A long time ago I had started to write up a comparison between MTC and Wiseco pistons. I had the idea to dig into it when someone had posted about one being better than the other. Later on I dug into it a little and made a post. I had save my text file, so let's start with this...
The two pistons are both 83mm 8:1. These are just factory stock parts. In the following, you can see the MTC is on the left, center is Wiseco and right is a stock GS1100ES (for most of you I guess this is a GSX part)
I use an upgraded tool steel pin and buttons for the MTC. The Wiseco used clips. The following shows the side view of the MTC tool steel left, stock center and Wiseco right.
Attachment:
wristpins1.jpg
I actually had APE make me some other pins that I have been using that are also a tool steel.
Using a Denver Instruments scale, the Wiseco weighs 365 grams and the MTC 399 grams with the pins and clips/buttons. I used the upgrade tool steel pins from MTC when I made the measurement.
Next I just took a few measurements of the two parts. If I measure the two pistons from the thinest part of the skirt, the Wiseco and MTC both measure 0.090. The amount of the skirt that is that thin is not in the same for the two pistons. Looking at half of the piston, the Wiseco's skirt is 0.090 for about 3.3" where the MTC is only this thin for about 1.1".
The following pictures show the Wiseco on the left and MTC on the right.
I was trying to get some ideas as to the material the two companies had used. I started out running a Rockwell B scale looking at 4 data points on the skirt of each part. The Wiseco has a hardness of 64.8 and the MTC 67.2.
Looking at some different kinds of aluminum, and their Rockwell B hardness:
2011-T2 B60
2024 B75
6061 B60
7075 B87
Very similar but if you know anything about metals, there is a lot more to the story. Before we dive into it too deep, it's time to have some fun. I was given one big ass industrial type Porter Cable saw for Christmas. It was found in a house fire that was being tore down. It was a little melted and needed a few parts but worth the investment. I love this thing as it's such a destructive tool in the wrong hands.....
Armed with the Porter Cable, I chucked the pistons into a vice and proceeded to chop them up. The MTC part above was brand new, but I have learned how to turn these into ash trays and had a few spares for this. The one I chose had the rings melted into place. The Porter Cable does not care. It goes through anything like butter.
I started by cutting the skirts off then slicing the top in half. As you can see from the following picture the Wiseco (left) is much thicker than the MTC part (right).
To analyze the two parts further, we need some real equipment. There are a few ways to figure out the details but we will use a glow discharge atomic emission system.
Using my trusty belt sander I ground the bottom then flattened it out on a standard grinder. The Wiseco is on the left, MTC right.
The small spots are from the sputtering process during analysis. We assume that with these both being a forged part that the material is homogeneous. A few sample points were taken to prove this.
Starting with the Wiseco we can see that the piston is made of the following analytes:
Al2 (%) 84.1 Aluminum
Si (%) 12.7 Silicon
Mg (%) 1.08 Magnesium
Cu2 (%) 0.890 Copper
Ni2 (%) 0.780 Nickel
Fe2 (%) 0.282
Mn (%) 0.0177
Sr (%) 0.0200
Zn (%) 0.0314
Ti (%) 0.0523
V (%) 0.00958
Cr2 (%) 0.00379
I understand that Silicon would not normally be seen in a wrought material. Using MATWEB.COM which is a free library of materials, we can see there are a few different materials that match up with our Wiseco part. 339 is very close, but we know the part was forged. So check out 4032.
Aluminum, Al 81.1 - 87.2 % 81.1 - 87.2 % As remainder
Chromium, Cr <= 0.10 % <= 0.10 %
Copper, Cu 0.50 - 1.30 % 0.50 - 1.30 %
Iron, Fe <= 1.0 % <= 1.0 %
Magnesium, Mg 0.80 - 1.30 % 0.80 - 1.30 %
Nickel, Ni 0.50 - 1.30 % 0.50 - 1.30 %
Other, each <= 0.050 % <= 0.050 %
Other, total <= 0.15 % <= 0.15 %
Silicon, Si 11.0 - 13.5 % 11.0 - 13.5 %
Zinc, Zn <= 0.25 % <= 0.25 %
Next we run the MTC part and again turn to the database for a match. The 2618 seems to be the material of choice.
As we look through the properties, we can see that the strength of the 2618 is higher than the 4032. This may help explain how MTC can make the dome thinner than the Wiseco part.
As to which piston is really better, I will let you make that choice yourself.
