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MP8 died after new air compressor installed

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Patient- 2011 mack pinnacle mp8.  My air compressor went out, when shop removed it the was a lot of tooth damage on the drive gear, mech. said he didn't see any other damage inside the block on any other gears.  With a new compressor and gear they put it back together, i made it 250mls down the road, heard a noise it died immediately,  after stopping looking it over, i tried to start it,  it just spins freely,  crank is turning real easy like it has no compression.  Any ideas on what may or may not have happened?  Thanks! 

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Yep; gear train blown up; probably idler gear bad; your mechanic made bad call!

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I myself haven’t did one; but have read on here that some have pulled engine & some did in truck. If it’s as bad as you say, it’s got metal all in engine. Its a bad situation!

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I'm guessing the cam/ valve train is not turning, like i said when the engine spins its almost effortlessly like it has no compression at all. 

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We just finished one in the shop roughly fifty hours into it tandem tandem mixer plus 10 grand in parts not a nice situation!

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Yup and it was still running that’s the bad part for you yours is not  30 grand could go away in a hurry!

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1 minute ago, fjh said:

Yup and it was still running that’s the bad part for you yours is not  30 grand could go away in a hurry!

Unfortunately the dude who put the compressor on blew it big time when you got broken gears you need to go looking for why they broke! And these engines have a track record!

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Any chance of valve to piston issues?  Head damage? From when it let go? 

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Posted (edited)

At speed there's a good chance of valve damage minimum bent valves and possibly damaged pistuns

 

 

 

 

 

 

Edited by 41chevy

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I was running down the hwy, approx 1500 rpm when it happened.......so...

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10 minutes ago, 41chevy said:

At speed there's a good chance of valve damage minimum bent valves and possibly damaged pistuns

 

 

 

That why i ask, because now it turns over like it has zero compression 

 

 

 

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Posted (edited)

Sorry to say but in my mind right now you got mostly a big red boat anchor under your hood from what you have said! it may not be worth repairing this ! Due to the age of the unit!

Edited by fjh

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Pretty sad,  truck only has 514k mls guess it is what it is. 

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Very sad!

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I haven't heard anything good about the MP series engines. I'm gonna stick to e7's for the next 20 or 30 years til they get their act together. Or I'll go Cummins.

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The Vee design two stroke Detroit Diesels ran rear mount geartrains for years and very trouble free. What is the difference with the MP8 geartrains from those?

I've never seen an MP8 apart in person as far too new for me.

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Posted (edited)
41 minutes ago, Rob said:

The Vee design two stroke Detroit Diesels ran rear mount geartrains for years and very trouble free. What is the difference with the MP8 geartrains from those?

I've never seen an MP8 apart in person as far too new for me.

It’s not because it’s at the rear; my understanding is that the idler gear has a nut that sets the tension & it’s threaded the way when it runs it backs off. (My understanding) why in the WORLD you would have it like that! I think now they use locktite. ????  Same as there cup & injector problems!! DD the flywheel housing held it. All the years I worked on DD never saw an idler bearing go down!

Guess what I’m wanting to say is; them Volvo folks are stupid.

 

Edited by 1965
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They had a campaign, certain year models by vin. could get a pinning. They would drill a hole through bell housing into the locking nut to keep from backing off. Somewhere in there they knew which 1’s had locktite.

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I just pulled the #1 flywheel housing from a locked 8V-71 a week ago to scrap the engine. The idler gear will still roll on it's stub shaft and most likely pull right free. Doesn't make a lot of sense that another manufacturer would not follow that proven concept. 

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Posted (edited)
3 hours ago, 1965 said:

They had a campaign, certain year models by vin. could get a pinning. They would drill a hole through bell housing into the locking nut to keep from backing off. Somewhere in there they knew which 1’s had locktite.

Another bandaid! They now lock tight and stake the nut horse is out of the barn though! Day late two dollars short!

Edited by fjh
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12 hours ago, JoeH said:

I haven't heard anything good about the MP series engines. I'm gonna stick to e7's for the next 20 or 30 years til they get their act together. Or I'll go Cummins.

Stay gray(E7, E-Tech, ASET) till CNG or Battery gets here.

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