Rebuilding an engine - what precision instruments to do measurements

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0xDEADBEEF

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The 6.2 might all be 58x. I wonder if you can have the reluctor changed out ... seems like you could.
 

Schurkey

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Are they the same CRANK, or just the same STROKE?

I bet the balance is way different, which might mean the same casting but different drilling for balance; or it might mean entirely different castings with bigger/smaller counterweights that could be...difficult...to balance correctly.

I don't know...but you need to find out.
 

stutaeng

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Are they the same CRANK, or just the same STROKE?

I bet the balance is way different, which might mean the same casting but different drilling for balance; or it might mean entirely different castings with bigger/smaller counterweights that could be...difficult...to balance correctly.

I don't know...but you need to find out.
Yes, you are correct there.

Here's the article (now 12 years old :rolleyes:) I was thinking about said:

"The 6.0L crank has the same stroke (92mm) as the 5.3L and 5.7L cranks.
In 1999-2000 this crankshaft was identified with c
12552215 and had
only a wide flange. Then in 2001-’04 the 6.0L went to narrow flange
only with c
1255216, the same as the 5.3L and 5.7L.
The piston weights are different enough for the 5.3L, 5.7L and 6.0L
that you would not think that any of them would interchange. However
word on the street is that 6.0L and 5.3L cranks will interchange and
that there have been no complaints."


Maybe it's one those things that GM doesn't recommend, but folks do anyways? I don't know. Probably good idea to get the rotating assembly balanced...
 
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0xDEADBEEF

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You got me all curious, so I've been doing some web sleuthing. I found this at Holley:

The smallish 4.8L engine use a specific 3.26-inch stroke while the 5.3L, 5.7L, 6.0L and even the 6.2L engines all spin a 3.622-inch factory arm. It’s also possible to interchange these cranks to allow using a 5.3L crank in a 6.0L block and balance will be close. GM achieved this by making its smaller bore pistons heavier so that balance between all the various displacements would not require massive machining.

 

stutaeng

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Ok, just dropped off the block at this local shop called Dennis Wells in Duncanville. The guy asked what I was doing with the engine and quoted me $600 for vat clean, magnaflux, line boring, cylinder boring with torque plate and new cam bearings.

He said to look into pistons if I wanted 20 or 30 thousand over. He said 10 over pistons are made but too expensive and 20 may be difficult to get? I need to figure that out and call him back.

He also gave me the number of another local place that machines crankshafts as an option for me.
 

Erik the Awful

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$600 is a little bit on the high side, but not unfairly so - especially considering inflation. Make sure that he doesn't bore the cylinders until he has the pistons in hand. I ran back and forth with my machinist when I realized my ring end gaps were too big, and discovered my block was actually bored to 4.033". When I asked him he told me the Sealed Power pistons were machined to 4.030"! Fortunately he bores the blocks to match the pistons so I was okay. The .032" ring end gap isn't terrible, and it's not like I had many options - they're the Sealed Power rings spec'd for the pistons.
 

0xDEADBEEF

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$600 is a little bit on the high side, but not unfairly so - especially considering inflation. Make sure that he doesn't bore the cylinders until he has the pistons in hand. I ran back and forth with my machinist when I realized my ring end gaps were too big, and discovered my block was actually bored to 4.033". When I asked him he told me the Sealed Power pistons were machined to 4.030"! Fortunately he bores the blocks to match the pistons so I was okay. The .032" ring end gap isn't terrible, and it's not like I had many options - they're the Sealed Power rings spec'd for the pistons.

You might as well boost it now, with that ring gap.
 

Schurkey

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NORMALLY, I'd say to bore/hone the minimum oversize to clean the cylinders. .010-over seems likely in this case.

But these are not "normal" times.

Supply shortages and Bidenomics are squeezing us like at no other time in this country's history. It truly may be that "ten-over" pistons can't be had in reasonable time...or for reasonable money. Or both.

Wouldn't hurt you to do some price-and-availability research at the usual sites--Summit, Jegs, Amazon; and any others you can think of.
 

stutaeng

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Summit sells a whole kit with pistons and crank to get a 408.
Yup. The option now is:

1.) Find myself a take-out $100 crank and a set of Pro-LS, or whatever brand is available pistons (in the appropriate diameter).

2.) Spend $1700+ on a 408 rotating assembly, assuming it's available. I did ask the guy there and he said he thought it was more like $2500 "now".:oops: Thank you Mr. useless President!

Question to myself now is: do I really "need" a 408? I'm thinking it's kind of overkill for anything I'd drop it in (Cherokee JK, GM truck or SUV 1500/2500/3500?)... I'm not really into r-a-c-y stuff.

And I'm still upset about my property appraisal protest being denied, so there's that....$#@*!?

I'm going to start cussing here in Spanish (with English mixed in there too!) now....
 
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