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Allowable crank journal taper and out-of-round specs? #866605 11/29/10 05:34 PM 11/29/10 05:34 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	For a performance / race engine, what do you consider allowable crankshaft rod & main journal taper and out-of-round measurements? EDIT: This question was asked by somebody else ("STANTON"?) on another current thread, so I figured I'd split it out as a separate post because I was interested in the answer, too. Last edited by Blew My Budget!; 11/29/10 06:11 PM.

Re: Allowable crank journal taper and out-of-round specs? [Re: BradH] #866606 11/29/10 05:36 PM 11/29/10 05:36 PM
Joined: Jan 2003 Posts: 25,200 Upper Midwest M MoparforLife Too Many Posts
MoparforLife Too Many Posts M Joined: Jan 2003 Posts: 25,200 Upper Midwest	0

Re: Allowable crank journal taper and out-of-round specs? [Re: MoparforLife] #866607 11/29/10 05:38 PM 11/29/10 05:38 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	Quote: 0 Yes, Mr Callies, I understand that's what we'd all LIKE to see. But for those of us who may not be living in that world, how 'bout some realistic #s by which to base things?

Re: Allowable crank journal taper and out-of-round specs? [Re: BradH] #866608 11/29/10 05:57 PM 11/29/10 05:57 PM
Joined: May 2009 Posts: 511 Temperance, MI 6 68 HEMI GTS mopar
68 HEMI GTS mopar 6 Joined: May 2009 Posts: 511 Temperance, MI	its pretty common to have 0.0003 or so. how much do you have?? 68 Dart GTS "HEMI" 10.30 @ 131 pump gas street car 3780# 69 Roadrunner 511 six pack 10.92 drive to track street car

Re: Allowable crank journal taper and out-of-round specs? [Re: 68 HEMI GTS] #866609 11/29/10 06:06 PM 11/29/10 06:06 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	Quote: its pretty common to have 0.0003 or so. how much do you have?? In the case of the crank I have for my 448 build, the mains are .0002" or less in both taper & OOR. Three of the four rod journals are .0003" or less in both measurements. The fourth rod journal has .0002" taper, but also has .0006" OOR. Last edited by Blew My Budget!; 11/29/10 06:26 PM.

Re: Allowable crank journal taper and out-of-round specs? [Re: BradH] #866610 11/29/10 06:19 PM 11/29/10 06:19 PM
Joined: Jul 2010 Posts: 2,091 Delray beach, Florida P Performance Only top fuel
Performance Only top fuel P Joined: Jul 2010 Posts: 2,091 Delray beach, Florida	i can tell you that the industry standard is .0002 allowance for taper and less than .0001 out of round. that .0001 is really splitting hairs IMO. on the stuff we grind i typically see 0 out of round and less than .0001 taper, which is basically immeasurable with the human touch. machine shop owner and engine builder

Re: Allowable crank journal taper and out-of-round specs? [Re: 68 HEMI GTS] #866611 11/29/10 08:05 PM 11/29/10 08:05 PM
Joined: Oct 2005 Posts: 8,926 Ontario, Canada S Stanton Don't question me!
Stanton Don't question me! S Joined: Oct 2005 Posts: 8,926 Ontario, Canada	Just wiping the crank with a paper towel would take off .0002" !

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