Those with CZT engine kit and ALL others -- READ THIS!

[babyblueMX3]

ok guys,
remember my thread about my blown pistons ?
http://forums.probetalk.com/showthread.php?t=1701191391

and remember this one (specially post 17)?
http://forums.probetalk.com/showthre...ghlight=wiseco

well they were both related.

My pistons were hitting my valves all the time !!!
They kept hitting and with 20psi the piston wall? finally broke. As you can see in the pic the first link, ALL the pistons failed at the SAME EXACT plate. On the intake side. So I blame it on detonation cause I thought my timing was wrong (well myabe it was a little) but what I think is when the valve hit the wall, the wall was already thin, boost just killed that little piece. I didn't noticed at first because they were all broke and I couldn't see any valve damage (valves looks nice btw).

So I took the other head off (the rear one) and noticed one pistons was still in fairly good condition. So upon further inspection I noticed a mark on the intake valve pociket, I said to myself WTF, that's the same thing that has happened with the second thread). I started to look at the pistons damage and also noticed the valve mark. Take a look again at my first link and noticed in the third pic on the left side, you can see a little mark over there.

so those that are in the process of installing czt engine kit, BE CAREFULL.
I think Wiseco changed their pistons design not too long ago. So if your kit was purchase more than let's say 3-4 months, there are good chances you'll be stuck in the same boat as me.

You guys think I can get new or some of my money through Wiseco for this ? Obviously they know there was a problem with the pistons if they changed design

[TRWeiss1]

Damn dude, I'm really sorry to hear that. I purchased my Wiseco + Millenia S rod combo about 2 months ago, so I hope I'm ok. Definitely going to do my best to avoid that problem!

Edit :: On another note, I don't think you'll be able to get any money from Wiseco. As they state on their disclaimer as soon as you open the box w/ your pistons in it, they carry no warranty, and are not responsible for what happens after installation.

[mx6gt04]

Hmmmm.... still no so sure about that. My stock pistons broke the EXACT same way with detonation. Wiseco bases their piston crown off the stock design, and thats bad news. MUCH too thin of a cross-section

The lean charge will always affect the intake side, thats the concentration of the a/f mixture and thats where all the heat is.

[babyblueMX3]

what happened with janzz(sp?) pistons ?
the same problem happened to him, did he get his pistons changed ?

[FRCFD6]

Damn dude, I'm really sorry to hear that. I purchased my Wiseco + Millenia S rod combo about 2 months ago, so I hope I'm ok. Definitely going to do my best to avoid that problem!

Edit :: On another note, I don't think you'll be able to get any money from Wiseco. As they state on their disclaimer as soon as you open the box w/ your pistons in it, they carry no warranty, and are not responsible for what happens after installation.

you should still be able to get replacement pistons for free. thats a design flaw.

[mx6gt04]

It is possible. Thats weird either way. I slapped in some 300zx TT pistons and rotated the crank with the timing belt off, heads on with valves open, no contact. And that was with a different valve relief pattern and much smaller pockets, with a 2.5mm bore differernce. 1500 miles to boot on it

[TRWeiss1]

you should still be able to get replacement pistons for free. thats a design flaw.

I think I'm going to call Wiseco and try to get ahold of Brian there. That's the person that Jasbro and Janz dealt with when they had piston clearance issues. Apparently he admitted to a design flaw in late 2005 and said that it would be corrected, so I'm hoping he's a man of his word. In any case, I'm going to call and read them the specs on my pistons, just to be on the safe side.

[janz99]

Well, the problem i had wasnt that my pistons were wrong, it was that i had set the timing completly wrong on the engine, and the pistons hit the valves. So i had the heads re-built, then checked the clearance between the piston and valves when i had set the timing properly.

The clearance on my valves and pistons was WELL over .350" !! Thats a mile when were talking piston to valve clearance. When i checked my clearance, i had the machine shop make up a SOLID aluminum bucket/lifter, that was the same size as the stock bucket/lifter. I checked teh clearance on both the intake and the exhaust side.

Now i only checked it on ONE piston, but they should all be the same!

Your cams also make a diffrance when taking into account the clearance on the pistons/valves. If you have ze cams, they have higher lift, meaning they open the valve further, which in turn means the valve is getting closer to the piston top. If you had your heads milled this will also effect the clearance!

Keep us updated, im very intrested in this, as you know im also running the czt piston/rod combo!

Ryan

[mx6gt04]

you should still be able to get replacement pistons for free. thats a design flaw.

I disagree.

If it was enough to break FORGED pistons, youd have bent valves. Plus, that damage would have happened very quickly.. Im sorry, but that is clearly detonation damage. Especially the fact that it was on the intake side. Ask anyone who breaks pistons, always the intake side. I have broken several in my day, in a handful of different motors.

Had this happened on a bad tune, or bent valves, or made a mark on a piston, my take on it might change. Ever see an interference motor snap a belt? I did. It put DENTS in the pistons and molested the valves. Nothing broken or cracked though. A forged piston will dent long before it cracks. Cracking is from impact and heat (detonation) on an already poor design.

[babyblueMX3]

[QUOTE=mx6gt04]
Had this happened on a bad tune, or bent valves, or made a mark on a piston, my take on it might change.[QUOTE]

it made a mark on the pistons, all of them

[janz99]

Ya, when my valves hit the pistons, it bent the crap out of all my valves, but never cracked a piston. It made nice little circular marks though

I really think this is more of a detonation issue then an interferance issue!

Can you take better pics of the piston tops?? Its really hard to make out the marks your talking about?

Ryan

[mx6gt04]

Ya, when my valves hit the pistons, it bent the crap out of all my valves, but never cracked a piston. It made nice little circular marks though

I really think this is more of a detonation issue then an interferance issue!

Can you take better pics of the piston tops?? Its really hard to make out the marks your talking about?

Ryan

x2. I'd like to see these marks.

[babyblueMX3]

Ya, when my valves hit the pistons, it bent the crap out of all my valves, but never cracked a piston. It made nice little circular marks though

I really think this is more of a detonation issue then an interferance issue!

Can you take better pics of the piston tops?? Its really hard to make out the marks your talking about?

Ryan

I will do. I'll get them tonight
it didn't broked your pistons because you didn't run on it seeing how new your pistons were. run an engine with boost with that problem, it'll break trust me. Timing was good on my engine (mechanical timing)

[mx6gt04]

Just for clarification, what was the mileage on the motor before the 20 psi untuned meltdown?

Here is a pic of my detonated stock piston as well.

http://www.supermotors.org/getfile/2...e/Im001195.jpg

And that MSQ I sent you and you used, it was around 28 degrees timing under WOT. You didnt have a wideband either did you?

That map was for a smaller turbo, 700cc water/methanol injection, and 260 degrees charge temps (pulling 1 degree timing per 10 degrees IAT over 120)

[janz99]

Thats true. but trust me, if your valves were hitting your pistons, you would know it! Mine made a terrable noise when they were hitting! The car also wouldnt run properly, constantly stumbling and never ran for more then a few seconds.

Yes if it only hit SLIGHTLY it would still run, but you would probably still be able to hear it hitting!

But try and get some nice clear pics for us to see! It might make this alittle easier!

Other then me, you and Rayman, i dont know of anyone else that is using this combo of rods/pistons, or anyone that actually has a running czt engine other then MYSELF........

Ryan