10 replies to this topic

[d-lux]

is there anyway of telling by looking whether or not my engine is a 1275. the person it was purchased off said it was, but i've been told that a 1275 has 2 extra bolts either side of the cylinder head? is this true? :sad:

[Bungle]

only cooper s heads :smartass:

i think the only way is to take the head off a measure the bore and stroke :smartass:

[siggy]

Only Cooper 'S' Innocenti and some 1275 GT have 11 stud heads.

Check the angle of the thermostat housing.



Siggy

[dklawson]

Not all 1275s have the extra stud and bolt you were told about. The non-S 1275 heads have the standard 9 studs. Take a look at the position of the heater valve on the head. All the 1275 heads I'm familiar with have the heater valve angled at about 45 degrees. I remember seeing somewhere that small bore heads have the heater valve perpendicular to the long axis of the engine. You can put a large bore head on a small bore engine but there are block modifications required so this is rare.

On the back of the block, near the radiator end of the engine you may find a tag riveted in place. This may tell you the displacement.

There are probably other external clues but these are the two I am most familiar with.

[siggy]

Doug is right check the heater valve, looking from above, on 1275s are at 45deg and on small bore engines are inline with the centre line of the car.

Doug 1300 GT engines also had 11 Stud heads.

Siggy

[Oldskoolbaby]

what about the easiest option....tappet chests? If you look at the back of a 998 block, you will find removable plates. These are fitted to enable access to the cam followers etc. If you have these and only 9 studs then you have yourself a 998. If you have chests and 11 studs your a lucky chappy and have got your self an S. If you find you have none then you have got a 1275 block. Simple :smartass:

Bassicly, 998 blocks have 9 studs and two tappet chests
1275 blocks have 9 studs and no tappet chests
1275 S blocks have 11 studs and are fitted with two tappet chests

[siggy]

Don't forget that 1300 GT blocks have 11 studs and no tappet chests

Siggy

[clubman katie B.F]

maybe i am over simplifting things...but what is your engine number......there should be a plate on top of the block on the right hand sie at the front of the engine am i right in assuming an engine number starting in 12 means you have a 1275block?

[Gogobroom]

Can you posta pic of it - usually find that on the 1275 you can fit your whole thumb easily on the head at the side of the rocker cover - but all that will tell you is that it isnt a 998 or 1098 - well thats how I used to check many years back whe I first started

[d-lux]

there's no plate at the top of the block. however, heater valve is at an angle and there is no tappet chest so it looks like it is a 1275. thanx everyone

here's a picture of the block. the pistons seem to be dished is this a good thing or not?

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[dklawson]

I'm not trying to be a smart a$$ or anything here...

But if you had the head off the engine the whole time, you could have simply measured the bore and stroke to determine what size the engine is.

Whether you want dished pistons or not depends on what type of engine you're building. For a street engine running regular fuel, dished pistons are fine. The flat top pistons will give you higher compression which can equate to more power, but it often means buying premium fuel as well.