Cummins ntc 475

@OLDSKOOLERnWV can probably help.

 

With older equipment, especially the stuff that has sat. I’ve found, most ones you just have to take it out and give it a good work out. Nothing over the top. But maybe a good week doing what your going to do with it. Keep a close eye one it 2-3 times a day and look for anything that changes. Get those fixed and put her to work.

 

Way back when my cousin built an FLD glider and he put an NTC twin turbo.He was hauling gas 9k gal.tankers.He loved the way the truck pulled(13over,3.55eatons,22.5,lo pro)but he wasn't too thrilled with the mileage,getting just a little over 5mi. a gal.He always did have a heavy foot though.Good luck with your new ride and know that your driving one of the best looking trucks ever built, especially if it's an EX.Wanna trade for a T600 B with a DD12.7,450hp.At least you'll get better fuel mileage,lol,you just won't look as cool.

 

The mechanical Variable Timing system on the engine used to give trouble once in a while.
It uses air to change the timing. Keeping your air dryer maintained will help.
I used to replace the MVT system with fixed time cam followers which made it more reliable.
They are a very smoky engine.

 

We actually have one in a power shredder that was built in germany. This motor so far has been bullet proof and it takes a lot of abuse. Its actually a really cool motor and nice to work on. Couldnt tell you about parts availability because i've never bought parts for the motor. The rest of the machine is a whole different story....

 

I could be wrong but a '81 big cam should have fixed timing. Smokes like crazy at start up and clears up after it warms up a bit.

 

If the MVT system is working I would not change it. There is an air cylinder on the middle cam follower.
Cummins had an update where an oil line was connected to the air cylinder to lube the seal rings. If it does not have the oil line you need to remove the cap from the air cylinder and lube the seal rings. If I remember correctly Cummins recommended using WD40.

The air cylinder has a rack that rotates a segment gear that rotates the shafts in all three cam followers.
There are eccentrics in each of the injector cam follower levers that change the timing. The teeth on the rack and segment were bad for failing and the rubber seals between the cam followers were a major oil leak once they hardened.
They were a good engine. If the air to the MVT system leaks off when parked they will smoke horrendously till the pressure builds again
They need a lot of intake air. Dirty air filters will drop your fuel mileage.

Could you post a picture of the cam follower side of the engine?