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I have a friend who has a 1275 S engine that he bought in the late 70's and has had stored since in the back of his garage. He asked me if I knew what year mini it came out of and based on Parnells book all I can seem to find out is that it is probably out of a 67 but I don't know. The date on the PCV valve is 1-66 so who knows. I figure somebody on here will know more about it. Also it has the 333 box with hardispicer joints. Are there any other numbers on it other than the serial number we should look for? Based on the serial number is it possibly the original box to the engine?

I guess I am asking what should we be looking at to see if everything is original and correct to the engine. I will attach a couple pictures incase it helps to see what we should be looking for.

Engine ID 9F-SA-Y 46558

The A is smaller than any of the other letters. Still a capital letter A but smaller. Not sure why.

Brian

My early April '67 built Morris S Mk1 is in the 458xx range. So yours is a little after that.

Engine numbers are less easy to track than chassis numbers, but here are some other Mk1 S engine numbers that I have seen posted from around the net:

453xx March
458xx April (my car)
463xx July
471xx August
469xx October

So if they were knocking out about 500 of the 1275S a month, at a very rough guess, that puts your 465xx around June/July. But as you can see the sequence is not consecutive, so without looking at the original factory registers this is all an approximation.

The 'small capital A' is correct for an original engine plate. Repro plates have either a full-size A or a lowercase a.

12FA is the correct prefix for a 1275S 'Q' 333 box, and hardy spicer outputs means it's April 66 onward.

Nice engine You can also check the dates on the distributor, starter, dynamo and even the radiator to see if they match each other.

Sometimes there is also a date on the base of the gearbox, stamped into the flat boss area.

pdb wrote: ↑Thu Nov 19, 2020 7:49 am Nice engine You can also check the dates on the distributor, starter, dynamo and even the radiator to see if they match each other.

Thank you, I wish it were mine. I told him about the starter and dynamo and will relay on to him about the radiator and dizzy. The dynamo is from 12-63 and I havent heard about the starter. Might take a few days because he is an older gentlemen who's slowly going thru his mini stuff. Took him a few weeks to get to the S engine in the back of his garage. I wish I had that problem.

iain1967s wrote: ↑Thu Nov 19, 2020 12:09 am My early April '67 built Morris S Mk1 is in the 458xx range. So yours is a little after that.

Engine numbers are less easy to track than chassis numbers, but here are some other Mk1 S engine numbers that I have seen posted from around the net:

453xx March
458xx April (my car)
463xx July
471xx August
469xx October

So if they were knocking out about 500 of the 1275S a month, at a very rough guess, that puts your 465xx around June/July. But as you can see the sequence is not consecutive, so without looking at the original factory registers this is all an approximation.

The 'small capital A' is correct for an original engine plate. Repro plates have either a full-size A or a lowercase a.

12FA is the correct prefix for a 1275S 'Q' 333 box, and hardy spicer outputs means it's April 66 onward.

Thank you Ian. I am suspecting it's probably a june/july built engine but could be a little later. I think thats a good enough estimate for what he was after. Between your and the other response he has a few more things to look at. I completely forgot about the boxes being stamped on the bottom. I know early boxes were certainly stamped because I dated a 59 box for one of my minis. It would be grest if his is too. The engine and box were painted blue at some point before he got it in the late 70's which has brought up these questions about it having it's original parts. The dynamo is from a 63 so we know thats not original. I remember reading somewhere that there is an AEG number perhaps on the flywheel cover or bellhousing on the S boxes. do you knoiw anything about that? Also what intake manifold would be on that engine? It appears to have the original pipe on it and am curious if the intake is too. I am going to have him see if there are tags on the carbs or not. I really appreciate you taking the time to respond to this post. I don't know a lot about the S minis; very little really. I have a June 62 Cooper and am still learning about those!

Brian

Light blue engines ? Anyone know the history of them?

I have a medium/light (looks like metallic) blue 333-Q gearbox with rubber couplings.......

I'll look a bit closer tomorrow, to see if I can find traces of other paint under the blue...

Perhaps other country builds?????Austrailia, Africa, Italy etc.....

Has anyone asked whether the bottom of the engine block is a thin flange or thick flange type? If I recall, all MK I Coopers S's were thin flange blocks and when the MK II was introduced in late '67 they switched to thick flange one's which continued on to 1971, perhaps longer with Clubman's. If this one was produced mid-year '67 it would likely be a thin flange type. I'll gladly defer to the knowledge of the serious historians found here..

CALIMKIIIS wrote: ↑Fri Nov 20, 2020 12:44 am Has anyone asked whether the bottom of the engine block is a thin flange or thick flange type? If I recall, all MK I Coopers S's were thin flange blocks and when the MK II was introduced in late '67 they switched to thick flange one's which continued on to 1971, perhaps longer with Clubman's. If this one was produced mid-year '67 it would likely be a thin flange type. I'll gladly defer to the knowledge of the serious historians found here..

The MK2 Blocks were also thin flanged in the beginning, and can be found well into 1968.
I believe it was around October 68 when the Thick flange started to appear, along with the 4 Syncro box.
Correction. blocks were thin flanged untill late 69 not 68. Thanks David for that information.

bwaminispeed wrote: ↑Thu Nov 19, 2020 11:01 pm I have a medium/light (looks like metallic) blue 333-Q gearbox with rubber couplings.......

I'll look a bit closer tomorrow, to see if I can find traces of other paint under the blue...

Perhaps other country builds?????Austrailia, Africa, Italy etc.....

He asked me if I knew of any Cooper S engines that were originally blue because he doesn't see any other color under the blue. I told him I thought they were all green but I really don't know. Perhaps it is from a different country.

TECH396 wrote: ↑Fri Nov 20, 2020 3:56 am

CALIMKIIIS wrote: ↑Fri Nov 20, 2020 12:44 am Has anyone asked whether the bottom of the engine block is a thin flange or thick flange type? If I recall, all MK I Coopers S's were thin flange blocks and when the MK II was introduced in late '67 they switched to thick flange one's which continued on to 1971, perhaps longer with Clubman's. If this one was produced mid-year '67 it would likely be a thin flange type. I'll gladly defer to the knowledge of the serious historians found here..

The MK2 Blocks were also thin flanged in the beginning, and can be found well into 1968.
I believe it was around October 68 when the Thick flange started to appear, along with the 4 Syncro box.

It appears to be a thin flange block. Hard to tell but looks like it to me.

If it helps, I have a pale metallic blue 12G1805 S head. No trace of other colours underneath either. I've included a picture of it on my brother's mill getting a slight skim. It came with my Inno, but as far as I know Inno heads were all black and not blue. But I have heard of other 1805 heads in this colour...

Interesting that it has a earlier 1071 Oil Cooler, but a late Mk2 /Mk3 Air cleaner assy. Shown in that last photo.
What are the casting numbers on the block? I'm just trying to re-learn everything I've forgotten, I'm a bit rusty

While you're there, maybe take the rocker cover off and see what casting number is on the head near the middle rockers.

hanlminiman wrote: ↑Thu Nov 19, 2020 5:43 pm Light blue engines ? Anyone know the history of them?

Blue Riband Engines used to paint all their reconditioned units that colour back in the day. They were quite a big supplier and an alternative to the factory "Gold Seal" units. That is a possibility.