LMM: Wisco Pistons

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jkholder09

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Jan 8, 2012
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I have tuned these pistons. I did not notice piston knock or any other noises.

Weisco does not incorporate an offset piston pin for noise reduction.
The factory pistons with 2 arrows do have about a .040" thrust offset.
The lml engine had a piston tick and if you check with gm parts they do have updated lml pistons where all 8 are identical. So they deleted the offset. Make your own assumptions and hypothesis on this information. I am only stating what Iknow to be factual about the parts.
I sent weisco a sample 2 years ago to aid in design and have given input on the design of the Dmax piston. I was much more involved in the 6.7 and 6.4 powerstroke pistons.
These are still new parts but I have been impressed thus far.

I will say the sets I used were 16.5:1 and 17.2:1. I have not tuned a 15:1 set.

The lip on the bowl is cut at a long angle so the flame front will propogate differently. I did adjust timing and pilot injections.
This is just my personal experience. I think the hot spot on these pistons is in a different location. Nozzle angle could ultimately be the best tuning tool.
I think you have a great piston but its a new item.
This forum if full of smart guys and knowledge.
You will get it sorted out.
And mark is a great guy to do it for you. One of the best for sure!
 
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Dave c

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Jul 7, 2013
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Potthoffdmax said:
That guy is an a$& to say Mark doesn't have experience!!
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My references about experience was not questioning marks overall building experience. But his experience with wiseco pistons. Yes there are others such as wade at ngm who have sold and built more wiseco pistons equipped engines than anyone here. Me as a customer have yet to hear that complaint from him. Last i knew He started the dmax piston project with wiseco almost 3 yrs ago or so. As for the sound being different due to the pistons alone is bogus. Camshaft. Tuning. Clearances even compression ratio is way more likely than the piston.
 
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S

S Phinney

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Aug 15, 2008
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Dave c said:
My references about experience was not questioning marks overall building experience. But his experience with wiseco pistons. Yes there are others such as wade at ngm who have sold and built more wiseco pistons equipped engines than anyone here. Me as a customer have yet to hear that complaint from him. Last i knew He started the dmax piston project with wiseco almost 3 yrs ago or so. As for the sound being different due to the pistons alone is bogus. Camshaft. Tuning. Clearances even compression ratio is way more likely than the piston.
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I hate to say it brother but you are wrong about pistons in itself making a engine sound differently. Bowl design and material influence sound and tuning has to be changed to accommodate for this. In general timing in certain areas will be different(usually lower) for the engine to run properly and sound like it should.
 
moparkxracer

moparkxracer

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Jun 25, 2010
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I do not have these in mine. I can say my engine does have a different sound to it though. I'm sure someone on here has heard mine in person.
 
J

jkholder09

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Jan 8, 2012
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S Phinney said:
I hate to say it brother but you are wrong about pistons in itself making a engine sound differently. Bowl design and material influence sound and tuning has to be changed to accommodate for this. In general timing in certain areas will be different(usually lower) for the engine to run properly and sound like it should.
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I have to agree. The flame front slamming the piston and the resulting echo is probably the biggest factor that effects engine sound from the exhaust. The other being turbine wheel size and shape and exhaust system design.

Now the actual shape of the engine and valve cover etc will effect noise from the engine compartment.

The op would be doing everyone a favor to post a video of the sound.
Maybe some data like number of pilot injection pulses, timing, rail pressure, and temps.
There is a chance something will stand out and someone can be more helpful.
 
LWATSON

LWATSON

future trans limpers
Jul 30, 2008
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moparkxracer said:
I do not have these in mine. I can say my engine does have a different sound to it though. I'm sure someone on here has heard mine in person.
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I've heard the oval bowl Pistons produce a different tone, and your engine does sound different than the other built ones I've heard.
 
Fingers

Fingers

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Apr 1, 2008
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Now, I don't know Sh!t about pistons, but I can almost always tell when an engine is running forged. Besides the slap when they are cold, they tend to ring. The amount I am sure varies with piston shape and exact alloy used.

Take a forged and a cast piston. Tap each one. You will hear the difference.
 
PACougar

PACougar

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Jun 27, 2012
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Fingers said:
Now, I don't know Sh!t about pistons, but I can almost always tell when an engine is running forged. Besides the slap when they are cold, they tend to ring. The amount I am sure varies with piston shape and exact alloy used.

Take a forged and a cast piston. Tap each one. You will hear the difference.
Click to expand...

You lie, what do you know about this mumbo jumbo:hug:
 
DPC

DPC

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Jan 2, 2012
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I thought the OP was talking about fuel knock, not engine noise?? Fuel knock, from what I have seen, has its own very distinct sound and sounds nothing like piston slap or engine noise??
 
S

S Phinney

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Aug 15, 2008
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He is talking and a sound similar to a fuel knick on a gas aka detonation. Piston design will give a similar sound on a diesel if the tuning isn't right for the design. I experienced similar noise with the Arias pistons. It took less timing on the right places. Fingers even describes one fact if his pistons as hazing more than normal designs because if less surface area to keep heat in the process. The problems come up when guys make a change and need to change tuning to fine tune that overall combination.
 
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