Welding pistons

SoDak24valve said:
I understand the heat treat part also from what I gathered the only time it really causes a issue is when it gets the skirts really hot and takes the heat treat from them it makes them brittle, this is to just see if and how the pistons turned out from being modified by welding on them, I had heard and seen a picture of some 6.7 pistons monster pump mike had welded up and re machined for custom applications. How about valve reliefs on new piston if a person takes their time and does not cerate excessive heat would something like that be possible.
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We have 4 engines going together using his components throughout, including his modified pistons. I will post the results when the trucks are up and running, and dialed in.

Mike
 
Once the pieces have been in use they should be inspected to see anything deteriorated do to the temps among other things. Too bad I need a flowbench more than I need a couple sets of kustom machined and welded pistons.

Looks like I could develop something with Zeigler Diesel on my Cummins powered Super Street truck if I can put a bug in his ear for a idea hmmmm.
 
a flow bench is fun . I have had one to use for the last 20 years and as much help as it can be. It can also lead you in the wrong direction if your not use to reading the results
 
Not to continue a thread derail on the 6.4 build thread about pistons, figure this is the more appropriate spot for the matter and Smokem mentioning his bowl being used with Wiseco's product. I would like to hear his viewpoint on combustion.

Smokem, or anyone else for that matter, whats your view with crown design incorporating a flat design verse a deeper combustion chamber. Greg strongly stands by shallow wide layouts, obviously. While some still stick with deeper designs.

With what I see when we are making black smoke is what I call the 'rolling' coal front' which the fuel can't evaporate quick enough at the temps present even with the particular injection parameters causing a push not just from pressure developed by heat but by the flame propagation coming into not yet vaporized fuel. Wasting fuel and power. To create a mixture motion no just adequate rate of tumble & swirl but to provide a timed delivery of oxygen & heat to burn efficiently. I haven't designed a bowl, but I figure this would be fitting for the thread for Sodak.

Could we be looking at something in a 4th dimension that is not seen by the naked eye when observing and researching? :pop:

Keep personal BS to yourselves and talk tech.
 
Fahlin Racing said:
Smokem, or anyone else for that matter, whats your view with crown design incorporating a flat design verse a deeper combustion chamber. Greg strongly stands by shallow wide layouts, obviously. While some still stick with deeper designs.


Keep personal BS to yourselves and talk tech.
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^THIS^
 
Ever time we go with a wider and shallower bowl, the timing requirements go down. This is a result of making the combustion chamber more efficient. As flame front speeds up, the oxidation of the fuel burns more efficiently. I also look closely at BSFC.

The smaller bowls a throwback to fix a mechanical fuel system when you’re trying hard to get around peak torque but keeping the fuel mixture a rich as possible until the piston in rounding 15 to 20 degrees after TDC . This is also to reason they drop compression. Ricker mixtures burn slower . Leaner mixtures burn faster

With fast burn rates and variable timing, you cylinder pressure rise is much quicker, and requires less crutch “IE Timing”. With less timing and fast burns you can make power up higher.
 
As far as the volatility level of diesel being so poor, I can see a rich mixture burn slower due to close molecules absorbing heat not allowing the fuel to vaporize and light rather consuming droplets causing hydrocarbons or 'rolling coal front'. Other fuels, I believe differently but thats another discussion anyhow.

Perhaps Greg, Sodak could that deep bowl allow a hinderance just on its smaller diameter than the bore itself alone?

Smokem how deep is your design would you say?

I know not many in diesel throw around the words squish & quench. I believe we need to utilize squish more than we do a quench factor, but........ hmmmm
 
Fahlin Racing said:
Once the pieces have been in use they should be inspected to see anything deteriorated do to the temps among other things. Too bad I need a flowbench more than I need a couple sets of kustom machined and welded pistons.

Looks like I could develop something with Zeigler Diesel on my Cummins powered Super Street truck if I can put a bug in his ear for a idea hmmmm.
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you have my attention jim!!!
 
ive always had good luck with a very wide shallow bowl design. slightly delipped if you will. like has been said it seems to make more power with less btdc timing needed. also on a high hp/high boost engine set up i prefer to not get greedy with the compression. you have got my wheels turning on some designs though jim. like always!
 
Fahlin Racing said:
As far as the volatility level of diesel being so poor, I can see a rich mixture burn slower due to close molecules absorbing heat not allowing the fuel to vaporize.
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There is no one correct answer, in some applications with high manifold/cylinder pressures, fuel density is needed.
 
COMP461 said:
...With fast burn rates and variable timing, you cylinder pressure rise is much quicker, and requires less crutch “IE Timing”. With less timing and fast burns you can make power up higher.
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Right up until you run out of fuel rate...
 
dvst8r said:
Right up until you run out of fuel rate...
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maybe , but we have to toss it at the wall and see. I see putting even more compression in it , and backing off on late fueling. the fuel that dosen't get burned now will make power , if it can be burned quick enough.
 
Yes there is a correct answer, there may be more than one but for the majority the debate seems to be left to be answered exactly in that respect.

Taylor states in diesel chamber turbulence as follows....

...."in the case of Diesel engines the turbulence effect must be associated more closely with the MIXING process than with the propagation of chemical reaction."....
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Now Smokem, back to my question from earlier.

Greg, dvst8r, Sodak, Zeigler too. Whats rollin around with you guys as well?

With an employed shallow bowl I see more port influenced swirl, maybe even assisted by the wall, however; if the reduced timing caused by a better burn allowed by the area itself not having to restrict by structure parameters to cause a heavy mixture motion? (surface distance from your injection point)

Are we still able to have reduced timing even with a deeper bowl even though we see fuel coming into contact with the crown surface more often versus a flat top.

The meaning behind my 'coming into contact more often' I meant fuel actually adhering and becoming hydrocarbon and not being consumed. I know some guys that run these flat tops have said they just wash the piston off and put them back into service which tells me the soot buildup on the crown is little enough that combustion is fairly efficient. I still think there is a proximity factor as well as what I said earlier, Taylor states these happenings are known as burning velocity and transport velocity.

Greg, we must be sure the fuel left to burn/oxidize has not developed enough heat to set off detonation/pre-ignition prior to our flame front. Like you said, if it can be burned quick enough. Which also brings thoughts to heavy fuel molecules but I suppose that will be a different conversation.
 
COMP461 said:
maybe , but we have to toss it at the wall and see. I see putting even more compression in it , and backing off on late fueling. the fuel that dosen't get burned now will make power , if it can be burned quick enough.
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Been there tried that, made less power not more.
 
Maybe not all applications will react the same?

There is still something out there, shapes and areas, if I sound like I am beating a dead horse there still seems to be room for something involving charge motion at any point during the burn cycle or other point in the timed operation.

Sodak, do you have any pictures of your welding project here?
 
There is a lot more to combustion efficient then just a raise in compression, bowl design is a big part of it. Cam timing is critical as well. Cylinder head design

In any engine program, no matter what the fuel or use, RPM is the key to making more power, this is bedrock. Move your torque curve up and you will make more power, this is a given.
In 500 inch Pro Stock 10 years ago they were making 1250 hp at 9700 rpms, they are still making 1250 hp at 9700 rpms today. But they have mover the power up to 10.800 and now they are making 1500 hp.
The way to make more power is to work hard on cylinder heads, and cam design.

Now as to the problem you have to be smart enough to use this power

To say we have already tried it and it doesn’t work is with what we had last year, will mean you will be stuck in the same box
 
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