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Case 590Turbo engine problem

rpyne

Member
Joined
Jul 15, 2020
Messages
16
Location
Lynndyl, Utah, USA
We have an older 590Turbo with a Cummins 4T390 engine that died while we were using it a while back. In trying to diagnose the problem, I pulled the front valve cover and it looks like the camshaft isn't turning though the starter does crank the engine.

How hosed is it? Is that a zero clearance engine or is there a chance that it isn't going to require a major overhaul. It has 6450 hours on it, it had 6356 when we bought it, they told us it had an in-frame overhaul at about 5000 hours.

I'm not an experienced mechanic but can handle most things with good instructions and manual. I have the Service Manual and Parts Manual for the backhoe.

Any insights, help, or advice will be much appreciated.
 

1466IH

Senior Member
Joined
Feb 4, 2014
Messages
613
Location
prairie du rocher, il
Pull the round cover off in front of the injection pump and see if that is all still turning. Been a while since I have been in one of those engines but I do believe they are an interference engine chances are though all it would have done is bent push rods though
 

rpyne

Member
Joined
Jul 15, 2020
Messages
16
Location
Lynndyl, Utah, USA
Pull the round cover off in front of the injection pump and see if that is all still turning. Been a while since I have been in one of those engines but I do believe they are an interference engine chances are though all it would have done is bent push rods though

Dumb question time, how does that cover come off? is it threaded on or press fit?
 

rpyne

Member
Joined
Jul 15, 2020
Messages
16
Location
Lynndyl, Utah, USA
Thank you.

It doesn't have a tachometer drive, but there is a round cover where it would go, does that cover come off without removing the complete front cover? I have the manual and have seen the instruction to remove the tachometer drive assembly, but I don't have the magical knowledge of how it comes off.
 

Delmer

Senior Member
Joined
Jan 3, 2013
Messages
8,865
Location
WI
in the pic in "step 4" at the bottom of the hole, doesn't that look like a gap between the ends of a single thread? try unscrewing the cover counterclockwise.
 
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Dave Neubert

Senior Member
Joined
Jul 18, 2018
Messages
1,649
Location
Monroe NC
pull your valve covers and see if valves are moving or is anything wrong in there, bent push rods, broken rockers,broken valves
 

rpyne

Member
Joined
Jul 15, 2020
Messages
16
Location
Lynndyl, Utah, USA
Thanks. We started this by pulling the front valve cover and the push rods aren't moving. I'll pull the other three and check them.
 

doghead

Well-Known Member
Joined
May 27, 2017
Messages
98
Location
NY
One possibility is a broken cam drive gear. They can break in the “webbing” and that causes the cam to stop turning but the outer diameter of the gear can continue to rotate, driving the IP still.
 

melben

Senior Member
Joined
Jan 14, 2008
Messages
1,026
Location
Williamsport, Pa
Occupation
Retired 50 Yrs with Case dealership
Had one of those that the cam snapped right ahead of the front cam bearing, personally on those engines I have never see a broken gear but looking at the pic of that engine obviously it can happen!
 

rpyne

Member
Joined
Jul 15, 2020
Messages
16
Location
Lynndyl, Utah, USA
I guess I should give an update. We pulled the front cover and found that the cam shaft was broken right behind the front bearing. Along with that, the key on the crankshaft was sheared. We went ahead and pulled the engine so we could remove the (rest of) the camshaft and inspect further. As we continued our examination, we found that the bolt directly above the crankshaft that holds the front housing to the block had come loose and dropped into the gears.

Based on comments on here and from talking to a few seasoned mechanics, along with getting estimates of the cost for a full overhaul, we ordered a new engine today. We were able to get a complete new engine for significantly less than the labor estimate for work that would need to be done to do the overhaul.
 

rpyne

Member
Joined
Jul 15, 2020
Messages
16
Location
Lynndyl, Utah, USA
Okay, next noobee question. The manual says to put "loctite liquid teflon" on the intake manifold cover bolts. In searching, I don't find any product listed as simply liquid teflon, but I find about a dozen different products described as teflon thread sealant. What is the right one to use?

Thanks!
 

rpyne

Member
Joined
Jul 15, 2020
Messages
16
Location
Lynndyl, Utah, USA
Ran into another issue. four of the six bolt holes in the flywheel housing where the torque converter cover attaches are stripped. I've drilled and tapped them for heli-coils, but am wondering about the thread length. The bolts are 30mm long and the original holes were tapped to that depth, but the only heli-coils I can find are only 15mm long. Do I need to double heli-coil them or is the 15mm enough thread? From what I've been able to find the standard best strength thread depth is 1.5 times the diameter, which would make 15 mm right, but those are all talking about steel. What about aluminum?
 
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