The truck that I'm looking at buying has custom pistons that lower the compression. The guy I'm talking to about the truck said that it will make the truck harder to start in cold temps. I live in eastern PA and rarely see temps lower then the low teens, will this create a problem for me? Would it just take longer to start the truck up, or wouldn't it start at all? Could the problem be solved with a block heater for the really cold days?

Thanks so much,
George

 

Im confused.....these custom pistons LOWER compression???.....as far as I know thats opposite of what high performance pistons do. Why would lower compression pistons make the truck HARDER to start??

Am I correct in thinking that this truck has higher compression pistons??? More info and details about the truck will get you a better answer.

 

Yes, Mahle or Cummins marine pistons LOWER compression ratio (c/r). Lowering the c/r in a diesel usually means you compensate with higher boost pressure.

Lower c/r means it will either be hard to start or impossible to start without plugging in.
Sometimes 2-3 runs of the grid heater will be enough.
An Espar will assure it runs.....

Compression generates the cylinder pressure and temperature required to light off the fuel when injected. Lowering the c/r drops both pressure and temperature.

 

Really??, low comp. pistons in a diesel!! what are you trying to do??
no power, lots of smoke, bad fule mileage?? go for it if thats what your after

 

Spark ignition (gasoline) go for higher compression ration to get more power until, repeat until, you add a turbo or supercharger. Then the c/r is dropped a lot.

 

Yes, it has the marine pistons. The truck dyno'ed at 652hp and ran a 12.4s 1/4 the last time it was at the track, I was told that it'd probably rip an 11s 1/4 now.

What is an Espar?

George ( the diesel n00b)

 

Uh, 652 HP - whats his number??

 

www.espar.com
A diesel fueled unit that heats and circulates the coolant. The only thing that means I get the beast started in -30°F temps without plugging in.

 

Ive been corresponding through email up to this point. The truck is in Georgia and I plan on going down and driving it before I buy it. I just need to know that I have a truck that won't let me down so long as I take care of it, which I do with all of my vehicles.

Also, nevermind about the Espar, I searched and answered my question as for what it is. My next question is how does it work?

-George

EDIT: Found out how it works too. Next question is does it keep the engine running and would it be possible to just turn it on for really cold days? Say the night before I set it to warm the truck up at a specific time? Are there any extra things I should be concerned about with the Espar: precautions, hints, etc.?

Also, how much are we talking for the Espar D4 (I'm assuming this is the model I'd need) and to have it installed?

 

all of the pullers have their pistons flycut it lowers compression and they are larger in diameter, but when you mill .030 off the top that just gives you that much more room for fuel and air. does this truck have twins and does it have a grid heater. the pullers use ether to start their trucks. the last time i checked marine pistons didn't make that much difference are you sure there not arias custom machined pistons

 

I was told that they are marine pistons. It does indeed have twins and I'll ask about the grid heater.

 

No not much. Mahle on left, marine on right

 

It'll start. You might have to hold the pedal down a little bit until it fires, but it'll start fine. Just when it's cold cold, most of the time it fires right up. Mine did that after the marine's but I also had about some takin off the head to flatten it so that made up a little bit.

 

man, any of you guys ever been around a turbo motor?!?!

lower compression = more room for boost = more power at a given cylinder pressure

pretty simple actually

Forrest

 

Forrest Nearing: Thats what I was guessing. I just wasnt sure if it was the same thing with diesels because they already have a fairly high compression.

Lower compression = more boost, but it will also have a negative effect on how the engine's power off of boost

Higher compression = lower boost, but the engine will have more off boost power.

The truck already has a block heater and Im scheduled for a phone convo with the owner, who also owns a Dodge Dealership. Are there any specific questions that I should ask? I already have the basic questions answered.

-George