Lousy compression visualized

[GKLinMT]

After finding low compression (60/65 PSI) I pulled the motor and got the top end off last night.

Now I'm wondering when the last time this thing ran was? The oil was heavily mixed with fuel and water and looked like a gray milkshake, the filter was also matted with nasty sludge.

Here's a couple pics of badly caked and burnt pistons and head for you guys to enjoy.

I was hoping to get away with pistons, rings and gaskets. If I ever get the fan hub off I'll be cracking into the lower half for a good cleaning and inspection soon.

Wish me luck!

[CP241]

As long as the cylinder bores arent scored badly I think you should be fine. I've seen worse :)

[GKLinMT]

The bores are surprisingly smooth actually. no vertical scoring at all, just a slight ridge horizontally. I'll probably get the pistons out tonight, hoping for a crank that's unscored as well.

[Gearhead1956]

Those piston pic's aren't that bad. just a little over fueling as carb's do.

When you pulled the oil did you get oil first then water? if so that's good. means engine was not run with water in it. Water got in while sitting is more likely since these are air, not water cooled.

When I got mine it had been sitting with a rod knocking out side, for I don't know how long with carb off. cylinders filled with water and pistons froze up. Took days with WD40 and sand paper to get free. But cleaned up and honed like new.

The rods are aluminum, no bearings to steel crank. Mine had been run with a rod knocking! Thought it was trash. used 400/600/800 grit sand paper then machine buffed and the crank came out in speck.

With you starting with an engine that was running, think you will be fine. be sure to check for bell shaped cylinder.

[GKLinMT]

Thanks for the advice Gearhead, I've got it all apart now and the rear journal on the crank is pretty scored up. I'm hoping to recover it as you stated with progressively finer emery cloth. I don't think it was run with water in it as overall it looks pretty darned good inside.

I initially checked the oil with the dipstick and it actually looked really good and smelled acceptable. I churned it a lot trying to get it to kick over so I think I made the nasty milkshake.

On to cleaning up the whole case and really checking it over.

At this point I'm thinking I can get by with rings, 1 rod/cap and a gasket set!

After the first wipe down the pistons are looking pretty good.

[trig123]

I would put a micrometer on the crankshaft. The engine manual tells you what they should be.

[Gearhead1956]

Think your going to need intake valves, see how they are sunk into the head.

[GKLinMT]

Not until I started cleaning the head up, no.

I'm going to order one of the full rebuild kits and put that in. Rods, valves, pistons, rings full gaskets.

Now I just need to find a fan.