any tips on crank assembly?

I'm going to disassemble the crankshaft on my 850 MKII and clean the sludge trap. I have a new set of hardware comming in the mail. The factory manual describes the procedure but I've never been inside one of these before so I'm asking if there are any danger areas to be aware of or hard earned tips for doing it right.

TIA

Make sure that you mark the the flywheel so that it gets reoriented as it was prior to dissassembly. Also it won't hurt to number the studs to assure that they find their way back into the same hole they came out of, do look for a small interference fit on these studs; they should mic at .375x, unfortunatey there are a bunch that measure .371x to .374x. I purchased 6 extras from my Andover Norton dealer and only found one that was close enough to use...

On reassembly use red locktite torque what you can reach to 30 ft/lbs, you'll need a crow foot, but even then there are two that you will need to do by feel.

Great time to get the rotating and reciprocating parts balanced.

RS

RoadScholar said:

Great time to get the rotating and reciprocating parts balanced.

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Just curious why crank should be re-balanced? Are they not balanced well enough from factory? Since I am taking my crank to bits, do I give the engine/machine shop the whole assembled crank or the flywheel only? Should I really make this effort to balance more.

Cheers--Jerry

jerry if you,re not happy with the balance factor then go ahead and have it balanced,they will need the completed crank and the exact weight of your rods and pistons including big end shells,nuts and bolts, piston rings, gudgeon pins,and circlips

Jerry Doe said:

Since I am taking my crank to bits, do I give the engine/machine shop the whole assembled crank or the flywheel only?

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Normally for a balance job, you'd supply the complete crank, conrods, and piston assemblies. Or the weight of the reciprocating parts would probably have to be supplied to the balancer, along with the crankshaft?

http://en.wikipedia.org/wiki/Engine_balance


[Edit] (Chris posted while I was typing a similar reply!)

Thanks for the tips. I have already located a local place that can do it and clean inspect all. I am going to take the whole assemplby to them. Should I put all new conrod nuts/bolts & crankassemble nuts?

hi jerry, just to be on the safe side i would fit new big end bolts and nuts,and crank bolts,studs,and nuts

If you're working on the crank, it's worth wrapping something like insulating tape round the journals to prevent bruising or scratching them whilst you're working. An attempt at polishing the worst imperfections out of the sludge trap chamber is also worthwhile.

I usually give the crank parts a good session in an ultrasonic cleaner to make sure that every last part is super clean. Cleanliness when rebuilding is also paramount but apart from that, the job is straightforward. I would say that it's certainly worth at least dismantling it yourself simply for that all important bonding with the machine and also so that you know exactly what was in the sludge trap. It's all part of the process of learning what future maintenance intervals are likely to be necessary.

The NOC 'Service Notes' advice is that the conrod nuts should be replaced but that known quantity bolts can be better than new ones. Has your engine been apart before ?

Hello mate- I have never taken the crank apart before after 10 years and probably around 40K miles.. Maybe last owner did, but unlikely..

I have no idea what an ultra sonic tool is, so I guess I will do it by hand...

cheers

RE: Balancing

The factory did a very minimalist job, at best, in the balance department; can't you just see Geoff or Nigel, being close to tea, saying something like, "bloody close enough"...

The other side of taking your parts to a specialist is that they have reputation to lose, so service should be at its best. They should be offering magnafluxing of your parts, be offering shot peening, not polishing of your steel rod caps and glass beeding your beams, they should be capable of re-sizing your big-ends so that you can achieve a uniform clearance, side to side, the list goes on.

Be ware of Andover Norton's rod bolts; I ended up purchasing 9 to get 4 examples that had no VISIBLE voids, be ware of aftermarket bolts, especially if you are faced with forcing them into the beam ends, let your specialist advise you on this.

When your specialist is finished you can assemble with the confidence that your machine is more reliable than when it left the factory, assuming that you follow through??? I was so anal that I had my torque wrenches calibrated...

Best wishes! you will be very proud of the finished product!

RS

When you are reassembling the lower end be sure to protect the rods from hitting the engine cases, a single nick will spell disaster not long down the road

But all he wanted to do is clean his sludge trap...

batrider said:

But all he wanted to do is clean his sludge trap...

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hee hee

That IS all he's doing, really. All the rest is just "along the way".

Well here is the plan of attack:

New superblends on the way. Along with shim kit (outer race shims from Fred) , Norton Genuine conrod nuts/bolts and all new crank bolts and studs.

Crank is coming apart for sludge cleaning. Crank ears going to crank shop for checking, then fixing of drive ear where inner race was spinning a bit. 2 new inner races pressed on. Then back to me for re-assembly..

Thanks for all the help here!!

You don't fool around Jerry!

The big end journal diameter “As Stock” should be between 1.7509”-1.7504”
When you remove your con rods check for stampings on the underside of the bearing shells. “STD” or nothing at all would indicate no Regrind. "+ 0.010" on the shell would indicate the shell is +0.010 thicker and the journal has been reground by removing 0.010”
If you are going to send the crank cheeks in to the M/S and they must do a regrind, you should include the roll pin dowl in the crank flywheel. Use a drift to get it out and fit it with the two cheeks all bolted together again less the flywheel. You can grind the Dominator with the crankshaft as one piece but not a Commando. I would also give them a photocopy page of the Norton Shop Manual stressing the importance of the 0.090" Face Radius. They would dress the wheel before grinding the throws. You will find this in section C 20-21. You can do a quick check if you have a 1-2 inch Micrometer. If you find the big end journals out of round by more than 0.0015” you are looking at a regrind. Check the journal surface finish at the area closest to the roll-pin hole. (underside of the crank) if it is rougher than the top again you are looking at a regrind. Your M/S would be able to advise you.
CNN :wink: