Joseph Cummings Posted December 31, 2024 Share Posted December 31, 2024 I didn't know they made that much more power than a regular single ignition EN707 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74922-enf-707c-ad/ Share on other sites More sharing options...
mechohaulic Posted December 31, 2024 Share Posted December 31, 2024 it was days of engineering and competition . "make it better yet simple" . so glad I was part of it. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/74922-enf-707c-ad/#findComment-565091 Share on other sites More sharing options...
mowerman Posted Wednesday at 05:32 PM Share Posted Wednesday at 05:32 PM What a cool picture thanks for that.. bob Quote Link to comment https://www.bigmacktrucks.com/topic/74922-enf-707c-ad/#findComment-565150 Share on other sites More sharing options...
Popular Post D2Denny Posted Wednesday at 06:42 PM Popular Post Share Posted Wednesday at 06:42 PM The EN-707C was rated at 222 HP at 2100 RPM. The ENF-707C per the brochure is rated at 276HP at 2600 RPM. Not knowing for sure but I would bet my Mack Hat that the ENF designation relates to a fire engine rating. Dual ignition that a lot of gas fire engines had, and spinning it another 500 RPM for pumping applications would account for the 50 HP increase. 3 Quote Link to comment https://www.bigmacktrucks.com/topic/74922-enf-707c-ad/#findComment-565153 Share on other sites More sharing options...
Geoff Weeks Posted Wednesday at 09:36 PM Share Posted Wednesday at 09:36 PM On air aircraft and my generator, the plugs are 180 deg across the combustion chamber, so the "fire" is started at two points far from eachother. It does up the power considerably as noted when you kill one side. I think most of the power on the Mack is from higher speed, tho. It doesn't look like the plugs are across the head from eachother 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74922-enf-707c-ad/#findComment-565158 Share on other sites More sharing options...
Jack Mack Posted yesterday at 01:09 AM Share Posted yesterday at 01:09 AM I was under the impression that the dual ignition was mainly for a redundant start in case of failure of the distributor or coil in use. Our B85F has the selector switch for A, B or both. It is a fire truck it has to start , and start right away. Our truck is not running yet but soon, guess we will have to play with that….Jack Quote Link to comment https://www.bigmacktrucks.com/topic/74922-enf-707c-ad/#findComment-565170 Share on other sites More sharing options...
BOBWhite Posted yesterday at 02:05 AM Share Posted yesterday at 02:05 AM 49 minutes ago, Jack Mack said: I was under the impression that the dual ignition was mainly for a redundant start in case of failure of the distributor or coil in use. Our B85F has the selector switch for A, B or both. It is a fire truck it has to start , and start right away. Our truck is not running yet but soon, guess we will have to play with that….Jack In my mind it's for both redundancy and power. On airplanes you check right and left mag before you takeoff, you feel a big difference in power when you cut one set off and it drops about 50 rpm. Quote Link to comment https://www.bigmacktrucks.com/topic/74922-enf-707c-ad/#findComment-565172 Share on other sites More sharing options...
Joseph Cummings Posted yesterday at 02:09 AM Author Share Posted yesterday at 02:09 AM 4 hours ago, Geoff Weeks said: On air aircraft and my generator, the plugs are 180 deg across the combustion chamber, so the "fire" is started at two points far from eachother. It does up the power considerably as noted when you kill one side. I think most of the power on the Mack is from higher speed, tho. It doesn't look like the plugs are across the head from eachother I had a mag failure on a Cherokee 180 flying home from Cape May NJ one time. The thing felt gutless. I might have been around 4000 max, and it felt like I was at 10,000 feet. Got on the ground and did a mag check and one was dead. I can't remember if it was left or right, but it was the one without the impulse mechanism, because I got it restarted and taxied over to the hanger Quote Link to comment https://www.bigmacktrucks.com/topic/74922-enf-707c-ad/#findComment-565173 Share on other sites More sharing options...
Joseph Cummings Posted yesterday at 02:40 AM Author Share Posted yesterday at 02:40 AM Seems like those dual ignition fire truck heads were significantly different on the 707. Even different sides for intake and water manifolds Third picture is regular truck engine with updraft carb and single ignition 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74922-enf-707c-ad/#findComment-565174 Share on other sites More sharing options...
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