View Full Version : How much to machine my crank?


Powers76
06-29-2009, 04:09:51 AM
I called a machine shop around where i live and he said it would cost $110 to machine my forged 327 crank. Does that sound like a fair estimate?

sooner
06-29-2009, 11:52:15 AM
Last one I had turned was $100 so you are in the ballpark.

Cardinal
06-29-2009, 12:39:45 PM
What are they doing for $100? Checking it for straightness, indexing it, turning the crank, polishing it, chamfering the oil holes, and then balancing it (with the rods and pistons)?

69CHVL
06-29-2009, 05:32:02 PM
My 502 crank was 200.00 to turn, which I did think was high. But, 50.00 was just for magnafluxing. Things cost alot here on the east coast.

Camaro1194
06-29-2009, 06:43:33 PM
110.00 is what it cost to turn a crank around here in CO.

Mike

Powers76
06-29-2009, 09:24:06 PM
What are they doing for $100? Checking it for straightness, indexing it, turning the crank, polishing it, chamfering the oil holes, and then balancing it (with the rods and pistons)?

no idea what all there doing i just asked for an estimate and he said 110. that was the end of the conversation lol

RacerRick
06-30-2009, 11:36:12 AM
Turning a crank around here is about $150. They turn and polish it, check it for straightness, and straighten if needed.

P.S. - Don't ever watch someone straighten your crank if you can help it.

Powers76
07-02-2009, 02:03:46 AM
Turning a crank around here is about $150. They turn and polish it, check it for straightness, and straighten if needed.

P.S. - Don't ever watch someone straighten your crank if you can help it.
lol why not do they straighten it through force?

Marks71BB
07-02-2009, 02:09:37 AM
lol why not do they straighten it through force?

Lets just say they dont use a feather;)

a hunnerd bucks is about right for a turn and polish, add another hunnerd or more for balancing the assy.

stinkboy
07-02-2009, 11:57:04 AM
100 bucks to turn to 20 under, polish journals and take as much weight off as possible then balance it. it was the original crank and had too much mass for my HP so they lightened it prior to balancing.

when i got it back i lost a lot of weight and it looked like it got a bad hair cut.

Powers76
07-02-2009, 06:33:37 PM
thanks for the info when i get paid i will go talk and see what all they will do

earlysecond
07-04-2009, 11:48:54 AM
That price is almost exactly right on as far as a national average. With the help of my friend I actually was allowed to turn a crank one time. It is very interesting. For the price you posted you should get the crank turned, the oil holes chamfered and get a nice, final polish. The only reason that there would be to straighten it would likely be that after they put it in the machine, it was discovered that it would not make the new spec. 10 or 20 under.

The shop I hung out in for awhile, had a crank straightening press. Picture a 5 foot long steel rig with v's on both ends and the provision for a hytdraulic bottle next jack (12 ton in this case) affixed underneath. The crank is gently hand turned and indexed, with a dial indicator. If there is a spot that is out of whack, the jack, with the help of a massive "C" tool actually pulls the crank at the trouble spot, with massive force to straighten it.

A LOT can be done on this fixture. It IS scary but I have seen some crazy goofed up cranks be fixed and made to run, safely, again. Only one time did a crank come unglued on the press. When it did, it was a catastrophic failure resulting in 2 or 3 pieces of crankshaft on the floor. Closer examiniation revealed a small crack that was hidden but already there so the crank was doomed from the get go.

If you have a forged 327 crank that is decent, you will NOT beat the services of a good machine shop in making it usable once again. It is what they do. If they are reputable, you can count on a good, usable crank that is ready to be placed in some fresh oversized bearings and spin happily ever after.

Brent