Noisy VH engine - Roller mains

[nevhunter]

It's also very important to get the small end boss central. Where's the Noise coming from? Do you see any evidence of something being where it shouldn't be? Nev

[Roger Gwynn]

Simon - Your are correct about the FH, it is a long time since I worked on one but when the price of lipped roller bearings for SQ4 went through the roof I talked to a tech guy at a bearing specialist who told me that the lip was not there as a thrust face and if the end float was controlled by other means a non-lipped brg would be OK and much cheaper. He may have been wrong but it doesn't look like it has been designed to take end thrust, not that there should be much of that.

[Pete.Silson]

Nev

It's also very important to get the small end boss central.

The small end boss was central to the crankcase join and the big-end was smooth with no discernable vertical play. The relined standard bore and piston were smooth with little wear.

Do you see any evidence of something being where it shouldn't be?

The noise seemed to be from the timing chest and the valves were always "clattery" despite regular tappet clearance adjustments. The valves had different springs fitted - the exhaust had a 520-34 the inlet had a 525-35. The head of the inlet valve stem looks a bit hammered...

...and the valve cap very dished.

The timing side main bearing was rough...

...and, on the drive side, the crankshaft splines weren't the best.

All these engine 500 components going to be used in a different engine so will be having new mains (2 roller and 1 ball bearing), valves, springs and caps. I am not sure whether it is worth the expense of fitting a new splined shaft to the drive end of the crank. The current engine is being rebuilt as a twinport 350 with roller mains and steel flywheels.

Pete

[Simon.Gardiner]

....it doesn't look like it has been designed to take end thrust, not that there should be much of that.

I'm not at all suggesting that a lipped roller should be taking any significant end thrust - there are proper bearings for that - just that they don't seem to mind doing a bit of end-float 'constraining' in a motorcycle crankshaft application when they have to!

On the FH/A10 if you substituted a plain roller in the drive-side you'd be relying on the mechanics in the primary transmission line to prevent the crank moving outwards until the drive-side crank web was running against the crankcase, and/or the oil pump worm drive on the timing side stripped. The lipped roller definitely has some part to play in controlling the crankshaft end-float, and there's enough of these engines running quite happily without that being a problem that I don't think having to perform a similar function in an Ariel single would be an issue. I can't see a 'floating' Ariel single crank generating more end thrust than a big old 650 twin (also remembering that the same setup was used in the much higher tuned 650 BSA Rocket/Super Rocket twins as well).

SG

[nevhunter]

The set up of the Twins and SQ4 is different. Load carrying capacity of deep Groove high load ball bearings has improved. Corrosion and cage failure can happen with any. . For the amount We use this stuff a Ball bearing set up would be reliable and adequate. Till the extra bearing on the drive side happened a single Ball race was adequate on an 84 MPH machine. . A self aligning ball race had less than half the load carrying capacity of the later races. There's also nothing to stop a plain unlipped roller race outer sleeve from moving till it hits the flywheel if the FIT in the case is lacking interference when HOT. Magnesium alloy cases are a bit notorious for it.. Nev