BD144. Main bearing change w/out Crank removal?

neil33

New User
So I have a question for you guys......

Is it possible to change the main bearing shells without removing the crank from the engine? My thinking is that if I remove all bearing caps I might be able to drop the crank enough to push the upper shells out and push the new ones in.

My investigation in the low oil pressure on my restoration led me to drop the sump, only to find the oil pump gauze pretty well blocked with sludge. After changing the oil pump with a used (but known good) pump there is a small improvement in oil pressure but I feel the next step is the change the main and big end bearings but at this stage don't really want to remove the crank to have it reground.

Advice appreciated.....
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no knowledge of this engine but we used to roll old mains out with a modified cotter pin in the oil hole of crank shaft. bend cotter pin legs at the right angle to match oil port and put round end in crank and turn crank it will roll out upper shell.
 
first, have you actually checked the pressure with a master guage. i dont think just replacing mains will improve pressure much. what about cam brgs.? rod brgs. ?
but yes use the cotter pins to roll brgs. and make sure you have 15-40 oil in it.
most important is to get the before pressure readings and after. then you know. cant go by just the tractor guage.
 
Hi I have done the main bearings in a BD154 which I believe is the same engine just a larger bore.
Just used an old bearing to push the old one out or as another person said put a cotter pin in the oil hole in crank and turn crank to push the old bearing out.

JimB
 
Thanks guys, much appreciated.

Is it just as easy to push the new upper bearing into place using the same cotter pin method?
 
I use a short length of small OD brazing rod to make a pusher similar to your cotter key.

NO chance of scratching the crank or the bearing bore using brass.
 
I would definitely change the rod bearings as welll if the mains are showing signs of oil starvation. I would also recommend checking clearance with plasti-gauge. You may have meant rod bearings when you say ?big end? but I have never heard that terminology.
 

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