16 replies to this topic

[gutted]

I posted this thread some time back, and while everything's been fine during the warmer months I know that things are going to be bad as the weather starts to get colder: the cold-running problems are going to return 

 

I've got two things I want to try, in order of easiness/laziness when the problem returns:

• change the spark plugs for non-resistive ones (I'm pretty sure my HT leads are resistive type, and I know for certain I'm running resistive plugs at the moment); and


• install and hook up a water heated inlet

Maybe I'll get lucky, and swapping for OEM "Surefire" Unipart plugs (the correct part number for my car, according to the EPC) will fix everything.  I doubt it, but I'm thinking it's a 5 minute test I can do at the roadside so it can't hurt.  I think maybe it'll need something more though, so the heated inlet is where I may end up going.

 

I reckon I've got all the bits I need for the heated inlet, but I really want to keep the engine bay looking as original as possible - I want to keep my original air cleaner.  I've also been reading this thread about heated inlet manifolds...The question I have is about plumbing in the inlet.  I know on the MG engine there's a rail that goes under the manifolds and then connects to the inlet manifold, but I think it would foul the hot air duct/stove that sits under my air cleaner.

 

Is anyone using a heated inlet manifold and standard 1275 air cleaner?  How did you hook up the inlet manifold, and does the MG Metro water rail fit, or did you use a different rail (and if a different rail, where did you get it from?    )

[nicklouse]

The water heated manifold is nothing to do with cold weather running. It was to improve economy.

 

just get your carb set correctly.

 

cold weather kit included heaters on the carb bell. And a heating element spacer. Amongst other things. I think there was one more.

 

 

oh don’t forget to change your hot air flap to drawn air from the manifold.

[mab01uk]

The Austin Metro 1275 (ie. non-MG) has a combined cast iron inlet and exhaust manifold, so the inlet manifold is already heated by the hot exhaust manifold if you still have that standard set up currently.

 

Austin Metro 1275 exhaust/inlet manifold

 

MG Metro exhaust manifold
 

You might also find this old thread linked below of interest:-

Water Heated Alloy Inlet Manifold:-

https://www.theminif...inlet-manifold/

Edited by mab01uk, 21 October 2023 - 05:18 PM.

[gutted]

just get your carb set correctly.

 

cold weather kit included heaters on the carb bell. And a heating element spacer. Amongst other things. I think there was one more.

 Thanks, Nick!

 

The carb and timing was set on a rolling road about 18  months ago.  In fairness, it wasn't set during cold weather but the guy that set it up is fairly well respected (I think).  The car runs like an absolute dream when warm - and even with choke out, so long as the ambient temp isn't too low.  I think he tuned it for best possible performance, so I brought the mixture down a fraction for the last MOT, but otherwise it's never run better.  When warm.  The problem is when the ambient temp is cold - it's a complete nightmare to drive but the problem gradually fades as the engine warms.  There's no cut-off point, it just gradually gets better; but in the meantime it feels like it's running on 3 (except pulling the HT lead is equally bad on on 4 - so it's not a single plug or lead that's causing it).  There's a ridiculously strong smell of fuel out the exhaust (even with no choke).  I even get actual black smoke out the back.  I've been pulling my hair out trying to pin it down - I've now started thinking maybe fuel is condensing on the inside of the inlet manifold, hence thinking a heated manifold may improve things.

 

The cold weather kit was a heater for the suction chamber, plus a spacer with an induction heater.  I wouldn't mind giving that a go, if only I could find such a kit :)

[gutted]

The Austin Metro 1275 (ie. non-MG) has a combined cast iron inlet and exhaust manifold, so the inlet manifold is already heated by the hot exhaust manifold if you still have that standard set up currently.

 

 

You might also find this old thread linked below of interest:-

Water Heated Alloy Inlet Manifold:-

https://www.theminif...inlet-manifold/

 

Ah.  That's an exceptionally good point.  Yeah, I'm still on the standard (non-MG) manifold.

 

Thanks for the link - I'll check it out!

[mab01uk]

There's a ridiculously strong smell of fuel out the exhaust (even with no choke).  I even get actual black smoke out the back.

 

This smell of fuel and black smoke indicates something is wrong with the carb or its setup and it is running too rich as if permanently on choke. This would also result in poor fuel consumption (mpg) and cold running of the engine plus in the longer term piston/bore wear due to oil being washed off the surface of the cylinder bores. Might be worth you overhauling the HIF SU carb or swapping it for a known good replacement with the correct needle, etc.Have you also checked the choke is shutting off fully? At over a 100k miles the carb will likely be in need of an overhaul, clean and a check over for general wear.

Edited by mab01uk, 21 October 2023 - 06:26 PM.

[gutted]

It's only when the engine is cold - and more than that, it's only when the engine is cold and the ambient temp is cold.  When it's on choke when the ambient temp is higher, everything is fine.  So - for 3/4 of the year, it'll run like an absolute dream after the rolling road session.  It's dead smooth on idle.  It really is a cracking engine - for 3/4 of the year.  When I had it RR-ed, the guy took the dashpot off and set the jet depth (I think) as well as setting the mixture and idle.  Whatever adjustment he made after taking the dashpot off transformed it - it drove beautifully after that.  But as long as I've had the car, it's always been a total PITA over winter (before the RR and since).  I've changed the electrics (plugs, leads, dizzy cap, rotor arm, ignition amp (several times), the dizzy itself), the air cleaner, cleaned up the contacts on the LT side, checked the fusible links (but they're still clean), changed the vacuum advance elbows, dashpot oil is good.  I can't find the root cause - it's driving me mad.  I mean - right now, it's spot on.  I reckon through December into Feb it's going to be barely worth driving.

 

It's done around 100k miles now (just over).  If this could be a carb problem, I can look at overhauling the carb - I'd even be happy to get a new one if it'd fix things?  I don't have access to a known good one though - not a normally aspirated one, anyway.

 

When the problem happens, it takes maybe ~15 mins before the car behaves.  I can only think that it's a temperature thing, and when <something> (carb itself, maybe??) has got up to temp then all is fine.

 

I'd be up for finding a replacement carb to swap it over to see if it improves things - do you reckon these symptoms sound like a worn out carb?

[Steam]

If you pipe the manifold in as part of the heater pipework then it will come on with the heater tap in winter.
The ultimate setup is to have a 2 way heater valve and a tee piece at the bottom hose heater return, that way you have flow through the head all the time. If summer has you overheating then a small aux rad in the line will also be an advantage

[andyapanel]

It sounds to me you have carb icing.
Pull over as the engine fades and let the heat melt the ice.
Good luck

[mab01uk]

 

There's a ridiculously strong smell of fuel out the exhaust (even with no choke).  I even get actual black smoke out the back.

 

This smell of fuel and black smoke indicates something is wrong with the carb or its setup and it is running too rich as if permanently on choke. This would also result in poor fuel consumption (mpg) and cold running of the engine plus in the longer term piston/bore wear due to oil being washed off the surface of the cylinder bores. Might be worth you overhauling the HIF SU carb or swapping it for a known good replacement with the correct needle, etc.Have you also checked the choke is shutting off fully? At over a 100k miles the carb will likely be in need of an overhaul, clean and a check over for general wear.

 

 

Ideally when the cold weather and poor cold running symptoms return you need to take it to the Rolling Road you went to previously and get them to diagnose and pinpoint the problem while it is actually happening.

Back in the day you could have gone to a local breakers and picked up another HIF SU carb off a similar Metro for a reasonable price and then swapped over as a test. Not sure what the going rate on ebay is these days for a good or refurbished HIF44 SU but might be worth a try to eliminate the carb as the problem....

Edited by mab01uk, 22 October 2023 - 12:36 PM.

[gutted]

 

 

There's a ridiculously strong smell of fuel out the exhaust (even with no choke).  I even get actual black smoke out the back.

 

This smell of fuel and black smoke indicates something is wrong with the carb or its setup and it is running too rich as if permanently on choke. This would also result in poor fuel consumption (mpg) and cold running of the engine plus in the longer term piston/bore wear due to oil being washed off the surface of the cylinder bores. Might be worth you overhauling the HIF SU carb or swapping it for a known good replacement with the correct needle, etc.Have you also checked the choke is shutting off fully? At over a 100k miles the carb will likely be in need of an overhaul, clean and a check over for general wear.

 

 

Ideally when the cold weather and poor cold running symptoms return you need to take it to the Rolling Road you went to previously and get them to diagnose and pinpoint the problem while it is actually happening.

Back in the day you could have gone to a local breakers and picked up another HIF SU carb off a similar Metro for a reasonable price and then swapped over as a test. Not sure what the going rate on ebay is these days for a good or refurbished HIF44 SU but might be worth a try to eliminate the carb as the problem....

 

 

This is problematic because the RR (Peter Burgess) is in Alfreton which is about 30 mins drive from here.  By the time I get there, everything will be nicely warmed up and there'll be nothing to diagnose.  I guess - in fact I know - there'll be more local RRs, but I know that Pete Burgess is experienced with BL/Leyland stuff, and I'm a bit precious about letting other people tinker with my car :)  I'd prefer to only get a known good guy loose on it :)

 

Definitely am now looking for a replacement HIF44 carb.  I've done carb rebuilds myself before, and happy enough stripping down and reassembling with new components.  I'm now on the lookout for whatever gets listed on eBay.  I've seen that I can get a fully refurbed carb for a hefty price...  I don't know how good (or otherwise) the pricey rebuild might be, so I'm looking to find a replacement HIF44 and buy a Burlen rebuild kit.  If I get it all sorted, and then take a trip to Peter Burgess to get my overhauled one set up to see if that improves things over winter.  Fingers crossed!

[coopertaz]

is the choke actually working on the carb? if choke was not comming off car would run worse as it warmed up not better. could be worth changing plugs and leads re. black smoke possible plugs may be poor when cold or ht system poor condition. I  have had carb icing before but with seperate manifold and k&n filter, car normally starts mising then eventually stalls only restarting when melted but this was on a minus silly night in middle of dales not ambient round town

Edited by coopertaz, 25 October 2023 - 10:53 AM.

[beardylondon]

Drive it there early one morning, leave it to cool down for 4 hours or so, do some shopping or whatever and get him to look at it after lunch!l. Especially in winter, it will obviously cool down quick!

There's a ridiculously strong smell of fuel out the exhaust (even with no choke). I even get actual black smoke out the back.

This smell of fuel and black smoke indicates something is wrong with the carb or its setup and it is running too rich as if permanently on choke. This would also result in poor fuel consumption (mpg) and cold running of the engine plus in the longer term piston/bore wear due to oil being washed off the surface of the cylinder bores. Might be worth you overhauling the HIF SU carb or swapping it for a known good replacement with the correct needle, etc.Have you also checked the choke is shutting off fully? At over a 100k miles the carb will likely be in need of an overhaul, clean and a check over for general wear.

Ideally when the cold weather and poor cold running symptoms return you need to take it to the Rolling Road you went to previously and get them to diagnose and pinpoint the problem while it is actually happening.
Back in the day you could have gone to a local breakers and picked up another HIF SU carb off a similar Metro for a reasonable price and then swapped over as a test. Not sure what the going rate on ebay is these days for a good or refurbished HIF44 SU but might be worth a try to eliminate the carb as the problem....

This is problematic because the RR (Peter Burgess) is in Alfreton which is about 30 mins drive from here. By the time I get there, everything will be nicely warmed up and there'll be nothing to diagnose. I guess - in fact I know - there'll be more local RRs, but I know that Pete Burgess is experienced with BL/Leyland stuff, and I'm a bit precious about letting other people tinker with my car :) I'd prefer to only get a known good guy loose on it :)

Definitely am now looking for a replacement HIF44 carb. I've done carb rebuilds myself before, and happy enough stripping down and reassembling with new components. I'm now on the lookout for whatever gets listed on eBay. I've seen that I can get a fully refurbed carb for a hefty price... I don't know how good (or otherwise) the pricey rebuild might be, so I'm looking to find a replacement HIF44 and buy a Burlen rebuild kit. If I get it all sorted, and then take a trip to Peter Burgess to get my overhauled one set up to see if that improves things over winter. Fingers crossed!

[Cooperman]

Are you certain that the choke is working correctly? It sounds as though it is running too lean at low temps and at first start-up when cold. That indicates that the mixture is not rich enough at initial start up and this will magnify the symptoms when the ambient temp is low.

If it's running fine when warm, it really has to be weak mixture when cold.

I have never understood the idea of warming the inlet charge with a heated inlet manifold when the best thing is a cold mixture for maximum efficiency/power. Many turbo cars have an intercooler to ensure that the air/fuel going in is as cold as possible and a 'cold air box' is usually thought of as a good idea in modified cars in general. I always disconnect the manifold heater pipes when working on later cars with this arrangement.

[gutted]

is the choke actually working on the carb? if choke was not comming off car would run worse as it warmed up not better. could be worth changing plugs and leads re. black smoke possible plugs may be poor when cold or ht system poor condition. I  have had carb icing before but with seperate manifold and k&n filter, car normally starts mising then eventually stalls only restarting when melted but this was on a minus silly night in middle of dales not ambient round town

 

I've gone through various plugs - I'm currently running NGK BPR6ES.  When I had it dynoed the guy made sure the plugs were properly gapped (he also removed some shims I'd been using to make sure the plug gap was pointing at the inlet valve - he said it was unecessary).  A couple of winters ago I changed most of the electrics (leads, coil, plugs, dizzy cap, rotor arm) and thought I'd cracked it - but problem came back with a vengeance a few days later when it got very cold again.  Next thing I'll try when it inevitably happens again will be to try some Unipart plugs - I've got the correct part number for the car (GSP4452 or GSP4462 - can't remember offhand but one is for NA 1275 and the other is for the Turbo).  I'm not hopeful it will make much of a difference, but it's a test I can do literally at the roadside when it starts messing me about again.

 

When the problem happens, it doesn't really matter where the choke is.  Putting the choke fully in doesn't cure it, and giving it more choke doesn't help.  On a normal day, first thing in the morning, I don't need much choke - never more than half way out.  The RR guy is going to set up my choke for me when I'm next able to get over  - perhaps it's not doing what it should, as you suggest...  Thing is - when the problem is happening and when the coolant has got to temp, the choke might be fully in but the car is still misbehaving.  So - it's a PITA even without using choke at all (makes me think that it can't be related to the choke, though I could be wrong).