187 replies to this topic

[ajperry]

Hello all.

I’ve been a long-time supporter and viewer on this forum and can now finally post something mini-related as I now have some funds and garage space. No mini yet, just an engine as this is what current funds allow but this will help me to get things started and keep me busy. I should say I’m pretty much a novice but have been using the trusty Haynes manual and reading the numerous threads on here to get on with it. But please, if you see something that’s not right, shout. All advice and recommendations welcome.



I purchased this 1275 metro engine at the beginning of February and have been slowly dismantling it over the past few weekends when I have spare hours in the evening and weekend when the kids are occupied!

What I got:
1275 metro engine, A+ block bored out 0.060” to 1330cc, 12G940 head, not sure on the cam until I can get it out, pistons are dished (and very coked up) but again don’t know what they are until I can get them out, gearbox is standard as far as the previous owner knew. Also came with a HIF44 SU carb, water heated manifold and a few bits like alternator and starter motor.

What I’m planning:
I’d like to completely strip the engine and clean everything up to see what I’ve got and what needs attention, as with most builds I’m sure I’ll end up replacing a lot of bits as I start rebuilding. I’d like to come out with a fast road engine that I can use regularly on the road and rarely on the odd track day/drag strip. I’m thinking keep it as a single HIF44 SU, looking to get some larger valves installed something like 36 inlet and 31 exhaust, 276 cam, 1.3 roller tipped rockers, straight cut drop gears, 3.1 or 3.44 final drive. Not decided on diff so appreciate opinions on that.

The dismantling continues so next is the cleaning and sorting what needs replacing. Pics of engine in various states of undress below. Thanks for looking!

[whistler]

To my eyes you have a mixture. The block is A+ Metro. The engine number looks to be intact and not interfered with. Have you found +60 on any of the pistons? The clutch is pre verto with an inerter starter and the head looks like an earlier 1275 leaded non metro 12g940 with standard valve size.

There are duplex timing gears and chain fitted.

I would say the metro short engine has been fitted to an older mini transfer case/clutch and gearbox. 

[ajperry]

Hi, yes it is a mixture and I had noticed it was an earlier leaded head and pre-verto clutch. I was planning on getting the head converted to unleaded when I have the valve seats machined, if it hasn’t been already? It was used in a metro by an enthusiast so has been tweaked a bit so thought I would find some other non-standard parts. Haven’t seen any +60 markings on the pistons, just going off of what the guys said it was.
Anything else out of the ordinary you can spot let me know!

[Retroman]

Looking at your spec, I would save the money on the sc drop gears and put that towards having the head improved

 

Sc drop gears can be very noisy and you really don't need them

 

A well worked cylinder head should be a priority and give the best improvement in conjunction with a 276 cam

 

Diff wise go 3.44 its a good all rounder

[ajperry]

Thanks whistler and Retroman, your replies and input are much appreciated.

I’ll have a look around locally and see where I can get the head ported and how much it’ll cost me as I’m sure it won’t be cheap but as you say I can save the money from the sc drop gears.

Hopefully do a bit more dismantling tonight so I can see what the gearbox looks like. Apart from a central oil pick up is there anything else people recommend doing while
I’ve got the gearbox broken down?

Thanks all
Perry

[imack]

Mini spares twin cross pin diff for reliability.

[ajperry]

Mini spares twin cross pin diff for reliability.

Thanks imack. Will add it to the list!

[ajperry]

Just as a little extra info as I did some digging on the engine number on Guessworks/MiniMania and have found that my engine number 12H907AA is indeed a metro engine (leaving this here for my future reference too!)

 

Guessworks:

Source Vehicle :  Metro  Engine type & CC :  A+ 1275 cc Transverse mounted  Fueling :    Engine features :  Lucas 16AC alternator with -ve Earth Gearbox features :  Std. Ratio Rod Change gearbox with Pot Joints 

 

MiniMania:

12  =  1275cc

H  =  Transverse

907  -  Yd + Bf + Hm + Sk

(Yd  -  Mechanical fuel pump)

(Bf  -  Alternator with negative earth)

(Hm - LC8 design variant (probably means the 'Low Compression' A+ derivative of the A-series engine - as in '&' denotes a Mini engine))

(Sk  -  Standard ratio gearbox with 3.44 Final Drive, inboard CV joints and rod change)

AA  -  Carburettor crankcase ventilation and intake air temperature control

 

Now the question of whether the pics above show the engine is 'original' spec or as suspected a mixture of parts...

Edited by ajperry, 05 March 2019 - 01:40 PM.

[ajperry]

the head looks like an earlier 1275 leaded non metro 12g940 with standard valve size.

 

Looks to me like the cylinder head has already been converted to unleaded seats, can someone confirm?

 

[Retroman]

I would say so

 

A really good clean and you can see the hardened seats are a different metal

 

Finger in the port, there will probably be some really sharp edges on the actual insert...very bad for power

[Steve220]

Rather than just take it to anyone to do the porting, speak nicely to Turbo Phil on here, his work is incredible.

[ajperry]

Thanks for the responses. Turbo Phil has been recommended via another topic in the tech section so will be contacting a few people in the next few weeks.

I'm going to clean up the head and check as Retroman suggests.

[ajperry]

Bit more tear down today. Got everything except the gearbox dismantled.



Also I can highly recommend using an old baby changing mat under your engine when you don’t have a stand for disassembly. Easy to slide the engine around on the cardboard and keep the major spills contained. Now that the main disassembly has been completed it’s time to say goodbye to this old friend.

[ajperry]

So a few things have happened since my last post.

1. Thanks to AC Dodd for identifying my cam as a mini sport version of the old 544. I may keep for now but as has been stated cams have moved on a lot since the old 544 so I’ll see what happens as I continue the clean up. Recommendations always helpful.
http://www.theminifo...tifying-my-cam/


2. Turns out it’s a 1380. ?
Having removed the pistons and completely stripped the block I thought I should turn my attention to measuring and confirming a few bits. The guy I bought it from was sold the engine as a 1330 and he’s not done a major strip down while he was using it so that’s what he told me it was.
All of the pistons are AE 20659 measuring 73.5 at the skirt and seem to have different markings on the tops as shown below. The rods are all 12G1507/8 but looks like two have been swapped out/newer?

I weighed all of the pistons and rods and they have been reasonably well balanced as evident from the machining on the big ends.

Piston 1 - 1119g
Piston 2 - 1116g
Piston 3 - 1119g
Piston 4 - 1114g










Anyone know what dish these pistons have? 7cc? Ideally would like to keep these as the look to be in fairly good shape. Want to start working out the compression ratio so could someone assist with a recommendation on best CR for a 1380? Thanks

Beer o’clock ?

[ajperry]

Polished up the flywheel bell housing today. Just a little job but satisfying. Combination of degreaser, paint scraper, and wire brush drill attachment to remove an dthen polished up slightly with wire wool and some autosol.
Couple of ‘before’ shots I had in my records and the finished article. Pretty happy. Not sure whether to now prime and paint or polish up further and seal it to keep it shiny. ?