Deck height

[flyinlow]

How do you measure deck height with a bare block? (440)

If I had measured the distance the pistons where in the hole on tear down that would have given me a place to start. I am learning to check more stuff on disassembly .

How close to 10.720" are most blocks?

[Challenger340]

How do you measure deck height with a bare block? (440)

If I had measured the distance the pistons where in the hole on tear down that would have given me a place to start. I am learning to check more stuff on disassembly .

How close to 10.720" are most blocks?

Pretty difficult to measure deck height on a bare block without a BHJ fixture or similar ?    Can you re-assemble a mockup again and measure with a deck bridge ?
From factory Blocks can be all over the map....
mostly higher than 10.720" in the 10.720" to 10.73" range
however,
I've seen them as high as 10.735" and as low as 10.710" with most exhibiting .005" to .010" tilt from end to end and NOT parallel to the mains ?  
Most would be amazed at how much Deck "Tilt" exists in a factory originally machined Block from end to end on each deck.... meaning #1 can be .015" down at TDC and #7 can be .027" down ?

A little off topic....
but that's why at our shop here we start with the Mains..... because EVERYTHING else should be done off the main centerline which holds the Crank and everything else.
After Hot-Tanking/Mag and pressure testing the core casing integrity....
* We Machine the Main Caps , install the Main Studs and Line Hone.... then checking/ setting Vertical Main Bearing Clrc to the Crank. If the Block is core stock we STOP -.0005" down from final until the Block is to be used and a Crank/Brgs can be mated to it.
* We then do a "rough" cut on the Block Decks just enough to "square" the Decks parallel the the semi/finished Mains
* We then Sonic Test the existing Cylinders looking for imperfections/thin spots of special note
* We then Bore the Cylinders using the Milled Parallel Block Decks as a reference..... to CORRECT the Cylinders "perpendicular" to the Mains .... another thing people would be amazed to see how far off/tilted/skewed the factory Cylinders are from being "perpendicular" to the Mains on a factory Block.
* After Final Honing W/Torque Plate we Mock-up the Block with it's Crank/Rods/Pistons and do any Block Clrc'ing.....  then we can also check Deck Heights with a bridge on the Pistons and re-Mill the Block Decks for correct quench height/finish for example depending Cometics or Composition gaskets.

Remember the Casting Numbers on factory Blocks ?   the 440-"4" for example.... or 440-"8"... -9.... etc., etc. ?
Well those are farum numbers the last digit represents the numbers of Cylinder casings that have been replaced in each core half when casting a V8 = two core halfs of 4 cylinders in each = a -"2" Block
as the core halfs were re-used...
sometimes a single cylinder case in the half of 4 would get damaged and need replaced.... meaning that half had one "replaced" cylinder Core.... and any subsequent Blocks cast with that half became a -"3".
Long story short....
when looking at a 440-"8" Block for example ? know that it took "2" core halfs to cast the Block... so "8" minus the "2" means somewhere within that Block "6" single Cylinder Casings were replaced in that Block and they are NEVER perfectly "aligned" perpendicular to the Mains.... and even though at the factory all 8 Cylinders were Bored simultaneously the factory tolerances in mass production were what they were.... and cylinder alignment can be all over the map.
Does it matter ?
I dunno.... but we do it as part of Blueprinting, and ours always seem to make more power than the DIY guys same build on the Dyno ?
but then again, we also do Pin-Fitting, set side Clrc on Rods in Pairs...Cam Degree running mates...make our own Pushrods here for V/Train Geometry...   and on and on with "free power" things that just aren't done anymore because people want "price" .... and they believe "Machining is all the same" right ?

Just highlighting Block Decks from factory have 'tilt' end to end and are usually NOT parrallel with the mains.... nor are cylinders "perpendicular" to the Mains....
again... does it matter ?
Depends what you have access to I guess ?

[justcruisin]

I sat a new rpm head on my 1970 virgin block, I could rock it side to side. I measured .008" end to end.

[flyinlow]

I sat a new rpm head on my 1970 virgin block, I could rock it side to side. I measured .008" end to end.

That's a great idea!

Machine shop (Fowlers, Columbus,Oh) said the block needs decked.

[flyinlow]

Is a deck bridge a straight piece of steel bolted across the bore by head bolts?  If so I made one.

[Challenger340]

Is a deck bridge a straight piece of steel bolted across the bore by head bolts?  If so I made one.

We use a modified/Milled HEMI Rocker arm shaft bridge.... just mount a Dial indicator.   Zero it on the Flat Deck then move over onto the Piston.

You can make one out of anything, we just like Aluminum.

[c00nhunterjoe]

How do you measure deck height with a bare block? (440)

If I had measured the distance the pistons where in the hole on tear down that would have given me a place to start. I am learning to check more stuff on disassembly .

How close to 10.720" are most blocks?

Pretty difficult to measure deck height on a bare block without a BHJ fixture or similar ?    Can you re-assemble a mockup again and measure with a deck bridge ?
From factory Blocks can be all over the map....
mostly higher than 10.720" in the 10.720" to 10.73" range
however,
I've seen them as high as 10.735" and as low as 10.710" with most exhibiting .005" to .010" tilt from end to end and NOT parallel to the mains ?  
Most would be amazed at how much Deck "Tilt" exists in a factory originally machined Block from end to end on each deck.... meaning #1 can be .015" down at TDC and #7 can be .027" down ?

A little off topic....
but that's why at our shop here we start with the Mains..... because EVERYTHING else should be done off the main centerline which holds the Crank and everything else.
After Hot-Tanking/Mag and pressure testing the core casing integrity....
* We Machine the Main Caps , install the Main Studs and Line Hone.... then checking/ setting Vertical Main Bearing Clrc to the Crank. If the Block is core stock we STOP -.0005" down from final until the Block is to be used and a Crank/Brgs can be mated to it.
* We then do a "rough" cut on the Block Decks just enough to "square" the Decks parallel the the semi/finished Mains
* We then Sonic Test the existing Cylinders looking for imperfections/thin spots of special note
* We then Bore the Cylinders using the Milled Parallel Block Decks as a reference..... to CORRECT the Cylinders "perpendicular" to the Mains .... another thing people would be amazed to see how far off/tilted/skewed the factory Cylinders are from being "perpendicular" to the Mains on a factory Block.
* After Final Honing W/Torque Plate we Mock-up the Block with it's Crank/Rods/Pistons and do any Block Clrc'ing.....  then we can also check Deck Heights with a bridge on the Pistons and re-Mill the Block Decks for correct quench height/finish for example depending Cometics or Composition gaskets.

Remember the Casting Numbers on factory Blocks ?   the 440-"4" for example.... or 440-"8"... -9.... etc., etc. ?
Well those are farum numbers the last digit represents the numbers of Cylinder casings that have been replaced in each core half when casting a V8 = two core halfs of 4 cylinders in each = a -"2" Block
as the core halfs were re-used...
sometimes a single cylinder case in the half of 4 would get damaged and need replaced.... meaning that half had one "replaced" cylinder Core.... and any subsequent Blocks cast with that half became a -"3".
Long story short....
when looking at a 440-"8" Block for example ? know that it took "2" core halfs to cast the Block... so "8" minus the "2" means somewhere within that Block "6" single Cylinder Casings were replaced in that Block and they are NEVER perfectly "aligned" perpendicular to the Mains.... and even though at the factory all 8 Cylinders were Bored simultaneously the factory tolerances in mass production were what they were.... and cylinder alignment can be all over the map.
Does it matter ?
I dunno.... but we do it as part of Blueprinting, and ours always seem to make more power than the DIY guys same build on the Dyno ?
but then again, we also do Pin-Fitting, set side Clrc on Rods in Pairs...Cam Degree running mates...make our own Pushrods here for V/Train Geometry...   and on and on with "free power" things that just aren't done anymore because people want "price" .... and they believe "Machining is all the same" right ?

Just highlighting Block Decks from factory have 'tilt' end to end and are usually NOT parrallel with the mains.... nor are cylinders "perpendicular" to the Mains....
again... does it matter ?
Depends what you have access to I guess ?

And this is the difference between a backyard rebuild and a pro.

[flyinlow]

Great information ! Thank you.

The block we are going to use is a "78  440-4  the alternate was a '76 440-2

block cleaned up at + .025 on the cylinder with the damage. .All  bored to + .025 now . Block decked to 10.706 " height now. So a few of the variables are decided .