Piston to deck clearance

[jwrmach1]

I am finally assembling the 428 after 30 years for my Mach 1.  The block is an early service block with a C1 scratch and casting date of mid May 1970.  My question after mocking up my assembly is that I have a deck clearance on cylinders 1-4 of .017-.018", but on the opposite bank the numbers are .027-.028".  I have the TRW L2303 .030 pistons.  Is it possible the block is off that much.?  Is this normal for FE blocks?  Should I have the block zero decked a different amount on each side?  If .028" is taken off the drivers side bank, and .018" off passenger side bank, will I have intake sealing woes or do I need to do machining to the intake? 
Thanks,
Jack

[My427stang]

Seeing as this is a mock up, the first thing I would do is check your work, one technique is to carefully mark the piston at the same point top and bottom at the deck, measure at full piston rock, then add the numbers and divide by 2.  Note the actual numbers by the way, I would be interested in how much piston rock you have. I have been having some conversations outside of the forum on piston rock and trapped combustion and would like to see what those pistons give you

After that, even if your numbers shrink a little, I would still strip it down and either measure the decks with a set of 12 inch calipers, or have your machinist do it.

It is VERY common for FE blocks to be not only different from side to side but also end to end.  Your machinist should deck the block off crank centerline and hit any number you want

Your crank/piston/rod combo should be 10.154, an uncut FE block is 10.170.  So with a fresh block, you should be .016 below.  I have never seen an FE deck another 10 thou taller.  However, anything is possible, but the deck measurement will tell you that

If it's a parade car or show car resto, having it exactly the same really doesn't matter much and back in the day, people didn't even think about it unless they were racing.  However, there is no reason not to, especially if you intend to horse around a little

BTW, some guys will cut down to 10.150 and even 10.145 regularly, I really try not to do that unless I need to.  I like a 10.160 block where I can, but sometimes you can't get there, the two I am doing now are at 10.155

Your block, if able to square up at 10.160 would be .004 below and with a .041 head gasket (Felpro 1020, not engine kit Blue 8554s) would be a pretty good.street setup, same with a 10.155 deck, at that point you are near zero deck

As far as the intake fitting, it depends.  It's a function of both block and head cut.  So, if the heads are stock and you cut the deck, sometimes they do OK.  If the heads were cut and the block were cut, often you need to do some work on the intake as well.  The more you cut, the more you need to fit.

[Heo]

I can tell you my last block was more than that end to
end. I told the machinist to take it to 10,155
Zero deck with Speed pro pistons.
A competent machine shop deck the block off crank centerline
No problem with intake fitting that decking compensate for
the thicker than stock  feelpro gasket

[jwrmach1]

My first attempt at measuring the clearance did show a range which included the piston rock.  I was seeing .012-.027" on the passenger bank and .022-.033" on the drivers bank.  I then used a flat bar to measure to the center of the piston and those are the numbers I have shown in my earlier post.   I measured in all four corners and with and without the rings.  Is it better to measure with the rings or does it not matter?   I will measure the deck height at all 4 corners.  So it is better to convey the the deck height I want to the machine shop and not how much to take off the deck.  This will not be a trailer queen or occasional cruise night car, I intend to beat the snot out of it at the dragway once in while, after all that what it was made for.
Thanks,
Jack

[Heo]

Yes it is better to tell the machinist the deck height you want
If he has the propper equipment the final deckheight is what
he is interested in

[machoneman]

Neat trick: leave the rings off but wrap the lands with blue painter's tape. Enough turns for a slight interference to the bore. Also, use the same piston/rod in all 4 corners for measurements. Re-conned rods may not be the same length.

[My427stang]

My first attempt at measuring the clearance did show a range which included the piston rock.  I was seeing .012-.027" on the passenger bank and .022-.033" on the drivers bank.  I then used a flat bar to measure to the center of the piston and those are the numbers I have shown in my earlier post.   I measured in all four corners and with and without the rings.  Is it better to measure with the rings or does it not matter?   I will measure the deck height at all 4 corners.  So it is better to convey the the deck height I want to the machine shop and not how much to take off the deck.  This will not be a trailer queen or occasional cruise night car, I intend to beat the snot out of it at the dragway once in while, after all that what it was made for.
Thanks,
Jack

My opinion is that you tell the machinist to square deck it to the mains and hit a target deck height with a range you'll accept. 

An example, the two 461s we are doing, I asked for 10.160, but call me if he had to go more than 10.155 using using a Felpro 1020 .041 gasket, he did 10.155.

Those numbers would also work fine for what you have, you'd be either .006 or .001 below deck and with that gasket, .047 or .042 quench distance

If he calls back and says, it's too bad, needs to cut it more, you could say, 10.150 or 10.145 and then use a Felpro 8554 (about .051 thick) and you end up the same place.  The pistons actually sit above deck slightly, but you end up at the same 047 or .042 quench distance because of the gasket and the heads end up in the same place as well despite the cut

[jwrmach1]

I measured the deck height at all four corners with a cheap 12 inch digital caliper.   The results somewhat agree with my piston to deck measurements that the drivers side deck is high. 
front pass side 10.170
rear pass side 10.172
front drivers side 10.1775
rear drivers side 10.1775
So if I instruct the machine shop to square the decks to 10.160, I should be in great shape.  Is there anything else I should be instructing the machine shop to do or check?
Thanks,
Jack

[My427stang]

I'd likely ask them to check main alignment, they likely would want to do that anyway before decking.

However, having the mains align honed and at the bottom of the spec (smallest ID) makes for a nice strong base.

The final thing I like to do is tap all the oil galleys for pipe plugs.  Over the years I have stopped doing much for oil mods, but you could blend the transition on the passage from the oil pump as well

[jwrmach1]

Just an update, I took the block to the Machine shop and had them measure it first.  I asked them if it could be decked to 10.160.  Machine shop called today with the following measurements, confirming that the drivers side deck is .008" higher than the passenger side.
Front Pass side 10.164
Rear Pass side 10.165
Drivers side front 10.173
Drivers side rear 10.173
Machine shop said it can deck it to 10.160 if I wish.  This should bring my deck clearance to .012-.014.  Should I ask them to go more, less, or ok at 10.160?
Thanks,
Jack

[Joe-JDC]

Bob gave you the best method to square up the decks.  You need the mains align bored/honed correct, then recondition all your rods, or check all new rods for length, double check pin heights on all pistons, and then hang one piston on a rod, install it at all four corners, and take measurements.  Then deck block to square it up side front to back, corner to corner.  Any other way unless you use CNC machine, or BHJ fixture will be guess work.  Joe-JDC

[gt350hr]

  At the rate ( of machine speed) Ford uses I would think that heat build up has something to do with the irregularity. As shown , the block starts out "close" at 10.173 and gets worse as it goes. The machinist I use decks blocks at the slowest possible "feed speed" on his machine claiming it has less heat buildup that way. Makes sense to me. It also provides a much finer , smoother surface.
     Randy

[Ranch]

Seems since you discovered one problem you have to ask, just what else may be lerking, it's a new block and nothing has been proven  If it was me I'd have my machinist align bore (hone) the mains, they should be on the same plain as cam bearing tunnel. Then he'll deck it square with the mains and maybe check the bell housing mating surface. Most shops don't run their machines stupid fast to effect the heat, after all the are going for a finish and cast iron is pretty stable.  Would you ruin your machine or tooling to save two minutes?  After all it's been 30 years and now is not the time to rush things.  When I built mine I check compression height of all my new pistons then checked deck clearance with an indicator right over the wrist pin. My pistons only have .002 clearance so the don't rock much.  If you aligned hone and your rods are sized then you can run a tighter bearing clearance with little worry and your oil pressure should be higher..JMO,have fun 

[chris401]

Neat trick: leave the rings off but wrap the lands with blue painter's tape. Enough turns for a slight interference to the bore. Also, use the same piston/rod in all 4 corners for measurements. Re-conned rods may not be the same length.

I measure with the same rod and piston but the tape is a new idea to me. Do you wrap any at or just below the pin?

[machoneman]

Neat trick: leave the rings off but wrap the lands with blue painter's tape. Enough turns for a slight interference to the bore. Also, use the same piston/rod in all 4 corners for measurements. Re-conned rods may not be the same length.

I measure with the same rod and piston but the tape is a new idea to me. Do you wrap any at or just below the pin?

Just wrap some blue painter's tape around the ring lands, oil ring land and up. None much below the bottom edge of the oil ring land as the skirt at/below the pin will be the widest (tightest) to the bore anyway.