Sasqoutch

Im pretty sure i read a while back about the differences between the motors and it came down to, cp3 pressures, injector design and a better flowing head along with a bigger turbo. If this is true has anyone swapped the head? How much bigger are the intake/exhaust ports and do they have the same cam lift/duration? Truck just got paid off and with 130k miles its time for some upgrades but before just ordering a turbo and throwing in some injectors i want to do studs and a new gasket. Just want to do it right. Brian

Riflemanusmc

Im not sure about flow. Its my understanding that with high EGT's the valve seats in the 03/04 heads get loose. Sounds to me like a tighter press fit on the seats is in order. Dont know if CUMMINS made the 04.5 and later seats out of a differant material, maybe someone here knows.

soulezoo

04.5 and up heads are purported to have better flow. I have seen no emperical data from flow bench tests to support that. The valves are the same size; however, they are sodium filled to help withstand the heat. The valve seats are different and not prone to dropping as in the 03-04 heads, that is a fact. How they are different, I am not sure.
On 03-04 heads there is no difference between SO and HO engines.
I have put on a cummins remaned 07 head on my early 04 engine. It has been ported so I cannot report on any felt difference.

lmills

04.5 and newer heads have the inconel exhaust valves also. I am not much of a believer that the heads flow better. Some of the highest HP trucks are 03&04 engines with unmolested heads on them. Most of the people that change them out, do it for the better seats and valves

Big Blue24

I thought for sure I read a post once where someone stated the 235hp California 2003's don't have the same amount or size of oil cooling jets that spray the piston crowns from the backside. Is my memory bad or was that a misstatement?

lmills

I think he was referring to the heads themselves or the deck surface matching the head. But yes, you are correct. Early 235 motors did not have the same piston cooling jets.

Sasqoutch

Yea I believe the HO's have the piston cooling jets. Thanx for the info guys, that clears up alot of questions i had. lmills, when you said "inconel exhaust valves" were you referring to the valves or the seats? I'm familiar with the compound as we inlay RTJ flanges with the stuff from time to time, very durable. Just with the advantage of getting the valves to seat better and having sodium filled valves i see it as being a worth it swap when i do studs.

Riflemanusmc

OR like I and lloyd were talking about tonight, take YOUR head and have it updated...........

JJPage

Would like to know, what should I do, to keep from lifting my head off the block @ 50+ psi.

Can I re-torque my stock head bolts, or is this just wishful thinking.

What is the difference between 625's and ARP 2000's?

jtharvey

Is there a build date where the change was made or some other way to tell? What are the differences in the jets? When I had my oil pan off before the motor went in the truck, I looked for the cooling jets and my 235 motor has the saddle type jet. I don't know if this is the newer style or not. Build date on my engine is 10/2004.

lmills

if you had the saddle type, it is the older style. The newer style have a j jet that is bolted to the block with a banjo bolt. The oil comes thru a galley to the jet and sprays directly up on the piston

jtharvey

I remember seeing what appeared to be ports on the block for a J-jet, covered with a block off plate and a bolt. It had me wondering if someone couldn't go in and add them. However, I don't know if it's really necessary...

Sasqoutch

hey riflemanusmc and lloyd, could u guys send me some more info on having newseats installed/ sodium valves/ and porting the intake and exhaust passages?

Riflemanusmc

You bet......... check your PM's later today.......

Bswope

Alright Preston when is yours coming apart to be updated????