Lister CD 8HP named Ray

That bore is quite worn, right through the chrome, but with a light hone they will run just fine like that.

It's hard to tell from the picture, has that bearing been a bit hot?

Also, if it's worn you may not be getting full oil up to the piston (just guessing it's an oil hole in the bearing for piston oiling).

Jarrod.

Is that a chrome bore?

JOHN.K. wrote:

Is that a chrome bore?

Yes, they are.

Jarrod.

Chrome rings?

Hi Jarrod, yes it will get a light hone regardless of what the true bore size is. I discovered that my internal callipers pull in the tighter I do them up. I'm mnot sure if the mark on the big end is from heat or not but you would think if it was heat it would be across the bearing not running around it. The journal it runs on has no marks on it. I hope to be able to get better pics of the bore soon. Not until I pull the bearing shell out of the conrod will I know if there is a gallery running up the rod itself. My next step is to start to clean the parts up.
JOHN.K Listers mostly have what they call Listard liners wwhich is chromium on the bores and run normal black rings.
I started re-doing the bore sizes today and got better numbers that actually go above 4.5" standard size by up to 0.004". I will keep checking the numbers until I get more regular and constant readings.
This piston will be going into the lathe the same as the McDonald piston did to be cleaned up. There are 4 different ring sets for Lister and this one has a wider ring land for the top compression and all the others including oil ring ar narrower. All are made for a 4.5" STD bore. (Only in England would they do this. Is Lister tied up with Land Rover as they specialised in craziness too.)

I decided to play with the piston today and removed the conrod and took the piston to the lathe to clean it up. I used a dial indicator gauge and it showed 0.003" out of round. So I had previously washed the piston down with degreaser and then started with the wire brush while it turned about in the lathe. I then used a power hacksaw blade to start cleaning out the ring grooves. Finally I used some fine wet n dry paper on a flat file to polish up the skirt and then the top of the piston. This poor piston had had more hits than Elvis on the top but cleaned up ok. The area that looked as if there was chromium on the skirt also cleaned up fairly well but room for improvement. Tomorrow I want to drop the piston in the bore and check the clearance of skirt to bore using feeler gauges. Then I will decide whether to put it back in the lathe and make it round/er again. The other thing I read on the parts supplier is that they made 4 different ring sets and now I know why. The top compression and bottom oil rings are wider than the 2 middle compression rings. But what I took out was a thin oil ring the same width as the 2 middle compression rings. When I removed the gudgeon pin it broke a small amount of alloy out from around the hole, very small so I have filed that to be a bit smoother.

I tightened up the cap so I can measure the bore of the big end bearing tomorrow and then cleaned up the conrod . I went to put the gudgeon pin back into the little end bush and it was as if it was biting a bit. So I stuck it in the lathe and machined the tiniest of a chamfer on each end. Now it fits both sides of the piston and the little end just right. There is no movement in the gudgeon and top bush and it is a firm fit in the piston so nothing to do here. Hopefully when the Lister spare parts man, Rob, gets over the Festive Season I will be able to confirm the parts I do need. I will measure the journal on the crank tomorrow and compare that to the bearing and see what sort of a shock I get, good or bad.

Are you sure the gudgeon hasn't been seizing in the piston.

There are some interesting patterns on the gudgeon.

Scuffing on the side of the piston may suggest issues such as bent or mis-aligned conrod.

Zuffen, the gudgeon pin is a neat fit into the piston and can move in the top bush.

I haven't thought of that so will work on a way of making sure it is straight.