Hi, Can anyone help with this please.
I am building a 750 engine and I am at the bolting the crankcases together stage, I have new big end shells and main bearings fitted and a new camshaft. Everything is good until I fit the timing side main sealing washer,triangular washer,timing pinion and oil pump drive nut. When the nut is tightened everything locks up and the crankshaft will not turn. I have stripped,checked and reassembled several times but can't find anything wrong apart from the main bearing is wider than the shoulder it slides onto and protrudes about a mill or so past it, should it be flush? Because if it was it looks like everything would fit OK. I have bought all the parts separately and am now wondering if I have been sold the wrong crankshaft or a duff one. I would be very grateful of any help as I am tearing my hair out over this. Thanks. Billy.
Hi Billy. An interesting p…
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Previously john_marshall w…
Hi Jack, Many thanks for your reply, bearings are superblends with the captive rollers in the outer race, when I first bolted up the cases everything turned smoothly with a little end float,haven't measured it accurately yet but seemed fine. From what you say about everything bolting up tight to the inner race does this mean that the dished sealing washer also gets bolted up tight and spins with the crankshaft because it is a very tight fit in the crankcase and would not spin once bolted up? Billy.Hi Billy. An interesting prob. What main bearings are fitted? Are they the type with rollers captive in the outer race? What end float was set before fitting the nut which locks it all up? I expectany end float also disappears when nutted up? The pump nut assembly must be clamping onto some part of the outer bearingin the timing side.
I think the inner bearing race does overhang the crank shoulder a bit, but this should not matter, as the worm nut assembly should bolt up tight onto the inner race only.
You might try observing the end float disappear as you gradually tighten the pump worm. Might give you a clue as to where theclamping force is exerting.
TTFN Jack
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Hi Billy, I think you may…
Hi Billy, I think you may have your culprit with that dished washer. it all bolts up tight & spins as a complete assy. Should have clearance to do so. Try it without the washer & see what it does. Also check that end float with a dial gauge. A little can seem a lot & vice-versa.Best to get the actual figure.8 thou I got on my N15CS Atlas last year. TTFN Jack
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Previously john_marshall w…
Previously john_marshall wrote:
Hi Billy, I think you may have your culprit with that dished washer. it all bolts up tight & spins as a complete assy. Should have clearance to do so. Try it without the washer & see what it does. Also check that end float with a dial gauge. A little can seem a lot & vice-versa.Best to get the actual figure.8 thou I got on my N15CS Atlas last year. TTFN Jack Hi Jack, Yes it is the dished washer, far too tight in the case, will work on it to get it to drop in and invest in a dial gauge to set the end float,many thanks for your help. Regards,Billy.
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Hi Billy. An interesting prob. What main bearings are fitted? Are they the type with rollers captive in the outer race? What end float was set before fitting the nut which locks it all up? I expectany end float also disappears when nutted up? The pump nut assembly must be clamping onto some part of the outer bearingin the timing side.
I think the inner bearing race does overhang the crank shoulder a bit, but this should not matter, as the worm nut assembly should bolt up tight onto the inner race only.
You might try observing the end float disappear as you gradually tighten the pump worm. Might give you a clue as to where theclamping force is exerting.
TTFN Jack