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JoeH

E7 with a maxidyne fuel pump

Question

Can an e6 maxidyne fuel pump be mounted on an e7? Just curious, would be nice to capitalize on that extra liter of displacement in the e7. Not sure if an e6 fuel pump can put out enough fuel to make an e7 run like a bigger maxidyne

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If their both Robert Bosch they can if you install the E7 drive gear on to the E6 pump.Most E6 engines are set to 2100 and not many E7 is more than 1800

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8 hours ago, theakerstwo said:

If their both Robert Bosch they can if you install the E7 drive gear on to the E6 pump.Most E6 engines are set to 2100 and not many E7 is more than 1800

My e7-350 makes peak horse power at 1800 according to the engine plate, pretty sure it's governed higher than 18, never really took notice of governed speed though. 

Disregarding governed speeds, would this make an e7 pull like a maxidyne? Can the e6 injection pump put out enough fuel to run a 12 liter engine?

I believe the maxidynes run a higher oil pressure than typical diesels at low rpms, which allows them to turn so much power as low as 1000 rpm without causing damage from "lugging" the engine. My '79 endt676 makes between 60-90psi at idle. Don't think the e7 makes this kind of oil pressure, that would be a modification required if one wanted to put a maxidyne pump on an e7...

Edited by JoeH

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Completely different mounting surfaces. No go.

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IIRC the E-7 series never had an AMBAC pump. Always Robert Bosch and they are completely different in mountings. I was thinking there was a "Maxidyne" series build in the E-7 however. Probably wrong as I wasn't around trucks much when the engine series came out.

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3 hours ago, Rob said:

IIRC the E-7 series never had an AMBAC pump. Always Robert Bosch and they are completely different in mountings. I was thinking there was a "Maxidyne" series build in the E-7 however. Probably wrong as I wasn't around trucks much when the engine series came out.

There was a E7 maxidyne  up to about mid 90's they used  the 6,7and 8spd with that real wide overdrive, and used about a 5.50 or so rear ratio.    terry:MackLogo: I drove one for about 4 years

Edited by terry

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That equates to what I've heard also. I say heard as I've not seen one myself. Never have even heard however of a six speed behind an E-7 engine but again I wasn't around trucks when the engine was introduced.

Thanks,

 

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The early E6 used a AMCO and the last E6 used a Robert Bosch with a adapter 

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I think it was about 1985 when Eaton took over the injection systems division of AMBAC and things went downhill for support pretty quickly from there. Lot's of older parts support disappeared almost overnight.

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On 2/4/2019 at 5:22 PM, terry said:

There was a E7 maxidyne  up to about mid 90's they used  the 6,7and 8spd with that real wide overdrive, and used about a 5.50 or so rear ratio.    terry:MackLogo: I drove one for about 4 years

Was it a tractor? Triaxle? How did it do pulling 70k+ lbs?

I have a 95 e7 350 triaxle with an 8LL that I load to 73k and it's a bit of a dog. 1600rpm in 8th does 60mph, which is as fast as I ever need to go. It doesn't have a straight through muffler, inlet comes in the side. Exhaust temps run high pulling hills, water heats up to around 200.  Going to put a straight through muffler on it this year and see what that does for EGT and water temps. In the 4 years I've driven it all we've done are brakes, tires, a couple broken hubs, a clutch, and a broken combination cylinder in the trans. 

Before that I drove a '79 endt676 maxidyne with a 2 stick loaded to about 52k for 6 years. 

I love how that '79 pulls, up until the past 5 years even new trucks couldn't keep up with it. Would love to know how an e7 maxidyne (I think em7-300 from what I researched this morning) compares to the endt676 and my e7-350.

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The truck that I drove was a dump, not a good combo for a tractor, Pretty underpowered, does your 350 pull up to that 60MPH  pretty good? As for as them temperatures the worse thing I have found is being plugged between intercooler and radiator. taking intercooler clear out and steaming will help alot That E7 350 is a good engine. On that 676 engine, years ago I put a dump together with that engine and a 12 spd. overdrive with 4.17 rears and the pump turned up to 2300 RPM's it would surprise a lot of people.    terry:MackLogo:

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I've blown the radiator put with compressed air before, but I know it's still dusty. I've never taken the intercooler off to clean things up, I'll have to do that this spring too. It does pull good at 60, 1600 rpm is the sweet spot. It doesn't have much ass to maintain speed when you hit hills, not like the endt676. 

I've heard more gears on the maxidyne is a waste. With their torque band you have too many gears. A 2 stick and a Jake brake get you to speed fast. We took our Jake off our 676 because it has a weak valve spring that kept dropping the Jake disc that sits on top of the exhaust valve. No more Jake for shifting ...

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22 minutes ago, JoeH said:

I've blown the radiator put with compressed air before, but I know it's still dusty. I've never taken the intercooler off to clean things up, I'll have to do that this spring too. It does pull good at 60, 1600 rpm is the sweet spot. It doesn't have much ass to maintain speed when you hit hills, not like the endt676. 

I've heard more gears on the maxidyne is a waste. With their torque band you have too many gears. A 2 stick and a Jake brake get you to speed fast. We took our Jake off our 676 because it has a weak valve spring that kept dropping the Jake disc that sits on top of the exhaust valve. No more Jake for shifting ...

An inexpensive cold water only pressure washer at about 1500psi does a good job of cleaning radiators from the backside without folding over the fins. That is a very often neglected area to keep clean. 

I like a nine speed behind a "Maxidyne" myself with the rpm's turned up. It seems to still allow you to have the low end "grunt", but not be forced to downshift to keep the rpm's up. In the ENDT days of the Maxidyne, this allowed you to stay with traffic better too.

I've never had an engine with a Jacobs brake myself.

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4 hours ago, Rob said:

An inexpensive cold water only pressure washer at about 1500psi does a good job of cleaning radiators from the backside without folding over the fins. That is a very often neglected area to keep clean. 

I like a nine speed behind a "Maxidyne" myself with the rpm's turned up. It seems to still allow you to have the low end "grunt", but not be forced to downshift to keep the rpm's up. In the ENDT days of the Maxidyne, this allowed you to stay with traffic better too.

I've never had an engine with a Jacobs brake myself.

The engine brake makes the maxidyne drive like a race truck. Cuts shifting time down by more than half, and keeps turbo spooled up so when you're in gear again you're already spooled and pulling. When you get good at timing it, you make other brands look like a joke, and there's no hill you can't get to 4th gear on from a stop and still keep pulling. 

(4th puts you up around 35-40mph, 5th takes you from there up to about 62 mph on ours)

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I can see that being advantageous these days but back when that engine/trans combination was a staple on the roadways, it was what it was and accepted. Back then 300hp was a real "hot rod" too.

Used to be install AMBAC ADB 155M 169-7 injectors, (which you should have if original) and recalibrate the pump to APE 6BB 110T 6718 +15% and get just shy of 350hp reliably out of an ENDT-676 engine often. If you go with the later water cooled intercooler you could even get a bit more but be careful as the bottom end was stressed at those power levels in the ENDT, or E6 variants. A driver with a cautious foot would have no problems but a real "seat jockey" and the engine wouldn't last. 

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So if you can put the gear off the E7 vmac pump on a mechanical E6 pump to make a mechanical E7 engine could you put the E6 gear on a vmac pump and have a vmac electronic E6 then

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1 minute ago, 880joe said:

So if you can put the gear off the E7 vmac pump on a mechanical E6 pump to make a mechanical E7 engine could you put the E6 gear on a vmac pump and have a vmac electronic E6 then

Lol the e6 is a 3 bolt mount style, while the e7 is a 4 bolt. Totally different mounting pattern. =(

I have my eyes set on restoring our 79 R686ST with the original endt676 motor back to a tractor, but it'll be a few years. Will need to buy a truck to replace it first, it's still a work truck.

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Are you comparing American Bosch to Robert Bosch when you say one is 3 bolt and other is 4

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No. The blocks are different. 

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Remember there was a early and late E6.The later E6 used a Robert Bosch pump like the E6

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I have endt676's from the 70's, both 237s and 285s and we just bought an 88 em6-300. Blocks look identical from a quick glance. Heads and up are the only visible difference to me.

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Never was an ENDT-676 engine rated at 237hp. That was an ENDT-675 series. I believe all of the ENDT-676 series were good to build additional performance into but some of the ENDT-675 would give problems. Main saddle cracking from block twist was one problem. The ENDT-676 series was Mack's first foray into intercooling to up horsepower ratings with the first ones being about 1977. I remember them new but was just starting to venture into a short tenure of being a truck "mechanic".

I ceased that type work full time in 1984 so anything later is just passing knowledge to me. Never was around the four valve E6 series as example. Never have worked on one.

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On 2/7/2019 at 7:53 AM, Rob said:

Never was an ENDT-676 engine rated at 237hp. That was an ENDT-675 series. I believe all of the ENDT-676 series were good to build additional performance into but some of the ENDT-675 would give problems. Main saddle cracking from block twist was one problem. The ENDT-676 series was Mack's first foray into intercooling to up horsepower ratings with the first ones being about 1977. I remember them new but was just starting to venture into a short tenure of being a truck "mechanic".

I ceased that type work full time in 1984 so anything later is just passing knowledge to me. Never was around the four valve E6 series as example. Never have worked on one.

That hood scoop is yours if you still want it. If you want pictures send me an email or a cell number I can text pictures to.  I'll get around to cutting up the hood sometime in the next couple months I expect.

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Hi Joe, yes I would like to have it for my 80 R-612 which has a 300+ engine.

I'll PM you an email address to keep the spammers from loading me up.

Thanks,

Rob

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