how to: crankcase clean up

550surf

550surf

okay, so i know that a crankcase "clean up" doesnt mean to get mums cleaning supplies out. in fact, it means to widen the part where your piston comes down into the crank.

as i just bought 76.5mm pistons, I require a "crankcase clean up".

could someoone please shed some light on how i will do this? YES ive already searched but nothing!

- is this something i can do myself? or must a machinist do this?
- how much will it cost?


any information on this procudure is grossly appreciateld


its for a js 550, but i thought id post here as it applied to all engines.. right? :)
 
OCD Solutions

OCD Solutions

Original, Clean and Dependable Solutions
Location
Rentz, GA
I've had cases "clearanced" to fit 760 cylinders before. Not sure if that's the correct term either but any machine shop should be able to perform this task.
 
Dartman

Dartman

Location
usa
pull out the long studs-stud tools works best, but can be successful with jamming up double nuts...depending how tight they are
might use some heat if real tight
take it to a machine shop and have them bore the upper case in a mill with a boring head
simple operation for any machine shop
$60-90 would be close for price here in the states
make sure you bore cases .6 mm bigger than the measured piston size at the very bottom of the skirt
 
550surf

550surf

thanks guys, i spoke to a machinist and itl cost " a couple hundred bucks" Fk i hate how much we pay for things here. so wrong.
a porsche 911 s costs 77k in the states and a whooping 380 here! maddness in all directions
 
R

restosud

split the cases,remove the studs,mark the cases and do it free hand with a dremel or the like if it costs that much where you are! doing it on a mill will give you a much better finish but oh well!
plenty have done it like that and all worked fine but look around for another cheaper shop.usually takes way less than 1hr of labor for a competent person.
 
Sparkplug

Sparkplug

Location
Red Bluff CA
Just clearancd some 650 cases to fit 61x sleeves. Did it with a Dremel. Took prob 10 minutes. Granted you need to remove more material, but that's just time. It's easy. Who cares what it looks like as long as you don't go full retard.


Edit; your actually widening the part where the sleeve goes into the case. Unless im confused on what your saying. Which is totally possible
 
Last edited:
Informal

Informal

Location
SoCal
A couple hundred bucks? I've seen a handful of complete 550's on Craigslist for less than that. :/

Try other shops, should be less than $100 imo
 
You must log in or register to reply here.
Top Bottom