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Injection pump setting, maxidyne vs. thermodyne


b61fred

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  • 2 weeks later...

I am getting ready to install the injection pump. I was wondering how much advance to set the pump at? I was wondering what works best. I know there is a big difference on Cummins engines on horsepower and pump timing.

Fred

15 gears...no waiting!
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I have looked in the manuals and seen anywhere from 10 to 19 degrees. I would imagine that it was conservative to promote fewer warranty related problems. I will not load this truck hardly at all and will be using a pyrometer to drive by. So I am liking what you are saying. I read the manual about setting the timing by removing the delivery valve on 1# cyl and using air and a jar with fuel in it, I won't go into the details of the process here just yet but do you know what I am talking about. I don't have access to a A-B timing light and I would have to get close to assemble the truck to start it.

Morgan

15 gears...no waiting!
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  • 2 weeks later...

Wonder what it would cost to get a pump gone through and setup?

Last time I had mine gone over it was around $1600.00 The pump was worn pretty bad though and in need of an overhaul....This is on a 250 econodyne.

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  • 2 weeks later...

Update... Got pump back Friday, I would have been much sooner but I was in an accident with a riding lawn mower rolled over on top of me and haven't felt like doing much till now. Installed the pump and started the engine today. Ran much better than before, scored an A-B timing light and set timing. The difference between settings is the springs that basically let the rack open to full fuel at a certain RPM. I am looking for the puff limiter valve that installs in the intake, my pump man says it will be better to not have the engine over fuel until turbo boost is available. The pump was very worn and I he gave me all the old stuff to show just how shot it was. I had to buy a lot of stuff to get it back to spec. and It cost about $1200 to get it done. I hope that I feel go enough to work on it some tomorrow and may get to take it for a spin. If so I will let you know how it works out.

Morgan

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15 gears...no waiting!
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That is called reversing relay valve that goes in the intake.The more boost the turbo builds the less air pressure the relay allows to go to the puff limit valve that holds back the rack.Just remember when the puff limt valve is working proper it may fell like a slug till boost stars to build and also remember it does not cut the HP t top end but it does help keep your oil cleaner.

glenn akers

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  • 4 weeks later...

Got the truck all together, and worked all the little bugs out and just drove it on our first road trip. The result, It runs great, the power is right there when you split shift, has a narrow power band but hits hard at 1600 to 2100. Drops like a rock under 1550. Uses so much less fuel than before and the old duplex seem to be much happier shifting than before. It also starts scary fast, I rebuilt the polarity switch and starter, that 24 volts twirls the 675 like nothing.

Fred

15 gears...no waiting!
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Glad to hear it works good.

I just got 7.0 mpg going to York(hills, hills, hills). I got 8.0 going to Milan, Michigan this past weekend.

There is a 237 on local craigslist. Motor/trans/rad all for $1500. Just too much of a project right now to throw money at and just have it sit outside til I get around to it. Little things like roof, windows, AC, concrete and siding are taking priority(dangit).

IMG-20180116-202556-655.jpg

Larry

1959 B61 Liv'n Large......................

Charter member of the "MACK PACK"

 

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I have a 237 and 6 speed two stick I have been thinkin about putting in a B42/B61 conversion. I have the engine mounts out of the DM it came out of and they almost look like they would bolt up where the B model ones were. guess ill have to check. I don't mind a few new holes but I hate to drill 8 new ones. have to figure out the push to pull clutch to.

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It really wasn't too bad. The trans to frame mounts fell in different spots so 8 new holes were needed. Spacing differences between the B61 and B75 may make your situation better or worse with regards to the clutch. The original clutch cross shaft on the B75 had to be replaced with a pair of side mount industrial pillow blocks. Then an adapter was made to convert to a R clutch cable to the bell housing.

Jim

It doesn't cost anything to pay attention.

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Did you use the pump shop in Elnora?

Yes I did, John Jones did the work for me.

thinkin about putting another B together with a 237 and duplex but am kinda worried about that dead pedal problem everyone talks about .

dead pedal problem?

15 gears...no waiting!
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