Deck smoothness of a block and head from the factory

Cokedoctor

Slow Boost
Oct 29, 2007
38
0
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Buffalo, NY
IJ.;1153693 said:
DOH!

Possibly the finickiest MHG on the market with the highest smoothness requirement...

So, do you think that surface is too coarse? How smooth should it be? Should I be able to see my reflection or what? lol Do you have any values I can give to the machinist??
 

IJ.

Grumpy Old Man
Mar 30, 2005
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I come from a land down under
Unless he has an optical comparator specs aren't much use to him ;)

For the HKS I get mine as smooth as humanly possible, I have mine cut with CBN cutters.

I used to Lap both the head and block with Diamond paste but have since found a shop that can give me a perfect surface straight off the machine.

Reg Reimer used to sell small round lapping plates to do this job so it might be worth your while dressing up the surface you already have if the machine shop can't get it any smoother.

Grab a good Macro pic of the surfaces using flash please.
 

Tanya

Supramania Contributor
Aug 15, 2005
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Naples, FL
IJ.;1153693 said:
DOH!

Possibly the finickiest MHG on the market with the highest smoothness requirement...



hahahaha that's awesome to know. my ex just installed that very gasket on my 6M recently, after I blew up a cheapie ebay HG at 5,000 miles.

he installed it w/ arp studs though, wonder how long it will last (no boost)
 

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
10,730
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Valley of the Sun
The bead types pretty much seal the same...the best is the HKS stopper type.

HKS MHGs require a smoothness of 30 RA or better...Cometic (Titan) requires a 50 RA.
The Cometic can tolerate a rougher finish...it's less "finicky".
 

Poodles

I play with fire
Jul 22, 2006
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Fort Worth, TX
Most of the time the finish is related to how fast they run the machine over it. The slower it's done, the better the finish, but time is money...
 

Cokedoctor

Slow Boost
Oct 29, 2007
38
0
0
Buffalo, NY
I just loaded my block in the trunk of my Crown Victoria. I'm leaving for Youngstown, Ohio tonight. I'm taking my engine to a different machinist, whom I am real close with. I'll be dropping it off Saturday morning...and I'll be coming back Sunday night with it in my trunk, all smoothed out. :) I will tell my buddy Randy at Engine Machine Service to deck it with an RA value of 30 or smoother. Wish me luck!
 

Cokedoctor

Slow Boost
Oct 29, 2007
38
0
0
Buffalo, NY
The head was decked at the same shop the block was done at the first time, but the head came out alot smoother. I'm pretty sure it'll be fine.