VADSLRAM

Glow plug engines work because of two things. The glow plug stays red hot after ignition and nitromethane is very volatile. They don't use a blower (until the new really hot ones) because size and weight. to use reed valves you would need completely seperated charge compression chambers for each cylinder. What a nightmare in parts and seals.

Say what you will about DD but the 6-71 blower works real well on GM big block gassers. I helped a friend put one on a 75 chevelle that he had shoehorned a Caddy 472 block. We replaced U joints and tires way to often crappy car but a wailin power plant.

JD730

A friend of mine once told me that "Detroit Diesel's are the answer to the self lubricating truck"

Bigikediesel

I'm a fairbanks Morse Engine Field service engineer. The engine he was refering to was most likley a FME 8 1/8 bore 10 inch stroke Opposed Piston 2 stroke medium speed blower scavanged engine. usually 4 to a boat 2 to a engine room. They run forever and are indistructable, but to change the upper pistons you have to pull the upper crankshaft . I'm out in Mineral Wells texas working on 3 Natural gas engines, 2 8 cyl's and one 6 cyl. The 2 8's are turbo charged and push 2200 hp. and the 6 is natural assperated and runs 1400. Very fun engines. There was also a form of this engine by junkiers made for airplanes but the engine could not respond fast enough at altittude. And there is another produced by great britian it has 3 crank's! crazy engine. o well 2 cents.

Jay

bentwings

You guys that have been talking about model air plane motors and diesels. The glow plug while bright red hot has a platinum element which causes a catalytic reaction when burning nitro and alcohol which causes it to glow brightly without a battery connected after starting. They work very well and can mke a lot of power depending on displacement. ( and use lots of fuel) . O.S. actually made a roots supercharged motor that worked quite well.. For a while it was top of the line for its' displacement. Lot's of tech but too much for here.

Now for model diesel motors (engines) . These are true compression ignition and do not use glow plugs for starting. They have a contra piston head which mean variable compression adjusted by an external screw. I don't know what the compression ratio is but it is high. You use the adjustable feature to fine tune the motor. There is no FI as we know it but there is a carb with a throttle for R/C control. They work quite well and get unbelivable economy. The fuel is a blend of ether, kero , and a couple other igniters . It's a bit more expensive than glow fuel but you don't need as much. These motors run a little slower than the glow counterparts but can pull much larger props. Yes they smell just like a CTD. and puff a minature black cloud when run with too much fuel. ( rich ) They don't get real hot but will nicely toast your fingers if you don't respect them.

I don't use them myself as I prefer the brute force method of the so called chain saw motors. 5.8 cu in (100 cc)and 11 hp 7500 rpm. There are motors a lot bigger but cost a lot more. The pylon racer guys use up to 300 cc. twins. These motors only weigh about 16 pounds!!! and go past 200 mph long before they are wound out. The price of one of these would get you very close to 1000 ft lbs in a CTD. The price of one complete ready to fly 1/4 scale pylon racer would buy you a very nice DCTD truck. Most teams have several or many and have a DCTD and 5er!!

jrs_dodge_diesel

Bigikediesel, at my last unit (U.S. Coast Guard 378 ft cutter), we had 2 F-M diesel engines turning our props (also had 2 P&W turbines BTW). The main diesels were 12 cylinder, 24 piston vertically opposed. Rated for 3600 SHP (shaft horsepower). I don't remember exact specs but the bore was in the nieghborhood of 8 inches and the piston stoke was about 12 inches, maybe more onthe stroke. The engines had twins on them. I do remember them being smoky beasts though.

VADSLRAM

But can you forget the whine when the birds fired up?

Bigikediesel

we just got done overhauling on OP on a cutter in michagin. pain in the rear. we had to haul the parts up the ladder wells. fm op's smoke alot, due in part to the oil scavinging.

jrs_dodge_diesel

Nope. I can remember that sound clear as day. Even remember the entire ship doing the shimmy shakin action when we had the turbine going.


Yep, ours smoked a lot, especially during startup and warmup. Ran decent once they were up to temperature. Can't imagine how much wrestling it would take to get either upper or lower crankshaft out of the boat. The crank is about as long as my truck !

dieseldunce

Can anyone comment on the way this is handled in a marine application? I have been told that the reason some of these engines return from 5 to 9 times the fuel consumed to the fuel tank is to keep the engine from over-heating and damaging the cylinder head. Is that true?

cincydiesel

The real question to that would be: Will it take off on from a large conveyor? Just kiddin guys!!! I had to do it

DiezelSmoke

They liked them in the marine application cause they could get more HP out a small C.I.D., thus a smaller package motors. They could be wound up full load and last forever if they were not lugged down. I don't think they had anymore head problems than any other engine as long as they didn't overheat, and that wasn't a particular problem in a marine application. These motors have bought a lot of toys for me over the years. These were the motors of choice in the truck races. A lot of diesel history behind these motors, kinda sad to see them go by the wayside.

rip 112

here's a few cool ones.

http://www.youtube.com/watch?v=x1YXx...eature=related
http://www.youtube.com/watch?v=xUk8I...eature=related
http://www.youtube.com/watch?v=vrnwx...eature=related

jrs_dodge_diesel

Ours ciculated fresh water through the block, much like any other engine. The water that circulated in the engine was called jacket water, and ran through a heat exchanger, instead of a radiator. Salt water would get pumped through the heat exhanger and back overboard.

I don't recall any fuel returns from the engines, they only consumed the fuel required for any given speed.

Haulin_in_Dixie

that 6v does not sound like a 6v at all, it sounds like a v8 either a 318 or a 430. A 6v sounds just like a 238. I did enough miles on a 238 and also on a straight piped 6v92.

Hey big injectors and larger port liners and they would really pull. Advanced timing was also a power grabber especially on the later engines where they retarded them for EPA. California engines were 5% retarded from federal specs.

Haulin_in_Dixie

I don't ever recall seeing a diesel with no fuel return. I am not experienced on the large marine engines other than moving a bunch of them, but detroit uses a gear pump and a return with a jet to control the fuel pressure. I used to put larger pumps on them (12v) and dual returns to keep the fuel warm in the winter. In below zero weather when I would stop my tanks would be steaming on the outside.

I moved a couple of detroit marine engines that the hight was the problem loading. They were not much different than a 238 other than being bigger. I did fool with a 6-110 for a while in an old international.