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Slow turnover
Posted: Tue Jan 31, 2012 8:50 pm
by Boomlander
Hi Folks,
Seem to have a problem with Jethro's engine turnover speed.
I ran the battery down while rectifying a series of annoying electrical problems and while recharging noticed that the battery was only a 36A/H unit.
Despite being fully charged the starter doesn't spin the engine over very quickly and I was wondering what would be the most powerful battery that I could fit. I would rather have too much capacity than not enough.
Can anyone recommend a battery?
Re: Slow turnover
Posted: Tue Jan 31, 2012 9:09 pm
by Neil MG
It doesn't matter how "powerful" the battery is, it will make no difference to the starter speed. Try checking the battery leads, terminals, connections and earthing.
Re: Slow turnover
Posted: Tue Jan 31, 2012 11:06 pm
by beero
Agree with Neil, especially check the engine/gearbox to chassis earth.
A second earth strap to the engine really helped with the MG.
Re: Slow turnover
Posted: Tue Jan 31, 2012 11:26 pm
by bmcecosse
3rd for that - my 2 litre TR7 engine starts up just fine with a very small battery which is at least 6 years old now. Look to the connections - and possibly pull the starter and clean the comm and check the brushes, and a few drops of oil on the bushes. Also - check that end engine is free to turn - have a go with the starting handle !
Re: Slow turnover
Posted: Sun Feb 12, 2012 1:37 pm
by Boomlander
bmcecosse wrote:3rd for that - my 2 litre TR7 engine starts up just fine with a very small battery which is at least 6 years old now. Look to the connections - and possibly pull the starter and clean the comm and check the brushes, and a few drops of oil on the bushes. Also - check that end engine is free to turn - have a go with the starting handle !
Thanks Guys, I assume that a battery with larger capacity would only be beneficial if a great deal more high power equipment was fitted to the car, uprated headlamps, foglamps, spotlamps etc.
Where exactly should I be looking for the engine to chassis earth strap and is there also on on the gearbox?
Sorry to be so ignorant but I'm in new territory here.
Re: Slow turnover
Posted: Sun Feb 12, 2012 5:41 pm
by bmcecosse
The strap is at the gearbox to crossmember - under the car. But you can add one from the engine to chassis - can only be better.
Re: Slow turnover
Posted: Sun Feb 12, 2012 7:28 pm
by Boomlander
Many thanks Sir,
I will clamber underneath the car when the weather dries out a bit and see if one is present.
Your help is much appreciated.

Re: Slow turnover
Posted: Sun Feb 19, 2012 7:28 pm
by Boomlander
bmcecosse wrote:The strap is at the gearbox to crossmember - under the car. But you can add one from the engine to chassis - can only be better.
Found earth strap from gearbox to chassis - very thick braided cable in good condition and tightly secured.
Doesn't seem to be one from the engine to the body and the positive earth lead from the battery is simply connected to the side of the battery compartment.
I will take your good advice and fit an earth lead from the engine and fit a longer battery earth to a more substantial point.
Thanks once again Sir.
Re: Slow turnover
Posted: Sat Mar 24, 2012 6:19 pm
by Boomlander
bmcecosse wrote:3rd for that - my 2 litre TR7 engine starts up just fine with a very small battery which is at least 6 years old now. Look to the connections - and possibly pull the starter and clean the comm and check the brushes, and a few drops of oil on the bushes. Also - check that end engine is free to turn - have a go with the starting handle !
Removed Jethro's starter motor cable today and you were absolutely right about the connections. At the motor itself the cable connector was free to turn on the stud and several of the cable strands were broken. Fitted a new cable and the engine is turning over much more quickly, many thanks

Re: Slow turnover
Posted: Sat Mar 24, 2012 6:21 pm
by bmcecosse
Great success!