Heavy Duty starter motor

[picky]

Sorry if this has been covered before, but I cant seem to search previous topics in the forum

I was having starting problems after upgrading the cylinder head to a skimmed 12G295 one, which gives the engine a higher compression ratio, the starter would just turn the engine quite slowly. Now the starter motor wouldnt turn the engine at all, so new starter motor but still the same problem. THe voltage over the battery when you turn the key is only 3 volts. When jump starting it from another car with a larger battery (Nissan primera 1.6) the starter still turns it slowly before it starts. Do I need a stronger starter motor or am I missing something?? As it is still slow when run from another battery, new battery would make any difference?? the primera doesnt have any starting problems and the battery in it is fairly new. $(%&£$&£&!!
Thanks for your time!!
Tim

[Packedup]

You need a new battery, and you might need to clean all the earth points and connections.

You can, of course, also use the starting handle if you can't be bothered to do the above

[picky]

I havnt had much luck with the starting handle after changing the compression, it flicks back at you and I dont want to snap my wrist :s Mini mania are under the impression I need a high torque starter motor. Is anyone else running a standard starter motor on a 10:1 compression ratio??

[Packedup]

I've run standard Minis with somewhere around 9.5:1 (I think, certainly the high compression 998s were close) and never had a problem with the standard starter motor. Driven other cars that use the same starter and same again.

Going by the fact a healthy battery and starter can whiz the nuts off an umodified A series, I'd be greatly suprised if you *need* an uprated one. Your battery is certainly sounding ill dropping to 3v when cranking, and bear in mind all but the absolute best jump leads will have a noticeable drop from donor to recipient. I find with most leads it's best to leave the donor charging the dead one for a few minutes before trying.

My guess would be either you have far higher than 10:1 compression, your battery is duff, your connections are corroded, or a mixture of the lot. Going by the fact you say it used to turn but slowly, and now struggles at all, I'd go for bad electrics. The starter motor is unlikely to have suddenly become too weak! Might be worth checking your battery is getting and maintaining a decent charge too.

[rayofleamington]

If yur battery drops to 3v when cranking, then charge it for 24 hours and try again - if that doesn't fix it, then get a new (and bigger) battery. As mentioned allready, jumpleads usually give poor cranking due to the very high current required.
A good battery will not drop to 3 volts unless the starter motor is short circuited, and as you can start the car with jump leads and the previous starter motor was the same it's got to be the battery
(It's not likely to be the connections as the battery shouldn't go that low unless there is plenty of current flowing)
good luck!
(if you get bad luck, you'll find out that is was a faulty starter motor )

[Alec]

Hello Picky,
your timing may be a little too advanced if the engine kicks back on the handle. However 3 volts is far too low, (assuming your meter is OK) and that will also drag down the voltage of a battery used to jump it. Packedups advice is good, let the donor vehicle put something into your battery before trying.
Just a point, where exactly are you measuring the battery voltage, directly onto the terminals or on the battery post? If it is the posts and the battery voltage is 12 volts or more off load then the battery is likely to be the culprit. Certainly I would not be thinking of an uprated starter.

Alec

[rayofleamington]

Just a point, where exactly are you measuring the battery voltage

Very good point! If the 3 volts is measured on the connectors, not actually on the battery you need to re-check it on the battery to see what it gives (if it is different then the connections are playing up)

[picky]

The 3volts is across the + and - battery terminals. When there is no load on the battery it shows 12V. Im still using one of the old type of battery connector that has a screw in the top, Ithink I will replace this anyway, along with getting a slighty larger capacity battery. What should I ask for at the motor factor? the primera battery is 50Ah battery, but the morris one doesnt say its capacity.

[Packedup]

12v is a little low for a fully charged battery, besides which it might be failing and just falls over as soon as it gets any real load. As long as the terminals are clean and a tight fit I've never had a problem with the screw type ones myself, but I know others aren't big fans of them.

As for battery size, if you're not interested in getting the last thousandth out a lap time then just get the biggest you can afford that will fit! Although I imagine even the smallest "Mini" tpe ones will still do you just fine, but a bigger one is handy in the middle of winter when the car starts to play up in the mornings

[Alec]

Hello Picky,

if you measure across the terminals I would first check their connection. I personally don't like the old style 'cup' connector (neat looking though they may be) as it is difficult to be sure of a good contact over the whole of the cup. Before buying a new battery, I would ensure good connections to the battery.

Battry size as per Haynes' is 43 amp\hour, but of course, there is no harm in going a little larger if you wish but you may be surprised, if you haven't bought one recently, at how physically small some of these are.

Alec

[Cam]

I'm using a bog standard starter motor with a 10:1 compression ratio and it's absolutely fine. It does not turn over quite as fast as a standard 1098, but it still turns over more than fast enough! I would agree with the above and say it's most likely your battery that just can't supply the current. Charge the old one as Ray said first and try it, if it's duff then get a new one.

I too am not a big fan of the 'cup & screw' type battery terminals. I have used them in the past, but I prefer the 'clamp' type.

[Willie]

The screw top type battery terminals are a definite potential source
of trouble. I have experienced where the car would not operate the
starter but you could hear 'fizzing from the battery terminal which
when got very hot(arcing internally). Always fit the clamp type and
you have removed one more future problem.

[PaulB]

Picky, I am going to state the obvious, you have set the timing correctly? I had the same problem after engine re-build. Going back to basics, I found I had not set the timing up correctly, engine was very tight and turned over very slowly. Tried starter motors, heavy duty battery, just like yourselve.....please double check this as you have put on a new head.

Cheers PaulB

[picky]

Well it was a couple of months ago that I replaced the head, and the starter has just kept getting slower and less likely to start until recently it wouldnt turn at all. So its been a developing problem for a while, Alec reckons my timing might be too advanced, Ill check it out and see when im getting the spark in the cylinder.

[Willie]

PICKY of course check your ignition timing but it is perfectly normal
to have a 'Kick back' on the starting handle if you don't know the
technique. That is why you must NEVER hold the handle with fingers
on one side of the handle and your thumb on the other side(this is
a quick way to aquire a broken thumb) Always hold the handle with
all four fingers AND your thumb on the same side!! Your battery
is either not being charged sufficiently or it is knackered as you have
been advised.

[picky]

im assuming the starting handle technique has been discussed before... but I cant seem to search previous topics anymore

Ive had the battery charged for 24 hours and its still dropping to 3v when starter engaged and the engine doesnt turn....

new battery lead ordered from ESM, the later type as suggested, and ill get a new battery from halfords, hopefully get MOT sorted...
thanks for all the help as usual,
Tim