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01-21-2020, 09:21 PM #21
I question logic on post number 10: If an engine or family of engines was in use from before 1938, and was available as an option to power high quality fire trucks, pumpers and ladders all the way through 1970..
HOW could anyone consider the engine a FAILURE?
What put the straight 8 and V-12 engines out of business was the availability of turbocharged diesel engines that cost less than to make you own straight 8 or V-12 gasoline engine.
The Pierce Arrow engines from the 30's were upgraded to have insert connecting-rod bearings and also had dual spark plug cylinder heads designed and installed. Special dual distributor systems etc..
DualValve.
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01-22-2020, 10:16 AM #22
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01-22-2020, 10:39 AM #23
I remember a V12 showed up in one of the scrap yards in Elmira in the mid 1980's. As you say, dual plug heads and dual ignition systems.
I think the tag on it said American LaFrance. Back then there was a re-builder in town doing work on fire trucks. And of course, Elmira was home to American LaFrance and Ward LaFrance. Long gone now......
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01-22-2020, 11:15 AM #24
In the early 80's I saw an open cabin (no cabin) REO Speedwagon fire truck that had a straight 12.
I don't recall dual plugs tho.
That's normally an airplane thing aint it?
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Think Snow Eh!
Ox
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01-22-2020, 11:24 AM #25
That's the one !
That distributor cap had (24) plug wires IIRC.
Dual ignition was for the same reason as airplanes, reliability (and a large bore needs more spark
to light off the fuel, hence the mag drop when run up testing).
A fire truck get's WET, with all that water spraying around, as well as needing to run in ANY weather,
including with snow flying under the hood.
The shop owner explained how he ran Screeming deetroits in his highway snow plows (unheard of in the area at the time) as they would keep right on going in a blizzard, even when sucking in snow thru the air intake.
Conditions that stopped the gas engine trucks.
Also, fuel & oil usage, and noise be dammed when you need to rescue someone.
A Detroit will generally run once kicked in the ass, no matter.
I read the spec somewhere for a Detroit emergency genset, (maybe Joe posted it).
From light off to full load, 5 seconds.
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01-22-2020, 11:30 AM #26
Well - I for one can attest to the fact that I was VERY happy to go from a SBC to a 6.2 diesel in my plow truck!
No more standing 3 deep in line to get new dist caps at the auto parts counter on snowplow days!
(seriously had that happen - all plow trucks)
And THAT is a rear dist.
Not sure how a SB Ford would have been in same app?
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Think Snow Eh!
Ox
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01-22-2020, 11:36 AM #27
86 f-150 with the 300-6 raining heavy, won't start.
I take off the cap, have a handy air hose, blow out cap underside completely dry.
Still won't start.
Didja' ever read ALL the words on a can of Pblaster ?
In the smallest typeset it says "spray in distributor cap"
ONE SQUIRT, and I'm running....
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01-22-2020, 11:41 AM #28
I'm all for redundant ignition systems in any life support or life rescue equipment. You can get out and walk if the engine quits in your R-plane, but that first step after you contact Terra Firma can be a bit iffy.
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01-22-2020, 12:31 PM #29
Big gas V12's were popular for buses as well. GMC made a quasi V12 with two big GMC V6's, they has the advantage of OHV. The flat head V12's were torque monsters but really inefficient designs by the 1950's. The other thing that kept them in service was the cold start ability vs the diesel engines of the day.
Steve
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01-24-2020, 12:28 AM #30
I'll reiterate in different form a historical note that apparently missed a few...
The Pierce-Arrow V12 was initially purchased by Seagrave from P-A. That V12 was originally designed and built as a TRUCK engine, because P-A made trucks... that was their largest volume production (not cars). When P-A shut down, Seagrave continued using the P-A engines. I don't know how the 'business arrangement' went, but regardless of wether it was remnants of P-A, or if it was one of P-A's suppliers, or if Seagrave acquired the rights and tooling, THEY became the only major user of that engine platform... and they were certainly not poor performers.
The American LaFrance V12 appeared in several sizes, and it was a LYCOMING design... but not an 'aircraft' engine. It was designed and built for primary production to go in Cord and Auburn automobiles. It was given some modifications (dual plug being one) and sold to ALF for many years, until eventually C/A/D ceased automobile production of it, at which time ALF acquired the platform's rights. Like the P/A, the ALF Lycoming was no sissy.
While shorting ignition was a concern amidst all the water, the greater reason for diesel popularity was simply the fact that gasoline was a much more volatile fuel. Just as in tactical combat vehicles, diesel was a 'safer' source.
Dual ignition did provide redundancy, but the greatest advantage of dual plug is as noted above- flame speed. Large bore engines have a LONG flame traversal distance, and by igniting the mixture at more than one location, the amount of time required for the flame to complete the burn cycle is dramatically shorter. This means that LESS ADVANCE is necessary to get a complete burn prior to 90 degrees ATDC, and therefore, substantially more power with less advance. This means higher piston speeds don't cause such a dramatic loss in BMEP.
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01-24-2020, 02:19 AM #31
JH1 s motor is a silver 92 with DDEC.....this is one of a small select group of diesels with specific fuel consumptions under 200gm /KWH....even the best Euros only got marginally below this.In fact the 92s eventually washed out on particulates,due to oil carry over in the liner ports.These consumptions have never been bettered,and never will be....and in a true million mile motor.
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01-24-2020, 09:25 AM #32
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01-24-2020, 11:08 AM #33
I've done a lot of work on and around 16V149TI's. The full 1000 KW (and then some occasionally) load was dropped on dead cold iron the exact instant that engine achieved 1800.00 RPM and it held it there rock solid even with pretty bad stuff wrong with the engine.
That's like 4 seconds less than your 5 seconds and these engines would pretty much go indefinitely with heads and injector replacements every 10-15k hours.
They did burn some oil though. lightly loaded we had one that consumed 250 gallons every 24 hour period. During the day you couldn't tell, but look above the stacks at night and it was a nice deep blue hue.
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01-24-2020, 11:12 AM #34
SOME oil?
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Think Snow Eh!
Ox
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01-24-2020, 11:32 AM #35
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01-24-2020, 11:33 AM #36
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01-24-2020, 12:12 PM #37
I think the generators were around 500-1000 gallons of fuel a day. The other generators in good shape only used 5-10 gallons of oil a day. They have a huge sump, so hard to tell. On the same ship, the gas turbine propulsion engines burned about 250 gallons of diesel a minute at 30 KTS so wasn't a very big deal.
Big detroits are definitely impressive. They are very reliable and always start no matter what. I don't know about fuel efficiency though. The damn things weigh twice what an equivalent 4 stroke does and in an OTR application 2 stroke Jakes are pretty useless.
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01-24-2020, 12:21 PM #38
What fer boat had these power units?
I could see a tug using it as main power, but these must be freighters that you are talking about?
Don't those burn a heavier - crude type fuel?
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Think Snow Eh!
Ox
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01-24-2020, 12:25 PM #39
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01-24-2020, 01:49 PM #40
"Bunker C" is the tar like fuel.
I only heard of that being burned in a boiler, but let's see if someone has some evidence
of using it elsewhere.
Tugs (and other boats) I see are using the engines to spin alternators, thence on to
"pods" electric motors outboard...think "MinnKota on roids"
I was watching some video, tugboat captain in swivel seat with joysticks, the little swisil sticks
controlling VFD's and such to control the boat, much like a skid steer.
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