237 Acceleration Knock

[WOLFWALKER]

MY 237 HAS A KNOCKING NOISE UPON ACCELERATION, IT'S NOT BAD BUT AFTER IT WARMS UP THERE SEEMS TO BE A KINDA SPARK KNOCK LIKE NOISE WHEN YOU LUG OR ACCELERATE ON THE THROTTLE.THE TICK OR KNOCKING NOISE KINDA REMINDS ME OF SPARK KNOCK IN A GAS ENGINE. THOUGHT IT MIGHT BE VALVES NEED ADJUSTED,BECAUSE OF THE TICKING OR KNOCKING BUT SEEMS TO ME IF IT WAS THE VALVES IT WOULD TICK ALL THE TIME.BUT IT SEEMS TO DO IT WHEN YOU REV UP THE ENGINE,OR ACCELERATE,OR LUG THE ENGINE

SO NEED TO FIND OUT IF ANYONE HAS HAD A PROBLEM LIKE THIS AND HOW TO REMEDY IT,CAN ANYONE HELP?

[theakerstwo]

MY 237 HAS A KNOCKING NOISE UPON ACCELERATION, IT'S NOT BAD BUT AFTER IT WARMS UP THERE SEEMS TO BE A KINDA SPARK KNOCK LIKE NOISE WHEN YOU LUG OR ACCELERATE ON THE THROTTLE.THE TICK OR KNOCKING NOISE KINDA REMINDS ME OF SPARK KNOCK IN A GAS ENGINE. THOUGHT IT MIGHT BE VALVES NEED ADJUSTED,BECAUSE OF THE TICKING OR KNOCKING BUT SEEMS TO ME IF IT WAS THE VALVES IT WOULD TICK ALL THE TIME.BUT IT SEEMS TO DO IT WHEN YOU REV UP THE ENGINE,OR ACCELERATE,OR LUG THE ENGINE

SO NEED TO FIND OUT IF ANYONE HAS HAD A PROBLEM LIKE THIS AND HOW TO REMEDY IT,CAN ANYONE HELP?

Sounds like a blowed head gasket from here.That means compression leak by a head gasket and some times you can find it when it is running by pouring a little soppy water down around the headgaskets and between the heads. Look for water being blowed away from the heads.If you put one gasket on then puy both on.

[HK Trucking]

MY 237 HAS A KNOCKING NOISE UPON ACCELERATION, IT'S NOT BAD BUT AFTER IT WARMS UP THERE SEEMS TO BE A KINDA SPARK KNOCK LIKE NOISE WHEN YOU LUG OR ACCELERATE ON THE THROTTLE.THE TICK OR KNOCKING NOISE KINDA REMINDS ME OF SPARK KNOCK IN A GAS ENGINE. THOUGHT IT MIGHT BE VALVES NEED ADJUSTED,BECAUSE OF THE TICKING OR KNOCKING BUT SEEMS TO ME IF IT WAS THE VALVES IT WOULD TICK ALL THE TIME.BUT IT SEEMS TO DO IT WHEN YOU REV UP THE ENGINE,OR ACCELERATE,OR LUG THE ENGINE

SO NEED TO FIND OUT IF ANYONE HAS HAD A PROBLEM LIKE THIS AND HOW TO REMEDY IT,CAN ANYONE HELP?

Are you sure that what you're hearing is not just normal diesel combustion rattle? Those engines normally do have a definite combustion rattle when you crack the throttle or accelerate.

That would be pronounced on acceleration, and does sound similar to the spark knock of a gas engine with overadvanced timing.

Also, in the 1990's, Mack began producing a revised replacement piston design for the 237 and 285 engines which caused more of a "combustion knock" than the original design.

Mack issued a service bulletin at that time about the revised piston design and increased sound levels, maybe someone else here would still have access to that service bulletin.

I used the OEM overhaul kits on a couple of them back then and I did notice the increased combustion knock.

If your engine was overhauled with a Mack OEM overhaul kit with the new pistons, maybe that's what you're hearing? None of us can say for sure without observing it in person, but before you go on a wild goose chase and tear it apart, make sure there actually is a problem.

Overadvanced injector pump timing can also cause excessive combustion knock, so a timing check is in order.

[fjh]

Check close at exhast gaskets as well!Also an the older engines ABAC pump the engine will knock on #no 1 cyl due to cam shaft bearing wear in the fuel pump!the fuel supply pump pushes sidways on the cam advancing the timing on the front two cyls ,To verifiy this crack 1 and 2 at the fuel pump if the knock goes away you likly have worn bearings in the fuel pump.

[scooter]

Could be a loose injector. I had one come loose, I just put water on the top of the engine and saw the bubbles comming

from the loose one. It was all carboned up so I had to pull it and clean everything