Main Bearing Dowels

[perkdp]

I'm working on a 1973 18 hp, 1st one I've worked on down to the crank. What part does the main bearing dowels play? Does the crank bearing but against them as a guide or stop, or does it sit on top of them? (on top of being my first, i got this motor in buckets so i didn't get to watch it come apart) I have one of the generic service manuals but haven't found where they talk about these dowels. <br /> <br />thanks....

 

[WillyBWright]

Re: Main Bearing Dowels

They fit into a hole in the bearing cage and keep the shell from spinning.

 

[R.Johnson]

Re: Main Bearing Dowels

Beside's the bearing pins, those pistons have to face in the right direction! You will want a manual to guide you through this process.

 

[perkdp]

Re: Main Bearing Dowels

Thanks guys. I played with the bearings and dowels last night and got them like they're supposed to go. <br /><br />As for the Pistons,, the book I have isn't very clear on that either. Does the high side of the piston go toward or opposite the exhaust ports ?

 

[Paul Moir]

Re: Main Bearing Dowels

No, the sloped side faces the exhaust ports. The high side faces the intake. You want the fuel/air coming in from the intake to slam into the end of the ramp. <br /><br />Go here for exploded diagrams:<br /> http://epc.brp.com/login.aspx?ReturnUrl=/default.aspx?brands=ej&lang=e&brands=ej&lang=e <br /><br />It'll give you some clues as to which parts go where. Also, have a close look at the connecting rods. If there's holes to allow oil into the bearing area from one side of the rod, these holes must face upwards, so gravity encourages oil collected on the top of the rod to drip into the bearings.

 

[perkdp]

Re: Main Bearing Dowels

Thanks Paul. <br />I'll pay close attention to that. <br /><br />I also started a new thread 1973 18hp overhaul with that question and a couple more if you have a chance to take a look.