8 replies to this topic

[Jammys Secretary]

Hi all,

I've got a Minus that I've been building over the summer, and I've finally got to the point where I've got the engine in, wired up, and I'm trying to start it! This is where the fun begins.

The engine is from a Metro, that I've put a Ultralite steel flywheel on, along with steel backplate and orange diaphragm. I was told the engine ran sweetly when it was removed, oil had been put down the bores to keep it from rusting, and indeed there was no lip on the bore when the head was removed. Clutch cover was changed for a pre-verto, and starter was changed to pre-engaged along with the solenoid wired in on the inner wing. The wiring loom that was in there originally was found to be rubbish, so replaced with a loom from B reg Mini (84-85). I've wired in a permanent feed from 12V fusebox - fuse 1. Anyway, I'm sure the ignition side of things isn't causing the problem, as the problem persists even with the coil unconnected.

The problem is that on the starter the engine is turning over VERY slowly. And one or two points in each rotation it almost stops, as if its binding. They seem to be the same two points on each rotation, which makes me think it might be mechanical rather than a problem with the starting circuit.

Something I should point out now is that because of the fibreglass body, the engine earth lead is connected to the subframe, on the same bolt that the earth cable that runs straight through the car to the battery is on. The starter solenoid is also earthed via a cable to this bolt, however this earth cable isn't any sort of special wire, does it need to carry a lot of current?

When the spark plugs are in, as I say it spins over far too slowly, with the plugs out it still doesn't spin over as quickly as it should. With spark plugs out I connected jump leads directly to the starter motor transfer case bolt and one to the +ve terminal. It did spin over much quicker, but still not sure if it was quick enough to start it.

Is the engine binding a serious problem, a result of it being stood for a while maybe? Would this be enough to put too much load on the starter?

I have been told that sometimes bolts through the transfer case can catch the flywheel and cause it to slow, but I've looked for this and it isn't the case.

Any help with this. I've put in a great deal of money and time into this and I'm all but stuck now!

I bought a new multimeter a couple of days ago, can anyone go through the steps and readings I should take so I know that nothing is wrong with the wiring side of things?

Edited by MinusMan, 23 August 2007 - 10:30 PM.

[mk=john]

Hi
Make sure the earth strap is in place between engine and body! Its very important. I dont know where on your mini it should be, but on my Mk1, its a braided cable between the bottm of the clutch cover and inner right wing. If there is a cable here (or anywhere else) make sure the connection surfaces are clean, and coated in vaseline for corrosion protection.

If there is no cable visbile, it could be that the engine is trying to draw current along a different route, such as the throttle or choke cables. If so, this could lead to those cables welding themselves in due to the high current the starter is drawing!

Lastly, there could be another reason. Believe or not, the last time I removed and replaced my (side mounted) radiator, I used the wrong length bolts to hold the radiator to the top radiator bracket. The bolts were too long and fouled the fan blades. Due to all the leverege forces, holding the fan from moving can actually cause the starter to be slugish if the belt slips on the pulley.

[Ethel]

Hi all,

I've got a Minus that I've been building over the summer, and I've finally got to the point where I've got the engine in, wired up, and I'm trying to start it! This is where the fun begins.

The engine is from a Metro, that I've put a Ultralite steel flywheel on, along with steel backplate and orange diaphragm. I was told the engine ran sweetly when it was removed, oil had been put down the bores to keep it from rusting, and indeed there was no lip on the bore when the head was removed. Clutch cover was changed for a pre-verto, and starter was changed to pre-engaged along with the solenoid wired in on the inner wing. The wiring loom that was in there originally was found to be rubbish, so replaced with a loom from B reg Mini (84-85). I've wired in a permanent feed from 12V fusebox - fuse 1. Anyway, I'm sure the ignition side of things isn't causing the problem, as the problem persists even with the coil unconnected.

The problem is that on the starter the engine is turning over VERY slowly. And one or two points in each rotation it almost stops, as if its binding. They seem to be the same two points on each rotation, which makes me think it might be mechanical rather than a problem with the starting circuit.

Something I should point out now is that because of the fibreglass body, the engine earth lead is connected to the subframe, on the same bolt that the earth cable that runs straight through the car to the battery is on. The starter solenoid is also earthed via a cable to this bolt, however this earth cable isn't any sort of special wire, does it need to carry a lot of current?

When the spark plugs are in, as I say it spins over far too slowly, with the plugs out it still doesn't spin over as quickly as it should. With spark plugs out I connected jump leads directly to the starter motor transfer case bolt and one to the +ve terminal. It did spin over much quicker, but still not sure if it was quick enough to start it.

Is the engine binding a serious problem, a result of it being stood for a while maybe? Would this be enough to put too much load on the starter?

I have been told that sometimes bolts through the transfer case can catch the flywheel and cause it to slow, but I've looked for this and it isn't the case.

Any help with this. I've put in a great deal of money and time into this and I'm all but stuck now!

I bought a new multimeter a couple of days ago, can anyone go through the steps and readings I should take so I know that nothing is wrong with the wiring side of things?

Oh the joy of plaggy cars, still it's better than having rust to contend with eh?

You need as good a return to the battery's negative terminal as you do a supply to the solenoid.

I have two cables equivalent to a standard mini's battery cable (the earth one is bolted to the gearbox). You could probably force the exhaust into service
but it wouldn't be as much of a fit and forget solution. Very much doubt there's a mechanical fault with the engine if it turns over.

For a quicky test fix use a jump lead to link the battery -ve terminal to the exhaust but bear in mind not all jump leads are up to turning an engine over on their own they often just add a boost to the existing electrics.

[Jammys Secretary]

The earth lead is in place between the clutch cover and the battery earth cable (I have the same type of cables coming from and to the battery +ve and -ve terminals.

The radiator fan isn't on yet. Plus its only binding in two places per rotation, which makes me think its a cylinder problem.

When I was turning the engine over by hand (using the fan belt to bring it round) it was VERY hard to turn it past these two points.

I have placed a jumper lead on the battery feed terminal of the solenoid, and placed the -ve jump lead on the engine block and the starter still wasn't turning the engine over quick. This means its not an earth problem surely? That only leaves the solenoid, the starter motor cable (changed twice), the starter (changed twice) and the engine?

[Retro_10s]

Did you strip the engine down to the crankshaft?...

[Ethel]

Almost,

Could be a poor connection between between the starter and the flywheel housing.

An engine should have 2 'tight spots' in every revolution as the cylinders reach full compression.

Is the battery in top condition, all the contacts clean?

You could do the solenoid jump start again but use the starter post instead of the battery post to eliminte the solenoid from the list of suspects.

[Jammys Secretary]

Didn't strip the engine down, apart from taking the head off.

I did jump the starter off starter motor terminal, as I say, it was quicker, especially when I had the car I was jumping from running.

The battery was new, although its a bit run down now!

[Purple Tom]

Regarding the tight spots, have you tried taking the plugs out and seeing if the tight spots are still there?

I would say an earth problem really, especially on a Minus....but obviously you've looked at all that already. As for wire gauges for the earths, I wouldn't know, but looking at how thick the earth strap is from engine-shell on a steel Mini, i'd say they need to be a similar thickness - have you felt to see if there's any heat in them after cranking the engine, or if there's any excessive heat in any other wiring?

Might be worth putting a post up with the title 'attention all Minus owners' or something, and ask for someone to look at their Minus regarding earth leads, or have a word with Alburglar as he used to have a Swifty 1380 in his R1 Minus. I take it you're working to some sort of deadline so the sooner the better really

[Alburglar]

Hi,
my advise is use as thick a guage wiring for your earth as you can and high quality too, I used 4 guage (about 10mm thick) bought from a stereo shop. I had my battery neg side earthed directly to the front subby in one place and an earth strap from engine to subby in a different place as for reasons un-known it worked better this way. What dizzy are you using, because electric ignition behaves very irratically in minus' due to the earth- this could be the issue.

Ideally you should earth the neg side of the battery to both subframes and then provide a seperate link between both subframes. This will create what is known in the kit car world as an earth loop.
Hope this helps