rhinoo Posted October 17, 2023 Share Posted October 17, 2023 (edited) Looking at buying an 688st and the guy said his father in law had a rebuilt e7 engine into the truck. Was wondering if anyone can identify the engine off of a couple pics I got. I have an e7 in a Rd dump truck but haven’t been around an E6. Thanks Edited October 17, 2023 by rhinoo Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/ Share on other sites More sharing options...
rhinoo Posted October 17, 2023 Author Share Posted October 17, 2023 5 minutes ago, rhinoo said: Looking at buying an 688st and the guy said his father in law had a rebuilt e7 engine into the truck. Was wondering if anyone can identify the engine off of a couple pics I got. I have an e7 in a Rd dump truck but haven’t been around an E6. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540449 Share on other sites More sharing options...
JoeH Posted October 17, 2023 Share Posted October 17, 2023 Looks like an e7 to me. An E6 would have two removable plates on the side of the engine block next to the fuel pump. These plates provide access to where the pushrods set into the lifters. Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540450 Share on other sites More sharing options...
JoeH Posted October 17, 2023 Share Posted October 17, 2023 The oil fill tube on this does look like an E6 though. Doesnt match my e7's fill tube. More pictures would help. Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540451 Share on other sites More sharing options...
BOBWhite Posted October 17, 2023 Share Posted October 17, 2023 Yep more pictures. Its probably an early E7 if it's not an E6. Every E7 I've seen has the Bosch P pump and this doesn't look like a P Pump. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540457 Share on other sites More sharing options...
steeler Posted October 17, 2023 Share Posted October 17, 2023 Looks like a like an e6 2 valve to me, by what I think I'm seeing with the valve cover..... 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540458 Share on other sites More sharing options...
Licensed to kill Posted October 17, 2023 Share Posted October 17, 2023 (edited) Should be an aluminum plate behind the injection pump riveted to the block with all ID info on it. Little hard to see but with a bright flashlight you should be able to read it. Otherwise, the engine block ID is stamped into the flange where the front cover bolts on right in front of the injection pump. I you have trouble finding it I can post a pic. Edited October 17, 2023 by Licensed to kill Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540460 Share on other sites More sharing options...
Joey Mack Posted October 17, 2023 Share Posted October 17, 2023 The rear valve cover is rounded like a 2 valve... 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540468 Share on other sites More sharing options...
rhinoo Posted October 17, 2023 Author Share Posted October 17, 2023 19 hours ago, rhinoo said: Guy found the engine tag. It’s says E6-350R… I’m a little bummed because the e7 in my dump truck is impressive with stage 2 injectors and a big turbo but I talked to Brad at Rochester and he said we can still make it run good but a 10 liter engine just seems awfully small to get a whole lot out of. Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540508 Share on other sites More sharing options...
rhinoo Posted October 17, 2023 Author Share Posted October 17, 2023 Just now, rhinoo said: Guy found the engine tag. It’s says E6-350R… I’m a little bummed because the e7 in my dump truck is impressive with stage 2 injectors and a big turbo but I talked to Brad at Rochester and he said we can still make it run good but a 10 liter engine just seems awfully small to get a whole lot out of. I was gonna add a pic of the tag but I can’t figure it out. 😆 Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540509 Share on other sites More sharing options...
BOBWhite Posted October 18, 2023 Share Posted October 18, 2023 Tread lightly when tuning an E6 especially a 2 valve. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540520 Share on other sites More sharing options...
JoeH Posted October 18, 2023 Share Posted October 18, 2023 11 liter, not 10. Don't be fooled by its size, Mack rated their HP at the wheels, not at the flywheel. So a 350 Mack should make more power than another brand 350. I haven't driven an E6-350, but it should pull well. Only turn it up if you're the only one that's going to drive it, and don't do much. They're incredible engines for their size, and Mack maxed them out at the perfect power vs durability ratio. If you tip more towards the power then you'll lose durability. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540526 Share on other sites More sharing options...
rhinoo Posted October 18, 2023 Author Share Posted October 18, 2023 8 minutes ago, JoeH said: 11 liter, not 10. Don't be fooled by its size, Mack rated their HP at the wheels, not at the flywheel. So a 350 Mack should make more power than another brand 350. I haven't driven an E6-350, but it should pull well. Only turn it up if you're the only one that's going to drive it, and don't do much. They're incredible engines for their size, and Mack maxed them out at the perfect power vs durability ratio. If you tip more towards the power then you'll lose durability. Ok. 11 liter sounds better than 10.. is there any way to tell if it’s a two valve without removing the valve covers? It does have a 13spd behind it so that will help Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540527 Share on other sites More sharing options...
rhinoo Posted October 18, 2023 Author Share Posted October 18, 2023 34 minutes ago, BOBWhite said: Tread lightly when tuning an E6 especially a 2 valve. I did tune my e7 and it’s a powerhouse now. I am leery about anyone else driving it though because in those long pulls I have to lift up on the accelerator a little or it egt’s get a little warm. Does the 2 valve let it heat up even more? Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540528 Share on other sites More sharing options...
steeler Posted October 18, 2023 Share Posted October 18, 2023 It's a 2 valve. The valve cover is rounded, and has 3 mounting bolts on top of it vs a slanted valve cover with mounting bolts around the perimeter on the e7. Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540536 Share on other sites More sharing options...
BOBWhite Posted October 18, 2023 Share Posted October 18, 2023 2 hours ago, rhinoo said: I did tune my e7 and it’s a powerhouse now. I am leery about anyone else driving it though because in those long pulls I have to lift up on the accelerator a little or it egt’s get a little warm. Does the 2 valve let it heat up even more? Not much more flow you can get out of an only 2 valves per cylinder although I've heard some say they pull just as good or better than the later 4 valve E6. More fuel will just add to EGT and smoke out of exhaust. Plus the bottom ends of the E6's are made only as strong as they need to be and not much more. I've heard of crank shafts snapping. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540543 Share on other sites More sharing options...
JoeH Posted October 18, 2023 Share Posted October 18, 2023 Pyro on my E7 says downshift at 1025 degrees. Pyro on my ENDT676 (1979 2 valve precursor to the E6, pretty much the same engine except for fueling/powerband) says downshift at 1125 degrees. You'll have 13 gears so that'll help you keep in the powerband. The E7 is only 12 liters, so at 11 on the E6 youre not far off. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540544 Share on other sites More sharing options...
doubleclutchinweasel Posted October 18, 2023 Share Posted October 18, 2023 11 hours ago, JoeH said: They're incredible engines for their size, and Mack maxed them out at the perfect power vs durability ratio. If you tip more towards the power then you'll lose durability. That kinda sounds like what I was saying on Jo-Jo's thread! Well put, Joe! 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/73435-e6-or-e7-identification/#findComment-540561 Share on other sites More sharing options...
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