I have a 79 IH 2475 with a 350 big cam and it makes a knocking sound on crank up that sounds like it is coming from the harmonic balancer. I don’t know much about it, it quits after a couple minutes idling and runs great but it sounds bad on crankup. Can someone tell me what if anything I should check out first?
A harmonic balancer that old is more than likely frozen internally. What's oil pressure cold? Loosen belts and check side to side and end play on accessory drive first. End play should be no more than .012.
This engine is a Cummins factory reman that has low mileage. What is on the inside of the balancer? I’ll try to check that measurement and also see if it makes the noise with the alternator belts off, I will check that oil pressure but it seems like it was good because I haven’t been concerned and I usually watch that when I first get a different truck.
If it would make you feel better I might try removing the damper and start the engine for a few seconds just to prove it's not the damper.
It has a weight suspended in a viscous fluid. Mineral oil of some sort I think If the fluid leaks out, dries up, or it gets a dent that prevents the weight from moving it stops working Did the reman come with the balancer or did they reuse the old one?
I'm out the non mechanic einstein is in.
sorry if I was out of line with my thoughts!
All is fine.
Think he was talking about me
Not sure about whether it was replaced or not but the sound is very much like what you would think the weight in oil might sound like if it’s hitting the walls inside the balancer because the oil is pooled up or low. I didn’t know what was inside of it.
First off there is not enough clearance inside damper cause a knock, second just because it's a Cummins rebuild doesn't mean the damper was changed, third the easy way to tell if the damper is working is will be warm after 30 minutes of run time if cold it's froze. Being a 350 it should have a 12" damper-400's & N14 use 13.5" damper.
I’m going to change the damper and I have been looking online at them by just searching for ntc350 harmonic balancer and I’m seeing them from $215 to $850 and I was wondering if I should pull it and make sure I get the part number or is the 12” generic?
12" is standard, one thing to check before doing any thing--check the end play and radial runout on the accessory drive.
Does it have a stamped steel pulley behind the damper or is it cast? I have seen a couple of the stamped ones crack around the centre and make some very scary noises.
There are shops that can rebuild them. Truck a S2574? Never heard of a 2475.
I know of none that can rebuild them. If it's cracked pulley it won't stop making noise, but yes the stamped have been known to crack out, not real common but does happen. * 12" BC 350--Vibratech part # 715285-000.
Yea it’s a 2574,I hadn’t even realized that I made that mistake until now lol
Before I start trying to take anything loose,are the bolts that hold it on right hand thread? I have been known to go the wrong way.
Correct right hand--torqued to 190-200.
Don't get china ones they are often fake
Tell me something here in the U.S. that isn't with AI.