Crankcase oil sump plate holes - poor repair

[Swarfcut]

 That roller bearing is not the usual type.....The rest of us are stuck with bearings that leave the rollers on the crank, and adjusting the crank float is an absolute PITA.

 Plenty on the Forum about different main bearing types and their drawbacks and benefits.

 Me, I'd prefer to blank it off and not disturb unless absolutely necessary. Otherwise Musky's deal is the way to go. Camping stove also works. Be careful if it has plastic roller cage... in this case best left alone.

 Earlier posts would indicate this is far from a standard set up (belt drive primary) so has it an end fed crank conversion as well? Hence different bearing type.

 Swarfy.

[ADP91]

G'day Angus.
Yes I would remove the bearing. Heat the case in the oven (wait till SWMBO is out) to 150C or so and it will fall out. same for putting it back in, put bearing in the freezer first.
Cheers

Great thanks for the tip.

[ADP91]

That roller bearing is not the usual type.....The rest of us are stuck with bearings that leave the rollers on the crank, and adjusting the crank float is an absolute PITA.

 Plenty on the Forum about different main bearing types and their drawbacks and benefits.

 Me, I'd prefer to blank it off and not disturb unless absolutely necessary. Otherwise Musky's deal is the way to go. Camping stove also works. Be careful if it has plastic roller cage... in this case best left alone.

 Earlier posts would indicate this is far from a standard set up (belt drive primary) so has it an end fed crank conversion as well? Hence different bearing type.

 Swarfy.

Hi Swarfy,

I'll have to do a bit of research on what bearing this could be. First time I'm inside this motor but I know it previously had work done on it. What is the end fed crank conversion? Anything to keep in mind?

Also, I tried checking the crank end float before completely disassembling the motor and I couldn't see any detectable float. However, the motor hasn't been run since the previous work was done (due to the sump plate).

Attached another photo that might show the bearing on the drive side a bit better. No bearing conversion on the timing side. 

Cheers

[Swarfcut]

 A known weakness in the basic design is that oil to the big ends is fed to the oilway in the crank via that plain bush timing side main bearing. Wear between bush and crank journal results in a loss of oil to the crank as more escapes from the increased clearance between the two. A solution to this is to feed the crank directly from the oilpump end, usually by a tubular quill with an oilseal. All well documented (and expensive) and very clever in concept, if you care to search.

 With no end float to speak off I still maintain that bearing is best left alone. Most likely building up the crankcase will use  TIG  welding and problems from heat will be minimal. Compared to the weld area, the crankcase is a well conducting heat sink with a large surface area.

 No if's or buts, it's also crankshaft sludge trap time, plenty about this on the Forum and YouTube  viddys. Simple to inspect, if only to check P.O. bothered to do the whole job.. Many an engine has been rebuilt only to quickly fail because this aspect was neglected.

 Swarfy.

[trevinoz]

The bearing is probably an NJ series rather than the original NF.
Both work equally well.

[Colsbeeza]

Angus,
The standard bearing is an NF206, with rollers on the inner bearing on the crank as Trevor mentioned. Yours appears to be the NJ206 with rollers in the outer bearing and a brass cage. Attached are the bearings I used - NTN brand Japanese NJ206, as I did not want the rollers on the inner bearing so I could get the inner off the crank more easily without damaging the cage. You can obtain these bearings with either brass, steel or high temperature plastic cages (to 140 deg C). You will notice that mine has a C3 clearance, which I would ask for if you need to replace yours. My bearing supplier had no idea about clearances and looked at me as if I came from another planet, so stand your ground if ordering. Smaller clearances are not enough for our beasts. I purchased two, and ground out the centre on one for trial fits, so I did not have to use a puller or large hammer to get it off again after calculating shims. There is a fair bit of stuff on this subject if you have the patience to search. Getting end float is the same, with shims behind the crank bearing. No problems with mine sofar.
Col

[bikerboy]

Has it shown any signs of wet sumping it may be a good idea to check as you have the cases split apart already

[ADP91]

**Update**

Had a good friend of mine who works at a restoration shop cut, weld, and machine the previous repair. Very happy with the results

[groily]

Nice one!
If I were you (I'm not of course!) I'd use studs and nuts not allen-head set screws or bolts for the new plate, even if it won't have to come off that often  . . . First thing I did with the SRM plate on mine was  . . . ditch the fasteners.

[Colsbeeza]

So did I Bill.

[chaterlea25]

Hi ADP,
When you are finally fitting the SRM sump plate, turn it so the magnetic plug is as far away from the pick up pipe as possible. I had experiences of where the strong magnet stuck the ball to its seat.
I changed the magnet to a weaker one and turned the plate, no more problems

John

[Worty]

Pah, that damage is nothing compared to what RM did to mine (See Worty's A10 Engine Rebuild).

Was going to suggest you package it up and send it to Bergs, he's used to horror stories after building my motor!

[ADP91]

Nice one!
If I were you (I'm not of course!) I'd use studs and nuts not allen-head set screws or bolts for the new plate, even if it won't have to come off that often  . . . First thing I did with the SRM plate on mine was  . . . ditch the fasteners.

What studs should I use in this case? I definitely like the idea of inserting the studs and leaving them in place. I suspect the original poor repair was done due to repeated threading in of fasteners..

[ADP91]

Hi ADP,
When you are finally fitting the SRM sump plate, turn it so the magnetic plug is as far away from the pick up pipe as possible. I had experiences of where the strong magnet stuck the ball to its seat.
I changed the magnet to a weaker one and turned the plate, no more problems

John

Good tip! I imagine getting the ball stuck to its seat would lead to all sorts of issues...

[groily]

[quote author=ADP91 link=topic=18112.msg163958#msg163958 date=1710370457
What studs should I use in this case? I definitely like the idea of inserting the studs and leaving them in place. I suspect the original poor repair was done due to repeated threading in of fasteners..
[/quote]
Not sure exactly what might be out there off the shelf suitable for the thicker plate, I just made mine to be honest. Nylock nuts are good too . . .
The pretty SRM-supplied screws were useful for other things, nothing wrong with them, I just didn't want them there.