A Little Wide

[Donny M]

Don't you think

I knew better but Rose's hood came off yesterday anyway While the hood was off the head was calling my name so it too came off. While the head was off the pistons started complaining that they were being ignored so they too came out.

Rose was suffering from a case of blow-by. Since she is a 77 she does not have the pseudo PVC valve breather tube. Rose has always had good power but the blow-by was really starting to annoy me. As I pulled each piston, I found that all the ring gaps were aligned with each other on the thrust side of the pistons. The ring gaps should be 90 degrees from the thrust and 180 degrees from each other, so much for that, here's a couple of pictures of the ring gap for the oil contol ring in #2 (the other 3 are simular)

Ring gap at the top of the cylinder after carbon removed:


And down 1.25"


Near as I can measure the top gap is .102" and the gap near the middle is .104".

This engine will get a hone and some new rings then... I'll let er buck

[Boss Hog]

The block seams to be in very good shape Donny, you get the ring gaps where they need to be It want buck much
David

[kinelbor]

Thats a huge end gap! Wonder if I have the same problem with my Cub.

[George Willer]

Donny,

I don't see any noticeable ridge. Do you know whether one has been removed in the past or whether the wear is all in the rings? Have you miked the bores?

You already know my feelings about using oversized rings so the ends can be filed to get minimum ring gap if there's cylinder wear. Those gaps look wide enough to be standard rings on oversized pistons.

[cowboy]

Hi Donny

My dealer lists STD and +.010 as the same part #. I had to go to +.020 to be able to get enough to file my end gap down to the the correct gap.

Keep on keeping on my friend

Billy

[Donny M]

Donny,

I don't see any noticeable ridge. Do you know whether one has been removed in the past or whether the wear is all in the rings? Have you miked the bores?

You already know my feelings about using oversized rings so the ends can be filed to get minimum ring gap if there's cylinder wear. Those gaps look wide enough to be standard rings on oversized pistons.

Funny you should ask When I first pulled the head, I saw a pretty good ridge that turned out to be carbon. But when I first saw it I put the mic to each cylinder. I about started to cry when each of them mic'd to 2.636-2.637. I was really bummed until I scraped the carbon off the top of the pistons where I spied a stamp that looked something like this 010 The pistons are indeed .010 over as are the cylinders Each piston mic's around 2.634-2.635. I'll be in good shape getting .020 over rings and filing the gaps. The worst thing about this project will no doubt be drilling out the bolster plug the rest of the way.

[Harold R]

Maybe I forgot to mention it, but Roland donated his surprisingly "standard" pistons to Frankencub. It replaced the fire crater pistons when I broke one installing it. The flat-tops soaked for about 2 weeks in solvent before I could get the old rings off. I ended up using one compression ring from Roland as well to replace the one that broke with the aluminum piston. I went through them checking them in each cylinder to find the smallest gap. I ended up with one at about .008 in the #4 hole......so there it went. Works like a champ! It's just amazing how resilient some of these old parts are.

By the way.......I have three good standard fire crater pistons......if anyone has a need.

[drspiff]

Hey Donny! I just met one of the account managers for the Case dealership here in Bryan. He seems to think that he can get Case parts if we give him the part number, and he might be interested in getting a Cub. He has two small boys that are mad about tractors.

If you need something the Case dealer might be able to get, let me know and I'll pass it on to him. If I can get him hooked up with a Cub, who knows what can happen.

Rick (hey kid! wanna ride the tractor?) Dulas