First off great forum!! Lots of good info here.

I have a few questions that may be weird for you guys but here goes: The lift pump on the 12v motor seems to be a big problem and from my research it seems to be a standard carter electric gasoline fuel pump. Why not just replace this pile of poo with a high quality racing style pump made for gas motors( holley,aeromotive,weldon)?

Do these motors really not have any glow plugs? Ive read about the heating screens but cant figure out where they are or how they can possibly heat the air enough to start combustion? I realize the comp ratio is the actual sourse of combustion, but, all of the other obviously inferior diesels use them, what makes the cummins so much different that a glow plug is not nessary.

No one seems to be using any type of fabricated intake manifolds or lightweight reciprocating assemblys in their motors. Such as lightened cranks or rods is this because the diesel would murder any part less than what is in there or just becaue of the low RPM?

And finally whats up with the extreme cost of the injection pumps? 1800-2800$ i almost fell off of my chair!!! Is this one of those "if you cant make it your self dont complain about the price". What is the story for these pumps? Do the companys just change seals and gaskets or do they make their own billet parts and high strength cases?

Sorry for the length of the post Im just trying to learn.

 

Welcome to the site. You may want to check out this https://www.dieseltruckresource.com/...threadid=39359 thread for some good diesel info.

The lift pump is primarly a concern for the 24V (98.5 and newer models). Not so much of a concern on the 12V b/c it is mechanical. You should fill in your sig so we know what you have.

Cummins is the only engine (of the big 3 pickups) that uses a grid heater versus glow plugs. Check this out for more info: https://www.dieseltruckresource.com/...highlight=glow

 

it is the lift pump on 24v motors that suck, and every type of pump you can think of has been tried. the better ones have been writting up about.
they have a grid heater that looks like a big toaster element, it is between the intake and the aluminum air horn that is bolted to the intake. look at the intake and you will see some heavy wires running to it.
the air flow of a diesel is just not the same as a gas motor. all porting and polishing does is lower egts, the hp gained is a joke. for all the work that has been done. and when you are pushing 50 plus pounds of boost, air is getting in there. and most diesel never see over 4k so light weight stuff is not that important.
injection pumps are built to very exact tolerances, much more than the regular motor. and it is a bit of black magic, people don't know much about them so not much competion in the retail market, kind of like the airconditioning market. people don't know much about them, so they pay plenty for them. heck it is nothing more than a simple pump and a couple fans.

 

The grid heaters aren't needed to help the engine start until things get really cold, they just keep the white smoke from fogging out the whole street. It's an emissions/driveability thing more than a necessity. At work we have a medium duty Ford with a 5.9 Cummins that didn't come with grid heaters. When it's cold out and somebody forgets to plug it in, it starts just fine but it smokes like a mosquito control truck for a few minutes.

The intake manifold is an integral part of the head, though I suppose a better intake elbow could be devised. As stated above by gunracer, this would have more effect on EGT than HP. This means it would be helpful for towing, but not necessary for playing in traffic.

The beefy bottom end is needed because of the high combustion pressures in a diesel. GM tried to use slightly beefed gasser parts in the Oldsmo-diesels, and look how well those worked.

Injection pumps are built to very precise tolerances and require very clean conditions and highly skilled labor to rebuild properly. There's a reason that our pumps are from Bosch - until WWII, Germany was the only country capable of mass producing something as precise as an injection pump. Bosch got a 30 year headstart on everybody else, and they still lead the world in this area.

 

Thanks alot for the replys guys as I stated Im just trying to learn a few things about these trucks and I appreciate the answers. Im still looking for the right truck. But when I do I'll be well armed with info.