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Block Decking & Piston Limit values

fivestardsm

Well-known member
Joined
Sep 8, 2006
Messages
1,699
Location
Middle, Michigan
Does anybody have the values and limits on the piston side to side clearence, And also what is the max that I can have my block decked/ surfaced.

I was doing inspection on the block today and found out that the guy that tore it down last, used a grinder to clean up the top of the block, and slightly gouged the edge of the cylinder where the combustion ring seals. I ran a machinest flat across it with a feeler guage, and I think it is close, but im not sure.

I dont trust my manual..
 

Kenny_Kline

Well-known member
Joined
Dec 27, 2007
Messages
789
Location
Seekonk, MA
Just some numbers to reference during your build.


Compression min: 114psi
Compression difference 14psi
---
Flatness of gasket surface (cylinder head): less than .05mm or .0020" (limit .2 or .008")
---
Cylinder bore: 85mm or 3.3465"
Out-of-roundness & taper of cylinder bore: less than .001mm or .0004"
Flatness of gasket surface: less than .05mm or .0020"
---
Piston clearance to cylinder: .02-.04mm or .0008-.00016" / .03-.05mm or .0012-.0020"
Ring side clearance (top 2 tings): .03-.07mm or .0012-.0028" with a .1mm or .004" limit
End gap (ring #1): .25-.45mm or .0098-.0177" with a .8mm or .031" limit
End gap (ring #2): .35-.50mm or .0138-.0197" with a .8mm or .031" limit
Oil ring side rail: .020-.070mm or .0079-.0276" with a 1.0mm or .040" limit
Service size: .25mm (.010"), .50mm (.020"), .75mm (.030"), 1.00mm (.040") oversize

Hope some of this helps you. Let me know if you need anything else.
 

fivestardsm

Well-known member
Joined
Sep 8, 2006
Messages
1,699
Location
Middle, Michigan
Quoting somovr4:
could we get a pitcure of the said gouge?



I tried to get a pic, but my camera wasn't cooperating /ubbthreads/images/graemlins/banghead.gif
Anyway, I mic'd it the best I could and came up with between .003-.004 so, since the max serviceable surface grind allowed is .005 with a max limit of .008, I should be fine... /ubbthreads/images/graemlins/dunno.gif I'l find out when I take it to the shop.
 

3rdstrikedsm

Well-known member
Joined
Feb 17, 2008
Messages
3,402
Location
32159, FL
If someone used a grinder there is no way in hell I would not get that decked, Who would use a grinder?
There is no way a gasket would properly seal.

Yikes!!!
 

toybreaker

iconoclast
Joined
Apr 30, 2006
Messages
3,581
Be sure that your machinist knows that the deck surface is suspect.

Your machinist will need to reference the crank saddles when he sets it up for grinding, or you could end up with a tilt/taper on the new deck surface if he just flat-rates the location off what's there


Resurfacing the deck with a d.a. is bad juju, as there's no way to keep it flat.

Go kick the previous "technician" squarely in the sack.
 

fivestardsm

Well-known member
Joined
Sep 8, 2006
Messages
1,699
Location
Middle, Michigan
Quoting: toybreaker


. "Resurfacing the deck with a d.a. is bad juju, as there's no way to keep it flat.

. Go kick the previous "technician" squarely in the sack."


. "Be sure that your machinist knows that the deck surface is suspect."


Well, he is in Kentucky probably 6 to 8 feet under the top soil. The old dude passed away.

As for the machinist, he already knows what to expect we discussed it on the phone.
 
Last edited:

fivestardsm

Well-known member
Joined
Sep 8, 2006
Messages
1,699
Location
Middle, Michigan
Ok so I took the block to the Machineshop today and checked everything and found out that i had to repair the block because of the gouge. It was just to deep to mill off.
So here is what I did... God, I need to get a different camera. It won't focus in the light. Anyway..









Here is the goughe after I removed some material so that I could get some weld penetration.





This is after it was Welded and ready to be milled down and checked before the final decking.
 

Don't you have like 20 more blocks in all those cars of yours? /ubbthreads/images/graemlins/grin.gif
 

fivestardsm

Well-known member
Joined
Sep 8, 2006
Messages
1,699
Location
Middle, Michigan
Yeah but I am being anal.. I want the block vin to match the car. It will probably come down to a new block by the time I am done. /ubbthreads/images/graemlins/rofl.gif
 

fivestardsm

Well-known member
Joined
Sep 8, 2006
Messages
1,699
Location
Middle, Michigan
WOW, I should have heeded my own words^^ click

/ubbthreads/images/graemlins/banghead.gif
 
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