Blowed up my E6, should I upgrade to E7

[Randiesel]

I have a 1989 Mack with an EM-6 300 that spun a bearing and the piston hit the head. It looks as if the heads are ok but crank is to bad to be turned. From talking to my mechanic it looks like best case scanero 6-8k on rebuild. 

Ive had several local "Mack Guys" tell me I should not put that much money in an E6 engine and I should upgrade to the E-7. Also the E-7 comes in a 400 HP which I think if I upgraded that's what I go to. I realize the E7 300 & 350 both can be turned up to more horse power.....my question is this.....what exactly is the difference between an E7 300, 350 and 400? Is the only difference in the pump settings or does the 400 have bigger turbo and stuff like that?  Any help from someone that knows would be greatly appreciated

[TeamsterGrrrl]

What transmission does the truck have?

[Randiesel]

Mack 2070 

[TeamsterGrrrl]

That wide ratio transmission needs a high torque rise Maxidyne engine, so in an E7 you'll be limited to 300HP but probably a bit more torque. If you want to go to a 2004-06 Maxidyne they had up to 370HP ratings, but the engine accessory layout is a lot different and they used electronic controls. If you go to a conventional torque rise engine like an E7 350HP you'll need a closer ration transmission to go with it.

[Randiesel]

Thanks Teamstergrrrl for your reply.

Today I pulled the trigger and bought a1990 E7 400 HP manual engine for $6500. not really that familiar with the torque rise you mentioned......I do know the the newer higher HP Mack engines don't have the low end torque like I'm used to and you gotta shif before the RPM's get to low...... Let me tell ya what I thought and please correct me if I'm wrong;  I thought an E-6 & E-7 was an "econodyne" engine which pulled down to a lower RPM (1020 best I can remember) E6 being the older and the E7 being the later version. 

And I thought an EM6 & EM7 was Maxidyne version of the engine which pulls down to 1200 RPM  before shifting. I also know there a later model E7 that is not manual and I know to stay clear of that to keep swap as simple as possible. Plaese advise me ASAP, if you don't mind, before I make a HUGE mistake. I have a Mack 18 speed I could put in my dump truck but I like the 2070 because you drive it like a 5 speed....I don't care for all the gear changing.....but in order to run this tranny I realize I need the low end that the old econodyne Mack had. 

 

If I could get some clarification on E6 vs EM6 ,E7 vs EM7 and  Maxidyne vs Econodyne as well as torque rise info that'd be great. I'll be sick if I spend this much money and get wrong combination of motor & tranny. 

Thanks in advance for any input

Randiesel 

[TeamsterGrrrl]

The 400HP engine should be conventional torque rise and will probably need more than 7 gears, so you'll probably have to swap your 18 speed in there too. The other option would be to have the 400HP engine's fuel system recalibrated as a Maxidyne, not sure what all that entails.

[Timmyb]

If your pulling out an em6, you'll need an em7. 

They are the low revving engines, most limited to around 1800rpm. 

An e6 or e7 will need more gears than 5. 

[Randiesel]

TimmyB an Econodyne Mack engine is a lower RPM engine than a Maxidyne engine. And I thought E6 meant econodyne? Guys I'm not trying to argue but trying to learn???? Is this not correct? 

[Randiesel]

47 minutes ago, TeamsterGrrrl said:

swap

Do you know what's the largest HP engine that I can get that'll work with a 2070 trans......like I said earlier I don't like all those gears 

[Timmyb]

http://www.tyldenheritage.com.au/uploads/9/3/0/6/9306704/econodyneengines.pdf

Thats a read up on the econodyne. 

 

[theakerstwo]

Just dont forget what Teamstergrrrl has just told you.

[Randiesel]

49 minutes ago, Timmyb said:

http://www.tyldenheritage.com.au/uploads/9/3/0/6/9306704/econodyneengines.pdf

Thats a read up on the econodyne. 

 

Thanks for the info.....I'm trying to get my mind around all this.....

[Timmyb]

Yeah, it's a bit confusing. Basically your em6 was a maxidyne. Your e7 400 isn't a maxidyne. But you need a maxidyne for a 5sp.