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Re: Brand new MP 4" stroker crank out of round...
[Re: HerboldRacing]
#618593
02/21/10 10:24 PM
02/21/10 10:24 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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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.
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]
#618597
02/21/10 11:06 PM
02/21/10 11:06 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:
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?
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Re: Brand new MP 4" stroker crank out of round...
[Re: 540challenger]
#618599
02/21/10 11:08 PM
02/21/10 11:08 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:
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.
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Re: Brand new MP 4" stroker crank out of round...
[Re: RapidRobert]
#618601
02/21/10 11:21 PM
02/21/10 11:21 PM
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Joined: Sep 2007
Posts: 14,889
up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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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.
They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
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Re: Brand new MP 4" stroker crank out of round...
[Re: Supercuda]
#618602
02/21/10 11:40 PM
02/21/10 11:40 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 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)
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: Supercuda]
#618603
02/22/10 12:53 AM
02/22/10 12:53 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:
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...
???
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Re: Brand new MP 4" stroker crank out of round...
[Re: RapidRobert]
#618606
02/22/10 12:05 PM
02/22/10 12:05 PM
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
HerboldRacing
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Phoenix, Arizona
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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?
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Re: Brand new MP 4" stroker crank out of round...
[Re: Supercuda]
#618608
02/22/10 02:09 PM
02/22/10 02:09 PM
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Joined: Apr 2007
Posts: 2,826
NY usa
540challenger
master
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master
Joined: Apr 2007
Posts: 2,826
NY usa
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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???
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Re: Brand new MP 4" stroker crank out of round...
[Re: 540challenger]
#618609
02/22/10 02:52 PM
02/22/10 02:52 PM
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Joined: Nov 2009
Posts: 3,410
Belpre,Ohio
CHAPPER
master
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master
Joined: Nov 2009
Posts: 3,410
Belpre,Ohio
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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.
If you like drag racing, support your local track.
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Re: Brand new MP 4" stroker crank out of round...
[Re: Supercuda]
#618611
02/22/10 08:00 PM
02/22/10 08:00 PM
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Joined: Dec 2008
Posts: 127
Phoenix, Arizona
HerboldRacing
OP
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OP
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Posts: 127
Phoenix, Arizona
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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.
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Re: Brand new MP 4" stroker crank out of round...
[Re: HerboldRacing]
#618612
02/22/10 08:31 PM
02/22/10 08:31 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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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.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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