Engine just wont co-operate!

[MacQuigley]

After 18 years of restoration I was hoping to get an MOT next week but I just cant get the engine to fire.

Crazy t hing is its been running just fine for 6 months but now that I need it its just not working.

Ive tried everything I can think of. Ive reset the point, timing, Ive replaced the plugs, Ive removed, stripped and rebuilt the carb and still it will run but for a few seconds.

I do have a spark, though I must say its not that strong. Ive drained the tank and put new fuel in and still nothing.

Now Im using a leaded head on unleaded fuel. But Its run for less than 6hrs in total at idle only. I cant believe thats burnt the valve seats.

Im at a loss to work out whats wrong.

Anyone got any suggestions???????#

I should say its a standard 948cc engine. Absolutely nothing fancy.

[Monty-4]

I had this when I royally messed up the fuel/air mix, sounds like you might know better than to do that though!

[biomed32uk]

If the spark is weak in free air then it will struggle under compression more so, whats the condenser like as that has a huge impact on the spark. Leads on the dizzy in the right place ?.

[MacQuigley]

I cant see it being a mixture issue as it had been running just fine, though I will say that lately it was running rich. However, I have tried adjusting the mixture and thats not helped.

Leeds are all correct but the one thing Ive not got a spare is the condenser. Id change that if I had one. Id also consider changing the coil even though both were replaced 6 months ago.

I cant help but thing something has changed/failed as it was running just fine up until Thursday!

[The vast minority]

Very likely fuel,starvation.
Petrol in the tank may not equal petrol in the carb. Check delivery first as this may well be your problem.

A failing condenser normally results in much stronger sparks as the job it does is to prevent destructive arcing in the first place. It does not generate a spark itself.

Check all coil connections are clean and tight.

If you have 4 minutes, watch this animation and understand a coil ignition system better than any garage.

Al

https://m.youtube.com/watch?v=W94iksaQwUo

[bmcecosse]

Put the old coil back on... but you say it runs for a few seconds - and then peters out - which does rather suggest a petrol flow problem. Quick test is to pour an egg cup of fuel down the carb and crank it - does it run ok for a few seconds ? If so - nothing wrong with ignition. I assume the 'choke' control is actually moving the jet down when pulled.

[MacQuigley]

Spent most of the day o n this problem and I still cant get it resolved. I stripped the carb again and as far as I can see its working OK. Fuel pump is definitely delivering fuel.

I have managed to get it running for longer periods like 30-60 seconds, but there is still no power ie when I operate the accelerator nothing much happens.

Already changed the new for the old coil and for another I had and that made no difference.

Short of pulling the head and checking the valves are all operating correctly Im stumped! Its not like its complex! In fact it couldn't be simpler really.

Getting close to that gallon pf petrol and box of swan vesta's again!

[SteveClem]

You can see why most owners refer to their cars as 'she '! You do all the right things but still can't win.

[bmcecosse]

You can see the valves move - and set the gaps - simply by removing the rocker cover. Worth trying a condenser swap - and of course it;s in situations like this that a complete spare dizzy is really handy - just drop it in to see if it makes the difference. But I guess if you had that - you would have done it already. Absolutely sure about the firing order - 1342 anti clock round the dizzy cap ? I assume the carb piston rises easily and falls back with a nice clunk, and the needle fitted with the shoulder flush with the piston base.

[panky]

Did you remember to top up the carb dash pot with oil

[MacQuigley]

Steve, how true!

Yip, oil in the dashpot.

Reset the valves twice so far. The firing order is 1342 so thats fine. I do have a spare dizzy but from a later model. Need to check it will fit.

Now one thing I will say is that the carb piston doesn't move easily. Its a bit stiff in my opinion but Ive nothing to gauge it with at the moment. But considering the engine has been running just fine for a good long time I cant understand why that would suddenly cause a problem.

[bmcecosse]

With the damper out - the piston will slide up easily if ok and then back down with a nice clunk. Don't worry about the oil. Try the other dizzy - as long as you know it came from a running car and hasn't been fiddled with.

[bmcecosse]

I can't remember now if this has been asked - but have you done a flow test on the fuel pump? It should deliver a pint in about 4 minutes maximum - usually better than that. Other check would be - when it runs for a 'a minute' - if you immediately whip out a plug - is it wet, or dry ?

[MacQuigley]

Not tried the flow rate check though its a new pump so it should be OK and it fills the bowl in seconds. I'll try and check the plugs.

Ive another day off tomorrow (originally booked so I could go for an MOT!!!!) so I will try again, though it may be time to walk away for a while. Ive spent 5 days on this now and I had planned other things!

[bmcecosse]

Well -swap the dizzy and give it a try - only takes a few minutes.

[MacQuigley]

Well that seems to have done the trick.

Started off this morning by taking the head off "just in case". Ended up Swapping the distributor after fitting new points. Reset the timing and the points and she fired into life. Actually the engine is running better than before. Maybe the old distributor was on its last legs. Just a Shane it's taken 6 days to resolve.

Thanks for all the advice guys much appreciated.

Next hurdle- an mot!

[bmcecosse]

Well done, and good luck with the MOT - but why on earth did you take the head off ??? Nothing to see there... Be sure now to retorque to 44 ftlbf after the first heat cycle - and reset the valve gaps. I look forward to seeing you buzzing about Hamilton!

[MacQuigley]

To be honest I was clutching at straws! Anyway that only wasted 3hr out of the nearly 6 days it took me to sort the problem!

So I got to take her round the block a few times just to road test everything. The engine does need a bit of a tune up but it was very nice to drive after all these years. The gearbox was as sweet as anything - Maybe Im too used t o driving Land Rovers these days.

I'll double check everything tomorrow night. Try and book and MOT on Thursday for Friday and sort out insurance. She wont be on the road fully for a bit yet are there is some finishing to do and I need to do something with the interior until I can afford to replace it, but Im getting there.

[The vast minority]

Glad it's sorted,
Just be careful about publicly stating anything that may be, well..........I'm sure you get the point.
Al

[MacQuigley]

Booked an MOT this morning for tomorrow. Took the Minor out the garage basically to wash it but I also had to swap the various vehicles about so I could get it to the top of the drive.

First the distributor came lose! Timing reset, clamp, tightened - properly this time - and it was up and running.

Then the headlights stopped working! Traced the loose plug, working lights.

Then the offside front indicator stopped working! Traced the plug I obviously dislodged while fixing the headlights - working headlights.

Then the nearside washer wouldn't pass water! Quick poke about with a pin and hay-presto working washer.

Its no fun washing a car in the fecking dark! This car has got too comfortable after 18 years in the garage. It doesn't want to go back out on the road. So it it passes its MOT tomorrow "I'll be a suck egg mule"! (10 points to anyone that can tell me the western that reference is from!).