Well last winter I bought a set of 12:1 compression pistons from Monkey Wrench Racing (they custom designed/ordered them from Wiseco). I have two 2zz engine's so I built the 2nd one with the 12:1 pistons. Here are some pictures of pistons and them in.
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Look how shiny those cylinder walls are
I ran the car on 94 octane (we have a few stations here that carry it), well I started running the pistons and gave them a good 2000 km brake in period (I put the power fc to fuel cut at 4500 rpm's that way I wouldn't rev them high before brake in was done). At first the knock sensor levels were a bit higher then the stock pistons were, but weren't anything significant, forged pistons are more "noisey" then stock cast ones and that will be picked up on the knock sensor. During brake in the pistons slowly registered more and more on the knock sensor. So I called up MWR and talked to Matt, he said that "forged pistons make more noise then stock cast pistons and it's "normal it's just regular piston slap".
By the end of the brake in period I was getting really really high knock sensor level from the Power FC which I never got with the stock pistons. So I continued to tune and tried everything to get the knock down an couldn't. So I went out and got some VP racing 103 unleaded gas (thats 103 mon which is equal to 108 at the pump ((mon+ron)/2)) and ran the car, below is what I got for knock numbers from the power fc with the vp 103.
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All of the knock sensor readings was piston slap noise, in the entire time in this chart with the VP 103 gas I never went to full wide open throttle and the car was running on the rich side with conservative timing. There was almost no difference between the knock number on 94 octane and the knock numbers on the vp 103 octane gas.
So we pulled the head off and the inside of the engine on the front and back walls were totally scared to hell. The pistons were warn and scared and were no good after less then 2500 km. The sides of the walls were fine just the front and back were messed up. Here are pic's
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You can see the wear strating from the tip of the piston skirt (on every piston), their use to be little lines all the way down the skirts that were worn completely smooth, and you can see the virtical scratches in the piston.
So we pull the pistons and put the stock pistons back in, we pressure tested it and the best cylinder was 13 psi low and the worst cylinder was another 14 psi lower then that (27 psi low). The block was in perfect condition before and pressure tested great. So with the block fubared with scratches we took the car for a run to see what sort of knock levels we would get with the stock pistons, and this is what we got.
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Way less knock with the block fubared and stock pistons and I was going WOT on and off trying to make as much knock as possible.
So I contacted Monkey Wrench (talked to Matt again) racing and they instantly started to blame me and that I must have installed them incorrectly. They basically told me to F off. I offered to show them the knock sensor readings and pictures, they didn't want to see any of it they just told me that I must have done something wrong.
Getting nowhere with MWR I called up Wiseco pistons and talked with them, they wanted to see the pictures and the knock sensor readings. So I sent them off to them, after that they determined they need to see the pistons themselves and analyse them, so I sent 2 of the pistons in to them. They came back and said "I've got quite and analysis. There's a lot to it, but basically it calls for us to change the skirt profile", they said that the 12:1 and 11.5:1 pistons skirts need to be redesigned, but they felt that the 8.8:1 (low compression pistons) had a good skirt profile on them and they wouldn't suffer the same problem. So Wiseco custom make me new pistons with a redesigned skirt profile and sent them to me for free to replace the ones I bought.
But now I still have to buy sleaves ($350 us) for my engine and get a machine shop to put them in ($600 us). I thought that since Monkey Wrench Racing custom ordered/designed these pistons and sold them to me with the description of;
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LOOK they specifically say; "They are designed for tighter piston to cylinder clearances then other aftermarket pistons to MINIMIZE PISTON SLAP AND CYLINDER BORE WEAR."
They should help with the cost to repair the block, and with Wiseco admitting that it was a design flaw and sending me new pistons for free that MWR would look at the evidance now and come to a fair solution. I thought a resonable solution would be a free set of sleaves from MWR (since they sell them) so that I can get my engine repaired and I would pay the machining cost. So I called MWR and talked to Matt again, and he gave me the same storey as before, MWR thinks it's something that I did wrong, and didn't want to see any of the pictures, knock sensor data, or e-mails from Wiseco. Matt even accused me of "over reving" the pistons, I said I didn't but also didn't realise that the MWR pistons had a rpm limit to them, he said they did it was the stock 8300 rpm (which I never even went upto because I had way to much knock readings).
1) So a warning to any one with the MWR 11.5:1 or 12:1 compression pistons, you should be running sleaves in your engine to run these pistons
2) I would like everyones help on this to let Monkey Wrench Racing know that if they are going to claim that the Money Wrench products are superior and well designed that they should back it up and that what they did here is not acceptable. Please call them at (248) 624-9820 or Fax them at (248) 479-0775 or e-mail them at [email protected] and let them know this isn't right.
*EDIT*
MWR did nothing to try and identify or rectify the problem, in fact they did not want to see any of the information in this case at all. Which is one of the most alarming facts, for a company that is making new custom parts to turn a blind eye to a potential problem with their product. To not even look at pictures or investigae what the actual cause of the problem, that is not only turning their back on me but on every customer that bought these pistons. Who knows what other problems other customers had with their products and they refused to hear them or see picture. They may have people calling up with problems with any number of the custom product (valves, springs, pistons, sleeves, flywheels, etc) and I would be shocked if they treated them any better then they treated me. That is not the way to run it, MWR should have atleast investigated the problem to see if there were any design flaws in the product, not just instantly blame the customer.
Look how shiny those cylinder walls are
I ran the car on 94 octane (we have a few stations here that carry it), well I started running the pistons and gave them a good 2000 km brake in period (I put the power fc to fuel cut at 4500 rpm's that way I wouldn't rev them high before brake in was done). At first the knock sensor levels were a bit higher then the stock pistons were, but weren't anything significant, forged pistons are more "noisey" then stock cast ones and that will be picked up on the knock sensor. During brake in the pistons slowly registered more and more on the knock sensor. So I called up MWR and talked to Matt, he said that "forged pistons make more noise then stock cast pistons and it's "normal it's just regular piston slap".
By the end of the brake in period I was getting really really high knock sensor level from the Power FC which I never got with the stock pistons. So I continued to tune and tried everything to get the knock down an couldn't. So I went out and got some VP racing 103 unleaded gas (thats 103 mon which is equal to 108 at the pump ((mon+ron)/2)) and ran the car, below is what I got for knock numbers from the power fc with the vp 103.
All of the knock sensor readings was piston slap noise, in the entire time in this chart with the VP 103 gas I never went to full wide open throttle and the car was running on the rich side with conservative timing. There was almost no difference between the knock number on 94 octane and the knock numbers on the vp 103 octane gas.
So we pulled the head off and the inside of the engine on the front and back walls were totally scared to hell. The pistons were warn and scared and were no good after less then 2500 km. The sides of the walls were fine just the front and back were messed up. Here are pic's
You can see the wear strating from the tip of the piston skirt (on every piston), their use to be little lines all the way down the skirts that were worn completely smooth, and you can see the virtical scratches in the piston.
So we pull the pistons and put the stock pistons back in, we pressure tested it and the best cylinder was 13 psi low and the worst cylinder was another 14 psi lower then that (27 psi low). The block was in perfect condition before and pressure tested great. So with the block fubared with scratches we took the car for a run to see what sort of knock levels we would get with the stock pistons, and this is what we got.
Way less knock with the block fubared and stock pistons and I was going WOT on and off trying to make as much knock as possible.
So I contacted Monkey Wrench (talked to Matt again) racing and they instantly started to blame me and that I must have installed them incorrectly. They basically told me to F off. I offered to show them the knock sensor readings and pictures, they didn't want to see any of it they just told me that I must have done something wrong.
Getting nowhere with MWR I called up Wiseco pistons and talked with them, they wanted to see the pictures and the knock sensor readings. So I sent them off to them, after that they determined they need to see the pistons themselves and analyse them, so I sent 2 of the pistons in to them. They came back and said "I've got quite and analysis. There's a lot to it, but basically it calls for us to change the skirt profile", they said that the 12:1 and 11.5:1 pistons skirts need to be redesigned, but they felt that the 8.8:1 (low compression pistons) had a good skirt profile on them and they wouldn't suffer the same problem. So Wiseco custom make me new pistons with a redesigned skirt profile and sent them to me for free to replace the ones I bought.
But now I still have to buy sleaves ($350 us) for my engine and get a machine shop to put them in ($600 us). I thought that since Monkey Wrench Racing custom ordered/designed these pistons and sold them to me with the description of;
LOOK they specifically say; "They are designed for tighter piston to cylinder clearances then other aftermarket pistons to MINIMIZE PISTON SLAP AND CYLINDER BORE WEAR."
They should help with the cost to repair the block, and with Wiseco admitting that it was a design flaw and sending me new pistons for free that MWR would look at the evidance now and come to a fair solution. I thought a resonable solution would be a free set of sleaves from MWR (since they sell them) so that I can get my engine repaired and I would pay the machining cost. So I called MWR and talked to Matt again, and he gave me the same storey as before, MWR thinks it's something that I did wrong, and didn't want to see any of the pictures, knock sensor data, or e-mails from Wiseco. Matt even accused me of "over reving" the pistons, I said I didn't but also didn't realise that the MWR pistons had a rpm limit to them, he said they did it was the stock 8300 rpm (which I never even went upto because I had way to much knock readings).
1) So a warning to any one with the MWR 11.5:1 or 12:1 compression pistons, you should be running sleaves in your engine to run these pistons
2) I would like everyones help on this to let Monkey Wrench Racing know that if they are going to claim that the Money Wrench products are superior and well designed that they should back it up and that what they did here is not acceptable. Please call them at (248) 624-9820 or Fax them at (248) 479-0775 or e-mail them at [email protected] and let them know this isn't right.
*EDIT*
MWR did nothing to try and identify or rectify the problem, in fact they did not want to see any of the information in this case at all. Which is one of the most alarming facts, for a company that is making new custom parts to turn a blind eye to a potential problem with their product. To not even look at pictures or investigae what the actual cause of the problem, that is not only turning their back on me but on every customer that bought these pistons. Who knows what other problems other customers had with their products and they refused to hear them or see picture. They may have people calling up with problems with any number of the custom product (valves, springs, pistons, sleeves, flywheels, etc) and I would be shocked if they treated them any better then they treated me. That is not the way to run it, MWR should have atleast investigated the problem to see if there were any design flaws in the product, not just instantly blame the customer.
