Head Identification

[1098MOG]

Hi new here and i wonder if anyone can help

i have two minors, one is a 60 and one is a 71 which i have just bought for parts for the 60

when i bought the 71 he claimed that it had a oselli tuned engine in it, not calling him a liar as its got a torque master on it but he said its got a cam and such like which would be quite hard to determine as true at sale just because it had a oselli rocker cover sticker on it (could have bought it off of e-bay)

both cars are 1098 but have diffrent heads

the 71 has got markings 12G202, ive read conflicting info on this head, some say its a early cooper s and some say most 1098 engines have got them, was it standard in the minor?

heres a pick of the rockers as there much beefier than the other engine





now the other head on the 60' has the markings

RMO 21086 MOWOG 253D 2A629

and looks like this





any info on these heads will be great


also on a side note, this is the brake master cylinder on the 71 any idea what car it is off?




thanks

[bigginger]

From memory (could be wrong) 12g202 is the standard 1098 head - not sure about the other - does it not have a number similar to the other? That isn't a master cylinder, btw - it's a standard after market brake servo

[aupickup]

the last picture is a brake servo

[bigginger]

See? It is
a

[Matt]

2A629 - I believe is a standard 948 head...

12g202 is a standard 1098 minor head, however it was also used on 997 mini coopers.

The rockers on the '70 are the later type (sintered?) and have no real performace gains over the previous type.

The only real ways to tell if the engine has been tweaked is to get it on a rolling road, or to start taking it apart. It looks like the later engine has an LCB manifold, which will give a small boost in performance. What carb has it got, and what bore is the exhaust?

[bmcecosse]

Your 1960 car should have a 948cc engine - has it been changed ? The head is a standard 948 head casting although it does have the better 'pressed steel' rockers - only better because they don't break, no performance improvement. The 12G202 is a dead standard 1098 head - although yours may heve been fantastically modified - you won't know till you take it off. It's been fitted with Mini sintered rockesr which are fine for a standard engine - but can break if used with high lift cam and/or strong valve springs. To spec the cam you could take lift measurements all round the dial - v tedious - or inspect it when you strip the engine - it will have distinguishing marks/rings/numbers on it!

[1098MOG]

the 1960 more than likely had a change of engine when it was rebuilt in 95, engine block has a serial number starting with 10 so i presumed it was a 1098.

ive now took inlet off of head and exhaust and it seems like some port matching has been done to the inlet ports but cant see much opening to the exhaust and by god there tiny.

the exhaust is off but seems to be similar bore (mabe fraction bigger) than the standard exhaust

pic



outlet size is 1.5" which isnt all that great but probably is more than adequate on a 1.1, ill prob remake this so it end with 2" pipework to the rear when all is done

im new to the A series so bare with me, im a quick learner, how can you distinguish what su carb you have got on your engine?

ive tried the serch but its rather irattic and tends to scan the whole thread rather than a single post

thanks for input guys

god bless the internet!

[bigginger]

Looks like the standard over size LCB manifold to me. I've yet to hear of anyone needing to fit bigger. Are you aware that they originally came with a puny cast combined inlet/exhaust manifold?
Andrew

[1098MOG]

its a good improvement over standard, the branch is perfect but its the actual final bore size that may be a restriction on flow at high RPM, im just thinking safe rather than sorry at the moment, what does LCB stand for? excuse my ignorance

[bigginger]

Long Centre Branch (manifold). As I said, never heard of anyone *needing* bigger but I'm no expert - it's about 4 or 5 times the size of the standard exhaust. Jonathan and BMCecosse (and others) know their stuff re engines - one of them will be around soon, and can give proper advice on it.

[bmcecosse]

That exhaust looks fine (wish I had one!) - don't worry too much about the final size - it's only a 1098 engine after all !! That other head is definitely only a 948 engine head - but if the engine number begins 10 then yes that's a 1098 engine. Post a pic of the carb and plenty folk will tell you - but almost certainly it's a 1.5" carb (standard was 1.25") - which will be fine for the moderate tune of that engine. Anything bigger would be too big.

[1098MOG]

cheers guys

isnt there any castings on the carb to identify, the measurement that is that from the throttle plate.

when the heads off ill take some pictures of the ports

[alex_holden]

Take the air filter off (or the inlet elbow if it has one) and measure the diameter of the hole through the carb.

[1098MOG]

yep its a 1.5" one, HS4, found this on the internet which is very useful and told me all about the diffrent types etc.

if it stops raning ill take the head off tonight and see what other stuff its had done to it

[bmcecosse]

HS 4 is the older type - HIF 38 is the newer and better equivalent. Either will be fine on that 1098.

[IslipMinor]

Oselli heads should have information stamped at the rear of the head on the opposite side to the heater take-off. This will be OE-- and the combustion chamber capacity, such as 21.5cc. Does yours have this?

For the exhaust, it's worth reading Vizard as it is clear that going too big on the exhaust does not give more power! For a typical 'warm' 1098 something around 1 1/2" would be right. 2" isn't needed until you get to 100+ bhp.