Marina engine questions

[cadetchris]

So I’ve bought at 1275cc marina engine that I am going to treat to a total rebuild. It was previously in a traveller but has sat for several years and I’m going for belt and braces approach.
I do however have questions. As it’s an a series engine, I assume that various parts from a 1098 will fit it, but not all due to the natural size differences.
So, are the main bearings and thrust bearings the same as a 1098?
Is the timing chain the same? (I’d like to put a duplex timing chain in but I cannot seem to find them)
Is the timing chain front oil seal the same?
Are the cylinder head studs and exhaust manifold the same as the 1098?
Are the valve push rods the same length?
Is the rocker cover a direct swap between the 1098 and the 1275?
Can I use the current minor exhaust or do I need to upgrade to a larger bore one?
Is it the same dizzy in both engines?
Will the same clutch mechanism and plate fit the marina engine?


I’m sure there will be other questions along the way, but these are the main ones I have now.

[philthehill]

Is the Marina engine a pre 'A' Plus or 'A' Plus engine. The 'A' plus engine has strengthening ribs on the block.
The 1275cc 'A' Series engine is a different beast to the 1098cc 'A' Series engine.
Main bearings and crank are different size.
The timing chain is different. The duplex will fit. Plenty for sale on 'e' bay and Mini spares suppliers.
The timing chain cover oil seal is the same dimensions.
The head studs are the same but the 'A' Plus engine studs are better.
The inlet/exhaust manifold will fit but will be restrictive.
The push rods are different lengths. The 1275cc push rods are slightly longer to accommodate the taller block.
The 1098cc rocker cover can be directly fitted to a 1275cc engine.
The Minor exhaust is too small for a 1275cc engine and needs to be a larger internal diameter. At a push it could be used with the 1098cc inlet/exhaust manifold.
The distributers are different especially if the engine is a 'A' Plus engine.
To fit the 1098cc clutch assy you will need the modified flywheel from ESM if not already fitted. If fitted the 1098cc driven plate can be used.
The original Minor clutch operating mechanism can be utilised.
You will need to use a 1275cc Midget rear engine plate as the 1098cc rear engine plate is different. A modified plate can be obtained from ESM. You may find that a modified plate is already fitted to the 1275cc engine.
Any other questions please come back.
There are plenty of threads about this conversion on here just use the search facility.
Good luck.

[cadetchris]

Thanks for the reply Phil.
It’s a standard 1275 engine and not the A plus engine.
I aim to put a mini manifold and HIF carb on it and I’ll fit a large bore exhaust.
Thankfully the front and rear plates have been swapped for a standard 1098, as has the flywheel too, so that will make things easier.

If I think of anything else, I’ll ask/search through the many other posts on here

[philthehill]

The rear plate may be 1098cc but the 1098cc rear plate is not suitable for the 1275cc engine.
The oil pump centres are different which means that the 1098cc rear plate has to be modified which invariably leads to oil leaks or the plate cracking.
The opening around the rear main has to be opened out as well.
My advice is to fit the correct 1275cc Midget plate or use one of the ESM plates.

[cadetchris]

Thinking about it, as it came from a Morris, it must of had the rear plates swapped for an mg midget, otherwise it wouldn’t have fitted the previous Morris.

[philthehill]

That may not be the case - the rear engine plate may be a modified 1098cc item which as I said above is not the right plate to use.
If it is indeed a 1275cc MG Midget/Sprite rear engine plate the Pt No: AEG552 will be cast into its rear face below the oil pump aperture and to the left of the rear main cut out.
The 1098cc rear engine plate is not marked with a Pt No:.