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I wonder where the discrepancy is then? The cylinder should measure the same as all 4mm cubs do which is 4.079 which should put you in the hole .01-.012" I have done tons of 4mm cubs and thats how they always are. I measured another serval that came from the same batch as yours and thats what it measured as well. Ive never had one with positive deck... Curious if your cylinder is short or something else isnt right. A couple of thousands difference is no biggie but your off .015-.02?

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I couldn't agree more - of all the 4mm cubs I have done, this is the 1st that made me triple take the deck. I was like ... huh ?? :confused:

Will pull the cylinders & see.

 

I've installed nuts on a DM :cheers:

 

I feel ya ... I do. But the 12 point wouldn't go. So while I was in there I figured I'd take it out to accept the factory nuts.

Sometimes they are just a little snug, sometimes it's no problem.

Really no big deal.

Just giving my honest & unbiased review. :)

Edited by Forcefed
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Curious if your cylinder is short or something else isnt right. A couple of thousands difference is no biggie but your off .015-.02?

 

Ok ... Got the news.

 

Spec says .005 in the hole with a .012 gasket... don't know if that's compressed or not.

 

I have 0 to .002+ deck (depending on where you pick up the chamfer on timing edge of piston) with an as listed .020 cometic... torqued.

 

That's what ... - .013 to .015 difference... roughly.

 

Spec cylinder height is 4.079.

 

This one measures a repeatable 4.0735 with calipers & micrometer on both sides.

 

The .020 gasket measures .019 new & .0165 after removal of the cyl at 20 lb/ft.

 

There is .008(ish) combined.

With .005 to the cylinder.

I think the cleaning/etching process before plating may be suspect ? Similiar to why some castings become porous over numerous replates ?

 

That leaves .004 to .006 to machining tolerances within the:

Case deck height.

Case/crank bore.

Crank web stroke from center.

Piston pin center line to timing edge.

Crank pin to rod centerline.

And my margin of error.

 

To put a touch of deck height confirmation with things - a set of domes with a .025 step, measured .028 on several pieces of solder (+/- what, maybe .002 for the challenge of measuring a soft piece of tapered pasta) - lol

 

What do ya think ?

Edited by Forcefed
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Me and calvin updated the sidview as there were a few things a little mis marked. With a .02 gasket you should be .0135 in the hole. Doing the squish test the way you did is confirming your positive deck height but thats still got me scratching my head.

 

Are you 100% that your cases have not been decked?

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100% ... no. But, 99% yes.

 

Thank you kindly for the update.

 

Another thought I had that might could be added to the list of tolerances is:

 

Does this sideview incorporate the gasket crush & the machining required to square/true the decks of the fresh castings ... that could be another couple of thou ?

Edited by Forcefed
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100% ... no. But, 99% yes.

 

Thank you kindly for the update.

 

I see that the deck went negative corresponding to the increase in gasket thickness, but the rod centerlines only increased by a little over .003 ?

 

Another thought I had that might could be added to the list of tolerances is:

 

Does this sideview incorporate the gasket crush & the machining required to square/true the decks of the fresh castings ... that could be another couple of thou ?

if they had been decked the port timing would be less ... that would be the same thing with the rod trig. also.

Edited by Titan
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