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Re: Main end front bearing

You're not telling us which a/c bearings you've got - narrow outer race or wide outer race. The next move depends on this.

Location: Bonnie Galloway

Re: Main end front bearing

I've (apparently) the earlier, deeper housing with the narrower a/c bearings requiring a couple of 1/32 spacers.

Location: Bedford

Re: Main end front bearing

Shuttle,

you are welcome to phone me on 01419428037 and, if I can help you with this, I will.

Re: Main end front bearing

Hi Shuttle,

As I said in an email to you-

I think that If your bearings are narrow outer ring angular contacts then they could be approaching 80 years old.

For the cost of a new pair of standard width angular contact bearings you problem will be solved and you won't have to do it again with all the resultant work when the old pair fail after being disturbed as they might well do (providing you are careful fitting the new pair) .

As noted above, if interested you might check the Forum for recent discussions on Crankshaft Bearings.

Tony.

Location: Melbourne, Australia

Re: Main end front bearing

As Tony suggests, having stripped down the engine and with the ready supply of good (branded) bearings, I would never skimp on the the cost of replacing the mains.

Location: Farnham

Re: Main end front bearing

Had a good long conversation with Ruairidh. Gave me some very useful information which I'm certain will apply. Thanks.

This isn't my car, but belongs to a museum where I'm an unpaid volunteer one or two days a week. I'm trying my best to maintain standards against budgets and general ignorance, mostly mine as I've never encountered 7s before.

I'm sure I'll be back here sooner than later.

Location: Bedford

Re: Main end front bearing

When I was seriously running a Seven, much of the satisfaction was from eking many quality miles from discarded parts.

The bearings may be recent modified ones. But even if old, age is of no consequence if the balls and tracks are uniform shiny with no pits or indentations or rust patterns, and the external diameter not seriously worn. Cleaned dry bearings with the thick edge of outer rings abutting and the inners pinched together should have no or barely perceptible shake. Spacing the outer rings with a very very thin shim can restore this although it is a bit haphazard as track wear is not uniform.
I suspect that in their day the a/c races were a cheaper solution; load rating is not increased. Absolutely no clearance, which lessens the harshness, but expensive to obtain with rollers, was achievable/achieved. Significant preload brings a rigidity which seems a dubious goal with such a flexible crank and frail lip.
I gather some have used inexpensive ordinary ball races which would seem to offer radial clearances no worse than standard rollers but there has been no direct response to this on Forum.
Unfortunately, if the external rings have not been clamped, bearings have likely been moving and turning in the crankcase and may be worn undersize (and the crankcase lost the interference fit) although could still be within new tolerance. For new bearing outer dia may be ½ thou under nominal size; years ago, based on info provided by Tony P, the tolerance range was double this.

Location: Auckland, NZ