Looking for pictures of an AD COE engine layout, specifically intake/exhaust manifolds. (cab off of course.) What manifold changes would a COE engine need to convert to downdraft use in a 3100 pickup? Would the updraft fit a stock 3100 as-is?
Matthew 6:33
1952 Chevy 1/2-ton 3100 Late '55 235/SM420/torque tube 3.55 Dalton Highway survivor (using original 216) www.truckwithaheart.com
It's a 1950 COE. Engine is a 261. Finally found an internet pic (attached) of what I assume to be a typical COE layout. It appears I'll need both intake/exhaust manifolds.
Matthew 6:33
1952 Chevy 1/2-ton 3100 Late '55 235/SM420/torque tube 3.55 Dalton Highway survivor (using original 216) www.truckwithaheart.com
Have you run the casting numbers? A 1950 COE would have had a spray-oiler 235 originally. 261's didn't come out until 1954. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Have you run the casting numbers? A 1950 COE would have had a spray-oiler 235 originally. 261's didn't come out until 1954. Jerry
My particular engine has serial no. stamp ending F55N, indicating a 261 from 1955. Obviously not original to the truck. Not in my possession yet and don't know the casting number.
The pic posted above is not my engine. It's the only representative photo I've been able to find showing an AD COE manifold layout.
Last edited by Skooter; 01/12/202312:10 AM.
Matthew 6:33
1952 Chevy 1/2-ton 3100 Late '55 235/SM420/torque tube 3.55 Dalton Highway survivor (using original 216) www.truckwithaheart.com
Sounds like in the end you need to replace the current COE engine "updraft" style intake and corresponding exhaust with a "downdraft" intake and exhaust manifold set like Mike B suggested above to provide best fit when installing the 261 into your 3100.
Looking forward to seeing pictures of your 261 acquisition.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
Exactly what I'd hoped to find, thanks very much. I've found conventional downdraft manifolds and a Rochester B (both from a 235) that should work well enough. Bet there'd be room for the updraft arrangement in a 3100 if someone wanted to go that route. Doubt the exhaust pipe angle would match the updraft exhaust though.
Matthew 6:33
1952 Chevy 1/2-ton 3100 Late '55 235/SM420/torque tube 3.55 Dalton Highway survivor (using original 216) www.truckwithaheart.com
hi the disk brakes came off a chevy 3500 the rear axle was swapped from a chevy 3500. Had to move the spring seats I retained the original from axle and put bushings in the kingpin holes to accommodate the chevy 3500 front spindles
also my truck has a weber downdraft carb. I modified an aftermarket aluminum manifold. works great
I don't have any pictures to share, but I can tell you that converting a COE engine to downdraft use in a 3100 pickup will likely require some manifold changes.
Downdraft manifold, and carb., will work but carb. would stick up above floor level, and cause a problem with access when trying to depress the accelerator. I've run across several like this though the years of my COE Hunting Ventures.
Spanky Hardy Collector Of Fine Old G.M. COE Trucks & Antique Holmes Wreckers
skooter was asking about using an engine taken from a COE to put into his pickup.
There shouldn't be any problems with converting that engine to a downdraft manifold setup as that is standard for the pickups. No clearance issues to speak of in this case.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
I don't have any pictures to share, but I can tell you that converting a COE engine to downdraft use in a 3100 pickup will likely require some manifold changes. It's not a simple task, but it's definitely doable. If you're looking for a more straightforward solution, you might want to check out the kubota b3350 dpf delete kit. It's a great way to improve the performance of your engine without having to make major changes. Good luck with your project, and don't hesitate to reach out if you have any more questions.
Hi Lara -- Thanks for stopping by Stovebolt.com and welcome to our site. Interesting link -- does that programming have *any* application to obsolete/non-computerized GM gas engines?
Also, we would be happy to talk to you about advertising on our site, although I'm not sure if it would be a good return on your advertising dollars ... Not too many modern Kubota engines to be found among our users ...
Just checking ...
Thanks, John
~ John
"We are not now that strength which in old days Moved earth and heaven; that which we are, we are"
1948 International Farmall Super A 1949 Chevrolet 3804 In the Legacy Gallery | In the Gallery Forum 1973 IH 1310 Dump 2001 International/AmTran RE3000 "Skoolie" 2014 Ford E-350 4x4 (Quigley)
Skooter Anyone that EVER had experience with updraft system would not use it their daily driver. The last one I was around there was often a lot of expletives from under the truck.
hi the disk brakes came off a chevy 3500 the rear axle was swapped from a chevy 3500. Had to move the spring seats I retained the original from axle and put bushings in the kingpin holes to accommodate the chevy 3500 front spindles
also my truck has a weber downdraft carb. I modified an aftermarket aluminum manifold. works great
51 Chris, Do you have pictures somewhere of your build? PIctures of the steering linkage etc? Sure would be helpful....I would add them to Grigg's sticky at the top of the main page. Would be very good to summarize what you did, what parts you used(and part numbers) and where you sourced everything to do the front end conversion. Marty
