Sidevalve axle.

Post by **minor_hickup** » Tue Sep 23, 2008 9:33 pm

I was just wondering if anyone had any experience of how strong these are. Before I assume that because they only have 25 or so bhp to cope with they're weak I thought I better ask! I was contemplating keeping mine on my series II for a bit. But if I risk blowing it apart I won't bother, they're not going to make any more!

Post by **Dean** » Tue Sep 23, 2008 9:56 pm

Is it an 803?

Post by **minor_hickup** » Tue Sep 23, 2008 10:02 pm

It is, but it will probably have a warmed over 1098 by the time its running. I forgot to add its an early transition series II so lots of series MM stuff on it, like the axle.

Post by **Dean** » Tue Sep 23, 2008 10:11 pm

Mine has the same diff and lots of other MM stuff too. To be honest I've no experience with them but I wouldn't risk running a 1098 on it. You'd be better off running a diff you can replace than one you can't if it did break.

Post by **Scott** » Wed Sep 24, 2008 7:16 am

They're quite a strong rear axle assy but the Series II version of the sidevalve axle was 5.25:1 so you'll be revving out very quickly with a 1098 in front of it.

The sidevalve is better with 4.55:1 but you'd more than likely be better off with a 4.22:1 or 3.9:1 diff ratio so the banjo type rear axle is the way to go.

Post by **downsey** » Wed Sep 24, 2008 3:02 pm

They aren't nearly strong enough, you'll break it with time.

Post by **bmcecosse** » Wed Sep 24, 2008 3:04 pm

Yep - I would change it right away for a later axle with a 4.22 diff.

Post by **mike.perry** » Wed Sep 24, 2008 9:23 pm

The Morris type axle is quite capable of handling the power output from an Alta overhead valve conversion which will see off a 1098. It is also capable of handling the output of an Alta head with a supercharger. Ask Keith Luck. They can wear out eventually and can have a fair bit of backlash. Providing the axle is in good condition you should have no worries. If you are tempted to strip it down for a look read the workshop manual first then change your mind.
Check the axle ratio. It is stamped on the N/S axle tube near the diff. If it is 9/41 it is a Series MM axle ratio 4.55:1
If it is 7/37 or 8/43 it is a Series II axle ratio 5.286:1 or 5.375:1.

Post by **bmcecosse** » Wed Sep 24, 2008 9:30 pm

No doubt - but spares are hard to get now, and the 4.22 ratio of a 1098 axle will be better for fuel economy and (slightly) more peaceful cruising!

Post by **minor_hickup** » Wed Sep 24, 2008 10:05 pm

Agreed! I thought it could be a bit of fun to have super low gearing for a while! But if its at the expense of rare parts I'd rather forget it!!