Spitting Cases and Pulling crank

[Anthony0327]

This is gonna sound dumb but Ive only split a total of 3 250r engines. They all split just fine but when I split an 88 engine the crank bearing came off with the crank. The bearing on the stator side is the one that came off with the crank. Is that normal or does that mean I have an issue with my press fit of the crank bearings? Everything looks good like the bearing races and i can tell the bearing has not spun but like I said with my lack of experience I'm unsure. The other 2 engines which where an 86 an 87 engines, this did not happen. I took the new crank bearings I have to rebuild this and it won't go in by hand. Please advise an sorry for the dumb question. Just want to make sure I don't have an issue. I do know that the stator side of the crank is the press fit side for the crankshaft.  Thanks in advance for the help.

[Tbone07]

This is gonna sound dumb but Ive only split a total of 3 250r engines. They all split just fine but when I split an 88 engine the crank bearing came off with the crank. The bearing on the stator side is the one that came off with the crank. Is that normal or does that mean I have an issue with my press fit of the crank bearings? Everything looks good like the bearing races and i can tell the bearing has not spun but like I said with my lack of experience I'm unsure. The other 2 engines which where an 86 an 87 engines, this did not happen. I took the new crank bearings I have to rebuild this and it won't go in by hand. Please advise an sorry for the dumb question. Just want to make sure I don't have an issue. I do know that the stator side of the crank is the press fit side for the crankshaft.  Thanks in advance for the help.

I can't quite remember which crank bearing comes off still attached to the crank, but I do know one of them always does. So yours sounds pretty normal

I just make sure I use a bunch of heat when pulling the crank so that I don't put too much stress on the bearing races

Are you using a crank puller tool?

[Anthony0327]

Yeah. I have all the right tools. I have a tusk case splitter and crank puller.  I didn't use any heat though. Thanks for the help by the way. I have some nice parts I paid a lot for an don't want to mess anything up.

[udontknowme]

it doesnt make much sense to have the case bearing bore use less interference fit than the crankshaft. im thinking this could allow the bearing to spin in the case when they heat up. as a general rule i believe you want the bearings to stay in the case when the crank is removed

[Anthony0327]

I'm rebuilding the engine anyway with all new bearings and rebuilding the crank. I wouldnt split the engine without replacing all the bearings in it. It's cheap enough an reassurance. I'm not sure I understand what you mean UDK.

[udontknowme]

imo its better if the bearings slide off the crankshaft first instead of pulling out of the case. didnt meen to leave old bearings in

[Tbone07]

Yeah. I have all the right tools. I have a tusk case splitter and crank puller.  I didn't use any heat though. Thanks for the help by the way. I have some nice parts I paid a lot for an don't want to mess anything up.

Oh man you absolutely must use heat. Especially on these aging rare delicate cases. I stick a wood screw into the crank seal and pull it out before applying heat, so I don't have to breathe in all the burnt rubber

I'm rebuilding the engine anyway with all new bearings and rebuilding the crank. I wouldnt split the engine without replacing all the bearings in it. It's cheap enough an reassurance. I'm not sure I understand what you mean UDK.

He's saying the interference should be tighter between the outer bearing race and the case, as opposed to tight between the inner bearing race and the crank. So that the bearing stays in the case instead of coming out on the crank

Some people bore the inner bearing race so it's more of a slip fit.

[Anthony0327]

Ok. I understand that. Well I sure hope I didn't mess anything up. This engine was only on its second bore and had never been rebuilt before. never been split. There's no marks or anything like that. So pull the crank bearing seal and heat up that area while I'm splitting it before or during? Also how hot should I get it? I also have a brand new set of OEM Cases I'm using for my current build. Came in the plastic bag an boxes, never used. I'm updating the crank bearings in those to the 8 ball. Do those require heat also when removing the bearings to put in the new updated ones?

[udontknowme]

if everything goes smoothly you should never need any kind of torch on these engines. if you decide to use one becareful is all i have to say

[Anthony0327]

Is that beacause of their condition? Like I said the one engine is an 88 first time split an the other new cases. Using all OEM parts also. Rebuilt cranks an all.  I really do appreciate the help! Thanks UDKM An Tbne

[Tbone07]

So pull the crank bearing seal and heat up that area while I'm splitting it before or during? Also how hot should I get it? I also have a brand new set of OEM Cases I'm using for my current build.I'm updating the crank bearings in those to the 8 ball. Do those require heat also when removing the bearings to put in the new updated ones?

I use the crank puller and put a little bit of tension on it, then start to evenly apply heat around the bearing case bore. Then torque the puller in 1 turn increments, applying some heat in between.

You don't want to get it too hot like udontknowme said, but I don't think there's any harm in applying it evenly to relieve some of the stress from the cases. 8-ball or standard I use heat

[Anthony0327]

I can see how that would eleaviate some stress on the parts. Makes a lot of sense. When reassembling should I do the same and add a little heat upon pulling the crank onto the bearing?