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"Bullnose" lawn tractor project


Ifitaintbroke

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Sounds like great fun. Got my rebuild kit today. Took a piston to my machinist. I went with 0.020 over pistons and 0.010 under rods. The aftermarket rods are supposed to be stronger. Still cast, but stronger. I'm going to try some porting of the block and heads. Interestingly, shaving the head and increasing compression is NOT recommended. If you look at the head, it makes sense. The flow from the bore to the valves is completely in the head. The block is flat (duh). If you shave the head, you are restricting flow from the valves to the combustion chamber. Bad flow with higher compression isn't good. :nabble_smiley_unhappy:

On my Kohler twins, the difference between an MV16 and an MV18 is the cylinder heads, the MV18 has a smaller chamber in the heads raising the compression enough to gain 2 hp.

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No, they are flat head. The OHV Kohler twins are V-twins, I have a CV22S (24hp). You may be thinking of the OMC engines Cushman used in their golf carts and scooters. They were OHV opposed twins.

I guess it just depends on how the chamber is shaped. On the Briggs, there really isn't much room. I'll try to get some pics after I clean them up.

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I guess it just depends on how the chamber is shaped. On the Briggs, there really isn't much room. I'll try to get some pics after I clean them up.

Got the engine together and in. Runs great, but I only made it about 6 feet before the belt snapped into 2 PIECES. I've never done that before. After a new belt I should be tractoring again! Also when the belt broke it smashed into the choke cable, ruining it. So I need another one of those too.

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Got the engine together and in. Runs great, but I only made it about 6 feet before the belt snapped into 2 PIECES. I've never done that before. After a new belt I should be tractoring again! Also when the belt broke it smashed into the choke cable, ruining it. So I need another one of those too.

One step forward and two back is not progress. :nabble_smiley_oh:

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One step forward and two back is not progress. :nabble_smiley_oh:

Well it runs so that's progress! It didn't run when the engine was out. But it's totally my fault the belt snapped. You know those little wire holder thingies that keep the belt on the pulleys? Yeah I missed one of those. Or 2. Or 10.

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Well it runs so that's progress! It didn't run when the engine was out. But it's totally my fault the belt snapped. You know those little wire holder thingies that keep the belt on the pulleys? Yeah I missed one of those. Or 2. Or 10.

10? Yikes! Would be hard to get a belt on. :nabble_smiley_happy:

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10? Yikes! Would be hard to get a belt on. :nabble_smiley_happy:

Well I'm exaggerating a bit there. But when I pushed that clutch in.......I thought the engine blew up. Twas loud. I've seen a lot of broken and worn out v belts, but this is the first one I've ever seen the broke into 2 pieces. Maybe I'll have one in stock at work. Probably just wishful thinking.

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Well I'm exaggerating a bit there. But when I pushed that clutch in.......I thought the engine blew up. Twas loud. I've seen a lot of broken and worn out v belts, but this is the first one I've ever seen the broke into 2 pieces. Maybe I'll have one in stock at work. Probably just wishful thinking.

Word of advice, use a Lawn and Garden belt, preferably a Kevlar one. Automotive ones are not designed to be used for a clutch, and other than a Corvair, aren't real good for multiple twists and turns.

Bill

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