making diesel engine run quieter

case685 · Feb 19, 2006

Hi I was wondering if anybody had any advice on getting my Case 685 diesel engine to run quieter. Although it seems to run good I find it to be loud. It is a 4 cylinder 60 hp with aprox. 4500 hrs on it. I don't know if the tappets have ever been reset or if that would even make a difference. Also I'm wondering if I can put an oversize muffler on it and what type I should use.
I've noticed to on most newer tractors that the engine area is completely shrouded and was wondering if that would help to reduce engine noise. Thanks

RalphVa · Feb 19, 2006

Think I'd check the valve clearances, if this has never been done. Even a gas engine with mechanical tappets will get pretty noisey with lots of miles. It could reduce your fuel consumption (after resetting), too, if the tappets are so loose that they're so noisey. You'll always have the diesel rod clatter though.

Ralph

Mike_Lipke · Feb 19, 2006

If the valves have never been set, or have not been set for a long time, you really should do it, or have it done. If they are looser than spec, not only will they clatter, but they are not opening up enough, and opening late and closing early. In other words, valve timing is late, and you are sacrificing power and economy. The dealer should be happy to give you the specs, set hot or cold (probably cold, or under 100 degrees) and of course a new valve cover gasket.

5030 · Feb 19, 2006

( You'll always have the diesel rod clatter though. )

Ralph:

What on earth is diesel rod clatter?? Don't you mean injection noise?

jimmysisson · Feb 19, 2006

Actually, I've wondered how to turn over a diesel to set the valve clearances. You can't do it manually, the way we used to with gas engines, right? Stop valve pulled out and bump the starter? Loosen the injectors? I'd like to set mine to see if it quiets down a bit, but my owner's manual is mum on the topic.
Thanks, Jim

Mike_Lipke · Feb 19, 2006

You prolly have to take loosen an injector or glowplug to eliminate compression, then turn it over with a socket on the fron or rear pulley bolt. Starter bumping could take a week or two to get to TDC.

robison · Feb 19, 2006

Often a quart of ATF added to a full fuel tank will reduce diesel clatter. The advice about valve adjustment is good, also.

markct · Feb 19, 2006

( Actually, I've wondered how to turn over a diesel to set the valve clearances. You can't do it manually )

ya cant? i always turned them over manualy with a ratchet and socket on the front bolt, or with a chain wrench around the front pulley. the cummins engines use a tool that looks like a starter pinion gear that goes into a hole in the block and engages the flywheel. then you turn that with a ratchet. but either way, turning it over with a wrench is the easiest way

MMM · Feb 19, 2006

I believe he's speaking of exhaust noise, not the wondrous, exquisite sound of a diesel engine running. Do we want our tractors sounding like Nissan Sentras?
There was an underslung exhaust option for the 685. Much quieter, but might be spendy if you have to get it fromCNH.

JerryG · Feb 19, 2006

I have a good friend that has a welding / muffler shop. He does a lot of off road equipment, big trucks, buses as well as cars and pickups. If you can find a shop that is like his, they will be able to fix you up. A larger size is not always the answer. You don't want to over due the back pressure among other things. A shop that knows there stuff will be able to make a good recommendation for your exact situation. I don’t know if you are like me but I can't stand a noisy piece of equipment.