engine info please

[win]

Hi all
Can you please help identify an engine which has rested in my garage for many years.
engine no 12cc-D(then what looks like a small capital A)-H-15908.
Head casting No 12G984.
6 tapped holes in crankshaft, spin on oil filter,and duplex cam chain, and a damped fan belt pulley.
There are no bell-housing, or front engine mounting plates, and camshaft chain cover. will the parts from a 1098 fit?
Thanks Win

[bmcecosse]

Pretty sure it's a Marina engine - although the head should be 12G940 - never heard of 12G 984 !! 1098 flywheel can be drilled to fit - and you transfer the front and backplates over.

[IslipMinor]

With the 6 bolt flywheel drilling in the crankshaft, it looks to be a 1275, but which one? Where is the oil filter? If it is up by the distributor, and the filter fits on it upside down, then it is Marina/Ital - need more details to identify which. If the oil filter is in the 'normal' position towards the front of the engine and the filter itself fits the right way up, then it's a Midget.

There are ways suggested to drill the crankshaft to fit a 1098 flywheel, but relying only on 2 loose fitting bolts to provide the location for drilling the other 2 is not, in my view, good enough, and with no register location or accurate dowelling, I would not do it. The original, sound, design is that the flywheel is located very precisely on the machined end of the flywheel, which ensures that it runs concentrically, the dowel(s) ensure that it fits in one orientation and help to resist twist and the fixing bolts hold it all in place - they do nothing at all to provide the physical location, which needs to be something like an accuracy of 2-4 thou total concentricity runout - that's between half and the whole thickness of a human hair!! Even if the flywheel is clocked as part of the set-up for the drilling, how can it be maintained afterwards? You would need to clock it up each time and then rely totally on the bolt clamping force to hold it there (which should be OK, as it is the clamping force that provides the drive normally, not the dowels, but there is no back-up from the register for concentricity or dowels for drive).

I have seen the drilling/tapping suggestions many times, but what is the actual first hand experience of doing it and running the engine afterwards?

[mike.perry]

If the engine is a Midget block then there is no need to change the flywheel. Fit the engine complete with diaphram clutch and add a roller bearing thrust and modify the 1098 clutch linkage for manual operation

[bmcecosse]

Aye - but no mention of a flywheel in the original post. I believe most drill the 1098 flywheel - and fit 6 bolts into the crank - no drilling/tapping of crank. The alignment fears are all too relevant! Two bolts fit through anyway - and the dowel fits another hole. Best if there a drill jig in the form of a Marina flywheel handy - which is too large diameter to use unfortunately unless using a Marina gearbox - which comes with it's own problems but can be done I understand. Or indeed - source a Spridget 1275 flywheel - 'not common' I think!!

[IslipMinor]

Yes, pity there is no flywheel, but the alignment is an even bigger issue with using another flywheel as a jig as you are now using 2 sets of slightly oversize holes to do the job! You could use some special diameter pins to try as a good 'fit' in the holes, but since they were never used for location, I don't know whether is would work very well.

Is the recess in a 1098 flywheel the same size as a Midget 1275? I had understood from previous posts that it is defintiely not as a Marina/Ital? If it is the same size, then at least the basic location is good, so drilling the remaining 4 holes could be OK.

[win]

Thanks for the comments about the flywheel problem, the oil filter is just like a 1098, but a spin on.

[IslipMinor]

Win,

Makes it a 1275 Midget engine - very nice! That's what our 1380 is based on.

[bmcecosse]

It makes no odds really--still based on a solid cast block with no cam follower chest openings. But it is an advantage to not have the silly high mount oil filter which inevitably makes a oily mess down the block when changing it.

[Pyro]

Hi,

From memory the Austin-Healey 1275's had engine numbers starting 12CC.

Regards

Phil.

[RobThomas]

Might be your lucky day. The first few thousand 1275 Midgets left the factory with EN16 cranks and thin flange blocks which flexed so much that the production line had to be stopped. The early engines came back to the factory for their cranks to be replaced with EN40B Nitrided cranks that can be identified by the oilways in the big ends being drilled at 90 degrees to the original (now blocked off) hole, EN40 cast into one of the webs and finally a pale greay colour to the metal. If your block is about 6mm thick in places where it bolts to the sump then you may be onto a winner.
I sold my last EN40 crank for £300. Racers want them because they are almost unbreakable (within reason, obviously)

[bmcecosse]

Yes the EN 40B nitrided crank IS the one to have !

[win]

wow
Thanks everyone for the info. Looks like it may be too good for my S11, it may give her a heart attack.
Thanks once again.
win

[mike.perry]

I hope that you have a gearbox to go with it. An 803 box will not last long, and a decent diff would be useful and a brake upgrade.