Brand new MP 4" stroker crank out of round...

Brand new MP 4" stroker crank out of round... - 02/20/10 03:15 PM

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.

Posted By: ademon

Re: Brand new MP 4" stroker crank out of round... - 02/20/10 03:19 PM

Summit usually will pick up shipping in something like this.

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/20/10 03:34 PM

Quote:

Summit usually will pick up shipping in something like this.

They will? I'll talk to them and find out. Thanks.

Posted By: DAYCLONA

Re: Brand new MP 4" stroker crank out of round... - 02/20/10 05:33 PM

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

Attached picture 5818781-chryslercrankspecs.JPG

Attached picture 5818781-chryslercrankspecs.JPG

Posted By: ZIPPY

Re: Brand new MP 4" stroker crank out of round... - 02/20/10 05:47 PM

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.

Posted By: DAYCLONA

Re: Brand new MP 4" stroker crank out of round... - 02/20/10 06:16 PM

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

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/20/10 07:01 PM

You have a point that the run out appears to be pretty minor. However, it does take 2 hands to turn the crank for about 180 degrees of its revolution (with no rods or pistons) and there is scuffing on the number 4 main bearing when I took it out to inspect it. Any further thoughts on that? Here is a picture of the scuffing...

PS Just to clarify when I made that video there were no bearings on the 2, 3, & 4 mains.

Posted By: dusturbd340W5

Re: Brand new MP 4" stroker crank out of round... - 02/20/10 07:20 PM

Quote:

You have a point that the run out appears to be pretty minor. However, it does take 2 hands to turn the crank for about 180 degrees of its revolution (with no rods or pistons) and there is scuffing on the number 4 main bearing when I took it out to inspect it. Any further thoughts on that? Here is a picture of the scuffing...

PS Just to clarify when I made that video there were no bearings on the 2, 3, & 4 mains.

are you sure the problem with #4 is not a cap or bearing issue.

Posted By: DAYCLONA

Re: Brand new MP 4" stroker crank out of round... - 02/20/10 08:16 PM

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

Posted By: 6PakBee

Re: Brand new MP 4" stroker crank out of round... - 02/20/10 08:57 PM

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.

Posted By: RapidRobert

Re: Brand new MP 4" stroker crank out of round... - 02/20/10 09:11 PM

Quote:

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.

there for sure is a problem (just dont know where/what it is) that needs to be addressed. EDIT might take off one cap at a time & see if you can pin it down/make sure the #3 thrust bearing faces are aligned/put a dial indicator on #3 journal & check runout (not sure if #3 thrust bearings should be removed for this or not but if so for sure dont nick the journal on the bore or better yet tap the #3 upper bearing half around and out).Holler when you have some news.

Posted By: Dodgem

Re: Brand new MP 4" stroker crank out of round... - 02/20/10 10:13 PM

Did you have that block align honed??

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/21/10 12:53 AM

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.

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/21/10 12:55 AM

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.

Posted By: RapidRobert

Re: Brand new MP 4" stroker crank out of round... - 02/21/10 01:15 AM

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).

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 02:00 AM

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...

Posted By: dusturbd340W5

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 02:03 AM

#3 is the thrust bearing are you setting the thrust part of the bearing before you torque the nuts?

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 02:09 AM

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...

Posted By: 6PakBee

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 02:11 AM

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.

Posted By: dusturbd340W5

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 02:17 AM

Quote:

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...

To set the thrust you should take a large screw driver pry the crank forward between 1 of the other main cap and counter weight and use a brass hammer and lightly hit the rear flange while holding the screw driver and then torque the cap before letting go.

Posted By: RapidRobert

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 02:24 AM

You're sure the #3 bores are clean/no burrs/same w both bearing halves. Make sure the block half is hand seated all the way & flush on the little notch/groove. install/torque all exc #3 as before then install the #3 cap/bearing w it located loosely w the 2 bolts tap one side of the cap JUST in & hold it there and start the other side just in (both sides level) then tap the cap in the center so it evenly goes down and is lightly seated then LIGHTLY snug the 2 bolts then tap the crank back & forth several times w a deadblow hammer then w a screwdriver pry the crank forward at one of the counterweights/block & hold it there and torque the 2 bolts down. Still no go, might try another pair of #3 thrust bearing halves. Bearings are usually trouble free and made with high tolerances but on occaision a bad set slips thru.

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 02:49 AM

How much front to back movement should there be of the crank? I am getting less than .004" with just the block #3 bearing half installed without the #3 cap.

I hammered on one end of the crank with a dead blow hammer, measured the distance of a counterweight from the block edge with a dial caliper. Hammered on the other end, measured the same spot again. Difference was .004"...

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 02:52 AM

BTW if it makes any difference, the bearings I am using are these:

http://www.summitracing.com/parts/CLE-MS540H/

Posted By: RapidRobert

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 02:53 AM

Quote:

Difference was .004"...

your good there, what do you have w the other cap/bearing installed

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 03:06 AM

Quote:

Quote:

Difference was .004"...

your good there, what do you have w the other cap/bearing installed

With the #3 cap and bearing on there and the stud nuts finger tightened the front to back movement goes down to .0015"

...is this too tight?

Posted By: 540challenger

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 03:07 AM

You said yopu had this motor line honed for the mains since they were off another 340 but did you have it line hone with the studs you are now using or the old bolts. This could cause the problem you are having with the thurst bearing as the studs will seat the caps differently then bolts.

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 03:08 AM

Quote:

You said yopu had this motor line honed for the mains since they were off another 340 but did you have it line hone with the studs you are now using or the old bolts. This could cause the problem you are having with the thurst bearing as the studs will seat the caps differently then bolts.

The motor was align bored and honed with the very same studs I am using right now.

Posted By: RapidRobert

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 03:16 AM

Quote:

With the #3 cap and bearing on there and the stud nuts finger tightened the front to back movement goes down to .0015"
...is this too tight?

yes too tight and too much change.

Posted By: Supercuda

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 03:21 AM

Problem with studs is that the diameter is larger than the bolts they replaced. This doesn't allow the cap to float fore and aft, binding things up as you have found out.

There is a a machine shop that fabbed up a self piloting drill bit to fix this issue, but I'll be darned if I remember who it is now. Basically, you need to drill out the bolt hole in the number three cap a hair oversized to fix this.

Posted By: RapidRobert

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 03:40 AM

I do believe Supercuda has nailed it

. I've never studded a block so that particular problem never crossed my mind and if they did take care of it then the #3 thrust bearing halves need replacing (possibly w a different letter type)

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 04:53 AM

Quote:

Problem with studs is that the diameter is larger than the bolts they replaced. This doesn't allow the cap to float fore and aft, binding things up as you have found out.

There is a a machine shop that fabbed up a self piloting drill bit to fix this issue, but I'll be darned if I remember who it is now. Basically, you need to drill out the bolt hole in the number three cap a hair oversized to fix this.

Could the same result be achieved by simply sanding down the thrust faces of the #3 bearing? I read in a mopar small block rebuilding book that you need at least .002" clearance on each side of the thrust bearing and that if necessary you can use 360 grit (or something like that) sandpaper to sand down the thrust faces until this minimum is achieved...

???

Posted By: RapidRobert

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 05:12 AM

Quote:

Could the same result be achieved by simply sanding down the thrust faces of the #3 bearing?

that's for increasing the thrust clearance. On this, the ID of the 2 bolt holes in the cap need to be increased because main cap bolts are not tight in the cap like rod bolts are which is why main bolts can be replaced wo line boring whereas replacing rod bolts (in almost all cases) requires rebuilding the rod big end. you can do this at home if you have a drill press just measure the OD difference between your studs and an OE main bolt & drill out your #3 cap bolt holes ID's that amt.

Posted By: Ply72rr

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 05:35 AM

I'm not mister motor expert but if the problem was the bearing,dirt under bearing,cap misaligned why wouldn't the crank be tight all 360 degrees of rotation.It would seem to me that the crank is not perfectly straight if it's only tight 180 degrees of rotation. Like I said I'm no expert so maybe someone with more knowledge can explain where I'm wrong.

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 04:05 PM

Quote:

You can do this at home if you have a drill press just measure the OD difference between your studs and an OE main bolt & drill out your #3 cap bolt holes ID's that amt.

I do have access to a drill press. However I do not have any OE main bolts - can someone measure and tell me what the OD of the OE main bolt is? I am going to measure the OD of my studs and the ID of the holes in the cap and see where they are at now. This is all very interesting.

What about crush on the bearing - if there was too much crush on the #3 bearing could this cause the issue I am seeing?

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 05:52 PM

Just measured my studs - the OD of the ARP studs I have are .4975

Tried to measure the ID of the holes in the cap - proving to be difficult to get an accurate measurement... seems to be around .503

Posted By: 540challenger

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 06:09 PM

Quote:

Problem with studs is that the diameter is larger than the bolts they replaced. This doesn't allow the cap to float fore and aft, binding things up as you have found out.

There is a a machine shop that fabbed up a self piloting drill bit to fix this issue, but I'll be darned if I remember who it is now. Basically, you need to drill out the bolt hole in the number three cap a hair oversized to fix this.

Wouldn't that just effect the end play of the crank in every postion???

Posted By: CHAPPER

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 06:52 PM

I had the same problem with a 4" MP 360 forged crank a few years ago. I ended up turning mains .011" under and running .010" bearings. The crank was out of round and big or bent. It has ran fine for 8-9 years in a dirt modified. In fact, I have it in shop right now freshening it up. They ran it 2 seasons since I saw it last. They run about 25 races a year. Probably average 45-50 laps a night on 3/8 track. I put new bearings in it but could have ran the old ones another season. Mine may have been even a little worse than what I see in your video. I sure hated grinding on a new crank, but that's what it took to make it right and last for years of hard racing.

Posted By: Supercuda

Re: Brand new MP 4" stroker crank out of round... - 02/22/10 11:36 PM

Quote:

Wouldn't that just effect the end play of the crank in every postion???

You'd think so, but let's say the thrust surface on the crank isn't parallel to the journal, then you'd have a bind part of the time.

Which is kind of what the closing up of the thrust clearance is telling us here. As a temporary expedient, pull the studs on #3 and run a set of stock bolts there to see if the problem "goes away". Probably wouldn't hurt to measure the thrust clearance at 90 degree intervals.

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/23/10 12:00 AM

Quote:

You'd think so, but let's say the thrust surface on the crank isn't parallel to the journal, then you'd have a bind part of the time.

Which is kind of what the closing up of the thrust clearance is telling us here. As a temporary expedient, pull the studs on #3 and run a set of stock bolts there to see if the problem "goes away". Probably wouldn't hurt to measure the thrust clearance at 90 degree intervals.

That is just what I was thinking - that if the thrust surface on the crank wasn't parallel to the journal then that would explain the tightness I feel for only for part of the crank rotation.

I don't have OE bolts or any bolts. All I have are studs. But I can definitely measure the thrust clearance at 90 degree intervals. Or better yet 45 degree intervals since it won't take much time to do that.

Posted By: moper

Re: Brand new MP 4" stroker crank out of round... - 02/23/10 12:31 AM

Torque #3 and measure the housing. See if it's tight in that axis too. It will eliminate the bearing as a cause. In regard to the crank... If i had a journal that measured that way I'd bring it to a crank shop and have them look at it. I wouldnt feel right running that crank in it's pressent condition.

Posted By: JohnRR

Re: Brand new MP 4" stroker crank out of round... - 02/23/10 12:39 AM

Quote:

Just measured my studs - the OD of the ARP studs I have are .4975

Tried to measure the ID of the holes in the cap - proving to be difficult to get an accurate measurement... seems to be around .503

ream the holes in the cap with a 17/32nd reamer .

NO you do NOT want to sand the thrust face of the bearing .

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/23/10 03:11 AM

Quote:

Quote:

Just measured my studs - the OD of the ARP studs I have are .4975

Tried to measure the ID of the holes in the cap - proving to be difficult to get an accurate measurement... seems to be around .503

ream the holes in the cap with a 17/32nd reamer .

NO you do NOT want to sand the thrust face of the bearing .

Really? Why not? I found the book and page where it says to sand the thrust face of the bearing down until I have a minimum of .002" end play. It is in the "How to Rebuild Small Block Mopar Engines" by Don Taylor and Larry Hofer on page 119 under the heading "Crankshaft End Play". I will paraphrase here:

"Measure end play, it must be between .002" and .007", and must not exceed .010" as an absolte max. Blah blah blah...if end play is less than .002" the crank must be removed and the thrust bearings thinned... Do that by laying a piece of 320-grit sandpaper on a flat surface and lapping away bearing material to bring end play within tolerance."

Actually I have an update that I will put in my next post...

Posted By: HerboldRacing

Re: Brand new MP 4" stroker crank out of round... - 02/23/10 03:15 AM

And here is an update:

Just now for the heck of it, I pulled the #3 cap off, hammered the snout with a dead blow hammer so the crank is all the way back, slid the cap on and very very carefully made it go down into the seat evenly and pushed the cap as far forward as possible (my thinking was this lines up the bearing in the cap with the bearing in the block). Then I tightened the stud nuts in 5 pound increments starting at 20 ft*lb working my way up to 100 ft*lb, spinning the crank at each interval to check the tight spot. When it got to about 30 ft*lb I could start noticing the tight spot... then I actually made it all the way to 100 ft*lb and can still spin the crank with one hand... but the tight spot is still there... however I can spin the crank 360 degrees with one (strong) hand now.

I will try reaming the hole with a 17/32" reamer like Johnahah said first and see what that does. 17/32 actually would give me 0.531" which seems like a big change from my current 0.503"... maybe they make a 33/64" (0.515") reamer?? Or should I just go to 17/32"?

Posted By: RapidRobert

Re: Brand new MP 4" stroker crank out of round... - 02/23/10 04:19 AM

I'd deal w the stud OD to cap hole ID 1st (find a bolt to mike it) & I think when you duplicate the oe bolt to cap clearance that you'll be set and the end play will be OK since you had 4 thou w (1) bearing half in place which is fine and I got a feeling when the above is resolved & the lower bearing/cap installed that your end play will be the same (or maybe .0005" less) which is still perfect.

Posted By: RapidRobert

Re: Brand new MP 4" stroker crank out of round... - 02/24/10 04:11 AM

360 main cap oe bolts. went & checked: 1/2". the threads and the shoulder under the head are both 1/2" and the shank between the threads and the shoulder is 7/16" (checked w cheap plastic calipers, all I had when I was over there).