Scooped a Liquid Cooled Motor

[Weldangrind]

I found a guy on CL who advertised a Zongshen 250 motor for parts, so I swooped in. It turned out to be a liquid cooled CG250 pushrod motor, and he said that it was in place when he bought a used quad. The original owner that sold him the quad said the motor was locked up. The guy who sold it to me said that he got it to turn over, but it wouldn't fire. He subsequently bought a replacement motor and forgot about this one.

I grabbed it for pocket change and took it to Chez Weldangrind. I pulled the left side crank nut cover off, along with the timing plug and the head. The motor turned over just as it should (without the spark plug in place). As I suspected, the valves were way off. It's supposed to be 0.08mm / 0.003", but it was twice that! I set the valves and connected a battery to it. It turns over nicely with the starter; there is no kicker.

Since this was out of a quad, it has four gears and reverse. I'm thinking that this would be the perfect power plant for a home-made China trike / truck, so I might eventually go in that direction. What I need is for the community to help me figure out where I could get a differential for cheap / free, and I'm thinking of an open diff from an '80's Honda ATC, or similar.

I'm re-thinking my position on liquid cooled China motors, because this one seems to be very well built. I even have a couple of radiators from an old CR125, so I might be able to run it on a test bench before long.

The good news is that even if the top end is done, replacement parts are cheap. At the very least, I could swap the jug for an air-cooled version and have a 250 motor for my quad. BTW, the casting indicates 250cc, not 230.

The pics are a bit fuzzy, but here it is:





Something I stumbled on while shopping Taobao is an oil cooler kit that replaces the stock valve cover. I can see a few of these in my future: http://item.taobao.com/item.htm?spm=a230r.1.14.77.YOji84&id=18688252538 They're available in three different capacities, and they'll work for air cooled or liquid cooled motors.

[SpudRider]

Nice score on the engine, Weld.

I didn't realize the cylinder head of the pushrod engines contained pressurized oil.

[Weldangrind]

Yes, there's a nut on the valve cover that you can loosen to verify oil flow, much like the TW / Zong banjo bolt. The passage allows oil to be sprayed onto the rockers, after which the oil drains back to the bottom end.

[SpudRider]

Thank you. However, I still don't understand how the pushrod oil coolers are designed. Are they diverting the oil flow to an oil cooler, then returning the oil to the cylinder head with a second, additional port?

[humanbeing]

Originally Posted by SpudRider

...still don't understand how the pushrod oil coolers are designed...

http://item.taobao.com/item.htm?id=16654223397 | http://family.saycoo.com/thread-259830-1-1.html

[Weldangrind]

Spud, the oil is pushed up a passage (much like an OHC Honda, or your Zong), and it is then diverted to one of the banjo fittings in the special valve cover. The oil then circulates through the cooler, returns via the second banjo fitting and back into the valve cover. I haven't had the opportunity to examine one yet, but I believe the oil would then spray onto the rockers, just like a stock valve cover.

Make sense?

[Weldangrind]

Upon studying Humanbeing's second link above (thanks! ), I can see that there is a valve on the oil cooler valve cover, and it will allow you to circulate oil through the cooler when hot, or bypass the cooler when cold. Cool. I think I'll buy one and play with it.

[FastDoc]

Very nice Weld! Another win/win. :-)

[bogieboy]

Very nice score! as for a differential axle, Northern Tool has differential axles for go carts, or even ebay would be a good place to look, on a budget...

[Weldangrind]

Originally Posted by bogieboy

Very nice score! as for a differential axle, Northern Tool has differential axles for go carts, or even ebay would be a good place to look, on a budget...

Agreed. I'm hoping for guidance on something specific that I could hunt for. IOW, if a member told me that he once had an '83 Big Red and could confirm that it had an open diff, I'd know what to search for.

Perhaps somebody here already has something like that for sale or trade.

[bogieboy]

Originally Posted by Weldangrind

Agreed. I'm hoping for guidance on something specific that I could hunt for. IOW, if a member told me that he once had an '83 Big Red and could confirm that it had an open diff, I'd know what to search for.

Perhaps somebody here already has something like that for sale or trade.

honestly though, turning isnt that bad with a solid axle... my cart has a solid axle with 23/10.5-12 tires on it....

[Weldangrind]

Hmmm... Perhaps I'll go that direction if I have to. I'd like to engineer some suspension into it as well, and perhaps a shaft drive quad or trike would give me the axle tubes I need to weld to. I have an old Cadet 75 rear axle, but the axles are exposed.

[humanbeing]

Originally Posted by Weldangrind

...valve on the oil cooler valve cover, and it will allow you to circulate oil through the cooler when hot, or bypass the cooler when cold...

That valve may leak, so it's NOT there anymore.

http://item.taobao.com/item.htm?id=17104687488 is based in Guangdong. (SAME province as tbtrends ie. FAST shipping)

[SpudRider]

Thank you HumanBeing and Weld, for the explanations.

[Weldangrind]

Originally Posted by humanbeing

That valve may leak, so it's NOT there anymore.

http://item.taobao.com/item.htm?id=17104687488 is based in Guangdong. (SAME province as tbtrends ie. FAST shipping)

What is the mounting hole on top of the cover for? CG oil cooler valve cover.jpg