Hi guys
I have just checked my crank end float on my a65 1967 engine and it's 3 thou , it has had a needle roller conversion by someone and arm say that if that's been done there will be no play when the inner
R/h needle bearing is not fixed as like a 500 triumph which has a ball bearing on the timing side so I can't see how the crank doesn't move in operation or am I being a dumb arse
Another question my barrel has 5/16 studs and no location dowels is that normal ? Hopefully I can be enlightened
Hi Spike,
If the crank pinion and pump drive are fitted and tight then there should be no end float. If they are not fitted and tightened up then there could well be some as there needs to be room for a bit of expansion when the engine gets hot. Check the condition of the ball race on the timing side bearing as it is this that holds the crank in place.
I know the 3/8 studs have locators on two of the studs that recess into the cases and corresponding slightly larger holes in the barrel base. If the barrels are off look for two slightly larger holes in the barrel base and the cases - one on either side. I think on the 5/16 it was probably just the studs and barrel and there are two part numbers for the studs.
Dave.
I'll look at my 67 royal star crank cases a bit later for you.
The 70 on has very prominent studs as Dave mentions.
The timing side needle roller bearing has a combined ball thrust race.
As Dave says the crank is locked when the oil pump worm is tightened. The 2 parts of the inner race pull together and locate the ball thrust race and eliminate any end float.
Dont attempt to check for end float without the timimg side fully assembled with pinion and worm drive because you bottom end is not properly assembled, the engineer who carried out the conversion, presuming it was SRM, will have machined your crank and cases for proper fit when assembled.
Photo shows timing side bearing in situ with inner race and spacer, you can see the thrust ball race.
The dowel/shouldered studs on the front left side (near the engine number) and in position with above the idler gear (moving 4 studs along clockwise from the first one) this is same on all crank cases regardless of stud size.
thanks fellas
not sure if srm did conversion ,i renewed the bearings and the needle bearing is not a two part bearing , but will put together and re check
If you have the motor apart. Can you measure the sleeve race on the crank and take photos if possible.
I. Some cases a smaller bearing is used to minimise machining of the cases (more machining of the crank however)but with this you can still use the thrust washer and set the end float at 0.003"
If it is SRM then the crank would be end feed to the big ends with a quill like my photo above.
The SRM type conversion would also have a modified outer timing cover oilway with oil seal like the photo below.
It's a little different on the unit twins Compared To the pre units. A snail shaped
Quill is welded on to the inner timing case.