Who's running 18:1 pistons?

[great white]

I'm wondering what the cold start performance is like with them on a stock PCM program.

When I say cold, I mean in the -10 to -20 C (14 to -4 F) range....

 

[ak diesel driver]

IIRC Chicago TDP, Ratman, Smithville D, alot of these guys don't get on much anymore but you could probably shoot them an email

 

[JiFaire]

Also canadianrigger (haven't seen him in a long while) and dennisGO1 ( who has a schoolcraft engine )

Let's not forget our own Slim Shady, who also has an ATT with his 18:1 pistons.

 

[DZZ71]

i shaved 70 tho off mine so that puts me around 17:8 i will post results shortly

 

[JiFaire]

i shaved 70 tho off mine so that puts me around 17:8 i will post results shortly

Cool... you shaved them ... what did you coat them with, or did you go with hard-surface anodizing?

 

[DZZ71]

dident coat them with anything.....

 

[JiFaire]

dident coat them with anything.....

Ah ... I was under the impression that was required. Maybe I'm misremembering.

Let us know how it goes!

 

[DZZ71]

Yeah i talked with a guy that did it a while ago (1994 to be exact) and it still runs fine as of today. so i went for it. I will be starting a thread with a few videos here soon. got a few little things left to fab and weld up.

 

[Ratman]

I'm running the Mahle 18:1 marine pistons, and am decked .010" but running stock thickness gaskets (which should put it around 19:1-ish)

The coldest I have ever had to start it was when it was 12F when traveling out of town and staying at a motel in Eastern Oregon. It was unplugged all night, -and I was still running a so-so set of glows. It took me three attempts to get it chuggin' (I did give it a whiff of WD-40), -once lit, it started hitting on all 8 in about a minute, and settled into a nice crackly-idle in about 1-1/2 minutes.

With the 60G glows installed, I haven't had any problems at all when it's around 35F and not plugged in.

All in all, I love this 18:1 engine and have had no regrets, I'd do it again in a heartbeat.

For whatever it's worth, -I'm old-school with a DB-2 pump.

 

[Ratman]

Yeah i talked with a guy that did it a while ago (1994 to be exact) and it still runs fine as of today. so i went for it. I will be starting a thread with a few videos here soon. got a few little things left to fab and weld up.

Yep, I also know of someone who took a bang-load of material off a set of pistons and made a 15:1 engine. He ran 30+ pounds of boost with the Peninsular 300HP DB2 pump, -heck, he didn't even run a squirter-block, -and it lived, -all while outpulling his buddie's powerstroke and pulling over 11k while doing so. His EGT's were close to 1300+ sustained pre-turbo.

I guess as long as the piston to cylinder clearances are right (on the loose side versus being too tight), it shouldn't be an issue. Most 6.5 hotrodders I've talked to always seemed to be more concerned with scoring the piston skirts versus torching holes in them (assuming the injectors are in good shape). The coated pistons certainly reject a lot more heat than a set of "topped" ones, -so the word is, -don't run "too hot and too tight",...-or else!!

 

[Missy Good Wench]

My feeling is that if your using the rig mainly as a grocery getter/back and forth to work rig, the stock pistons are a great choice. If you are going to boost the sucker to the MOOOOOOOON or MARS thenn the 18:1 is great.

For hard work and towing, you betcha. To get the starting characteristics better, just use 60G plugs and set up a manual glow setup and glow it longer and add a little post heat to keep the fire going well.

Or if you dont care, you can kill a buttload of skeeters on the cold startups.

Missy

 

[ak diesel driver]

skeeters are fair game around here

 

[great white]

Interseting stuff.

I am considering buying a P400 6.5 at 18:1 instead of a 'max conversion for my 98.

I've got duraterms in the truck which will transfer over.

The glow cycle is easily adjusted with my tunercats program.

The truck is a "daily" that will be occationally pulling a 35 foot trailer.

Cold start is a concern for me.

I'm looking at an 18:1 because the gent in vancover who swapped a p400 into his 3500 has often made mention that he wishes he had gone for the 18:1.

With an 18:1 I can use tunercat II on the PCM to up the boost and fuel to the proggy's max of 80 mm3 and see how it goes.

And a P400 bottom end is more than up to the task....

 

[Ratman]

Or if you dont care, you can kill a buttload of skeeters on the cold startups.

Missy

Oh Missy, I surely do kill the skeeters, -and piss off the eco-freak libtards across the street too, -kind of like a two-fer! :hihi:

For all those that don't know, Robyn was a huge help during all of my 6.5 endeavors, she definitely knows a thing or two about the 6.2 and 6.5! :thumbsup:

Tim (TurbineDoc) was also a huge help as well.

The 6.5 community is definitely a "tight" bunch, -yet another one of the reasons I am going to keep driving this old truck until I can't fix it anymore.