Does this site have "auto restore"? I know the Marlin site allows you to reply again and had an auto restore facility which has saved all your input. This site probably has the same fzcility as it is based on the same generic software.

Good point Mike, I used to have a habit of copying every post to the clipboard because it was common on a forum I used a lot, it was very flaky but last few years I got out of the habit. Maybe I need to get back into the habit for longer posts.

I did use the MOC forum recovery occasionally, it was handy. It may be this forum is using a different version or it hasn't been activated.

I have PM'd JG so he may get back to me on it. It's just a bit disappointing when I have spent considerable time creating a post then it just goes 'poof'. I find it very hard to find the enthusiasm to re-type it.

For long posts I always type a draft in Word and save it. It is then quick to access when you revisit to continue editing later. Then when complete just select all (Ctrl+A) copy (Ctrl+C) and paste (Ctrl+V) into a forum and add any photos as a last task. Peter.

I very rarely set out to write a long post! I much prefer a single liner...

However... More often than not I find myself glued to the keyboard expounding on some topic or other because my enthusiasm gets the better of me. :typing:

I have never resorted to using a separate software to create the text for pasting into a forum, way too much of a faf. By far the easiest is to copy the text to the pasteboard and have it there in case things go pear shaped when posted, but this is the first time I have had an issue on this forum in about a year and a half, so I wasn't prepared for a loss of text.

Anyway getting back on topic! :focus: I have fabricated a little pipework to replace the kinked rubber pipe which was plugging the heater pipe outlets at the back of the inlet manifold. A kind neighbour has found me a piece of 90mm 316 stainless tube which will act as an expansion tank.

With luck tomorrow I hope to do a little TIG welding to refresh my skills and try out my new bottle of gas.

Update:

For a host of reasons I haven't got round to fabricating my header tank, but I have been making short trips in the Marlin. It seems that once the engine has worked hard climbing the numerous hills around here, it then refuses to start for about 30 minutes, once it has cooled it starts instantly and runs perfectly, pulling like a steam train and apparently without any vice.

Yesterday I chose a particularly hilly trip down narrow country lanes. At one point I had to stop for about 800 sheep to pass. I stopped the engine and immediately tried it but no go, it didn't even fire. A couple of minutes later once the sheep had passed I tried it on the starter again, but no go. As we were on a hill, I thought I would try bumping it off. I let the car roll a few yards and dropped the clutch in second, the engine started instantly! It didn't even spin over, it was instant power. We zoomed off. Later on my way back after a particularly steep climb, once we were over the summit I tried it again, in second gear, after a few yards, not more than walking pace, dropped the clutch and had an instant start with quite a hot (But not over-heating @ 80ºC.) engine.

This is beginning to make me lean away from fuel vaporisation towards PERHAPS a weak spark. I am using a 12 Volt coil and conventional (P5) old fashioned contact breakers.

I am thinking of trying a ballast resistor coil, perhaps without the resistor at first, just to prove or disprove the idea. If that does work, I may try the proper, original SD1 distributer, to see if that helps. I did try it right at the beginning when I had problems with the rev counter but once I realised the polarity for the rev counter was wrong and that was causing the problem, I re-fitted the old, points distributor.

I am hopefully a little nearer understanding what the issue is.

Other than that and a sad lack of ground clearance, it's going really well, great fun. A set of standard springs might be an idea...

How about hotwiring?, a direct feed from the battery to the coil with a switch in the wire. With the switch in the off position go for a ride around and when you get the problem of non starting then switch on your hot wire and try starting with the starter.
If it starts off the hot wire then you will know that the ignition switch is not providing enough power to the coil when the starter is engaged and a ballast resistor may help.
It would appear that because it starts with a bump start it is coil related or starter drain on the ignition side.
Phil

Neat suggestion, that should nail it. Thanks Phil!

That's my line of thinking, I need to follow it up.

I do have a second starter available and although the battery is in the back I used a 50mm (300+ Amp capacity) cable to minimise Volt drop to the starter. That said, I do have a battery isolator on the earth side which may have some resistance. Now I an reasonably confident about the electrics I might make a clean and direct earth connection bypassing the cut out to see if that does make any difference.

I still keep coming back to a nagging point which is why does a relatively small difference in engine temperature make the difference between starting perfectly and not even firing.

OK, progress!

I tried three basic volt drop tests. The earth (negative) side to the battery to the chassis, effectively bypassing the battery isolator, is losing 0.23 Volts while cranking. The main power cable and wiring to the coil is losing 0.95 Volts while cranking. The Voltage at the coil is 12.5 Volts and during cranking is 9.45 Volts, which is a difference of just over 3 Volts loss. 0.23 + 0.95 = 1.18; 3.05 - 1.18 leaves a cranking Volt drop in the battery of 1.87 Volts.

I don't feel the volt drops during cranking are worth worrying about.

We have just came back from a blast through the lanes up and down our biggest hills locally. At first I couldn't get the car hot enough to refuse to start but it is blowing hard and quite cool here so I suppose it's no great surprise. However, I noticed the engine temp rising a little so I pulled up at a small refuge and tried to re-start the engine... No dice! So I quickly installed one of my ballast resistor coil. Instant re-start, switched back to the 'original' 12V coil and no-go.

Cracked it, we thought. I drove homewards about 4 miles on an 'A' road, on the last down hill I stopped and tried to re-start on the Ballast resistor coil. No-go, we re-connected the original coil and it started perfectly.

It seems the coils are getting too hot.

Whether this is because of the ambient temperature under the bonnet or some fault in the distributer I don't know yet. The dwell is set as it should be, the points are new. It might benefit from a new set of plugs but given it runs so well I don't think that is the issue.

Ambient may be a factor but I don't know yet. My next move is to re-locate the coil to in front of the radiator. That is my coolest place, although not the driest, either that or make a hole through the bulkhead for the coil lead and have the coil behind the dash. That will be another day now, I have much else to do but at least I have a much better idea of what's wrong.

Are you taking your live feed for the ignition etc. from the starter motor live terminal or battery side of the solenoid.
If you take it from the solenoid live feed and the solenoid is dodgy you can get problems.
Also the 3 volt drop at the coil when cranking is similar to the voltage drop with a ballast resistor. Some vehicles have a resistor in the line to the coil as standard, may need some investigation.
Phil

Hi Phil, Am taking the car feed from the end of the 50mm cable from the battery, where it bolts to the starter solenoid, this is also where the alternator feeds it's output and the headlight power feed is fed from.

I think I will test the resistances of the coils, they are all very old, well over 30 years, so it may be worth investing in a decent new coil. Can you even buy them nowadays? LOL

The wiring is all my own work, grossly over spec, there is no hidden ballast resistor lurking! With the battery accounting for almost 2 Volts of the 3 Volt drop there is little I can do about that, the battery is good, and spins the engine fast enough for ages if needs be, so there is plenty of capacity. I have another battery of similar capacity but I think the issue has been narrowed to the coil. Cool coil instant start, hot coil no start.

Blooming heck! 30 year old coils are they from the antiques road show!
I would not rely on anything that old, except a 30 year old blonde eh eh.
For about £25 you can get most coils, but make sure you get the right one, electronic ignition coils work differently to the old points system ones, and if you upgrade your points to electronic, check which ones go with which.
Just think you could be sat in front of the telly watching day time TV if it wasn't your kitcar or going shopping with the missus or visiting rellies, there is a heaven.
Phil.

Hi Robert I sent you a couple of pm's since I came back of hols.
My dads motor home is wired like that alternator feed cable links to the battery feed to solenoid post, and randomly hot or cold it will sometimes just click like a duff solenoid, in the history of vehicle there are numerous receipts for starter checks new starters etc very unrelated to yours but I had wondered if the alternator is jiggered and putting out high/ irattic power if it was frying something, although surely the solenoid post is entirely isolated when the solenoid is idle, my next port of call is to run a new trigger feed to solenoid direct from a fused battery connection with a switch in the cab to rule out a Dickie ignition switch or intermittent break in the trigger wire,( his problem usually arises when he is in a queue to get off a ferry or at a busy petrol station never while calmly parked on a campsite)
Relevance to your issue and a long shot, could your alternator be doing odd things whilst hot? Stealing power or supplying high low power, i have had motors that didn't like to start unless the starter spins at a very specific speed, although usually deisels Ed

Hi Robert. Does your carb have an idle shut off solenoid? If yes replace it! I had similar symptoms on my Classic that has been retro fitted with a Weber 34ICH and the solenoid had an intermittent fault, usually when hot! If I did manage to get it to start it would then unsurprisingly not idle unlesss the choke was pulled out to artificially richen the mixture. Peter.

8 Valve Ed - Hi Robert,

Sorry, I've been meaning to "bump" your thread for ages and ask how things are going.

It has been a long time since your last post, so I hope all is well.

If you get the chance, it would be great to see an update on your build.

Take care, Paul. :)

https://c1.staticflickr.com/1/453/18...7a4e089e_c.jpg

Sorry all! :humble:

Just a quick update...

I have been so busy on stuff I haven't had time to continue my thread here.

In short I have more or less diagnosed the refusal to re-start when hot to it being caused by a hot coil.

If I take only a short run which makes the engine work hard for say 4 or 5 miles then stop the engine it won't re-start until things cool down, say 20 to 30 minutes. If I switch out the coil to another one sat alongside the first one, at the same ambient temperature, the engine re-starts instantly.

These are 12 Volt coils, running at 12 Volts. I have 3 or 4 coils one a new Bosch, all of which perform perfectly well when the engine is running but all refuse to re-start the engine immediately it's stopped if the engine has been working hard, unless you bump the car off down hill or with a tow.

I have moved the coil from the bulkhead to in front of the radiator. Am concerned about protecting it from water (rain and splashes from puddles and standing water) but for now it seems to have fixed the problem.

The car is laid up for now, I need to get some longer/stronger springs, it's WAY too low, grounding out on the slightest bump, speed bumps can stop me because I have less than 3" clearance, crazy!

Will do a better update asap.

I am sure you know this already but there are several types of coil depending on use. They have different specs - mainly the resistance. The list includes at least:

Coil for normal ignition - no ballast resitor
Coil for normal ignition - with ballast resistor
Coil for electronic ignition

If you use the wrong one it will overheat and the insulation will start to break down resulting in a weak or no spark...

You should be able to find more info on t'internet.

Cheers, Robin

Could be the alternator is pushing out too much and overloading the coil

One check you can make is the spark plug gap, the bigger the gap the harder the coil has to work and overheat, also the resistance in your HT leads, do they match the standards compared to the originals, your workshop manual should give this info.
Forgot to mention about the ignition module check to see if it is live all the time and not turning off with the ignition, a faulty module will kill your coil eventually.