Issues

[MoggyMatilda]

69 convertible engine issues.

So I changed the points, condensor , rotor arm , distributor cap & all new leads. New plugs. Put an inline filter on the petrol pipe to the carb. Fuel pump ticks nicely. Car sometimes starts sometimes doesn’t. When she starts & drives, goes well for 2-300 yards then starts to stall. I’ve adjusted idle etc.

Does it sound like a fuel problem? Or am I missing something?

I was thinking does the advance & retard pipe ever give bother?

I had the car running & driving great yesterday. Now today I went to drive it & it started messing about.

[svenedin]

To reply to your question, yes the rubber connectors on the advance retard pipe can perish causing a leak of vacuum, it can get blocked or kinked and the diaphragm in the distributor can fail. However, that does not sound like your problem. Your engine would still run and I wouldn't have thought it would stall due to a faulty advance/retard. It just wouldn't run very well.

I do not know why anybody fits inline fuel filters when there is already a filter in the SU fuel pump. Why would you need a filter downstream of an existing filter? All it achieves is to make it more likely you will have fuel vapour lock problems.

I would take the inline fuel filter out as my first step and see what happens.

If removing the inline filter does not fix the problem you will have to systematically check everything because a lot has changed in one go.

Check the spark to each plug.
Check the spark plug gaps and adjust as necessary
Check the points gap and adjust as necessary.
Check the points are clean. New sets of points need to be cleaned. Usually there is a coating that is to prevent oxidation in storage. I have had new points that measure very high resistance when closed. Use carburettor cleaner or petrol (you will have to take the points out to do this)
Check the points are installed correctly and especially the order on their mounting post. Ensure the insulators are in the right place
Check the condition of the low tension lead in the distributor
Check the condition of the earth wire in the distributor
Check low tension lead to distributor

If all of this is good, occasionally a condenser fails extremely quickly. The Distributor Doctor condensers are very good.


Stephen

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[Monty-4]

Without seeing the car I'd suspect a sticking needle valve in the carb float chamber or the fuel pump points. When my fuel pump points got a bit grubby it is was frustratingly intermittent!

[oliver90owner]

Apart from the very simple fact that a vacuum never leaks anywhere (by definition there is nothing to leak!), you have a restarting or just rough running problem, not a situation where you need to check and reset everything!

Checking for spark, immediately if/when it stops or won’t start, is the first (and easy) check to determine if the fault is ignition or fuel related.

Monty is more likely on the right track, but simple checks cost nothing.

If it is running and has a good blue spark (not a weak yellowish one), the ignition system is OK. Save yourself a lot of unnecessary hassle, if this is the case. Your mistake was changing several system parts at the same time. I would suspect the filter, initially.

[svenedin]

Apart from the very simple fact that a vacuum never leaks anywhere (by definition there is nothing to leak!), you have a restarting or just rough running problem, not a situation where you need to check and reset everything!

Checking for spark, immediately if/when it stops or won’t start, is the first (and easy) check to determine if the fault is ignition or fuel related.

Monty is more likely on the right track, but simple checks cost nothing.

If it is running and has a good blue spark (not a weak yellowish one), the ignition system is OK. Save yourself a lot of unnecessary hassle, if this is the case. Your mistake was changing several system parts at the same time. I would suspect the filter, initially.

Well obviously air leaks in causing a loss of the partial vacuum. Perhaps I should be more careful in how I phrase things.

[kevin s]

Might be worth trying the original condensor, modern ones have many quality issues and the symptoms fit one failing.

[svenedin]

Might be worth trying the original condensor, modern ones have many quality issues and the symptoms fit one failing.

Except the Distributor Doctor condensers which are excellent. ESM sell these as well as a cheaper one. My guess is either the newly fitted inline fuel filter (the SU is only a low pressure pump) or the new points weren’t cleaned of their protective coating giving a very high resistance.

The OP could run through the checks I suggested in 15 minutes
Stephen

[oliver90owner]

Might be worth trying the original condensor, modern ones have many quality issues and the symptoms fit one failing.

Except the Distributor Doctor condensers which are excellent. ESM sell these as well as a cheaper one. My guess is either the newly fitted inline fuel filter (the SU is only a low pressure pump) or the new points weren’t cleaned of their protective coating giving a very high resistance.

The OP could run through the checks I suggested in 15 minutes
Stephen

The OP could check for a good spark in about 15 seconds, if he has a helper, and not much longer on his own - if he knows how. Why recommend extra work when it may be totally unnecessary? Crazy, in my book.

On top of that you suggest the in-line filter first - then succumb to doing some basic diagnosis. Not exactly very scientific?

Proper use of terms is often important. Many think that vacuum ‘leaks’. None are correct, meaning that they likely don’t even know what the term ‘vacuum’ really means.

[svenedin]

Might be worth trying the original condensor, modern ones have many quality issues and the symptoms fit one failing.

Except the Distributor Doctor condensers which are excellent. ESM sell these as well as a cheaper one. My guess is either the newly fitted inline fuel filter (the SU is only a low pressure pump) or the new points weren’t cleaned of their protective coating giving a very high resistance.

The OP could run through the checks I suggested in 15 minutes
Stephen

The OP could check for a good spark in about 15 seconds, if he has a helper, and not much longer on his own - if he knows how. Why recommend extra work when it may be totally unnecessary? Crazy, in my book.

On top of that you suggest the in-line filter first - then succumb to doing some basic diagnosis. Not exactly very scientific?

Proper use of terms is often important. Many think that vacuum ‘leaks’. None are correct, meaning that they likely don’t even know what the term ‘vacuum’ really means.

I thought it was pretty obvious that if he had a good spark at each plug it would not be necessary to continue with every other check........

As a doctor of medicine I am well aware what a vacuum is but if you want to be pedantic then I shall not waste my time offering advice on this forum. I have other things to do. Sorry you don't like my diagnostic methods.

Stephen

[MoggyMatilda]

Thanks for everyone’s suggestions. I will go back & do the checks recommended starting with removing the inline fuel filter. Only reason I fitted one is that the car had been sitting a good few years & the tank have had some sediment in it. I did drain the tank but the filter was an extra precaution. I’ll also check the float needle as it could be sticking periodically.

As for the new points, I DID NOT clean them first as I didn’t know about the coating on them. Would the coating cause an intermittent spark?

I find it strange that with all these changes I made at the same time (as part of a good reconditioning service) the car fired up straight away & drove perfectly. Next day started giving issues.

But alas, I’ll do some checks today & report back with my findings. Thanks all for you thoughts and suggestions!

[svenedin]

Thanks for everyone’s suggestions. I will go back & do the checks recommended starting with removing the inline fuel filter. Only reason I fitted one is that the car had been sitting a good few years & the tank have had some sediment in it. I did drain the tank but the filter was an extra precaution. I’ll also check the float needle as it could be sticking periodically.

As for the new points, I DID NOT clean them first as I didn’t know about the coating on them. Would the coating cause an intermittent spark?

I find it strange that with all these changes I made at the same time (as part of a good reconditioning service) the car fired up straight away & drove perfectly. Next day started giving issues.

But alas, I’ll do some checks today & report back with my findings. Thanks all for you thoughts and suggestions!

Yes the coating and or oxide layer on the contact breaker pads would cause a poor or intermittent spark. It causes a high resistance and I have measured that on brand new points that have not been cleaned first. As an aside, this also applies to brand new points type fuel pumps and the RB106 control box. When you have set the points gap make sure you tighten the adjusting screw down so that the gap cannot close back up.

There's a fine mesh plastic filter built into the SU fuel pump, assuming that is what you have. You can remove it to clean it and if not already done that would be a good thing to do.

Good luck and hope to hear about success and you've been out for a Sunday drive!

Stephen

[geoberni]

As for the new points, I DID NOT clean them first as I didn’t know about the coating on them. Would the coating cause an intermittent spark?

I find it strange that with all these changes I made at the same time (as part of a good reconditioning service) the car fired up straight away & drove perfectly. Next day started giving issues.

Yes, they basically have a 'varnish like' film on them when they are made, to protect them in storage.
And I agree that it's strange it allowed you to drive around the first day.
But then that first drive might have 'burnt' the coating, making it more resistive.
Thus giving you the problems.
The minute arching that contacts have has caused all manner of problem in different environments, ever since the first contacts were used. It's just one of those things.
Special diamond coated 'Points Files' used to be really common tools, these days they are much harder to find, and not cheap.

[kevin s]

Don't assume the distibutor doctor stuff is perfect, I spent 2 hours freezing to death beside the A14 shen one of his roto arms failed!

To clarify, was it running fine before this or is this all part of an on-going re-commisioning?

If the later be aware there is a gauze filter on the pick up tube in the tank, it can easily get blocked by debris, unfortunately you also can't get to it to inspect or clean. Blowing backwards from the front can clear it for a while but the only real solution is to take the tank out and flush it out.

The paper filter you have added between the pump and carb will not have any effect if all is working well and gives you a usefull diagnostic tool, when it cuts out check there is fuel in the filter. They were also fitted as standard to the rover V8 with SU carbs. They provide a better quality of filtration than the gauze ones in the pump.

[MoggyMatilda]

The car had been parked up some 3-4 years so it’s part of an ongoing recommission to make it my summer daily. Because the parts are relatively cheap I decided to do a full service with new parts. (Thinking it would be more reliable long term).

I removed the inline filter & cleaned the points. Car is running a lot better than it was, but still takes notions of feeling hesitant in acceleration which makes me assume it’s a fuel related problem. When I first got the car the fuel pump didn’t work. I cleaned the points & filter in it when I had it removed & got it working nicely. Float needle was also sticking initially but doesn’t appear to be sticking anymore.

I used a bicycle pump to blow back down the fuel line into the tank to make sure it wasn’t blocked when I first got the car. Carb was also taken out & cleaned. I didn’t tamper with any adjustments as the car had been running when it was parked up about 4 years ago.

[svenedin]

Glad you have the car running.

If you want to test the advance/retard (your original query) you can connect a syringe to the carb end of the vacuum pipe using the rubber connector that the plastic vacuum pipe goes into. With the engine off, pull back on the plunger of the syringe whilst looking inside the distributor. You should see the platform that the points are attached to rotate as you apply vacuum. It is not a big movement but is noticeable. You can also just suck on the pipe but you are likely to get a taste of something foul and you may not be able to produce enough vacuum. Or you can connect a vacuum pump as used in bleeding brakes. I cannot remember exactly how many mm Hg (mercury) of vacuum should produce maximum advance (the information is out there somewhere!) but really you are looking to see if it works at all. The diaphragm in the distributor can harden and fail or the mechanism that rotates the contact breaker platform can get stuck. If your distributor is very worn out, you can buy genuine Lucas 24D4 distributors from Club Spares or you can have your distributor professionally rebuilt (but this is rather expensive).

Stephen

[kevin s]

Is the carb piston rising and dropping freely with a nice clunk when it hits the bridge?

[svenedin]

Is the carb piston rising and dropping freely with a nice clunk when it hits the bridge?

And is there oil in the damper?

[MoggyMatilda]

Update!!!!

I went back over everything I changed to make sure they were working as they should.

The car is running a lot better now which is great, I haven’t had the chance to take it a good long run yet but all seems good. I noticed it was running very rich before so perhaps it was flooding itself. But I’ve sorted that out now.

Also, The negative terminal on the battery was a little loose! perhaps that was the cause all along?

I’ve ordered new track rod ends as the bushes look worn out. There’s a little vibration in the steering wheel, I had the wheels balanced but the tire guy said they were a little out of shape & possibly need replaced. Which I’m going to do eventually anyway. I just wanted to get the car running reliably first before getting new tyres.

[svenedin]

Great news!

A loose battery terminal clamp can certainly give odd troubles but usually the car will not crank on the starter if it’s too loose.

From what you reported it seems that cleaning the new points did the trick but it’s good you found the loose battery connection too. The over rich mixture will not have helped at all either!

[myoldjalopy]

A couple of points worth noting. One is the importance of the points gap, If the gap is too too big or too small it will respectively either advance or retard the timing thus affecting the performance of the engine. The other is that if the car has been sat idle for a number of years and the intention is to give it a 'tune-up', the valve clearances would be worth checking as well as the ignition system and the mixture........