i knew that was a reason to cut them for lighter weight, but i thought you was talking about compression when you was saying to flycut them, it also helps drop the compression a little when your talking about a BIG boost motor Johnny, though with a .010 longer rod you dont loose much compression, cutting the skirt down too much causes piston rock and ring flexing, and will lead to broken rings or scuffed cylinder walls. you can cut factory LBZ pistons all ya want but it cant compare to a special built custom designed racing piston. factory pistons are also hollow compared to the racing pistons.

 

It does reduce the compression slightly or even quite a bit if you want, which seems to be the trend for purpose built diesel race motors making big boost. There are ways to regain the compression if desired. We do have purpose built race pistons and rods for the DMax. Nasty Girl is running the fly cut LBZ pistons. Actually most factory pistons are Hypereutectic which is not hollow but they do provide some flex.

 

the LBZ's dont have the oil cooling chamber under the bowl like the LLY's??? i know there are purpose built pistons and rods for the Dmax, they arent cheap thats for sure.

 

Yes, but the LBZ's are a little beefier. So far it seems that the best combination is to use the LB7 block, pistons, and rods with the LLY heads.

 

Now this is what I am talking about. THANK YOU

 

dont get all weiner rubbin happy on us noproblem.

 

, wouldnt it be easier to just make pistons rods out of a super light titanium alloy.

but then again, making them would be a pita, and paying for the would be 10x worse

 

I like my LB7 SO MUCH, Im just gonna use ALL of it!!!!!! ALL the Time.

Anybody out there with a LBZ and wants to do a little parts swapin, let me know. But im keepin' my block and all that other cool stuff they said

 

I missed this post somehow and boy did that have me lost.

I remember hearing about this stuff now. Shaving down the piston faces and playing with the rod lengths to get that "perfect" compression ratio depending on what you're running and what you're using it for. I had no idea that shaving the face would affect lateral movement and all of that though.

It's interesting stuff.

I'd take a guess you probably couldn't shave a diesel piston skirt much before it would try turning sideways on you. Are guys doing anything like cross drilling the skirts though?

 

I'm quite sure the new Crower and TTS rods have a titanium blend but the price really goes out of the roof and isnt feasible unless your running a full race application.

The main objective is to be able to run a hotter cam, increase RPM's, and reduce engine load. The compression ratio can remain stock by using a thinner head gasket that offsets the amount of piston shaving that was done but most of the time you want the reduced ratio in this application. A draw back is that now your using a longer con rod which increases loads at the moment of inertia points (ie. at the end of each up and down stroke). There are a few different methods that are used when modifying pistons. You can fly cut reliefs so you increase your valve to piston ratio to run a cam with longer duration and lift, you can shave the piston head down to reduce the compression ratio and loose some mass while maintaining the stock cam configuration, or you can do both. When you shave the head your shortening the piston which reduces the amount of side loading and increases the reaction speed but also weakens the pistons tensile strength and increases the point of yield because it now flexes more. Some have tryed shaving the skirts with mixed results and some catostrophic.