have any of you guys ever changed a crank while the engine was still in the car. i'm loosing oil pressure and going to change the oil pump. i was just checking autozone and o'reilly and they have a crank and bearings sets for 165. this is for the 250 in my car. so when i change the oil pump if my crank is bad i will buy a new one and replace it. i just would like to know if it is possible to change the crank under the car.
You have to unbolt the tranny so you might as well pull the engine. It is possible to change it but would not be much fun
Ditto. You would have the transmission, flexplate, starter, waterpump, front cover, timing chain & oil pan removed and all fluids drained. Then you have to push some of the pistons up in their bores while rotating the crank to get at all the rod bolts. Now you install the new crank (not a one-man job anymore) and try to pull those same pistons back down to install the rod caps back on without scratching your new crank journals. In the end, it would be more work than pulling the engine. If you can get by with just putting bearings in it, that's not too bad to do.
pulling the head would make this easier...but someone would have to drive the piston down while he lined the rod with crank... isn't some...gauging of the rod/main bearings... going on here also...
It's done all the time with big trucks, talk to a diesel mechanic who has done "in frame" overhauls. Just me, but I'd pull the engine to do the job. It's no fun laying on your back in filth trying to perform a job that needs a clean environment to do properly.
I changes rod and main bearings with the engine still in a Astro Van. Laying on a graveled driveway with the van sitting on ramps is not the best working environment.
I dismantled my entire 250 in the driveway before, new rings, bearings and head was machined. Not as fun or easy as putting on engine stand (Didn't have equipment at the time) but you do what you gotta do. :Handshake
I also would think, if replacing...crank/rod bearings...why not pop pistons and re-ring... don't forget...new rear seal... and any...freeze plugs...that may be behind the flexplate...
this is a situation where if you want to do it correctly you should do the full rebuild. im not sure why you want to change the oil pump. if you have a low oil pressure issue, it usually not the pump. its usually a bearing problem. i would just replace the main and rod bearings and try to look to see if the cam bearings have pushed out of the bores. you can look up from the bottom of the motor once you have the oil pan off and see the cam and should not be able to see the bearings poking out of the bores. is this a v8 or a i6?
Just pull the engine and do it on a bench/stand. Dont piddle futz in the driveway with critical components if your going to change the crank. OR, just throw new main/rod bearings in it and drive it...
