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Brand new MP 4" stroker crank out of round...
#618573
02/20/10 11:15 AM
02/20/10 11:15 AM
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
HerboldRacing
OP
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OP
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
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Check it out... this is brand new shipped from Summit Racing. http://www.youtube.com/watch?v=Lye9eoLUQdc WTH. What should I do? I know summit will take it back but I'd have to pay for shipping back to them. Then who is to say I won't simply get another crank like this again from them? If I put on all the main caps and bearings the crank spins easily for about 180 degrees and takes 2 hands to spin for the other 180 degrees. When I take the caps off I can see some scuffing on lower bearing #4 and some slight scuffing on lower bearing #3.
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Re: Brand new MP 4" stroker crank out of round...
[Re: ademon]
#618575
02/20/10 11:34 AM
02/20/10 11:34 AM
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
HerboldRacing
OP
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OP
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
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Quote:
Summit usually will pick up shipping in something like this.
They will? I'll talk to them and find out. Thanks.
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Re: Brand new MP 4" stroker crank out of round...
[Re: HerboldRacing]
#618576
02/20/10 01:33 PM
02/20/10 01:33 PM
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Joined: Dec 2007
Posts: 18,157
Mass
DAYCLONA
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 18,157
Mass
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Don't take this the wrong way,...but .0015 is nothing (about 1/3 of a human hair strand thickness), you'd be amazed at the amount of deflectional and elastistical movement that crank will go thru under high RPM loads,....even though your gauge is a cheap chinese dial indicator, it appears "good",....it may also be your method of indicating they may be seeing an error, even a small peice of debri or a nick in a bearing shell backside can cause false indications, cranks are sensitive to static loading, it's their nature inherent to their design,.....to swap/replace that crank, you might get one with even more run-out Granted we would all like to see "ideal" conditions in our engine builds, zero indications, but that ain't going to happen,....most people like to associate engine building to some form of "black art" that catastropic damage will result from the minutist trace of run-out being indicated,....it's a "micro managment" problem that most incounter IMHO the crank is good to go.......  What I see based on your dial indication #1 .0002-.0003 #2 .0003-.0004 #3 .0003 #4 .001-.0015 #5 .0001-.0002 Here's a page from Chrysler's FSM regarding V8 crankshafts Mike
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Re: Brand new MP 4" stroker crank out of round...
[Re: ZIPPY]
#618578
02/20/10 02:16 PM
02/20/10 02:16 PM
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Joined: Dec 2007
Posts: 18,157
Mass
DAYCLONA
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 18,157
Mass
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Quote:
I'm not sure what the print spec is, but it's probably in book range for a street motor.
Problem is you bought a racing/high performance crank that
(I would think) should be better? But that's just an assumption.
If you decide not to run it and Summit won't take care of you let me know. I'm aquainted with a few Mopar Performance folks who would be interested to know about this situation.
I could see an issuse if the OP was building a 13,000 RPM Pro Stock motor (not with Summit parts though!),.....at best, I'll guess he's building a 10 1/2 to 11 sec motor that will probally only see 6500 RPM max,....after a few hard passes/ 1 seasons worth that .0015 max runout he's worried about will be nothing compared to the other journals "new runout" value
Mike
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Re: Brand new MP 4" stroker crank out of round...
[Re: dusturbd340W5]
#618581
02/20/10 04:16 PM
02/20/10 04:16 PM
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Joined: Dec 2007
Posts: 18,157
Mass
DAYCLONA
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 18,157
Mass
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Marvin,....that "scuff" on the #4 bearing is concentrated right at the parting line only,...possibility of a burred edge deflecting the bearing inward on that corner?...either on the backside of the bearing, or at the caps parting line, IMHO Also a possibility the bearing is sitting just that much higher in it's saddle, that the crush is too much and distorted/mushroomed the bearing corner, causing a "high" spot, which could introduce the drag you feel rotating the crank in one direction only, as the crank will glide past a high edge, rotating "away" from it, but will wipe/cut in reverse  Mike
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Re: Brand new MP 4" stroker crank out of round...
[Re: 6PakBee]
#618585
02/20/10 08:53 PM
02/20/10 08:53 PM
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
HerboldRacing
OP
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OP
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
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Quote:
I hate to say this but using a dial indicator as you are is usually done to check for a bent crank, not an out-of-round journal. To determine if a journal is truly out-of-round you'll have to do at least a six point check with a micrometer. You may have some of both but you won't know unless you check. 
You are right. I got my terminology mixed up. I am going to mic the main journals either tonight or tomorrow and check for out-of-round journals. I will also check for taper.
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Re: Brand new MP 4" stroker crank out of round...
[Re: Dodgem]
#618586
02/20/10 08:55 PM
02/20/10 08:55 PM
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
HerboldRacing
OP
member
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OP
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
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Quote:
Did you have that block align honed??
Yes since the main caps came from a different 340 block I had the mains align bored and honed.
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Re: Brand new MP 4" stroker crank out of round...
[Re: HerboldRacing]
#618587
02/20/10 09:15 PM
02/20/10 09:15 PM
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Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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I'd suggest taking the bearings out & wiping the backsides clean along w the bores then reinstalling them along w the crank (wiping the main journals clean also), lubing the mains up again of course and making sure the bearing halves are seated correctly especialy #3 & if it still will not turn freely then as said I'd mike the journals and check them for runout installed (in the block or on a fixture (lathe or crank polisher).
live every 24 hour block of time like it's your last day on earth
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Re: Brand new MP 4" stroker crank out of round...
[Re: RapidRobert]
#618588
02/21/10 10:00 PM
02/21/10 10:00 PM
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
HerboldRacing
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OP
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
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Ok here is what I know so far... 1) Main journals on the crank are perfectly round at 2.499" everywhere. I mic'ed the journals all the way around and in many places up and down checking for taper... it's all perfect. They may still be off-center but at least they are round. 2) If I tighten up all the nuts to spec (100 ft*lb) on the studs except for #3 main (the middle one) the crank rotates 360 degrees with just one hand on the snout. 3) If I tighten up the nuts on main #3 even a little bit snug I can immediately notice a tight spot when rotating the crank. 4) Tightening up main #3 to spec (100 ft*lb) makes the tight spot tighter. However, the non-tight spot is still easy to rotate with just one hand on the snout. The tight spot requires 2 hands to rotate the crank. 5) I rotated crank into the tight spot then I put a bit of plastigage (about 1/4") at the top of the crank journal on #3 and put the cap and bearing on and tightened to spec, then removed cap and bearing. Looks like I have less than .001 clearance. Is this too tight?  6) I took only the #3 main cap and bearing off and put a dial gauge on it. Turned the crank - there very little movement of the dial gauge needle (I would say 0.0002 or less) Ok, educate me. Something wrong with the bearings? I'm trying to understand why it doesn't like it when I torque up the nuts on the #3 mains. I'm almost to the point where I think I am going to take this to the machine shop that align bored and honed my mains and have them look at it...
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Re: Brand new MP 4" stroker crank out of round...
[Re: HerboldRacing]
#618589
02/21/10 10:03 PM
02/21/10 10:03 PM
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Joined: Jan 2003
Posts: 4,616
Kissimmee Fl.
dusturbd340W5
master
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master
Joined: Jan 2003
Posts: 4,616
Kissimmee Fl.
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#3 is the thrust bearing are you setting the thrust part of the bearing before you torque the nuts?
70 duster full chassis super pro 416 CNC Indybrock heads 727 w/brake
best so far 1.212 60 6.219 in 1/8 at 110.88 9.768 at 137.81 1/4
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Re: Brand new MP 4" stroker crank out of round...
[Re: dusturbd340W5]
#618590
02/21/10 10:09 PM
02/21/10 10:09 PM
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
HerboldRacing
OP
member
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OP
member
Joined: Dec 2008
Posts: 127
Phoenix, Arizona
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Quote:
#3 is the thrust bearing are you setting the thrust part of the bearing before you torque the nuts?
Right, #3 is the thrust bearing...
What do you mean by "setting the thrust part of the bearing"? I'm not doing anything special to #3...
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Re: Brand new MP 4" stroker crank out of round...
[Re: HerboldRacing]
#618591
02/21/10 10:11 PM
02/21/10 10:11 PM
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Joined: Jan 2003
Posts: 10,731
North Dakota
6PakBee
I Live Here
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I Live Here
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Posts: 10,731
North Dakota
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Just my . At the tight spot, use a piece of plastigauge that is the full width of the journal on all five mains. Torque them down and check the clearances. Then rotate the crank 180 degrees and repeat for all five mains. The two times in my life that I've line honed a set of main bearing bores, a plastigauge check prior to the machine work showed a steady increase (or decrease) in the bearing clearances from one end of the block to the other.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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