17 replies to this topic

[spaulwill]

Having completed the rebuild of my engine 1275 a I have no spark at the points and obviously not plug spark. This is what I have done so far:

New mini spares wirining loom, new Aldon dizzy, new coil and leads. All fuses ok I have voltage at the coil. When I turn the engine over the + terminal goes 12v then 0 as if the poit are switching but I cannot see a spark between the points and again with cap back on and plug shorted no ht spark. I suppose the dizzy could be faulty but it is brand new. Any advise appreciated thanks

[katana]

Did you clean the points before putting them in (some have a grease on contacts to protect them),& is the gap set correctly?

[minidaves]

have you got the points fitted correctly?

[spaulwill]

I have not cleaned them no will have a look at that as for fitting as this is a brand new dizzy I would hope Aldon did it they look as they should but I will check anyway against the manual thank you

[chrisandsarah]

Been a while since I had points. But I think a dead condensor will prevent any spark at points....

Could be wrong...

[sonikk4]

As with chrisandsarah the condenser could be dead but i would check to ensure the points are fitted correctly and gapped.

[spaulwill]

Thanks to everyone for their help turned out it was a bad connection on the fuse box, now got a spark at each plug but the car won't fire I've gapped the plugs to 0.8mm and have fuel to the carbs but no fire. Plenty of power to turn over just wondering if this could now be a timing issue I have tried altering the dizzy but nothing again this is probably something simple again but I am missing it. Any ideas guys????

[chrisandsarah]

Choke set up properly? Lean mix will prevent firing?

[dklawson]

Since the distributor is "new" then by all means you should check and set the static timing. If you are not familiar with the process, read the document linked below.
http://home.mindspri...taticTiming.pdf

Also check that your firing order is correct, 1-3-4-2 counterclockwise around the dizzy cap with #1 being about 2:00 on the dizzy cap and #1 cylinder being the one closest to the water pump. You can also be "out" 180 degrees so check to make sure you are making the ignition settings with #1 near TDC on its firing stroke. That is discussed in the PDF document.

[spaulwill]

Thank you doug , does it mean that when the prison 1 is at top of its stroke and the vales are closed so tapets are loose should the rotor arm be pointing to 2 o clock ie piston 1? I have no timing marks on my engine for some reason either also will the vacuum pipe off the carbs need to be connected some where as there are no hoses connected yet. Also the spark is there but looks faint the gap is 0.8 mm as the manual says and there is a new Lucas sports coil and leads. When I took the plug out there was a smell of fuel so I am happy some fuel is getting there.

[dklawson]

Yes. #1 at TDC, rocker arms loose. That's #1 on its firing stroke.

Early Mini engines did not have timing marks on the pulley and timing chain cover. Their timing marks were on the flywheel and you have to remove a cover plate on the clutch cover to see the flywheel marks.

Any and all open ports on the carb and intake manifold should be capped when you are trying to start the engine.

If you find there are no timing marks on the flywheel, set the static timing to fire right at TDC. Then note exactly where the dizzy housing is and turn it clockwise an additional couple of degrees... let's say 3mm on the outside diameter of the dizzy housing. That should be close to 5 BTDC which should let you get the engine started. After that you can tune by ear. I leave guidance on that to others reading this thread as I don't do it that way.

You do not want to see bright sparks at the points. There should only be a small blue spark there. Big sparks at the points indicate something is wrong that will likely lead to quick wear and burning of the points.

You have referenced .8mm. That is not quite right for the spark plugs on a car with points and it is way wrong for the points themselves. The points should be set close to 0.015" or 0.016" (0.4mm). The spark plugs should be closer to 0.025" (0.64mm). When electronic ignitions are fitted you don't have the points to worry about and the change allows running wider spark plug gaps... but for points, keep the plug gaps closed up a little bit.

Finally, too much fuel is as bad as not enough. If this is an engine that has not run for a long time and whose carbs may have been sitting full of old fuel, make sure the float valves are set right and that they are properly closing off the fuel supply when the float is up.

[spaulwill]

Once again thanks very much Doug, some real useful stuff here for me to get on with, I have built the engine so it hasnt run in ages the carbs were refurbished 2nd hand ones so dont know when they run, did say 2009 on the service lable on them, typical, I have replaced the flywheel with a lightweight one which has no marks but im sure from your advice I can get this lump going I will let you know. Thanks again..PW

[spaulwill]

Just out of interest I have high cr pistons and am running on Ron 95 do you think I need higher octane fuel as the engine still won't fire??

[dklawson]

No. Actually, lower octane fuel burns faster. That does not mean better, just faster.

Do you now have spark and is it happening at the correct time?

If you have spark, try pouring a thimble of fuel down the carb throat. If the engine starts and promptly dies, you have a fuel delivery problem, not an ignition problem.

[spaulwill]

Hi Doug, me again, I think the problem maybe deeper than thought. The engine spluttered and did fire momentarily however smoke was coming from the push rod holes which raided alarm bells I thought straight away this coul be the head gasket which looked in a bad way although no holes. What did alarm me the most was there appeared to be a large gap between the cylinder and piston I only have a vernier gauge so not too accurate but what I did find that overall the prison bore was 71mm but the pistons are standard which roughly measured about 69.8 so overall the piston is around 1.5mm smaller. Now that to me looks wrong so I wanted to run it by you. Qis this correct or has the block been rebored and standard pistons fitted?. Many thanks again in advance.