How smooth does the top of the block deck need to be for MLS ?

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It needs to be pretty smooth which a broach or a Van Norman Block master cannot provide. You need to have a shop with a CBN (for cast iron) and PCD (for aluminum) cutter resurface your block. A surface grinder with segmented stones can also get there. J.Rob
 
IIRC it's smoother than 30Ra. Like RAMM said - the shop needs the modern equipment to achieve that.
 
greymouser7 said:
If I need to utilize a thicker head gasket to lower my compression for pump gasoline use. MLS - Multi Layered Steel Gasket
Thank you
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Says who? You never got back to me with the final figures so I could calculate SCR and DCR. You might be alright. Why would you want to lower compression without knowing for sure?
 
So does that mean I can't use MLS gaskets on my junkyard Magnum shortblock without having the decks machined? I'm using aluminum heads...
 
MOPEkidD-3 said:
So does that mean I can't use MLS gaskets on my junkyard Magnum shortblock without having the decks machined? I'm using aluminum heads...
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I've had the same question, but I was wanting to leave out a layer or two
 
RustyRatRod said:
KB107 .060 over. Un-cut J heads Un-cut block. This cam: Crane Hydraulic Flat Tappet Camshafts 693511 I couldn't find the intake closing event, so I stopped looking. I was playin around on some calculators using .039 for compressed thickness, but without solid numbers, I just don't know.
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RRR and OP, use 61 ABDC for the ICA for this cam. (It can be worked out for the published ICA @.050, along with the advertised vs .050 intake durations..... and assuming the lobe is symmetrical which is a good assumption on this cam. My son has that cam in his 340 BTW.)

FWIW, I get a static CR of 9.5 and DCR of 7.8, for stock deck height, stock open J heads, and .039" head gasket. DCR drops to 7.6 with a standard Felpro it head gasket (8553PT).
 
MOPEkidD-3 said:
So does that mean I can't use MLS gaskets on my junkyard Magnum shortblock without having the decks machined? I'm using aluminum heads...
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Sure you can. It just might leak. You can try some spray copper on it too.
 
j heads (these particular head have NOT been milled, 2.02" 1.6") , crane cams 693511, kb 107's ( +.060") but I don't know deck height yet or a mock up of the rotating assembly's height yet // - flywheel B or F body, highway gears
-rob for 693511 intake opens 25 degrees, closes 63 degrees, and the exhaust opens at 73 degrees, and closes 25 degrees (IAW Crane phone line)
intake Duration at 050 inch Lift:212

Exhaust Duration at 050 inch Lift:220

Duration at 050 inch Lift:213 int./220 exh.

Advertised Intake Duration:268

Advertised Exhaust Duration:272

Advertised Duration:268 int./272 exh.

Intake Valve Lift with Factory Rocker Arm Ratio:0.459 in.

Exhaust Valve Lift with Factory Rocker Arm Ratio:0.480 in.

Valve Lift with Factory Rocker Arm Ratio:0.460 int./0.480 exh.

Lobe Separation (degrees):112
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the second build will be J heads, crane cams 693901, Speed Pro H116 pistons, same ignorance on deck height
crane 693901 the intake opens 19 degrees, and closes at 61 degrees
exhaust opens at 69 degrees closes 23 degrees engine goes with flywheel, into an F or B body with highway gears
Intake Duration at 050 inch Lift:204

Exhaust Duration at 050 inch Lift:216

Duration at 050 inch Lift:204 int./216 exh.

Advertised Intake Duration:260

Advertised Exhaust Duration:272

Advertised Duration:260 int./272 exh.

Intake Valve Lift with Factory Rocker Arm Ratio:0.427 in.

Exhaust Valve Lift with Factory Rocker Arm Ratio:0.454 in.

Valve Lift with Factory Rocker Arm Ratio:0.427 int./0.454 exh.

Lobe Separation (degrees):112
 
I believe that the concern in regards to surface prep is overstated. Smoother is better but a 30RA is about 180 grit. A freshly machined block is more of a concern, but a seasoned deck surface is usually pretty smooth.
 
nm9stheham said:
RRR and OP, use 61 ABDC for the ICA for this cam. (It can be worked out for the published ICA @.050, along with the advertised vs .050 intake durations..... and assuming the lobe is symmetrical which is a good assumption on this cam. My son has that cam in his 340 BTW.)

FWIW, I get a static CR of 9.5 and DCR of 7.8, for stock deck height, stock open J heads, and .039" head gasket. DCR drops to 7.6 with a standard Felpro it head gasket (8553PT).
Click to expand...

@greymouser7 read this post.
 
You dont need an MLS or cometic...but you do need to cc the heads.
At the moment, I dont forsee any issues of having to high dynamic..but you wont know or be able to make the most of it either without knowing what you got.
 
MOPAROFFICIAL said:
You dont need an MLS or cometic...but you do need to cc the heads.
At the moment, I dont forsee any issues of having to high dynamic..but you wont know or be able to make the most of it either without knowing what you got.
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Been trying to tell him that. Like talkin to a brick wall. And I can say that cause he's my brother from another mother.
 
RAMM said:
It needs to be pretty smooth which a broach or a Van Norman Block master cannot provide. You need to have a shop with a CBN (for cast iron) and PCD (for aluminum) cutter resurface your block. A surface grinder with segmented stones can also get there. J.Rob
Click to expand...
Don't tell my wife's 3g hemi. I surfaced the heads and block on my van norman 570. I don't want it to start leaking!
 
Mopar Sam said:
Don't tell my wife's 3g hemi. I surfaced the heads and block on my van norman 570. I don't want it to start leaking!
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I ran one of those among all kinda other stuff in the machine shop I worked in as a kid. The owner had converter it from the turntable that held the blades to a rock and that thing cut to a mirror finish depending on which rock you used. Dang good machine.
 
RustyRatRod said:
I ran one of those among all kinda other stuff in the machine shop I worked in as a kid. The owner had converter it from the turntable that held the blades to a rock and that thing cut to a mirror finish depending on which rock you used. Dang good machine.[/QUOTE
Yeah they are good machines for a small shop. I have square decking fixture set up for mine also. I just recently decided to quit taking in work. Tired of chasing people for money. My sons and I will just work on our own stuff for now. Maybe I will have time to build my stroker this year!
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