Which A-series?

Post by **chrisryder** » Sat Jan 15, 2011 12:59 pm

found that head on ebay:

http://cgi.ebay.co.uk/MINI-METRO-1275-B ... 256061ab36

£75

those valves are massive though, almost touching!

Post by **cmea** » Sat Jan 15, 2011 10:32 pm

I thought the big valve heads had 2 extra holes to assist with bolting them on and torqueing them down. That looks like a 1275 head with big valves in.
What sort of price should they go for - this one dosnt appear to be moving at £75.

Post by **Mogwai** » Sun Jan 16, 2011 11:50 am

The 266 is not to dissimilar from the MG Metro cam just has a little more lift & I think slightly longer duration

If you already have a head that's needing work you could have the throats cut & blended in for larger valves at the same time

Post by **chrisryder** » Sun Jan 16, 2011 1:58 pm

i've not had the head off yet. engine still sat in the midget that it came it

so for all i know it could have been breathed on anyway. will have to get around to clearing some space in the garage to strip the midget. although my dads wolseley 1500 is taking up all the space at the mo waiting for some new sills... i cant complain really, the other half of the garage has had my 2 door shell in there for 5 years now...

that head on ebay hadn't even met its reserve at £75... optimistic seller methinks.

Post by **bmcecosse** » Sun Jan 16, 2011 4:35 pm

The big valve heads didn't all have the extra holes - only the few that were on Cooper S engines - although many seem to drill the holes in and pretend...... Note the Metro Turbo engine (most powerful factory A series) didn't have the extra holes - so they really aren't necessary...... And yes - don't worry about unleaded. Yes - that's the only big valve head going at the moment and that price is now realistic although not so long ago I used to get them for ~£20..... The valves are close - and that's why the head can't be made 'unleaded' - although the original Cooper S head had same size inlets and even larger exhausts - so they were even closer together - and tended to crack between the seats. Hence the down size on the exhausts in the 940 head. The valve guide centres can be relocated away from each other to allow even larger valves (and sometimes installed at an angle - the famed Longman 'angle valve' head) but these mods are not for the faint hearted ! It is indeed possible to simply bore (or even manually grind) out the throats and install the larger inlet valves in a normal 940 head - and this should be a standard part of any head modification scheme......However - if it is an unleaded head - the inserts may come loose - so not a great idea...

Post by **chrisryder** » Tue Jan 18, 2011 10:53 pm

Right, running with the idea of using the 1275, i've been galvanized into action to get the engine out of the midget and find out exactly what i've got and what i need to get!

Glad i did as upon removing the HIF carb i discovered that it wasn't a 38 as i thought, but a 44. awesome! saves me finding a 44!

Silly thing is...[frame]

[/frame]...some bright spark put it on an inlet manifold for a 38! so there's a huge (oddly offset) 'collar' offering a massive amount of turbulence, and an equally massive puddle of fuel!

I think there's enough meat in the manifold to open it out, bit worried about breaking through though. i suppose i can always sleeve it if i do! it looks a well designed manifold, fairly long shot unlike some short mini manifolds. biggest problem with it was getting it off! you can barely get a spanner at the manifold nuts to undo them!

i decided to whip the rocker cover off too while i was at it. can just about make out 12G940, so that's a relief! Oddly aswell, the rocker cover had been bolted up so tight you could barely make out the gasket! and i had to lever it off with a screwdriver as it had stuck to the head! and the rocker cover was full of 'mayonaise', hope that's not too much of an issue!

I've had no experience of 940 heads. i notice this has got double valve springs. do all 940's have doubles? i'll get the head off in the next day or two to see if it's been unleaded or anything. already. just want to know what i'm working with so i know what to keep an eye out for!

(extra perk, 2 gallons of petrol in the tank

that's saved me a bob or two!)

Post by **bmcecosse** » Tue Jan 18, 2011 11:33 pm

That old petrol will be worse than useless.................... Few 940s have twin springs - it 'may' have the larger inlet valves.

Post by **cmea** » Wed Jan 19, 2011 12:00 am

The petrol should be ok for an A series. I had a moggy laid up for 8 years (awaiting welding prevented by children coming along!) which I never topped up, but I used to start it every 6 - 12 months and occasionally drive it out of the garage to clean it.

Post by **chrisryder** » Wed Jan 19, 2011 12:14 am

hopefully i do have a good head then

the 'old petrol' won't be that old, the car was still roadworthy and used daily until october when its mot ran out.

i decanted it into a 1 gallon can which i poured straight into my minor (the tank that is...) and filled that can again. when i went to fill it a 3rd time, it only pumped for 30 secs then the pump was pumping air. so that last bit out of the bottom of the tank (which i was worried could be a bit contaminated) has been saved for cleaning purposes only.

cant wait to rip the head off, but got to go to uni tomorrow and thursday!

Post by **bmcecosse** » Wed Jan 19, 2011 2:42 pm

Student life is hard indeed.........in my day I had yo go everyday - all day long too.

Post by **chrisryder** » Wed Jan 19, 2011 5:31 pm

i'm not complaining about not being in every day. gives me more free time to play with the cars (in which i learn more than i do at uni...). But i'm not here to debate the pros and cons of student life.

i'll be doing a compression test before i take any more off the engine to see if i've got any losses, and to see if i can afford to take the compression up while the heads off. fingers crossed i've not got low compression on number 3 (always seems to be the low one for me, on numerous engines!)

any ideas how to get the engine out of a midget? i can't see that the front comes off like a minor, and as the bonnet doesn't open very far, i imagine i may have to take the bonnet off to lift it out!

Post by **cmea** » Wed Jan 19, 2011 7:10 pm

bmcecosse wrote:Student life is hard indeed.........in my day I had yo go everyday - all day long too.

and I thought that in your day you had to either go down the pits or up the chimney!

Post by **bmcecosse** » Thu Jan 20, 2011 4:35 pm

Or - work on the railway.......... Wish I had gone that route!

Yes - Spridget bonnet off then lift it out at an angle.

Post by **chrisryder** » Thu Jan 20, 2011 5:21 pm

right-oh, got the head off today. not sure what i've got though! having no experience of 1275's or even 940 heads, i dont know if what i've got is standard or modded! so here are some piccys!
[frame]

[/frame]
very thick oily mess, but i noticed that there is little shape to the top face of the head. i recall that there are different kinds of 940, some are all flat (between thermostat and rocker cover) like mine is, and some are profiled a bit like a 202 or 295 head. does that make a difference?[frame]

[/frame]
i don't know if this chamber shape is standard of if that's been opened out at all. the valves are 33mm inlet and 30mm outlet, so 1.299" and 1.181" respectively. is that standard? i can make out 'rings' around both valves, more predominantly on the exhausts, do they look like unleaded seats? or are they just witness marks from machining? the chamber measures roughly 9mm deep too. is that too much? too little?
[frame]

[/frame]
the inlet ports have a circle machined in, i'm guessing this was for 'locating rings' when it had the twin carbs. does anything else look different?

the only other thing i measured was the bores in the engine. they're 71mm approx (battery died in vernier!) is that standard bore for a 1275? i could see anything on the piston crowns, they're a bit black and it's a bit dark now!

Post by **chrisryder** » Thu Jan 20, 2011 9:08 pm

i forgot to mention, i did a compression test before i took the head off. the engine wasn't warm (as i'd taken the manifolds off a day or two ago) so i'd guess the reading for cold would be lower than warm. the engine didnt turn very fast as the batt was a bit low, but i only got 60-70psi on each bore after a few turns. i didnt see the 'first pump' pressure as i didn't have enough arms or eyes, but 60-70 was the norm on all bores. Does that scream 'worn rings' to anyone else? or is it to be expected from the engine not being warm?

Post by **AntB** » Fri Jan 21, 2011 1:25 pm

quick suggestion, if you want to know all there is to know about identifying different a- series heads and haven't got a copy of Vizard's book i'd really recommend it.

warning, you will end up wanting one of these though:

Post by **chrisryder** » Fri Jan 21, 2011 3:43 pm

blimey! i think there's an a-series lurking in the middle of that lot!

is that a bmw bike head by any chance?

i purchased a copy of the big yellow bible several years ago. then my dad duly pinched it to rebuild my sisters minors engine. i've finally got around to yanking it out of his hands so i can read up on what i've got!

Post by **chrisryder** » Fri Jan 21, 2011 4:45 pm

ok, the vizard book informs me that the 'flat' 940 head is the earlier type, pre-turbo design. and the valve sizes are standard for the flat head too.

the bore is standard too by the looks of things. oh well, on the bright side that means it hasn't been messed about with!

Post by **AntB** » Fri Jan 21, 2011 4:57 pm

chrisryder wrote:is that a bmw bike head by any chance?

KAD make their own heads.

http://www.kad-uk.com/

from what Vizard says (and he should know) the one thing that stopped the a- series being a truly great engine was the power limiting siamesed port, non- crossflow design.

that's why 8 port heads are so great.

http://www.med-engineering.co.uk/home.php

Post by **chrisryder** » Fri Jan 21, 2011 5:09 pm

i've seen arden 8 - port heads on the market. not cheap though! and then you get lots of more expensive things like the carbs, manifolds... all adds up. i don't want a rocket that costs a fortune and wears everything out rapidly. i just want 80 or so bhp so it moves a bit quicker.

i did stumble accross the 'big bore engines' section of the vizard book. had no idea you could take a 1275 up to 1596! not planning on doing that myself before you ask

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