Piston Weights

As I had to install new pistons, I was a bit worried that it would ruin the balance of the moving parts. So, before taking the old pistons to the machinist, I weighted them. After getting them back, I did a comparison. These weights contain the piston, pin, rings and connecting rods.

Piston	1:	2:	3:	4:	5:	6:	7:	8:
Old	1374 g	1370 g	1379 g	1376 g	1377 g	1370 g	1374 g	1373 g
New	1377 g	1375 g	1381 g	1378 g	1378 g	1372 g	1378 g	1375 g
Difference	3 g	5 g	2 g	2 g	1 g	2 g	4 g	2 g

Wow, only a few gram difference in each piston. I think I'll call a professional and ask if that makes any difference. Most likely not as, according what I've read, they didn't even balance the moving parts in the factory and my engine would not see high RPMs.

And just in case someone is interested, I also weighted just the new Sealed Power hypereutectic pistons and pins. They were between 750 and 753 grams. And for the new piston rings:

1st pressure ring	2nd pressure ring	Oil ring
17 g	20 g	22 g

Block Party

It took a bit longer than expected but I got the block back from the machinist yesterday. I drove to Koneistamo Aaltonen in Mäntsälä and we went through the work that had been done. They had bored and honed the cylinders, cleaned the block, replaced the cam bearings, checked the head surfaces for straightness and checked the crank line for straightness. In addition to the work with the block, they inspected the connecting rods and replaced the pistons.

I also brought my new Comp Cams XE250H camshaft with me so they could check that it fit correctly. The cam was installed in the block but rotating it was harder than expected. The cam was inspected and found to be a few hundredths twisted. They straightened it and got it turning properly.

After getting all the parts to the garage, I checked the basic stuff. The block itself looked fine and just needed some paint.

The piston rings that I had bought were molybdenum faced and the cylinders had been honed appropriately. With moly rings the honing stone must be much finer as they do not need the coarse walls to hold the oil. Everything was good in that front.

Then I made sure that all the cam bearings had been installed correctly. Their surface was nice and you could see their oil hole through the main bearing channel.

Next came the pistons. I measured their weight and visually inspected all of them. I did notice that the wrist pin clips had not been installed. I'll have to make sure they are needed and then squeeze them in.

My crank had already been machined earlier. All the bearing surfaces seemed perfect. I'll just have to measure the clearances later.

After these basic checks I can start planning the actual assembly.