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I'm thinking that while my new (secondhand though) BP is on the engine stand and needs the sump to come off to have an oil return tapped maybe I should do the bearings? Is that feasible, and does it require dropping the crank, if so what else needs to come off and if you have to drop the crank can you get the pistons out from the bottom to put new rings on or is that only from the top?

Cheers

With the engine up side down you should be able to remove the crankshaft bearings without removing the crankshaft. While I believe the usual way to insert the pistons is from the top, I can't see why you could'nt do it from the bottom.

You have said you are removing the sump to fit an oil return line. I assume this is for a turbo? Having fitted an oil return line myself, and being very nervous at the time, it can and has been done many many times with the sump still attached. Having the engine on a stand will make it even easier as you have no issues with air cond or power steering stuff getting in the way. IMHO, unless you have a reason to be concerned about the engine internals, or want to prepare the engine for high levels of boost I would leave them alone and leave the sump in place when you fit the oil return.

J

Juffa, I've not done an Mx motor, but i have never come across an engine that i could get the pistons in or out through the crank case ... they all seem to have webs and strengthened sections in the way !

Bearings shouldnt be a problem, you can definitely change the big end ones no hassle, but the mains, i'd be taking out the crank just to make sure the galleries are clear and the journals are all in good shape.

Good luck !

J

pistons need to come out the top.

i'd agree with taking the crank right out to replace bearings.

Are there any indications that the bearings actually need changing? I just did mine because I was putting in a new crank (long nose problem) but honestly all the bearings were still within new fitting tolerances after 175,000kms. If I wasn't changing the crank then those bearings could have stayed in.
BTW Aussie made ACL bearings are so cheap from US ebay.

Jap importer engine, havent heard it run, just figured it may be better to do it before it goes into the car incase they're stuffed

Pull off the mains caps, drop some plastigauge in there and see what reading you get. That'll give you an idea what the clearances are. If you can see copper in the bearings, you'll know straight away they are done but if the clearances are right, leave them be.