My Build Thread

SouthFlstrokin' · Jun 7, 2012

I was wondering when you were goin to post that

UNLIMITED_DIESEL · Jun 11, 2012

Choupique108 said:
Raising compression has been talked about but its still undecided. I do know the bowl will be centered in the piston rather than offset like usual.

What's the thought process for centering the bowl? Are you aware that the injectors are sitting at an offset angle in the head? Are you getting new nozzles made?

Hotrodtractor · Jun 11, 2012

UNLIMITED_DIESEL said:
What's the thought process for centering the bowl? Are you aware that the injectors are sitting at an offset angle in the head? Are you getting new nozzles made?

I think there could be an entire thread made on combustion chamber theory.... LOL I had the same initial reaction as you probably did to the idea of a centered bowl - but the idea is growing on me....

Take a look at the attached photo of a Duramax with OVAL fuel bowls....

The thought process behind them is to add material where they fail, and to remove material where they could - so since the weak area was around the pin bosses - and there was extra material away from the pin bosses - this is what they came up with. Its stronger than stock, has a minimum bowl width that matches stock from my understanding, and obviously has a wider width than stock in other areas.

Just some out of the box food for thought. When I first saw the oval bowl I hated the idea - then I had time to process it.... I like it - I can see where this could parallel right into an offset bowl for the 7.3.

Jason

fbilly420 · Jun 11, 2012

HMM Very interesting

TARM · Jun 12, 2012

With that design and based on the spray angle of the injectors can you go oblong, increasing surface area of the bowl but go shallower to keep roughly the same bowl volume? Would this then still allow for more degrees of injection time to hit the bowl? (going with the larger and shallower bowl design idea)

I have not seen exactly what the spray pattern of our injectors looks like but I assumed they were circular not oval. If that is the case would having a oval bowl shape take away from getting more crank degrees worth of spray time. Given injection is where our issues seem to be I would think that would be the priority. Larger and thus shallower piston bowls. I understand the strength aspects mentioned but do not have the experience to how this plays with spray pattern and increases in bowl diameter etc..

Hotrodtractor · Jun 12, 2012

TARM said:
With that design and based on the spray angle of the injectors can you go oblong, increasing surface area of the bowl but go shallower to keep roughly the same bowl volume? Would this then still allow for more degrees of injection time to hit the bowl? (going with the larger and shallower bowl design idea)

I have not seen exactly what the spray pattern of our injectors looks like but I assumed they were circular not oval. If that is the case would having a oval bowl shape take away from getting more crank degrees worth of spray time. Given injection is where our issues seem to be I would think that would be the priority. Larger and thus shallower piston bowls. I understand the strength aspects mentioned but do not have the experience to how this plays with spray pattern and increases in bowl diameter etc..

Remember - that is a Dmax - just in case it was missed.

Also remember - it doesn't matter one bit if your putting all the fuel into the bowl if you keep cracking pistons. Sometimes there are tradeoffs that just need to be made.

Oh - and I have never seen a spray pattern that was not round.....

Magnum PD · Jun 12, 2012

Are you filling the block?

jwlandry · Jun 12, 2012

No fill

TARM · Jun 15, 2012

Hotrodtractor said:
Remember - that is a Dmax - just in case it was missed.

Also remember - it doesn't matter one bit if your putting all the fuel into the bowl if you keep cracking pistons. Sometimes there are tradeoffs that just need to be made.

Oh - and I have never seen a spray pattern that was not round.....

I understand. I had thought you were stating that some of that could carry over to the 7.3 piston. But I picked up on the wrong part obviously.

I figured you had likely done a fair share of custom bowl dimensions with the 7.3 as part of your projects. I have thought a shallow larger bowl would be better along with a number of things you have mentioned at various times on the forums. Injector set a bit deeper, heads milled to a bit more etc..

Hotrodtractor · Jun 15, 2012

TARM said:
I understand. I had thought you were stating that some of that could carry over to the 7.3 piston. But I picked up on the wrong part obviously.

I figured you had likely done a fair share of custom bowl dimensions with the 7.3 as part of your projects. I have thought a shallow larger bowl would be better along with a number of things you have mentioned at various times on the forums. Injector set a bit deeper, heads milled to a bit more etc..

I was just paralleling the centered fuel bowl on a 7.3 to the oval bowl on the Dmax pictured in an attempt to relate the varying distances of the spray to the fuel bowl wall.

Magnum PD · Jun 15, 2012

Choupique108 said:
No fill

Why did you decide that. With that much being removed from the cylinder walls thought you would want to strengthen the block.

jwlandry · Nov 16, 2012

its been awhile, but here is an update

new pins. Stock on right, new on left. They are made from H13 tool steel and are 125 grams lighter then stock and much stronger. They also have DLC coating on them.

Billet pistons made out of 2618. The bowl has been opened up with only a slight drop in compression. Hardcoat Anodized the Entire piston with a teflon coating on the skirt. Valve reliefs on both sides for balance.