I will slightly disagree with Tom. The wear limit is for the old piston with the old rings. If you put new rings in with the excessive clearance you will wear out the pistons very quickly with the increased "bite" of the new rings. I've also found that my old rings often have smaller end gaps than new rings. I would either use all old or spring for new pistons.

-Andy

I got the spare motor in yesterday but noticed it's missing an oil return tube so I've got one on the way.

On my motor, I'm waiting for my stud removal tool to arrive so I can remove the head studs and split the case. All the other parts are here ready to go.

http://img831.imageshack.us/img831/9...ugsmotorin.jpg

Uploaded with ImageShack.us

Disassembly is complete. One of the cams has a pretty sizable pit in it and there's a spot in the case that looks strange.

Here is the cam wear in the lobe closest to the center of the picture. There's actually a little chunk missing there.

http://forums.pelicanparts.com/uploa...1304285735.jpg

Are these stripes normal?

http://forums.pelicanparts.com/uploa...1304285788.jpg

Here is the spot in the case.

http://forums.pelicanparts.com/uploa...1304285761.jpg

The spot in the case is normal, they all have that. It is a core print from where they cast the case and wanted to put a steel insert in it, so had to support it with some sand that took up space that Aluminum would otherwise occupy.

The cam looks like the rockers have been too tight and dragging all the way around the cam, that will burn vlaves.
The small nick in the lobe doesnt really affect the lift because the rocker still has the other 90+% to lift it. The nicks are being blamed on the lack of ZDDP in the oil. As long as you havent lost the whole face from running without oil on the lobe or gouged a face completely I would just put it back to work.
Bruce

I got the case pretty clean and the heads are coming along.

My arsenal of chemicals:

http://forums.pelicanparts.com/uploa...1304605177.jpg

http://forums.pelicanparts.com/uploa...1304605203.jpg
http://forums.pelicanparts.com/uploa...1304605227.jpg

And my homemade (not by me) wrist pin circlip injector.

http://forums.pelicanparts.com/uploa...1304641963.jpg

Got the case back together today.

http://forums.pelicanparts.com/uploa...1304733928.jpg

Looking good..
Bruce

Ps and Cs back on and I'm waiting on the heads to return now.

http://forums.pelicanparts.com/uploa...1305245363.jpg

I was having trouble lining up the wrist pins with the rods and came up with a little trick to help get them started. I pushed the pin in far enough so that it stuck out just a little which allowed me to get it started into the rod. I could then hold the cylinder in place while putting a little pressure on the rod/pin so that it wouldn't move. Then I just tapped the pin in far enough to engage the rod, then all the way in using the end of a screwdriver as a drift.

http://forums.pelicanparts.com/uploa...1305245652.jpg

I'm trying to calculate the compression ratio. Feel free to point out any errors.

V1= 2994/6 = 499
V2= Pi (R*R)(1.31) = 3.14*2256.25*1.31 = 9.28 1.31 is my current average deck height as measured in four spots on the piston.
V3= 86 Measured with the standard burette/plastic circle/alcohol method.
V4= 31.9 I raised the piston in the cylinder until the dome was even with the top of the cylinder, then added fluid until the top of the dome was just covered. I subtracted this measurement from the theoretical volume if it were a flat-top piston. Shouldn't this number be a standard within the same type of piston?

CR = V1+V2+V3-V4/V2+V3-V4

499+9.28+86-31.9/9.28+86-31.9 = 8.87 and it's supposed to be 9.8.

How can that be right? 0.020" came off the heads and I only added 0.25mm to the deck height.

If that's the head above that they took .020 off the sealing surface make sure you check a cylinder on that head. Usually you have to cut the same amount off the complete head casting surface or its going to hit the cylinder fins.

More calculations...

If I use the same formula and a stock head volume of 90, 1.0 deck height, and my calculated 31.9 piston dome volume, I get a CR of 8.66.

Using my calculated head volume of 86 after machining, 1.25 deck height, and the same 31.9 piston dome volume, I get 8.92.

Using my calculated head volume of 86 after machining, 1.0 deck height, and the same 31.9 piston dome volume, I get 9.16.

Maybe my piston dome volume is incorrect? If I use a stock head volume of 90, 1.0 deck height, and a compression ratio of 9.8, solving for the piston dome volume yields 40.31.

Using 40.31 as V4 with deck heights of 1.0, 1.25, and 1.5 I get CRs of 10.4, 10.14, and 9.85.

Is the piston dome volume not a standard value just like the cylinder bore, stroke, etc?

FWIW

When I built my 3.0 RSR spec motor here are the volumes I found.

v1= 499
v2= 8 (1.1mm deck ht)
v3 = 84 (heads flycut from the stock 90 cc size)
v4= 40

This gave a CR of around 10.3 with the flycut heads and would have yielded a CR of 9.8 with stock heads.

Your piston dome volume seems to be too low. Try rechecking it.

What type of piston was that? RSR?

Mine were Mahle Motorsports RSR pistons

http://forums.pelicanparts.com/uploa...1305682938.jpg

I realized I was filling up the cylinders too much while trying to calculate the piston dome volume. After performing the measurement correctly, I was coming up with right around 40 routinely.

I removed the pistons and cylinders so that I can install 1mm cylinder base gaskets in order to keep the compression ratio where I want it. Thanks for everyone's input. On we go...

Where did you get 1mm cylinder base gaskets?

I'm currently looking at a need for 2mm, I think, to get the piston/head clearance I need, or will have to have the edge of the piston dome cut some, after I cc things and recheck my solder squish figures.

EBS has 1mm and there is another company that will make custom ones for you. They are called Flatoutgroup.com and the best way to do it is for you to call first then send them one of your gaskets so they can make the correct pattern. I talked to them about a week ago when I thought I was going to need a 0.75mm gasket.

2mm is a lot to shim. I don't know what all is involved or what it costs but having the pistons cut may be a better option that might allow you to avoid problems with your chain housings, but maybe you've already dealt with this.

Are you coming to Watkins Glen?