pistons and other stuff...

[1992mx3]

After doing alot of reserch and a bit of impatiance I decited to go N/A for now with the possability of boost later. My question is, of all of you that have boosted and blown your stock engins how many actually fried your pistons? Not rods cause I read alot of posts about bent rods but can't find much on burnt or warpped pistons. and of those who were not running an intercooler? I was pondering about building my motor, DE block 10.1:1 pistons, kl31 101 1a1 heads, 210 cams, stock crank (balanced) and obviously square port intake and 67mm t/b. Money is not a real big issue cause I do not drive the car and don't have to. My thought is is to get eagle rods and get stock replacement 10.1:1 ZE pistons.

Your input is very welcom and appreciated thanks.

[SpatialTerror]

hmm i also have been wondering about how bad the kl blows with boost.
and i believe that the de and ze blocks are the same. im not 100% on this but i believe that the diffenences between the ze and the de are pistons cams and intake. other than that i dont know of any differences

[1992mx3]

your right about that but the only difference in the block is the parts, 9.1:1 DE 10.1:1 ZE but that was not my question. The over all question in when those who boost their stock motors and blew them was there any dammage to the "pistons" themselves. I know of a few folk's from reading almost every page on this forum who have blown their stock engines while boosting, but i can't remember or find but one person reporting their pistons warping, cracking or distorted. The one I remember had run something like 12psi with no inter cooler and the waterpump gave out aswell. or maybe that was two different folk's???

[wytbishop]

Generally speaking when a piston goes under boost it's due to a very lean condition at high boost levels. That's what causes the combustion temperature to skyrocket. A typical cause of that kind of thing would be an injector failure or sensor failure which causes the ECU to trim fuel. Have seen it on a few boosted B6's on other forums. It's not necessarily a B6 problem, it's an injector problem.

To my knowledge there are no real inherent flaws in the K engine family design. Very reliable engine.

[PATDIESEL]

Agreed, the K series engines are pretty reliable. However, most of the issues I have read about were rod or wrist pin related due to overstresses with boost and or boost spiking and timing.
The K series bottom end is a 4 bolt and the crank is forged so you are pretty clear there. Watch for valve float and breaking or cracking guides, upgrade the rods and pins.
A NA build is completely different than a turbo build so I would stick to one or the other. Otherwise expect to loose money when you go to sell your NA build stuff in favor of turbo build parts.

[1992mx3]

Well I will be running N/A for awhile but my intentions are to go boost at some point and that is why i want to build a strong motor up front. I do NOT plan on trying to get 350/400hp. I would be just fine with 250/300hp range. I think pauter rods, forged wrist pins, stock replacement 10.1:1 pistons, ZE heads with new springs and retainers, 210 cams, 280cc injectors and MS boosting 7 to 10 psi will get me close to where I want to be and not have to worry to much about blowing the motor. Besides My build will be alot about re-designing the MX-3 trying to to bring it to the 2000's using only Mazda parts either factory or aftermarket. This is my plan and not to worry I love the basic design of the mx3 so the body will not get a crazy ugly update. When I get the info that I need and start I'll post in the worklogs section. Thanks for the info given.