters as opposed to grinding. The machinist doesn't think its finished fine enough for "MLS" head gaskets.
Can the Cometics be coated prior to installation to make up for the rougher finish?
What about using 2 gaskets - a Felpro on the block and then a standard steel next to the head (aluminum).
The issue is the deck height is too low and I need to gain a bit to make sure I've got enough clearance. A .051 is still leaving me real tight - .033 quench. If I could use a .039 Felpro and a .019 steel that would yeild a vertually perfect .040 quench.
The alternative is to mill a bit of the top of the piston. The assembly has already been balanced. Since they're partially dished the weight removal would be minimal BUT would a gram or so affect balance that much ??
I wouldn't touch the balanced assy, and I definetly wouldn't stack gaskets....I don't know if it's still avaliable, but Victor had a Teflon coated composition head gasket for both big and small block mopars,...installed height was .068, compressed/torqued height was .045.....I used a set few years back (about 10 yrs ago) to drop the compression on my 11:1 SM Blk Mopar,...still on there, also used a set on a customers BigBlk where the heads were "cut" too much,....I don't recall any numbers, but they were Victors....
Mike
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Re: Deck and head surface finish.
[Re: Stanton]
#686711
05/02/10 09:38 PM
05/02/10 09:38 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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As said I'd leave the short block alone. Get some MLS Cometics custom made in the thickness you need to get your quench where you want it as depending on the app .033" is scary and with the piston rock measure twice (at least) and on my next one I am going to place a piece of lead shot in a cutout on the head gasket and check exactly how much quench I have as I am a firm believer in it and I want it exactly right. One guy said he could not get his cometics to seal until he sprayed each side of each (3) one with permatex "high tack", the red stuff which may increase the thickness a bit also affecting the quench dimention. If I waste a set of gaskets I can live w that. In a MP bulletin from 20 years ago they said to check it by eng upside down on a stand & taking off a rod cap then carefully get the crank all the way down (TDC) then push the rod/bearing down from the crank & see how far it will go further down before the piston hits the head.
live every 24 hour block of time like it's your last day on earth
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Re: Deck and head surface finish.
[Re: moparman89]
#686713
05/02/10 11:43 PM
05/02/10 11:43 PM
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Joined: Oct 2005
Posts: 8,879 Ontario, Canada
Stanton
OP
Don't question me!
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OP
Don't question me!
Joined: Oct 2005
Posts: 8,879
Ontario, Canada
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Quote:
The machinist doesnt "think" the finish will be good enough because he doesnt want the liability
This guy is a long time friend and he does a good number of the local race engines including the blocks for a successful nitro funnycar team. So I trust what he says about the finish not being suitable for the MLS "out of the box". I was wondering if there was an alternative - like a sealer or something.
Quote:
d do a felpro/steel shim/felpro combination
That's way too much. The Felpros are .039 and the steel shim is .019. That would put my quench at .079 !!
What about the Copper "Head Savers" ????
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Re: Deck and head surface finish.
[Re: moparman89]
#686716
05/03/10 10:14 PM
05/03/10 10:14 PM
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Joined: Oct 2005
Posts: 8,879 Ontario, Canada
Stanton
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Don't question me!
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OP
Don't question me!
Joined: Oct 2005
Posts: 8,879
Ontario, Canada
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Quote:
how are you doing funny car blocks and can't get a finish for an MLS
The blocks are sleeved and the decks rarely need to be touched.
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