crank endfloat & x stamp

[tim1920_1]

Hi all,my silver century plus has 3-4mm/120+ thou of endfloat when i pull the magneto flywheel up & down,no side to side just up & down.I know some endfloat is normal but is this amount excessive,the motor runs very well otherwise,is the lower crank bush worn to cause this or is it not a problem,i can't find a max amount in my manual.Secondly on the alloy crank case where the steering handle(tiller ?) bolts on a single x is stamped,does anybody know what this means it has the relevant century wspc letters on the other side of the case,as normal,cheers Tim

[Oyster 49]

I've just checked the century I have just rebuilt for a friend. End float is approx 1,0mm or 0.040 inch. It might be worth having a precautionary look at your crank & main bearings if the top end can be stripped down easily.

[GDTRFB]

My end float is .035" or maybe a tad more. From my post a few weeks ago, that is very normal even new. 3-4 mm does seem excessive.

but I am a rookie too these things, so my knowledge is minimal!

[tim1920_1]

cheers guys,i would more likely expect the figures you are quoting,but i can't find a max value in the manual so who knows? In the diagrams in the manual,there appears to be a lip on the main bearings,which i guess is a running surface to control the crank end float,maybe this lip on the lower bearing is worn,the engine still runs sweetly tho,i've never stippped one these engines so not quite sure what it looks like inside.

[Charles uk]

I've never seen any published figures on maximum permissible crankshaft endfloat, so don't worry, I don't think it makes any difference.

The X stamped on the tiller was the code number of the engine builder at Seagull, no records remain of which member of staff these codes relate to.

[tim1920_1]

Hi Charles,ok thanks thats reasuring,i suppose to a certain extent the mentality of if it ain't broke don't fix it applies to these motors.It's funny i run two modern rally cars with approx 600hp between them that require to be connected to a laptop before they can be started,a few modern off road bikes & a rib with a modern engine on the back (the century is it's auxillary) yet i get a huge amount of enjoyment tinkering with a 40 year old antiquated British outboard engine the design of which has'nt really changed since D-Day,and is the marine equivalent of a BSA Bantam.Drives my wife nuts,says all ever talk about lately is "bloody seagulls" LOL.

[Oyster 49]

Hello Tim,
I've recently been suffering from the same problem "seagull addiction" which also comes with associated earache, which can be fixed with earplugs.

No cure for addiction I'm afraid. As your therapist I presribe buying another seagull to restore.. Only problem is that this will lead to more addiction..

[charlesp]

'...the design of which has'nt really changed since D-Day'

A bit before that - 1936 I'd say for a 102. Many would say earlier.

[Oyster 49]

Charles,

Do you know the main reasons for the change in design which resulted in the century, and why did the 102 continue after the century was introduced?

[charlesp]

Why the Centuries?

I have never got a satisfactory answer to that one. The other Charles has said it could be that the Centuries were cheaper to make, but I simply don't know.

I do know that the early Centuries (Villiers ones) were filling a gap between the Forties and the 102 series.

There is also the fact that a clogged set of waterways in a Century can be unclogged, those of a 102 can't.

[Charles uk]

I was told several years ago by the ex production director of British Seagull that the wastage factor on the 40 series cylinder block was much lower than the 102's which had always been a major problem/cost as more often than not as some flaws were not found until at a later point during the machining process or on the final test tank run prior to dispatch. Obviously causing some significant costs!

I have seen many different 102 styled cylinders, perhaps 6 or 8, & it has always been felt by the Seagull racing fraternity that the early 102's produced more power than the later ones, though there is no documented evidence of this, that I've seen.

So it might be valid to assume that British Seagull did not modify their foundry casting patterns to give more power, but to lower the scrapage & therefore the unit cost.

It would also be logical, that the Century 100 & the following Century generations were just part of this process to achieve a lower cost modern looking more maintainable product, that would enhance the Seagull brand name as their fore fathers had done.