MGB GT electronic ignition conversion - car won't start

[N5 NRO]

Finally got a few minutes in the garage today. House stuff has been keeping me busy recently, as well as having my Ford fail its MOT and need replacing unexpectedly.

Only a small update, but it lives! With the Accuspark kit fitted I managed to get the engine running. With a fully charged battery it started (just) and was then running very poorly, I know most of that is probably timing related, although I think the fuel level is perhaps too low (there was some in the filter, but not as much as usual). I'll get some more fuel in as soon as I get the chance and will then sort out my timing light to try to get things going properly.

Hopefully I'll have a better update soon, will post here whenever I manage to make some progress.

[nta16]

N5 NRO said:

(there was some in the filter, but not as much as usual)

ignore that, sometimes the filter will be full other times looks empty and other times half full

yes it's the timing you probably need to adjust

the order for setting up is - tappets/(CB points)/plugs/timing/carbs mixture – in that order, if you have to adjust any item in this chain then you’ll need to check/adjust all the items that follow it in the chain

so if your tappets and plugs are OK but you're setting the timing then you'll also need to check/adjust as required the carb mixture

if you've got good spark plugs in good condition (NGK less than a couple of years old) and better still good quality HT lead set ('performanceleads' - order over the phone via their web site) - http://www.performanceleads.co.uk/ then you can widen the gap on your plugs to take advantage of the quality of spark you should be getting

(a dissy cap in good order wouldn't go amiss - you should have a good quality rotor from Accuspark)

[nta16]

always a very good idea to keep the battery(ies) fully charged but especially if you're having electrical difficulties you want to solve and even more so on top of that if these difficulties included starting the engine

as starting the engine is a main drain on the battery and a battery in low charge may hinder progress with the problem solving or even disguise when you've sorted things because it's then the battery that is too low to start the car

[N5 NRO]

Thanks for the advice - will definitely be keeping the car plugged in until it's back on the road.

The plugs are relatively new (well, low mileage anyway), but one appears to have a slight crack in it, so I'll replace them along with the leads. I've never adjusted tappets before, but it doesn't seem too difficult from what I can see online so I'll give that a go once I have the new leads and plugs in. The carbs definitely need some tweaking - I had a garage "sort" the timing and carbs just before taking the car off the road, but they did an awful job of it. The rotor arm is one of the red ones, so should be ok and I have a spare dissy cap ready to fit.

Hopefully it'll be running right soon!

[nta16]

as PH appears to be playing up today and I've just lost my post have the raw info -

this web site is full of info, Paul Hunt's mgb-stuff - http://www.mgb-stuff.org.uk/hammertext.htm

among John Twists 200+ video, many on or relating to Bs, are these on carbs

35 Tuning HIF Carburetters - http://www.youtube.com/watch?v=ASeMfXfjNpw&fea...

147 MG Carburetter Tuning - http://www.youtube.com/watch?v=4nvGLgO6pj0&fea...

44 Secrets of the SU Carburettor Part 1 of 2 - http://www.youtube.com/watch?v=7GRAcqDySog&fea...

43 Secrets of the SU Part 2 of 2 - http://www.youtube.com/watch?v=60Bj_2cZQnc&fea...

41 Matching SU Air Pistons - http://www.youtube.com/watch?v=IfU47Oqq9wA

123 MG Carburetors & Doors (first part needles and seats, springs and carb oil) –
http://www.youtube.com/watch?v=v9QI3NlvwiY&fea...

222 MG SU Carburetters: Setting the Float Height - http://www.youtube.com/watch?v=82YNx-RkGNI&lis...

232 MG Carburetter Needles and Seats (Needle and seat) - http://www.youtube.com/watch?v=pVX_JClyeDQ&lis...

HS Carburetor Jet Repair - http://www.youtube.com/watch?v=Elgfc1xZkt8&fea...

Edited by nta16 on Friday 18th July 11:34

[N5 NRO]

nta16 said:

as PH appears to be playing up today and I've just lost my post have the raw info -

this web site is full of info, Paul Hunt's mgb-stuff - http://www.mgb-stuff.org.uk/hammertext.htm

among John Twists 200+ video, many on or relating to Bs, are these on carbs

35 Tuning HIF Carburetters - http://www.youtube.com/watch?v=ASeMfXfjNpw&fea...

147 MG Carburetter Tuning - http://www.youtube.com/watch?v=4nvGLgO6pj0&fea...

44 Secrets of the SU Carburettor Part 1 of 2 - http://www.youtube.com/watch?v=7GRAcqDySog&fea...

43 Secrets of the SU Part 2 of 2 - http://www.youtube.com/watch?v=60Bj_2cZQnc&fea...

41 Matching SU Air Pistons - http://www.youtube.com/watch?v=IfU47Oqq9wA

123 MG Carburetors & Doors (first part needles and seats, springs and carb oil) –
http://www.youtube.com/watch?v=v9QI3NlvwiY&fea...

222 MG SU Carburetters: Setting the Float Height - http://www.youtube.com/watch?v=82YNx-RkGNI&lis...

232 MG Carburetter Needles and Seats (Needle and seat) - http://www.youtube.com/watch?v=pVX_JClyeDQ&lis...

HS Carburetor Jet Repair - http://www.youtube.com/watch?v=Elgfc1xZkt8&fea...

Edited by nta16 on Friday 18th July 11:34

Woah - thanks for digging all those out!

Will start making my way through them this week, hoping to get the new parts I need next month and then I should have everything running properly not long after. I think the carbs need a rebuild and a few bits replacing, so those videos will be particularly helpful.

[nta16]

have this for good measure then

10 MG Valve Adjustment - http://www.youtube.com/watch?v=fezXUwVfH7U&lis...

the John Twist videos with mgb-stuff and the relevant Driver's Handbook should help to get you a long way to what you need/want

[N5 NRO]

Didn't realise it had been so long since I updated this!

I eventually got the car started using the AccuSpark kit (fully charged battery and lots of fiddling), however it was running VERY poorly. When I connected the spark plug testers I could see that there was a strong spark on cylinder 1, but next to nothing on the other three and nothing I did seemed to make any difference. I have since switched back to points and condenser and the engine is running much better than when I last drove it. I adjusted the tappets and found some of them had no clearance at all, so I think some valves weren't closing properly and what I had previously thought was a misfire was just a lack of compression (and the garage I asked to sort the timing etc. out didn't bother to check it seems).

I'll still be converting to a 123 distributor later in the year, but I'm going to focus on getting the car back on the road first. The only things which really need doing are some welding (got a welder now and have been practising), some rust proofing and new coolant pipes. In the summer I will fit a stainless exhaust, new distributor and service the carbs.

Thanks again for all the help and advice last year - I really didn't want to be defeated, but I'm pretty sure the kit I had was faulty (or at least that's what I'll tell myself!).

[Faust66]

Glad you eventually got the car running… the Accuspark units do seem to be a bit hit and miss: over on the Volvo Owners Club forum I frequent there are a couple of people who've had no problems and they are very happy with their purchase. On the other hand (as I stated earlier in the thread) I had very similar symptoms to you. Even if I managed to get a car running using an Accuspark unit, I would still keep a set of points etc. in the boot as I wouldn't ever trust it… which kind of defeats the whole point of installing a 'fit-and-forget' conversion IMO!

I am still thinking about the 123 unit, but I quite like running points and a condenser (plus my dizzy itself is fine) so I see no reason to upgrade. I can't help but think that if we all switch over to electronic ignition conversions then valuable knowledge of how to set up and gap points will be lost, and that would be a shame.

Plus, I find the whole feeler gauge and turning the engine on the crank pulley procedure strangely relaxing and enjoyable.

[nta16]

it's great to see when posters report back, well done

with some of the Accuspark combined kits you do seem to get an awful lot for the price so I guess there'd be weak areas, I know Darren found the HT leads he got were poor and I too have seen hit and miss reports about the igniter heads

I've got a 123 fitted to my Midget and it was an improvement over the whole rev range fromr the previous (new) Aldon igniter head in existing dissy

the good thing about the 123 is that the whole dissy is electronic and new, putting just a new igniter head on still leaves the rest of the dissy old and the dissys were out of synch 2-3 years after use from new and most are now decades old and many unattended to

the art of setting using feeler gauge is kept by setting the tappets (when required)

[N5 NRO]

Once again I've left it for far too long since my last update - thanks for the replies back when I last posted in January.

My MG is now back on the road! It isn't running very well - initially I thought ignition and whilst I will be changing to a 123 distributor I can't justify the cost at the moment (over £650 to get the car back on the road, plus I'm getting married next year so I've been trying to work out what needs doing and what I want to do). As a temporary alternative to points and condenser I decided I had nothing to lose trying a new Accuspark kit - by buying a new one I knew I'd have a guarantee and warranty, so if it didn't work or if it breaks I'm covered. I tried fitting it on Wednesday evening and the car started first time, I adjusted the timing and it seems to be running far better than on the old setup. I fitted it the same as the old unit I had, so I'm assuming the other one was broken - there are a few definite changes in the design of the two. I'll still keep a set of points and condenser on board just in case though.

As for the still not running well - that appears to be carburetor-related. It was running particularly poorly yesterday on my way home from work so I pulled over to have a look and could see fuel pouring out of the overflow pipe on the back carburetor. A quick tap sorted it out, however pretty much as soon as I rejoined the main road it was flooding again and continued to get worse until I eventually got home. It runs fine from cold for about 15 minutes, but once it's up to temperature the problems start. I've ordered a carb. overhaul kit and a new pair of needle valves which I intend to sort over the weekend while re-watching some of the videos Nigel linked earlier in this thread.

After two years off the road I'm not too surprised there are a few issues, hopefully next week I'll have more reliable transport!

Edited by N5 NRO on Friday 10th April 08:39

[mgtony]

Have you ordered new floats as well? Might be worth replacing them. Also how old is the fuel hose from the fuel filter to the carbs and the piece between the carbs? It could be perishing inside and sending crap into the carbs, only a few quid to replace and eliminates another possible cause.

[N5 NRO]

mgtony said:

Have you ordered new floats as well? Might be worth replacing them. Also how old is the fuel hose from the fuel filter to the carbs and the piece between the carbs? It could be perishing inside and sending crap into the carbs, only a few quid to replace and eliminates another possible cause.

Haven't ordered new floats yet - I did consider it and will likely replace them in the near future though, or sooner if the new valves don't sort the flooding issue. Hadn't thought about the fuel pipe causing problems - it'll be about 3-4 years old and I've got some spare available so will replace that over the weekend too. Thanks for the advice