Yep, big fan of rowing my own gears. I'm not really into drag racing so I wouldn't hold my breath waiting to see how it runs the quarter. However if someone wants to donate some axles and the guys at FFTEC have time to run it before shipping it back I'm good with that. ;)
No prob, I understand.
These high boost little engines are a whole new world to me...just eager to learn something new and compare to the low boost/nitrous/NA stuff I'm used to. Hell, I haven't even bought a car yet. Trying to finish a couple restomod projects up, one mine and one for a friend, and kinda waiting for some people to do some 'fatigue testing' on these stock short blocks before I commit.
I'm too conservative w/ my wallet to be a guinea pig on stock parts, and not rich enough to do what dragon's doing...
I thank you again and agree with you 100%. My last drag car started out as a four speed which was a blast on the streets (corvette thumper) but it (yours truly) sucked at being consistant at the track.
I love a good Auto on the Track too.
It appears that way to me. It looks like just a small amount of the minor thrust surface was machined away...not a 'true' asymmetric design, but would save a small bit of friction and weight.
Where it appears to have been a full skirt piston that's been machined, would that not affect the load support of the piston? That's kind of what I was wondering. What, if any, implications are gonna be present from going that particular route?
Shouldn't be any, they machine only the minor thrust side of the piston so as long as they are installed facing the correct way where the non machined side is the major thrust side, the slightly less surface area of the minor thrust side will still encounter a force per cm2 far less than the major thrust side
W/ how little is gone, I don't believe there will be any load issues. Most of the surface is still there, and it still has the same 'depth' as the piston was produced w/. Note that this surface is not nearly as loaded as the other.
Always a great read as I'm a huge fan of Asymmetrical pistons. Unfortunately machining the minor thrust side to be smaller than the major thrust side doesn't really get you the benefit of a true asymmetrical piston that was designed as such. They decreased the weight of the piston, and slightly decreased drag on the cylinder. However they lost the load support of a true full round piston. Full round pistons distribute force around the outside of the piston hence the lack of center skirt bracing as shown in the link you provided above.
It doesn't appear this piston has that portion machined...are you sure this piston is a 'full-round' w/ the ring of material below the pin to begin w/? I looked it up in an older Manley catalog and it has it, but it could be a generic picture. Found an online seller showing a pic that doesn't have it, but again, could be generic photo.Always a great read as I'm a huge fan of Asymmetrical pistons. Unfortunately machining the minor thrust side to be smaller than the major thrust side doesn't really get you the benefit of a true asymmetrical piston that was designed as such. They decreased the weight of the piston, and slightly decreased drag on the cylinder. However they lost the load support of a true full round piston. Full round pistons distribute force around the outside of the piston hence the lack of center skirt bracing as shown in the link you provided above.
As you can see in this Asymmetrical vs Full-Round piston picture below they introduced structural integrity for the skirt by adding center support bracing.
As mentioned above, machining the full round piston doesn't net you some of the other benefits of an asymmetrical piston.
- Shorter wrist pin
- Offset wrist pin
- Contoured crown
- Friction reduction
- Weight reduction
The offset wrist pin is another key component, when JE reduces the size of their skirts they move the wrist pin towards the major thrust side with the wider skirt. They move it to make up for the new center of balance. The Manley piston has an offset wrist pin as well, but only to assist in stroke engine dynamics and as a center of balance for the design they intended.
Here is another good read: http://www.jepistons.com/Articles/101124-Asymmetrical-Forged-Pistons.aspx
I don't think there will any catastrophic failure with their machined piston, but it's better to utilize a piston designed for it's intended use instead of making modifications to a shelf stock piston.
Why would the pin need to be offset more than it already is if this is not a true asymmetrical piston and very little weight has been taken out?
Because that is how piston designing works. You want to have the pin located as close to center balance as possible. Again, it was outlined in the links above.
