General Discussion     Tech Questions     Parts & Services     Suggestions/Ideas     Help & Website Instructions     Blogs    

small cam to big cam, what interchanges?
Print Topic | Close Window

By Nebraska Diesel Dude - Tuesday, December 07, 2021 5:30 PM
Hello, greetings from Nebraska. I have a small cam Cummins from a parts truck [1975 4070B], missing alot of pieces [heaads, turbo etc]. It is a 350 from 1975, CPL 160. The engine in my cabover international [the one im working on] is a 290 big cam from 1979. CPL 353. Now I am at the point that the parts truck is basically down to the frame rails and the engine short block. I called several places { even the one in western PA} but could not get many definitive answers. Trying to figure out what will interchange. Specifically the front timing cover and the gears under the covers. Also would like to know if any of the clutch/flywheel parts are the same. How about the belhousing? I would hate to junk any good usable parts especially if I could use them. What external pieces I have removed so far are; fuel pump, air compressor {nice bendix tu flo 501}, power steering pump and oil pump, the water pump and thermostat housing,and the starter. A bendix fan clutch, the alternator. Oh, also the oil cooler. It did not have the heads, turbo manifolds, or the water manifolds [the ones on the heads. Also missing was the oil Pan and the after cooler. Other various stuff is either missing or removed.I was just going to junk the block but thought I might see if anyone would need it. The block looks really good as did most of the components. It was a one owner truck [farmer]. Anyway thanks to all out there in advance.
By Newto - Saturday, December 11, 2021 10:02 AM
Pretty much everything except the block, camshaft, camfollowers, water pump, oil pump and oil cooler are interchangeable between your small cam and your big cam 2.

All the jewellery (timing covers, gears, air comp,flywheels and housings etc will all interchange.

By Geoff Weeks - Saturday, December 18, 2021 11:11 AM
The Bellhousing will not directly interchange, one bolt hole is in the wrong place, but it can be made to fit in a pinch.
By Newto - Sunday, December 19, 2021 2:14 PM
Yeah....I forgot about that 1 bolt hole thats slightly off centre because of the larger camshaft.....enlarging it slightly cures the problem....thanks Geoff.

By Nebraska Diesel Dude - Monday, December 20, 2021 7:26 AM
Thanks for the replies guys. I took the block to the scrap yard but stripped all I could off of it. The only thing I left was the gear on the camshaft and crank. Still kicking myself for not saving those. Wish I could of saved the whole thing but I dont have the room. Guess I could go back buy it from the yard. By the way, the clutch had the dual disc setup, which I thought was a newer set up. {1975 truck}. Anyway, the flywheel and clutch discs are like in new condition {almost}. I think I got a good deal. Paid 850.00 for the parts truck. Got some really nice windshields, a 12513 trans, a tu-flo 501 compressor, cabmate air ride, the front axle was in mint condition {spindles, drums and even the shoes and bearings}. Project is going slow. Will try to post some pictures. I married a '96 freightliner rear frame section to the original front frame stub.
By Geoff Weeks - Monday, December 20, 2021 10:27 AM
I don't know when the 14" double disk came into use, I do know that the same CPL I took apart had one.
When in NE are you? I am 50 miles east of Omaha in western Iowa.
By Geoff Weeks - Monday, December 20, 2021 10:27 AM
delete double post
By Nebraska Diesel Dude - Wednesday, December 22, 2021 4:07 PM
I'm out here in Hastings, NE. It is south of Grand Island about 25 miles. I go through Iowa a lot. {work}.
Not too far from you. I'd guess about 200 miles give or take. Got more questions guess I'll post some more.
Like I said, I cant believe how good some of these parts look. Wish I had more space. Thanks guys.
By Geoff Weeks - Thursday, December 23, 2021 11:15 AM
I've got two Big cam cores and a bunch of special tools for working on them, PM me if any of it is of interest.
Not too far from you. I've been thru many times over the years.
By Nebraska Diesel Dude - Sunday, December 26, 2021 8:15 PM
10-4, will do. Actually, I'm looking for a few things water cooler for the intake would be nice and a set of jake's would be nice. I dont know what jakes would work. I'd like to step it up to 350 horse. It's a 290 now {CPL 353}. I would like to use this truck for work someday. Just staying in the "flat" states {Nebraska, Kansas, South Dakota. maybe even as far as Texas}. Dont need a ton of horsepower, maybe 350 would be good. Thanks for reply.
By Geoff Weeks - Monday, December 27, 2021 12:54 PM
You are going to have to change/add so much for the 290 to safely handle a big bump in power.
Since what needs to be done is the same for 350 or 400, there isn't much point stopping 1/2 way.
New pistons timing re-set and an aftercooler, injectors and a turbo to handle the increase in fuel.
The only big choice to be made is: do you cut it for lower press fit liners while it is apart or leave the upper press fit and hope they last.
I have all you need in terms of core parts but you'd be best not doing it piecemeal. There are always little parts you don't think of that are hard to find. I don't want to break up the cores, I want all to go.
If you don't have storage, it is going to be hard to assemble everything.
If I were going to build an early Big Cam, I would build internally to CPL 676 and external to either high or low flow depending on what you are set up for. My experience is low flow will return .75 to 1 MPG better fuel mileage.
By Nebraska Diesel Dude - Tuesday, December 28, 2021 2:39 PM
Sounds like good advice. I guess for now It'll have to be a really good running 290, {it runs really good any way}. Maybe I could concentrate on a precise tune-up. I got the room for another engine just dont have room to waste at my shop. Its 24 deep by 30 wide. With the truck in there it takes up alot of room. Did the 676 cpl have the 14 to 1 compression? By the way the old cabover has some nebraska history. It was originally owned by an IH implement dealership in Albion NE {Kayton International}. If anyone has any pictures of this old truck, I would be interested in seeing them.It is painted the original paint, two tone gold and bronze. thanks
By Geoff Weeks - Wednesday, December 29, 2021 2:54 AM
Yep, it had 14:1 and took a lot of boost, so made good power.