Having difficulty removing crank sludge trap plug

[tonyduc]

All
On my 250 MK3 NC got the engine torn down and figured this is a good time to clean the crank filter. The screw type plug impossible to remove. Before going with further force, I assume that it’s right hand thread?

Any suggestions on removing is appreciated!

Tony

[blethermaskite]

Most crank plugs are punch staked at the screw driver slot to stop accidental loosening, I normally remove this staking with a small diamond burr on my die grinder, then with the crank supported at the rim edges on a couple of shaped hardwood blocks an impact screwdriver should get it out, (as long as its not in with loctite tread locker)and then best replaced with a female hex plug, (I think Nigel Lacey does them). Another way to get a stubborn plug out is to drill two 6mm holes in it and the fabricate a "peg" spanner to fit and that should shift it.
Cheers,
George

[tonyduc]

Thanks George
I picked up a wide screwdriver socket bit, ground it to fit tightly and with an impact driver reversed it out. Lot of torque needed to take it most of the way out, I didn’t see any blunted threads however. Good thing I did this because the entire collection area was packed with hardened sludge which I removed with a pick. Then from the shaft openings on both ends I sprayed WD40 which pushed out more crap thru the trap area. I hope this cleared the oil galleys leading to the trap because I don’t have a machinist conveniently close to split the crank. I will also order a new plug from Nigel.
Thanks
Tony

[blethermaskite]

Tony,
To help getting the crank clean, if you have the time, submerge the entire crankshaft in paraffin for 24 hours in a suitable deep container then blow all the oilways out with compressed air, remember to take out the little blanking slug from the primary drive end of the crank, this will save any "bits" getting stuck in there, (and don't forget to put it back in again ).
Cheers,
George

[tonyduc]

Will do. Thanks, George.

[gregwils]

I purchased a flat blade bit in a 19v torque driver. Here is the blade https://www.harborfreight.com/12-in-drive-professional-bit-socket-set-6-pc-64994.html. I had to grind a mil or two from the blade so it would fit into the screw slot. The difference was the small pounding action of the torque driver, it came right out. It wasn't moving under my power.

[tonyduc]

I purchased a flat blade bit in a 19v torque driver. Here is the blade https://www.harborfreight.com/12-in-drive-professional-bit-socket-set-6-pc-64994.html. I had to grind a mil or two from the blade so it would fit into the screw slot. The difference was the small pounding action of the torque driver, it came right out. It wasn't moving under my power.

That's exactly the set I bought. I ground the widest one until it fit snug. However, it was still a struggle and the plug (which looks like it was never removed) is ruined now so I am getting a new one as recommended above from Nigel.

[Jordan]

I have used a hammer-driven impact driver for this job.

[Geordie]

I will tag onto this thread as I currently am trying to clean out the crank oilways.
My crank is a Mototrans and it has 3 ~ 9mm aprox, slot-head plugs in periphery of the R/H side flywheel arranged at 90, 180 and 270 degrees from TDC of the crank pin. I can find no other evident plugs. Which one, if any, should give me access to the sludge trap? All are tight and I have not yet applied an impact driver.

CRANK.jpg

[Jon Pegler]

The Mototrans plugs are 10mm if I remember correctly.
You really need to remove all three to clean out the crank oilways, preferably including the Welch plugs either end of the crankpin.

Jon