Bearing

[makobuggie]

Thanks for the info about heating the case to install. The problem is its on the crank, stuck on there? Im thinking of buying a new crank? And im thinking it might still be good? Im going to put a new rod bearing on it, should it be ok to use?it fells not bad,what can go wrong with a crank? With new bearings? Thanks

[slonomo]

Not really sure what you're asking, but I can tell you that if the current engine has a lot of hours on it then the rod bearing is most likely worn. How worn? Well you have to measure the side movement and compare that to specs. Will it still work if it's out of spec? Sure, but it might be noisy and after a long time the roller bearings will eventually fail. Inside the roller bearings there is a plastic keeper that "keeps" all the rollers in place. The plastic degrades over time and can break. Also if the rollers are really worn there will continue to be wear which can be accelerated after a fresh top end rebuild with the added compression. So my advice is if you plan to keep this cart and drive it alot, I'd invest the extra cash in the crank kit. It will have a new crank, new rod, new rod bearing, all ready to go.

My trick on how to get the bearings out of the engine case? Line your bbq grill with foil and heat up to 400 degrees. Put your cases in there for like 10 minutes and the bearings will fall right out. If not, leave in for another 5 min. The Aluminum cases warm up and expand at a greater rate than the steel bearings, this is why they fall right out.

By the way, it will help to wear big heavy leather gloves like welding gloves so you don't get burned.

Installing new bearings is the same procedure. Put the cases in the grill and slip the cool bearings right in. Wait a few min and they will be stuck.

To install the crank, put the crank in the freezer overnight right next to where the cold air comes out, the coldest part of the freezer. In the morning put the engine cases in the grill again (with the bearings in) but only for 10 min or so, be careful the bearings could still fall out again. Take the crank out of the freezer and quickly put oil on the shafts of the crank and slip the crank into the bearings one side at a time. Make sure you have the crank facing the right direction or you'll have a heck of a time getting it all apart, been there done that. Have your hi-temp silicone gasket maker ready to go (grey stuff) and spread a thin amount on one surface of the case. Put the case together and hold for a few minutes for the temps to cool down. I used a fan blowing on the engine cases to speed up the cooling process. Install a few of the case bolts and squeeze tight. Wait until the cases are cool to install and torque your bolts.

Now you can install the bearings and the crank at the same time if you wish it will save a step, but it might be trickier and you'll have to work quicker.

With that said, make sure you have a service manual for all your bolt torque specs and patterns, and also for reference for where stuff goes and how to check other stuff. Technical term "stuff". Anyway, you should be okay as long as you have that manual to refer to, I found it extremely helpful, and I've rebuilt many engines in my day.

Good luck.

[daveswaves]

I like your method Slonomo, wish I could do it that way but the fellow I got the 250 engine from had already put the seals in the crankcase halfs, reluctant to try and get them out again without damaging them. I am thinking of using longer crankcase bolts to draw the two halves together evenly. Ever tried that?