This has already been mentioned, but it is worth repeating; Your deck height may vary because the rods vary. Or because the crank is not the same stroke on every throw.Or because one deck is shorter than the other, or because one or both decks is not running parallel to the crank. If you square deck it you have paid a lot of money, possibly to not correct anything at all. Before spending money, you have to prove whats what.
Here's how to prove it in your garage;
Drop the crank in with just the front and back main-bearings,snug up the bolts to like 80% torque, no big deal. Get a Sharpie. Grab any piston and rod assembly.Drop into #1 hole with a new top-half bearing. Set it just below the deck. Lay a STRAIGHT square rod across the hole on it's centerline in the fore/aft direction, on the wrist pin axis. I use a 1/4sq by about 8" length of keystock. Here is where I am a bit confused, to confirm you use a 1/4 by 8 inch length of keystock? So you have it laying on top of the deck over the piston, is that correct? Set your dial indicator up on it, your saying here to put my dial indicator on top of this piece of keystock? set to zero. set to zero ok but where is the pointer resting, on the keystock, on the deck, on top of the piston? Now roll the crank over to push the piston up out of the hole. What if the piston is still below the hole like my 440 is? What then? The piston will raise the bar and the indicator will read the deck-height. Ok so it sounds like you want the dial indicator on top of the keystock and the pointer or plunger of the dial indicator on top of the deck? When it peaks, stop. Ok so it sounds like once again you are measuring how far the piston is rising above the deck. Rock the piston and record the MINIMUM height. Im sorry but Im confused, Im more of a visual guy, what do you mean minimum height? Write it on the deck with the Sharpie on the valley side of the hole.
Repeat in every hole with this same piston assembly. I will do this for sure
Now you have a picture of where the decks and crank-throws really are! You will find some tall deck heights and some short heights.
Now,number your cylinders 1 thru 7 on the drivers side and 2 thru 8 on the passenger side, in proper Moparese. Stupid question but are all mopar engine ( typical mopar engines ) from the 60/70s have the same cylinder order, it is the same as firing order correct ? Find the cylinder with the tallest deck height. No problem I can do this once I understand whats written above What ever the number of that cylinder is, mark the top of this piston assembly with that number and the deck height in that hole,and set it aside. Ok its getting tougher to visualize since Im not clear on the first few steps
Next grab another assy and stick it in this same hole. Measure it's deck height. Mark the top. Repeat with each of the other assys.
Now, line those assys up from tallest to shortest. You know where this is going right? I do have a vauge idea of what your doing and I like it. Im gonna have to wait I think to go any further. I need to understand the first steps better.
Take the longest assy and mark it with the number of the shortest hole. Then the next longest, gets the number of the next shortest hole and so on.
On a separate sheet of paper, right down all these things you have discovered, using the stamped number on the rod, as a reference. Record also the number of the tallest deck ht with what rod # was used, and what rod ended up in what hole. The important thing is to be able to identify the various deck-heights by the rod number, so that when the Sharpie IDs get erased, you can still find what assy goes in what hole.
Ok
Finally, stick each one in it's designated hole and measure it's deck height, in it's new hole. Erase all the old numbers. Mark it with the number of the HOLE on the top now, and the deck height in that hole.
Make a map like the one you earlier made but now with the holes correctly numbered in the Mopar way. Record all the final information, and what rod goes in which hole.
You might be concerned with what happens if you separate the pistons from the rods.And I was too. I found tho, that the piston tolerances are extremely well managed with differences in compression heights almost negligible.
So after you get this far, you will want to restamp your rods, to make it easier to correctly locate them at some future rebuild/freshening.
Now if you actually perform this exercise, you may find the deck-height variance to be acceptable. I got mine to within 002/003 IIRC.
If you get yours this close, then the block can be left alone.
At this point, you can shave the tops off the pistons equally to achieve your very-tight Q. I run .034 in my 367 with those same heads and rods but with KB hypers. The machine shop that I trusted, opened up the skirt clearance to .003/.004. Boy was I mad. This is partly why I run a minimum water temp of 205*, that's another story.
Now back to your post, above. If you square deck your engine, and it comes back perfect, but your crank is goofy and you have eight different length rods, you may actually be making things worse, cuz you have lost the opportunity to use the crooked block to your advantage. Only careful measuring can prove the block will or will not, work,......as is.
One more thing to think about;This is the best time to check the fit of your intake flanges to the heads to the decks. If it too is messed up, then the sq-decking is back on the table.
To do this, you can set the clean heads on the clean decks and snug down just the four corners, of each head, no gaskets. Drop the intake on. Measure the valley gap to the nearest 1/16 or so, and find some straight bar stock to lay on the china-wall to elevate the intake and produce a gap at the intake gasket surfaces. Drop the intake back on and skate it over to one side. Push it up tight and eyeball the fit where the gasket should be. If you see a gap, stick a feeler gauge in it. Check the front then the rear. Then slide it over to the other side and repeat. If there are gaps, you might be in trouble. If the gaps are on the bottom, it will never seal. The running engine will pull in oily crankcase vapors and fog the neighborhood, and it will run like crap. A slight gap at the top may be permissable, depending on how many corners are standing open, and how you are able to torque it down to average them all out.
So now you have, possibly, a second reason to SQ-deck.
Here's how to prove it in your garage;
Drop the crank in with just the front and back main-bearings,snug up the bolts to like 80% torque, no big deal. Get a Sharpie. Grab any piston and rod assembly.Drop into #1 hole with a new top-half bearing. Set it just below the deck. Lay a STRAIGHT square rod across the hole on it's centerline in the fore/aft direction, on the wrist pin axis. I use a 1/4sq by about 8" length of keystock. Here is where I am a bit confused, to confirm you use a 1/4 by 8 inch length of keystock? So you have it laying on top of the deck over the piston, is that correct? Set your dial indicator up on it, your saying here to put my dial indicator on top of this piece of keystock? set to zero. set to zero ok but where is the pointer resting, on the keystock, on the deck, on top of the piston? Now roll the crank over to push the piston up out of the hole. What if the piston is still below the hole like my 440 is? What then? The piston will raise the bar and the indicator will read the deck-height. Ok so it sounds like you want the dial indicator on top of the keystock and the pointer or plunger of the dial indicator on top of the deck? When it peaks, stop. Ok so it sounds like once again you are measuring how far the piston is rising above the deck. Rock the piston and record the MINIMUM height. Im sorry but Im confused, Im more of a visual guy, what do you mean minimum height? Write it on the deck with the Sharpie on the valley side of the hole.
Repeat in every hole with this same piston assembly. I will do this for sure
Now you have a picture of where the decks and crank-throws really are! You will find some tall deck heights and some short heights.
Now,number your cylinders 1 thru 7 on the drivers side and 2 thru 8 on the passenger side, in proper Moparese. Stupid question but are all mopar engine ( typical mopar engines ) from the 60/70s have the same cylinder order, it is the same as firing order correct ? Find the cylinder with the tallest deck height. No problem I can do this once I understand whats written above What ever the number of that cylinder is, mark the top of this piston assembly with that number and the deck height in that hole,and set it aside. Ok its getting tougher to visualize since Im not clear on the first few steps
Next grab another assy and stick it in this same hole. Measure it's deck height. Mark the top. Repeat with each of the other assys.
Now, line those assys up from tallest to shortest. You know where this is going right? I do have a vauge idea of what your doing and I like it. Im gonna have to wait I think to go any further. I need to understand the first steps better.
Take the longest assy and mark it with the number of the shortest hole. Then the next longest, gets the number of the next shortest hole and so on.
On a separate sheet of paper, right down all these things you have discovered, using the stamped number on the rod, as a reference. Record also the number of the tallest deck ht with what rod # was used, and what rod ended up in what hole. The important thing is to be able to identify the various deck-heights by the rod number, so that when the Sharpie IDs get erased, you can still find what assy goes in what hole.
Ok
Finally, stick each one in it's designated hole and measure it's deck height, in it's new hole. Erase all the old numbers. Mark it with the number of the HOLE on the top now, and the deck height in that hole.
Make a map like the one you earlier made but now with the holes correctly numbered in the Mopar way. Record all the final information, and what rod goes in which hole.
You might be concerned with what happens if you separate the pistons from the rods.And I was too. I found tho, that the piston tolerances are extremely well managed with differences in compression heights almost negligible.
So after you get this far, you will want to restamp your rods, to make it easier to correctly locate them at some future rebuild/freshening.
Now if you actually perform this exercise, you may find the deck-height variance to be acceptable. I got mine to within 002/003 IIRC.
If you get yours this close, then the block can be left alone.
At this point, you can shave the tops off the pistons equally to achieve your very-tight Q. I run .034 in my 367 with those same heads and rods but with KB hypers. The machine shop that I trusted, opened up the skirt clearance to .003/.004. Boy was I mad. This is partly why I run a minimum water temp of 205*, that's another story.
Now back to your post, above. If you square deck your engine, and it comes back perfect, but your crank is goofy and you have eight different length rods, you may actually be making things worse, cuz you have lost the opportunity to use the crooked block to your advantage. Only careful measuring can prove the block will or will not, work,......as is.
One more thing to think about;This is the best time to check the fit of your intake flanges to the heads to the decks. If it too is messed up, then the sq-decking is back on the table.
To do this, you can set the clean heads on the clean decks and snug down just the four corners, of each head, no gaskets. Drop the intake on. Measure the valley gap to the nearest 1/16 or so, and find some straight bar stock to lay on the china-wall to elevate the intake and produce a gap at the intake gasket surfaces. Drop the intake back on and skate it over to one side. Push it up tight and eyeball the fit where the gasket should be. If you see a gap, stick a feeler gauge in it. Check the front then the rear. Then slide it over to the other side and repeat. If there are gaps, you might be in trouble. If the gaps are on the bottom, it will never seal. The running engine will pull in oily crankcase vapors and fog the neighborhood, and it will run like crap. A slight gap at the top may be permissable, depending on how many corners are standing open, and how you are able to torque it down to average them all out.
So now you have, possibly, a second reason to SQ-deck.
