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Man lift JLG 40h timing belt

Lewis12

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Apr 1, 2014
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Texas
I have busted timing belt on JLG 40 H just want to know if this requires a timing of the engine or can I just put it on? Has a Air Diesel Deutz engine. Am going to replace the idler and of course the belt but not sure if the engine needs to be timed.
 

kshansen

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Not knowing what engine this is it would be just a guess but if this is the belt that drives the cam shaft yes it would need to be timed. The other thing is would need to know if this is what is called an "interference" or "non-interference" engine.

The difference is with an interference engine if the belt broke while engine was running there is almost a guarantee there will be some internal damage such as pistons hitting valves. Where the non-interference engines are designed so even if the belt snaps on a running engine no parts inside are damaged.

This is why most engine manufactures have recommended belt changes. Trying to save a few coins on a belt can cost many times more in engine damage.

Now if this is just a belt that looks like a timing belt that drives cooling fan, alternator or other accessories then there should be no need to time engine. Just make a note of how long the last one went and change the new one about 10 to 15% sooner. Better to have machine in shop and not with boom up to full height with somebody in basket when it fails!
 
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Lewis12

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Joined
Apr 1, 2014
Messages
120
Location
Texas
Not knowing what engine this is it would be just a guess but if this is the belt that drives the cam shaft yes it would need to be timed. The other thing is would need to know if this is what is called an "interference" or "non-interference" engine.

The difference is with an interference engine if the belt broke while engine was running there is almost a guarantee there will be some internal damage such as pistons hitting valves. Where the non-interference engines are designed so even if the belt snaps on a running engine no parts inside are damaged.

This is why most engine manufactures have recommended belt changes. Trying to save a few coins on a belt can cost many times more in engine damage.
The cover say Air diesel duetz
 

kshansen

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Retired Mechanic in Stone Quarry
The cover say Air diesel duetz
Sorry that does not really help much.

Do you have any idea what this belt runs?

Does it run the cooling fan or the alternator?

What makes you think it is a timing belt?

Sorry for all the questions but you are there and I'm probably over 1,500 miles from the engine in question so if you can't give us something to go by there is not much I or anyone can do to help.

Not trying to be a jerk just pointing out the problem from my end.
 

thepumpguysc

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Deutz engines have to be timed, with 2 pins.. 1 in cam & 1 in crank.. LOTS of timing belts kits online that come w/ pins & instructions.. BUT.. as stated above.. broken timing belt = more damage {pushrod damage}
Remove the valve cover & take the rocker shaft off as an assembly.. check all the push rods.
I haven't seen any damage the valves but its been known to happen..
I HAVE SEEN them BREAK the rockers tho.. Just remove the valve cover.. it'll be obvious if anything is broken.. BUT your gonna have to inspect the PRods one by one for straightness.
Sorry for your bad luck..
 
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Knepptune

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Nov 22, 2012
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Indiana
Yep. And if it broke while running your guaranteed to need new push rods. Your also gonna need a tamper proof torx drive set.
 

thepumpguysc

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Yup, a tamperproof torx set & an inverted torx set.. that's what I call them anyway..
Just look at the bolt heads.. they're not hex heads.. they're star..
 

kshansen

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Retired Mechanic in Stone Quarry
Glad to see others chime in here as my experience with Duetz is very limited.

Only touched two in 45 years pulling wrenches! One was run with no cooling fan belt, kind of got a little hot and scuffed up some pistons and jugs! Replaced the worst ones and it was back to work like nothing had happened!

The other one was in an IR compressor that one had a mouse build a nest under the tin work around the jugs, at least the over-heat switch was working on that one. Popped off tin and blew out nest and it was good to go.
 

thepumpguysc

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Those little Deutz engines can be your best friend or your worst enemy..
The NEW ones w/ common rail, ARE A FRIGGIN NITEMARE!!!
Like w/ everything else on the marked these days> they sent them out into the field in MASS PRODUCTION w/o "REAL WORLD" time on them.. & the support is very limited.. & you can forget about "calling" their technical line.. might as well ask your WIFE what SHE THINKS the problem could be.. LOL, LOL.. {I crack me up}..

The older ones will run + or - a bucket of dirt & keep on going.. t
They're only drawback is/was.. the timing belt. BUT, I guess they HAD TO build-in a problem, so they could sell parts & service??
There IS an option on those engines.. BUT its was/is ONLY an "OPTION"...
Its a tension sensor that gets engaged when the T. BELT gets sloppy & needs changing.. BEFORE it breaks..
BUT, 90% of the people "by-pass" them & keep on running.. Lol..
so you can guess what happens next.. a month or 2 down the road the belt breaks, takes out the push rods, breaks the rockers & on & on.. THEN you hear from the customer, "what a piece of junk" that Deutz engine is.. Lol
 

thepumpguysc

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LEWIS>> I think I have the timing belt procedure in a "file" on my computer..
Its the same for all the Deutz engines, I think..
If you want to private msg [start a conversation] me w/ your email address, I'll shoot it to ya..
OR just put, at a o l dot com after my screen name in your home email server..
 

Knepptune

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Nov 22, 2012
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757
Location
Indiana
I agree pumpguy. Those deutz engines are great little engines. Other then the timing belts and ring gears they never really need anything.

Man if they blow a head gasket they will smoke like crazy. And it'll leave an oil trail out the exhaust.
 
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