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Discussion Starter #1
I was looking at a bread truck today that was diesel but was not a cummins the engine was blue and had (white) on the block is this a good of bad engine thinking of buying it for a swap project any help would be greatly appreciated.
 

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lots of Frito Lay style bread/ delivery vans came w/ Gm 6.2 and 6.5 engines, if its a V-8 its probably one of those...they are pretty reliable but finding a turbo is expensive and in my opinion not worth swapping
 

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If it's a 4 cylinder and not a Cummins it could be a White/ Hercules 3.7. The series I were painted blue. It should have an ID tag on the turbo side of the block near the bottom, but it might not as I have one without the tag. FWIW, the series II 3.7 Hercs are the desirable ones, they were painted red and have several other external features that allow one to tell the difference if the tag is missing. There are big differences in power ratings between Series I and II. I can help identify Hercs as I have several of them.

Ken
 

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Discussion Starter #4
what are the hp ratings of the herc engines?are they good engines worth doing a swap with?
 

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what are the hp ratings of the herc engines?are they good engines worth doing a swap with?
The series 1 should be considered only for something smaller like a Jeep. Even then, it's not going to knock your socks off but should give excellent mileage. They can be turned up but they don't have some of the features of the series 2 that allows them to survive at the higher power levels. The Hercs weigh 125 lb less than the 4BT so they are a viable option for smaller vehicles where that weight savings can matter. 85 HP is a number I've seen around, and 70 HP another. There are various versions and end uses(vehicle vs industrial).

The series 2 are similarly rated as the 4BT, 108 HP and 125 HP w/intercooler. They have a good reputation but nothing like the 4BT. And parts availability is also nothing like the 4BT. They are still being remanned but I don't think any new ones are being produced.

I'd only use one if I got it cheap(which I did).

Ken
 

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Discussion Starter #6
the one i'm looking at is the smaller of the 2 do you think it would be a decent swap into a scout or should i hold out.i can pick up the engine for 300 or less maybe.worth the money?
 

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the one i'm looking at is the smaller of the 2 do you think it would be a decent swap into a scout or should i hold out.i can pick up the engine for 300 or less maybe.worth the money?
300 is a good price on a small diesel that runs good. Does it come with bell and clutch, maybe even transmission?

Will it work in a Scout? Yes. It was, afterall, in a larger vehicle and the early Scout s made do with a 152 cu.in. gasser.

Will it be slow? Yes.

Will you be happy with the results? Most people these days would not. Most people these days would not be happy with the original engine in the early Scouts or even the 196 in the later 4 cyl versions.

If your expectations are in line with delivering original performance of a 4 cylinder Scout but in a diesel package then it's probably not a bad swap. What were the 152s making? ~75 HP and 120 lb.ft. (half of the 304 SAE numbers). Well the 70 HP of the Herc is at 2600 rpm. At that rpm torque equals twice the HP, so torque is 140 lb.ft. at 2600 rpm. That's 20 more than what the 152 provided. The peak torque numbers are likely to be a bit higher at a lower rpm. And series 1 engines were available in 85 HP at 2600 versions(170 lb.ft.). Add in that these are turboed and thus are affected by altitude much less than an NA gasser and one can see where they are an acceptable engine for these older, smaller vehicles. Particularly so if not upgrading axles where the extra weight and torque of the Cummins would be damaging these parts more readily.

I plan to put one of my series 1 Hercs into a '68 CJ5 where a 134 cu.in. 4 cylinder resided(75 HP, 114 lb.ft. but these are pre-SAE, SAE are lower). I live at 5K feet ASL and go up from there. I don't expect great power performance(I'm hoping to get good mpg) but I know it'll produce more power and torque than the engine that this jeep came with.

Of course, the Hercs can be modded to get some more power. A series 2 IP and turbo would wake up a series 1. However, the series 1 lacks some features internally. One is the oil squirters on the underside of the pistons. This means to me that the series 1 has a lower acceptable EGT before piston damage because the pistons aren't being actively cooled with oil as in the series 2.

One thing I'd consider is that if $300 gets you a running 4 cylinder diesel that's similar in size to the 4BT, this would allow you do a diesel conversion to a known good config(~4 liter 4 cyl diesel), especially so if the Herc is from a Ford stepvan(like my 2) whereafter a 4BT with SBF bell pattern would bolt onto the existing bell/trans/transfer setup. If after the Scout is running and driving you feel you must have more power, you can either track down a series 2 Herc as a bolt-in replacement, or swap to a Cummins 4BT. With all the other sundry items already taken care of in swapping in the Herc, changing to a 4BT shouldn't require much.

Ken
 

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Discussion Starter #8
Thanks for the reply great info on these engines and the swap. few questions do the herc have the same vibration problem at idle that the 4bt has.and you said that the turbo on the herc ll will wake up the herc l.Last but not least what kind of mpg can expect from this engine.this has my intrest perked.
 

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I don't know about the vibrations. I'd assume similar to 4BT and be happy if less. It is a 4 cylinder without a balance shaft(AFAIK).

For the power upgrade, I mentioned the series 2 parts for the series 1. I forgot the injectors. So swap on an exhaust manifold with the turbo from a series 2, likewise the IP and the injectors(requiring injector lines too), and a series 1 could make the power a series 2 does but it won't live as long. Perhaps not nearly as long, I don't know.

The IP is a Roosamaster/Stanadyne unit that I assume can be turned up a bit like the pumps for the 6.9/7.3 IDI(DB2), but I may be wrong here. I see a cover on the side of the pump, similar to the DB2, wherein I expect a screw controls a range of the fuel rate. Turn it one way, you get more fuel for a given above idle governor setting, turn the other, get less fuel. The series 1 turbo could also be swapped to another turbo if more air is needed, etc. It appears to me the series 1 turbo is a T25 size whereas the series 2 is T3. The injectors between series 1 and 2 are different, requiring the appropriate lines. Perhaps simply an intentional difference to eliminate accidental use of one in the other.

I don't know what mileage as I don't have one driving. I have one in the beginning stages of a swap into a CJ5. I conservatively expect 25 mpg, but won't be surprised if I get 30+, no highway miles. It should provide similar mpg to a 4BT as it is a 4 cyl 3.7L DI turbo diesel designed in the same era as the 4BT. Folks with series 2 in much larger vehicles(M37,M175) report plenty of power and good economy and a relatively quiet engine. Series 1 reports are of sluggish stepvans...

Ken
 

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Discussion Starter #10
The herc I'm concerting is a turbo but a blue engine I believe a 1 what kind of lifespan problems does it have and can the problems be fixed?
 

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...what kind of lifespan problems does it have and can the problems be fixed?
I don't know on either count. I just know that some changes were made for series 2 and that series 2 are rated quite abit more than series 1. As I mentioned previously, I know piston oilers are one difference and this to me is a significant change in allowing more power in the series 2. I don't think the series 1 will have major problems with hard parts making the power, excepting the pistons, though I could be wrong.

I don't need 100+ HP in my little Jeep so I'm not worried about it. Mine is more an exercise in economy, both in cost to build and cost to operate. The price of admission for a 4BT was too much for my goals on this one. Take away the funding issue and I'd choose a 4bt over the Herc everytime, there are simply too many pros of the Cummins over the Herc when money is not a constricting factor. I picked up 2 complete engine/transmission combos out of Ford stepvans for a good amount less than just a 4bt engine.

The accounts you'll find online concerning these engines in Dodge M37 and Kaiser M715 are of series 2 engines. It seems that the stepvans all had series 1 installed. I don't know this for sure but I have yet to see a series 2 surface in/from a stepvan.

Ken
 
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