VP pistons in a 12v???

turbominivan

turbominivan

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May 5, 2013
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has anyone done this and what are your thoughts on it?

i have a 12v in a rat rod that i broke the edge off of #3 the other day.

i have a full set of 24v VP pistons i was thinking to swap in.

is this worth while? bad idea? im kinda new to the internals/combustion aspect of things.

my current issue....

IMG_0246.jpg


VP piston on the left, 94 12v piston on the right.

IMG_0346.jpg


the reason im considering this is because of the VPs larger bowl, as well as its thicker top ring land (its about 3/32" larger between the face and the top ring groove... from my eye balls best measurement)

my general specs are in my sig below if that helps deciding factors. i know there is alot that goes into deciding on a piston design that works best, just looking for info on what others have done and why, with what set up.
 
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You can also get custom injectors made to work with a 12V head but that's expensive.
 
With decent timing it will work, even just dropping it in. I would rather see the bowl delipped however. An ever better setup would be 04-07 pistons with a 155° injector, but that would loose the top ring landing gap your looking for.
 
if i remember right, i think im running 23* or 25* timing.

what about cutting the 12v bowl open a bit? i hear of people doign this but im not sure of all the reasons for it. perhaps i should look into this?
i have a theory in my head about using an old piston as a 'jig' and being able to use a router and cut all 6 pistons open the same while they are still in the block.
 
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I have had that discussion before. Seems a narrower cone angle performs better on the engine dyno, but the wide angle still performs on the track. Hard to get accurate testing done on the track however (sled pulling). Had talked about maybe it was something to do with loading the motor differently. Maybe its the high timing/narrow angle with over fueling that is the benefit.

I have been playing around some with similar bowl designs to the 04-07 with wider angles with mechanical injection, and "most" are doing well. Maybe I can get better measurable results running at the drag strip this summer, but until then I cant prove anyone wrong or right.

Care to elaborate on your findings at all on the subject?
 
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I enlightened you once before, you then took that info and started a business based on it, seems rather foolish for me to do so again.
 
thanks, but im all the way up in canada and i have some good friends with a bunch if i need.
this is why im trying to see what options are out there. i have access to a few different factory styes that i could go with.
 
I would give the VP pistons a try with the 12V head. If it doesn't work well your really not out much. We have piles of different pistons to try.

I even have that 6.4L engine we could drop in buddy.:poke:
 
can anyone give me general pros vs cons to opening up the factory 12v pistons?
i know compression ratio will drop allowing for more timing, and making it a bit harder to start (thats ok with me), but will it create higher EGTs and so on?

from what i read and have gathered, the main advantage is that you can run higher timing safely.

im just trying to gather is his is something worth doing while its open, or should i just put it back together and go with it?

i dont usually like like putting things back together without moding something, or at least having a few bolts left over. =)


also, what brand of head gasket do you guys use? my head is O-ringed.
 
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Seems to me that it would be easier to just get non i/c/marine pistons and throw a set of 155s in the head and be done. Rather than the trial and error of trying to find just the right angle and timing advance to make it run well with 24v pistons. The non i/c/marine pistons with 155* SAC nozzle has been a proven setup when it comes to producing power. What exactly are you trying to accomplish with this motor?

As was mentioned above, you COULD have 12v injectors modified to complement the 24v pistons. However, if you're willing to spend that kind of money, why not just buy a replacement set of 12v pistons?
 
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Watching for later. I have seen A few 12v engines with cr pistons. Wasn't sure if it had much benefit
 
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