5 replies to this topic

[1968S]

My 1968 Cooper S has an A+ engine installed, what would be the correct engine?

Thick or thin flange?

9F... prefix and serial number range?

 

Some data from the web:-

1275cc
9F/Sa/Y         31001 to 31504 Purolator oil filter
9FD/Sa/Y    Closed circuit breathing with oil light switch in filter head from eng No. 32178
9FE/Sa/Y    Closed circuit breathing with oil light switch in Purolator filter housing
9F/Sa/Y       32378 on, closed circuit breathing with Purolator filter with oil light switch
                     40006 on Aeg510 camshaft
                     42730 on cross- drilled EN40Bcrank
                     42548 on metal dipstick tube

 

Thanks in advance

[floormanager]

Thin flange.  I believe the thick flange blocks were for Mk3s.

[Spider]

It's likely be Thin Flange. The Thick Flange S Blocks were phased in from around June to August 68 - give or take a few months.

[Cooperman]

I once restored a 1969 Mk.2 'S' and it had a thick-flange block. Of course, the engine might have been changed years before as it was easy to get a reconditioned 'Gold Seal' or 'Silver Seal' engine from BMC. With an 'S' in those days it was usual to need a new engine at 60,000 miles, or even less if driven hard, which most of them were.

A BMC recon engine could have a thin-flange or thick-flange block when it arrived. In terms of originality in an 'S' it probably doesn't matter too much and won't affect the value.

[floormanager]

Mine had a recon engine in the early 1970s and had a think flange block on a 3 synchro box (registered Jan'68).  Recently, I've replaced the engine with a thin flange variant.

[Cooperman]

The main thing is to have a genuine 'S' block, crank & rods. This includes an EN40B crankshaft with the 1.625" big-end journals and a block with the cam-follower access panels in the back.

I have to say, if asked to validate an engine as 'genuine 'S'', I tend to ignore the flange thickness so long as the other identifying features check out OK.