piston bowl

The determining factor in the difference pistons the amount the Topring is located down from the crown. For 12v ers, 160 and 175hp ratings have 8mm to the top ring. 190 and 210 have 10mm. Industrial app is 14mm down.

I'll look up for some spec's on the CR apps

Smokem, What specs did I give you for the ISB's? Were the ISB300's 10mm down?

Anyone have piston crowns and skirts coated?? I think the hot ticket would be to take some Industrial pistons, shave the crowns some and have them coated
 
Forrest,

I'll ck and see what I can find out on the CR pistons. You still have a centered inj. Mahle is to be coming out with monotherm pistons for the B's so they should be the hot ticket if they hold up anything like the ISX ones they have out.
 
Anyone have piston crowns and skirts coated?? I think the hot ticket would be to take some Industrial pistons, shave the crowns some and have them coated[/QUOTE]

Yes our project truck has the Gold Coat along with Skirts coated. By Swain Tech .

Look at my photobucket , sorry but there is a butt load of pics there .
 
Smokem,

Thanks, If we get an industrial CR engine in rebuild I'll ck out the topring height. From researching the 5.9's and ISB's it appears the industrial apps have the 14mm spacing.
 
I'm still looking for some part numbers for a ISB 275 piston, I've PM'd about everyone that posted about using them in the past (that I could find searching).

I got my engine disassembled yesterday, everything looked good w/ 145,000 miles on it. Getting new bearings, cam, pistons (still undecided) and everything balanced.
 
With the help from my good friend Google, I came up with this:

ISB 275 serial # 56537917

Cummins dealer gave me # 3800325 for a standard size (grade C) piston.

Cost is the same for a stock 2001 piston or 2005 piston or ISB275 piston. They were all within a dollar of $165 each (piston, rings, retainer). No piston pin included.

Does this price seem in line?

Also, why does cummins use graded pistons? A,B,C for different protrusion heights from the deck? Is this to account for varying deck heights as the blocks were produced?

Will each engine have the same grade pistons in every hole or did they come from the factory with different grades in each hole to account for the crank not being perfect?

Are pistons marked to show what grade they are?
 
Sounds about like a normal Cummins quote for pistons. Check around and you can find genuine Cummins parts for less than their dealers.

I don't know on the grade, I've used grade A for all.
 
Wow, pistons are expensive for these things. I could get a whole topend rebuild kit for my CR250 Dirtbike for 130 bucks. 66mm piston, two rings, two circlips, wrist pin, bearing, and head gasket.

Now I see why they sell used ones on ebay.
 
showphoto.php


These are the pistons i believe to be out of a 24V. For you guys that are wanting a set of 6 piston for a rebuild im trying to get these gone. PM me an offer and they are yours.
 
If you currently have an ISB engine you can get the grade off the #'s on the piston. The reason for the grading/heights is to reduce smoking for emissions reasons. The common rail engines do not have graded pistons, but 2 different thickness headgaskets depending on piston height.

You can have different grade pistons throughout the engine not all could be the same grade.

Mahle makes most of the pistons for the B's
 
With the help of fellow member "Sarge1", I found what might me the answer to a good factory piston. Found a bulletin on a marine engine called QSB 5.9-440 and QSB 5.9-480. Bulletin states these motors as 440hp & 480hp @ 3400 rpm. Bulletin states the following features about the pistons used in these motors.

"Double heat treated piston with 30 percent improved yeild strength and 0.2 mm (0.008in) radius at bowl lip to reduce stress and to make sure no cracking occurs at higher power. Use of DCX CKS top piston ring with wider end gap for lower blowby and improved wear (durability) at higher rated speed and power. "

Also states " Use of DCS "MEGACRANK" with larger counterweights to reduce block bending momentum and fretting on main bearing caps and viscous damper at higher ratedspeed and power. This will also result in reduced engine vibration." "Use of lighter weight, "common" connecting rods, Use of bi-metal bearings, Use of a Larger waste gated HX55 turbo."

Plus some other good reading, trying to find more out about these motors, but real interested in the pistons....

scot
 
Last edited:
coating the pistons is a great way to improve reliability and gain HP

after coating the pistons( top and bottom) on our race motor we saw oil temp drop about 15* and egt's rise about 200*, which makes sence due to the heat reflection of the coated piston top.
 
QSB 5.9 480hp--16.7:1 compression ratio

QSB 5.9 305hp--17.2:1 compression ratio

scot
 
Last edited:
That's pretty good, a factory rated 480 hp 5.9 cummins...

I see that the info also said one of the QSB 5.9's features was:

Strengthened block for
long life and reduced noise

I wonder what the difference is?
 

Attachments

  • qsb.GIF
    qsb.GIF
    7.5 KB · Views: 33
Oil-Burner,

Appears you have been busy. Did you get the CPL's for the engines. As far as I know there is only the Storm block out. Did you find any #'s for the pistons??
 
You must log in or register to reply here.
Back
Top