Newbie MG Midget questions

[nmealey]

I've recently bought an MG Midget, its a 1978 1500cc, and have a few questions for those with a little knowledge.

How do I know if the car has had an unleaded conversion - The previous owner's daughter who I bought it from says it has.

If its unleaded, should I use regular or super unleaded ?

How do I know if its had an electronic ignition conversion ?

As you can tell, I've got very little experience with these, the last time I saw an an older engune was about 20 years ago.

Thanks in advance, Neil

[Markgenesis]

No way of telling if it has had an unleaded conversion as it involves fitting hardened valve seats, even if you stripped the engine down you cant tell by looking at the seats, you will just need to take the sellers word for it, unless they can tell you where the conversion was done and you can contact them to confirm.

Should be ok on plain unleaded, some additive wont do any harm, just listen out for pinking under load (a metallic rattle sound meaning the timing needs adjusted).

Electronic ignition, pull the distributor cap off, look under the rotor arm, if there is a chopper wheel with four blades on it next to a pick up with wires on it it's electonic, if there is a set of points with a small round can next to it (the condenser) it's still running points.

Hope this helps

Edited by Markgenesis on Sunday 6th July 12:03

[nmealey]

Thank you very much sir.

A final wee question, the carb float chamber has a suspiciously clean nozzle on it, should there be anything on the shiny bit ?

[nta16]

well as that screw isn't the usual one used perhaps that isn't the correct lid?

to learn about your car you should buy and read the relevant Driver's Handbook, this is not a repair manual but a prevention manual that will tell you how to operate the controls and details of the full servicing schedule and how to do it - (Ref: 0058) - http://www.mgocshop.co.uk/catalog/Online_Catalogue...

in the Driver's Handbook it will show the 36k-mile service I suggest you carry this out fully as at least a check up on some items, staggered between regular, reasonable distance journeys use of the car

the servicing/check up will help to find and prevent issues and the regular use, throughout the whole year, will help maintain the car in good order and find issues to be dealt with, the more use the quicker and better the car will get and remain

contents page of my 1275 DH -

[nta16]

ETA: it depends on how your car has been set up on whether it runs well on 95 octane, the Driver's Handbook will tell you the original requirement which I believe was 97 octane - as it's a car new to you I'd suggest a couple of tank fulls of Tesco 99 Momentum or Shell V-Power Nitro+ not for their 99 octane but for their packages of cleaning additives and some long runs to blow the muck out of the fuel system

[Markgenesis]

From what i can remember with the SU's on Mini's i've had it will do no harm leaving that pipe as it is, think it's a breather for the float chamber ?, anyhow i've ran Mini's with it like that with no i'll effects.

As mentioned that screw in the fore of the pic is'nt right so the lid has been off before.

[nta16]

Markgenesis said:

think it's a breather for the float chamber ?,

sorry I've got to disagree with that, I've never owned a Triumph or Midget 1500 but have owned a few SU carb'd cars including my present Midget and I'd guess that might be an overflow but the float chambers don't have breathers

I don't think that the lid is necessarily correct for the model

as you say if it's doing no harm then leave it alone as there'll probably be more pressing things to attend to

[anonymous-user]

I think the pipe is an overflow. If the float sticks fuel will flow out of here so it should have a plastic pipe routed straight down to the road.
That screw isn't the right one but as long as the seal is ok I'd leave it.

[RichB]

rovermorris999 said:

I think the pipe is an overflow. If the float sticks fuel will flow out of here so it should have a plastic pipe routed straight down to the road.

Exactly, and as it's simply a bit of tube it means the float chamber can "breath"

[imagineifyeswill]

As has already been said it is an overflow/breather whatever you want to call it, it should have a pipe routed down to the road to avoid any overflow getting near the hot exhaust, you have said the carb float chamber I assume it has twin carburettors?.

[Spitfire2]

The 1500 (Triumph) engine isn't really bothered by unleaded. The general advice is not to worry about it. If the valve seats eventually recede you can have the hardened seats fitted at that point (if it happens).

For advice on your engine you'll find great advice on Triumph forums, less so MG forums.

[nta16]

looks like twin carbs (they were originally) but I don't think they had overflow pipes originally (I could be wrong)

quite right though that if it is an overflow it should have a mixture of rubber and solid pipe to lead it away from the hot exhaust

[RichB]

nta16 said:

...I don't think they had overflow pipes originally (I could be wrong)

Having looked at several pics on Google it seems they do.

[nmealey]

Thanks for your replies, and the picture of the contents page. I'm already waiting for the handbook to arrive.

Both carbs have the same cap on them so I can only assume they are both wrong. I'm going to leave them as it's working and running. I'll get some hoses and pop the down towards the road. I'm sure I'll have more daft questions soon enough.

[Dogwatch]

Not a member, or even an owner, myself but the MG Owners Club is worth joining.

[//j17]

Spitfire2 said:

The 1500 (Triumph) engine isn't really bothered by unleaded. The general advice is not to worry about it. If the valve seats eventually recede you can have the hardened seats fitted at that point (if it happens).

Just to second Spitfire2's comment - Triumph always used quite hard valve seats anyway and even ran a brand new engine on unleaded in the 70's to see what the effects were and didn't see any noticable issues.

Run it on unleaded and fit an unleaded head if/when you find yourself having to tighten up the tappets all the time.

[nmealey]

Thanks for your help folks, I really am a novice at this old car thing. I'm away from home for a few days with work and will be spending most of July away.

I hope to make my wee mg a bit more daily usable. Is it worth getting it converted to electronic ignition? There is a wee bit of over run when she's warm and a bit of rough idle. I'm guessing that the carbs need tuned.

If I were to pop some aftermarket air filters on, would I be correct thinking that I'd need to get the carbs tuned afterwards?


Neil

[RichB]

I'm not so familiar with the ex-Spitfire unit as the good old BMC A-Series which I know like the back of my hand. However if it's running on a bit you may want to whip the head off and give it a clean up inside, you could re-grind the valves while you're at it. Clean the plugs and put it back together. Nice job for a weekend. As for the carbs I'd have a go at tuning them yourself, you've got to learn and it's quite cathartic. All you need is a small key (like half a spanner) to adjust the jets and a piece or 1/2" rubber tube to stuff in your ear! As for electronic ignition, I know people swear by it but I've never had it on any of my old cars. There's nothing wring with contact breakers as long as the system is kept in good order.

[Hooli]

nta16 said:

RichB said:

aving looked at several pics on Google it seems they do.

ah, bless, you trust Google images

I could be wrong and often am but I'll take a small bet with you that Neil's cap at least isn't original to the car as it is now and that certainly the earlier 1500s at least originally didn't have overflows and that none of the 1500s originally had overflows fitted

but the beauty is that when Neil gets his Driver's Handbook he wont have to rely on my poor memory or dubious Google images he will have the correct facts of what the car original had fitted

in that photo I can only see the supply from the pump then the feed from the back carb to the front carb, no overflow, am I missing something

Neil,
I do a set of mon-mechanical, non-technical notes for new owners, most find them OTT and ignore, I know because I see the problems they post asking about later, but as you've followed the best bit advice that can be given by getting (then reading and referring to before starting any work on the car) you might have interest in them, if so just PM me

Edited by nta16 on Sunday 6th July 22:52

I had a '78 Midget for about nine years.

That's a breather connection & it's standard. It should have a hose as shown in the google pic that routes over the manifold to the same connector on the other carb. Halfway along it'd have a T-piece to connect it to the air filter body. You're right though that the screw isn't original.
As for unleaded, I always run mine with Castrol Valve Master (the one with octane booster) because I could feel it being more responsive than without. Super unleaded would do the same, but back then the booster worked out cheaper.

Enjoy the car OP, they are great fun.

[Spitfire2]

nmealey said:

Thanks for your help folks, I really am a novice at this old car thing. I'm away from home for a few days with work and will be spending most of July away.

I hope to make my wee mg a bit more daily usable. Is it worth getting it converted to electronic ignition? There is a wee bit of over run when she's warm and a bit of rough idle. I'm guessing that the carbs need tuned.

If I were to pop some aftermarket air filters on, would I be correct thinking that I'd need to get the carbs tuned afterwards?


Neil

Not as much room under the bonnet of the midget as on the Spitfire but you get a useful poer increase from

- free flowing air filters
- a free flowing/straight through exhaust - and a tubular exhaust manifold (though the cast iron manifold on the spitfire engine is actually quite good).
- with those improvements you'll want to change the needles in the carbs to (probably) AAQ
- definitely fit electronic ignition. I recommend the Pertronix one which you can buy cheaper than the identical Aldon branded one from retrorockets.com

There are a few other quite cheap DIY improvements which can make the 1500 more responsive still - mine is quite rapid for a 1500. Running the vacuum advance pipe into the inlet manifold rather than the rear carb made for a much improved throttle response for example.

Doug.