Valves rattling on a 6.2?

[cjkeeliii]

When I accelerate, I hear a rattling that sounds like that which comes from a gasoline engine with low octane fuel. Is this normal and do some diesel fuels have a lower octane, (or is it cetane)? I'm not sure if this is a new sound, maybe its been there all along. The engine has approximately 63,000 miles.

 

[acetomatoco]

Cucv engines make all kinds of funny noises...most all related to the compression ignition of the fuel. Mechanical noises will usually manifest themselves in a skip or a smoke or a catastrophic failure.

 

[CCATLETT1984]

check the oil level, how long has it been since you did an oil change.
I agree with ace, after you do the above just drive it and see if the noise changes or goes away.

 

[Croatan_Kid]

It could just be the timing set, I heard they are quite prone to making a rattle that sounds just like valves. Mine certainly does.

 

[cjkeeliii]

The oil change is on schedule, but what's the timing set? I should have asked how is the timing set? I used some ehter the other night to start the engine and it revved really high. Now I'm wondering if the rattling has always been there or if I've damaged somehting. What are the damages that could be done when using ehter?

 

[Croatan_Kid]

I was talking about the crank gear, cam gear and chain, just like a small block Chevy. I think the noise is just the timing chain because this also drives the injector pump which is sometimes subjected to pretty high temperature spikes. When that happens the slack in the chain makes a pretty good racket. I'm sure somebody else could explain that a little better though.

 

[ida34]

Are your glow plugs working at all? If they are do not use ether. Disable the glow plug system before attempting to start with ether.

 

[acetomatoco]

Good batteries cure most of the cold weather starting problems..long fast cranking does the job. Since I put a 12V starter in my CUCV and run it on 24V it really cranks over on two brandy new 1000CCA group 31s. Just remember not to crank too long or you will see liquid solder running out of the poor starter...My flex plate has a low spot in it, so at some point I will have to pull the tranny and then put in the rebuilt 24V starter and maybe even the front seal in the xfer case which in cold weather leaves little red circles in the snow. Be careful with the ether..!!!

 

[cjkeeliii]

I've been listening to this new rattling as I drive to and from work. I'm fairly certain that it is new. My dilema started the other day when, after I cranked the engine, it slowed RPM's a couple of times and then quit. The tank had enough fuel but something had stopped the fuel flow. At any rate, the engine was cold and when I have used ether in the past, the engine has been at operating temperature. This time, I disconnected the GP's and used ether but it would not crank after several tries. I reconnected the GP's,( because I thought that the ether had passed from the system), and cranked the engine which resulted in extremely high RPM's for about 1/4 second and then I shut it down. That happened twice before it cranked and ran at normal RPM. The rattling comes and goes, so unless someone can tell me if I need to park the vehicle and have it looked at, I'm going to drive the thing and hope for the best.

 

[KD]

6.2 rattling noise

Hi CJ

Have you changed the fuel filter lately? This engine seems pretty finiky on that item. Plus it is a relatively cheap and easy cure to alot of starting and running issues I have seen on the CUCVs.

Good luck,

KD

 

[underdog]

I was talking about the crank gear, cam gear and chain, just like a small block Chevy. I think the noise is just the timing chain because this also drives the injector pump which is sometimes subjected to pretty high temperature spikes. When that happens the slack in the chain makes a pretty good racket. I'm sure somebody else could explain that a little better though.

6.2 is all gear drive. No chain.
Depending on vehicle and weather they make all kinds of racket.

 

[gringeltaube]

6.2 is all gear drive. No chain.

How comes you sound so sure about this????
See TM 9-2815-237-34, 2-28 or any other 6.2 book!

G.

 

[underdog]

Had one of ours apart.
Water pump change is just loads of fun.
Guess i needed to dig deeper to find a chain.
My bad.......
Could of swore i searched for a chain to check on while i was in there.
Oh well.

 

[CCATLETT1984]

underdog, FYI the factory setup has a chain driving the IP, you can however buy an aftermarket gear-set to replace the chain.
To see the chain you have to pull the front cover off of the engine, you prolly didnt have that off when you removed the water pump, as you would have had to pull the crank pully and damper off.