Detroit Series 50 swap into FC

[DFB052686]

I have an acquaintance talking to me about the Detroit. got me thinking...

I have looked at basic digital specs. seems very similar apart from slight weight penalty, it's at 2200lbs dry vs 1800lbs on the Cat. and it is an S60 with two fewer cylinders, ...used in MCI's and not uncommon in general.

Detroit S50: 8.5L(519CID) I4, 42" long and 48" tall, 2200lbs, 350hp/1200ft lbs TQ
Caterpillar: 10.4L(636CID) V8, 57" long and 40" tall, 1750lbs, 300hp/ 640ft lbs TQ

assuming it will run with a standalone ECM(looking into that now), what say you about replacing the cat with it? double the torque would be fantastic. and I'm thinking it would probably net a gain in economy, and cut down on smoke, leaks etc.

they could be configured with a front mechanical fan and serpentine system vs pusher config.

FYI: found a few on fleabay with ZF ECOMAT 2 transmissions (6HP592C), same effectively on highway as the 5HP500 in the 87+ caterpillar equipped birds. like them however, these are all discontinued and electronics are nearly as rare!!
Except:
6= 6 speed (vs 5)(.69 Double OD after *our final* .80 OD)
H= Hydraulic(same)
P= Planetary(same)
59= 1250 tq input(vs 1100)
2= 2nd Generation(vs first gen)
C=Can bus(vs "n/a" on the WL )

seems with a conservative spec engine(not maxed to 350/1200lb ft) I could maintain the factory 87 ZF until an Allison popped up. again; ideas?

am I off-base here in thinking this would be a good solution to power/age/size constraints in the FC drivetrain? think to maintain FC oem intercooler and radiator.

I think this would be a HEAVY duty alternative to a 5.9CTD, and seems like it would fit my comfortably than an 8.3 or DT466.

my 3208 is going strong @ 110k miles(and 36yrs!), but as is normal for them, the smoke at cold & off idle is off-putting in mixed company (non-bus people), and S60 modern diesel reliability would be highly welcome. in my case, the bus flies as-is, double the torque would likely enable me to cruise at the speed limit in all but extreme outlier conditions.

[Hspencer]

I’ve had the same thought, I’ve seen a few used ones on eBay with the ZF. Looks good on paper and they were used for similar applications. Hopefully someone more knowledgeable will chime in.

[Randy Dupree]

the 50 is a wide engine,i'm thinking too wide for an FC.
i known where theres one for sale.

[DFB052686]

Originally Posted by Randy Dupree

the 50 is a wide engine,i'm thinking too wide for an FC.
i known where theres one for sale.

An inline 4 that’s wider, and heavier than a v8 of larger displacement. The mind boggles. Taller makes sense. But width I had not considered as a factor.

I’ll have to measure, I’m thinking of going to Orange County to check out a few (5!) combos from a breakers yard. They’re missing the controllers though, so it’s not likely to be a fruitful trip apart from visualizing. 70 miles each way to look…

[Randy Dupree]

The one i know about in Ga has a controller.
heck,it may have a trans bolted to it.
its out of a airport crash truck or something.
And at a junkyard in Fl theres about 5-6 of them,with v drive trannys,out of some pusher bus,people packer.

[tqwrench]

Originally Posted by DFB052686

I have an acquaintance talking to me about the Detroit. got me thinking...

I have looked at basic digital specs. seems very similar apart from slight weight penalty, it's at 2200lbs dry vs 1800lbs on the Cat. and it is an S60 with two fewer cylinders, ...used in MCI's and not uncommon in general.

Detroit S50: 8.5L(519CID) I4, 42" long and 48" tall, 2200lbs, 350hp/1200ft lbs TQ
Caterpillar: 10.4L(636CID) V8, 57" long and 40" tall, 1750lbs, 300hp/ 640ft lbs TQ

assuming it will run with a standalone ECM(looking into that now), what say you about replacing the cat with it? double the torque would be fantastic. and I'm thinking it would probably net a gain in economy, and cut down on smoke, leaks etc.

they could be configured with a front mechanical fan and serpentine system vs pusher config.

FYI: found a few on fleabay with ZF ECOMAT 2 transmissions (6HP592C), same effectively on highway as the 5HP500 in the 87+ caterpillar equipped birds. like them however, these are all discontinued and electronics are nearly as rare!!
Except:
6= 6 speed (vs 5)(.69 Double OD after *our final* .80 OD)
H= Hydraulic(same)
P= Planetary(same)
59= 1250 tq input(vs 1100)
2= 2nd Generation(vs first gen)
C=Can bus(vs "n/a" on the WL )

seems with a conservative spec engine(not maxed to 350/1200lb ft) I could maintain the factory 87 ZF until an Allison popped up. again; ideas?

am I off-base here in thinking this would be a good solution to power/age/size constraints in the FC drivetrain? think to maintain FC oem intercooler and radiator.

I think this would be a HEAVY duty alternative to a 5.9CTD, and seems like it would fit my comfortably than an 8.3 or DT466.

my 3208 is going strong @ 110k miles(and 36yrs!), but as is normal for them, the smoke at cold & off idle is off-putting in mixed company (non-bus people), and S60 modern diesel reliability would be highly welcome. in my case, the bus flies as-is, double the torque would likely enable me to cruise at the speed limit in all but extreme outlier conditions.

Hi Dennis,


If your primary concern is white smoke (it's not really smoke - it's unburned fuel), then why not put a 3" diesel oxidation catalyst on it? I know someone with similar concerns on an Olds Diesel that did so with favorable results. It had a pencil injection setup similar to many Cat's of the era. https://www.donaldson.com/content/da...talyst-DOC.pdf

[1984Lodge]

The series 50 is a large displacement 4 cylinder which means they have balance issues. This is a common issue as you go into larger displacement 4 cylinder engines, that’s why you do not see many of them. I think you would be swapping to another engine with issues, so a lateral move as opposed to getting something a bit more reliable.

Here is some info on secondary imbalance:
https://youtu.be/gdHQ8aTfiQQ

I also think Randy is correct the Detroit is bigger than the Cat:

[kunzelj]

The series 50 was a short lived engine for production and really meant as a transitory engine to fit where an 8v92 once lived. You'll get lots of smoke with them too as there are no emissions controls. Do what I do... Add a webasto and preheat your engine. Then add an aux air compressor. When I start my coach it's warm and fully aired up. I start and leave the campground, just like a car.

[Randy Dupree]

On ebay there was a dt466,also sold as a series 40 by detroit.
the one on ebay was complete with 4000 allison and both confusers and harness,as removed from a bus of some sort.
DT466 were good,and if this one has a 4000 allison it much be high hp.
ohh,the trans had a retarder too and a pto with hydraulic pump.
interesting package for sure,a scrapper has it.

I was always interested in the s50,and the bus conversion guys all talked about using one to replace 6vs and other inline detroits.
I never saw many converted to the s50,but that kind of stuff is regonal.
as far as balance issues i bet detroit has some kind of balance shaft,anything bigger than 2.5 litres in a 4 banger (gas or diesel) has balance issues.

[Randy Dupree]

Hey,great topic.
Way back at the fmca conventions Detroit would bring a bunch of engines.
when the S60 was getting popular they had one on display,along with the S50,the S40 and the 6v and the 8v.

Of course Cat and Cummins all had massive displays.
On an engine stand where the oil pan would be at about ride height those 60's and 50's stood way tall,heck they were almost 6 feet tall.
and i bet the valve cover alone on a 50/60 is almost a foot wide.

I mentioned this years ago and if i was younger i would make an FC a pusher,put the engine in the back,move the fuel tank to the front.
you need to be a good welder and not be scared,but that would be a cool project.