Moss Motors, Ltd

Hi I was wondering if someone out ther could help me. I have a 1959 austi healy 100-6  the engine has been restored  and was running fine until one day i went to start it and it started to backfire back into the carbs with flames coming out and had no power only way I could keep it going was to keep the choke out I have tried everthing from tuning carbs replacing distributor.I finally pulled the engine to see if maybe the timing chain had jumped a tooth but everything looked all right but i thought i would try and time it according to the shop manual with #6 exaust valve just closing and input just opening but when i did that nothing lined up,so i put crankshaft and camshaft where the book said to and everything lined up perfectly i was just wondering what was going on if i have to reposition crankshaft or camshaft because the valves weren,t in position they should be according to the book. IF anybody could help me out here it would greatly be appreciated thanks alot rrl

rrl,

Wow!, You've certainly put in a lot of effort to try to solve the problem. It's been my experience over the years that timing chains seldom "jump a tooth". It's one of those things that is often suspected, but just doesn't turn out to be the cause. When you replaced the distributor did you replace the cap and rotor as well? The symptoms sound like crossfiring in the high tension ignition system. There are other possibilities,but I would start there, where the cure is the cheapest and fastest. I'm not sure what method you used to check cam timing, but if in the end you had it where it was when you first took it out, and that was correct according to the marks on the sprockets, and it had run OK that way in the first place, I'd call that good. The only things left are ignition and carburetion. If nobody played a trick on you and messed with your firing order or radically changed your ignition timing, then only the condition of the cap, rotor, and wires, and the timing of the ignition is left. As for carburetters, tuning them while this problem exists would be just about impossible. I would first have said that you had a lean condition, or a fuel starvation problem, but that rarely results in flames shooting out of the carbs. However, a bad distributor cap, which is "mixing up" the firing order. could do so. I am not drawing a firm conclusion here. I would just like for you to investigate in that direction first and get back to me. Good luck.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

This sounds very much like the problem I'm researching on here. I just bought on Saturday and 67 Austin Healey Sprite MKIV with a 1098 motor. The previous owner spared no expense with a Malory dual point distributor an Weber 40 DCOE 151 carb. The cap and wires are old, I've got a new set on order, I put new plugs in yesterday and they are already covered in soot. With the choke all the way out the engine will fire right off. The idle is a litle rough, but not horrible. The car has an electric fuel pump that seems to be ding just fine at pumping clean gas from the new gas tank. As the enging comes up to temperature, I can ease off on the choke, but not all the way. If I give it any gas with out closing the choke back down at the same time, the engine will die. I can increase the engine speed slowly working the choke and throttle, but it will backfire through the carb occasionally if I do. I haven't yet confirmed the valve timing. I have looked at the distributor closely with #1 and TDC and the points are just opening. I did this basic static timing, but can't find the scale on the crank to set the timing with the light. I thought it should be close enough to get some kind of runability out of the engine, but no, still dies when I give it any gas at all. I'm thinking that the engine is getting too much gas and that I should change the carb jets to smaller jets. But that's my best guess. I'm going to pick up a book on webers tomorrow, that might shed some light on things. The jet thing is just my best next guess. Other things on the table are: 

New Coil, and points. Distributor cap, rotor and plug wires.

I also noticed what I thought was a lot of play in the distributor shaft. Which begs the question, what is too much play in the distributor shaft? 

Also, where should the scale for timing adjustment be on this engine?

I'm pretty lost with this one........HELP !!!!!