7 replies to this topic

[andyjmapex]

Hi guys,

 

Had problems with removal of the flywheel for the last three weeks, after breaking 2 pulleys, 4 meters of studding, a bottle of propane, a hydraulic bottle jack and alot of effs i resorted to using the grinder All went well taking it carefully however when the clutch plate popped off several feet, scareing me stupid, it revealed i had taken a cm^2 x 3mm deep chunk out of the crank taper. With my dad saying 'yeahhhh go on son that will fine to use again' and my brain saying 'nooooo new crank time' i'm confused as to what to do.

 

it's such a shame as the engines only done 60k and is in perfect order. if i buy a second hand ebay crank is it a 'bolt on and go' solution, or will the crank journels/bearings have to machined? i'm reluctant to spent £250 on a brand new crank.

 

The engines a '88 998, completely standard, until now

 

thanks

 

Andy

[Carlos W]

You're going to need the correct main bearing shells for the size of the crank!

998 cranks shouldn't be expensive! I've got a couple that need work

[andyjmapex]

Oh right, so a second hand one from another engine wouldn't run in my current bearing shells?

[johnnyblaze]

short answer maybe but NO, get a 2nd hand crank get it sized and maybe its only going to need a polish or it will need grinding nothing major and then new shells for both mains and big ends bang it back together and away you go, make sure the flywheel taper is in good nick before buying, so id suggest buying a local 1 that you can hold and physically look at

[carbon]

Alternatively...

 

If you were not planning to get your current crank reground and it was running fine then I would just get another flywheel and put it all back together using your current crank. Lots of cranks have bigger grooves that that for keyways...

[Gr4h4m]

if your looking for a new one.  I have a

 

998 A series crank, Fresh re-grind, Balanced, and Heat treated by Force Racing - Comes with ACL mains bearings, which were installed into the caps torqued plastiguage and turned over so have some witness marks on them.

MB = +0.020

BE = +0.010

Only selling as I got a wedged crank cheap.

[andyjmapex]

thanks guys - I have been given a FREE crank (woppee) by a mate, same casting and measures up the same however the journals are mildly pitted. still mics up the same though. I'll get some photos and post here later as i'm a bit offput about the grinding of it - both cranks obviously been roughly ground by BL but there is ALOT of meat taken of the new crank on the opposite side to my old one. hard to explain but hold on and i'll get you some pics :) 

 

just out of interest how much were you looking for the balanced crank bud?

 

Andy

Edited by andyjmapex, 29 May 2013 - 02:44 PM.

[KernowCooper]

Do not use the old shell bearings again on the crank you've been given, I assume your going to fit a new oil pump check crank for ovality and  fit new shells/ thrusts as required ?