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MR688S frame work


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I beleive the runout procedure came from early engines, like an E-6.. I believe they had eccentric pins that can be rotated to align the flywheel housing.  But to the best of my knowledge, the E-7 didnt really need to be checked.  yes lots of movement in the tranny input shaft, .020" runout, is probably nothing to worry about. especially because my E-7 book said so. It doesnt hurt to check it, but I dont know how you would adjust it.  But if excessive runout was found, then I would try to find out WHY so I dont build the issue back into it again..  just my thoughts, combined with the book knowledge, :)  I always welcome more opinion's..  I learn from them..  jojo  

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9 hours ago, Joey Mack said:

I beleive the runout procedure came from early engines, like an E-6.. I believe they had eccentric pins that can be rotated to align the flywheel housing.  But to the best of my knowledge, the E-7 didnt really need to be checked.  yes lots of movement in the tranny input shaft, .020" runout, is probably nothing to worry about. especially because my E-7 book said so. It doesnt hurt to check it, but I dont know how you would adjust it.  But if excessive runout was found, then I would try to find out WHY so I dont build the issue back into it again..  just my thoughts, combined with the book knowledge, :)  I always welcome more opinion's..  I learn from them..  jojo  

I believe the earlier Mack’s, after the flywheel housing was dialed in, you reamed the holes for a oversized dowel then tapped them in.  Terry

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17 minutes ago, terry said:

I believe the earlier Mack’s, after the flywheel housing was dialed in, you reamed the holes for a oversized dowel then tapped them in.  Terry

I may be wrong but i dont remember that.I have never seen one on any mack that was off center unless the block was line bored but then it would be very little off center.When we did dial them and found one off it was always a bad housing or distorded or broken.In later years on a E6 and E7 i got were i would not put a dial on one if it was a replacement.You want to see from top to bottom same and from one side to the other same and i think the reading can be as much as .010 off center.

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glenn akers

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Glenn,,,  you have a ton of knowledge..  I just posted what the book said..  Myself , I dont recall having runout issues with all the E-7's I have been around.  The loose bolts I have had ,caused damage to the bell housing on Mack trannys that was not fixable without a case replacement..  200 + 300 series trannys..  for what it's worth,,  youre never guessing to me..   jojo

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8 hours ago, Joey Mack said:

yes Glenn. and My Mack E-7 book shows .020" runout..  I guess that would be .010" per side. jojo

To my understanding runout is a difference between max and min distance from the crankshaft center. Actually you need the basic size of that circle specified to be almost accurate. Say 24.098 +-0.010". But Mack specified just the runout. Probably in practice its fugure would be much bigger if the housing is worn really bed. Or anything else. Mack engeneers had something on their mind when established the check procedure.

E6 and earlier dowel pins I saw were all cylindrical. I can't boast I saw really many Mack engines though. But kept my attention on readings on here for years. What I learned is what Terry posted above. This way Glenn's comment is really interesting pointing out he during the years of his experience seldom saw the runout issues and (never?) oversized dowel pins. So seems the runout procedure is mostly aimed to check on seriouse damage of the housing.

Honestly I still can't figure out what kind of damage loosy tranny bolts did to the housing. If they damaged threads they went into you would swap the flywheel housing. And if they didn't damage them I see no reason the bolts were getting loose again after some milage. Another seemed issue is the tranny centering flange (rim) wear. That would affect the centering but actually of the spoken input shaft. And I don't understand how that may affect the bolt tightness.

Никогда не бывает слишком много грузовиков! leversole 11.2012

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12 hours ago, theakerstwo said:

I may be wrong but i dont remember that.I have never seen one on any mack that was off center unless the block was line bored but then it would be very little off center.When we did dial them and found one off it was always a bad housing or distorded or broken.In later years on a E6 and E7 i got were i would not put a dial on one if it was a replacement.You want to see from top to bottom same and from one side to the other same and i think the reading can be as much as .010 off center.

.010 is if you're using a Machined Dowel type runout gauge that fits into the engine in place of the crankshaft.  .020 is if you're bolting a runout gauge to the crankshaft.  The difference in runout tolerance is because of any wobble in the crankshaft/bearings.

 

According to the book.

Edited by JoeH
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Glad to hear that you are at least treading water with her @JoeH!  Having to adjust the brakes every morning doesn't sound like much fun, but at the same time you know what the problem is and how to fix it, now to find the time.  

Good to see her on the road and making money.

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  • 2 weeks later...
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Truck is working well; concrete season is over, now we have to keep our heads low to pay off the mixer over the next 4 years. 

 

This is our current project we've been working on. Hopefully we can get this mixer rebuild completed sometime in the first half of 2023. Less Mack related stuff on this build, so it probably won't find it's way onto the forum. The horse is a 1988 RD690S with an EM6-300L.

KIMG1156.JPG

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