10 replies to this topic

[mini93]

Hi guys just trying to figure out a problem with the bloody thing.

iv got a problem that the car has, since this engine has gone in really that the engine turns over slow. Sounds similar to when you have a battery low on voltage, cranks, slows, cranks slow etc
the battery however is fully charged 306 diesel battery so should have ample cranking amps.

The engine when assembled wasnt very tight on the bearings and was able to spin as it should, even when you jack a wheel in the air you can turn the engine over etc

The start motor has been changed perviously and didnt effect the cranking at all.
The compression ratio isnt silly high either so shouldnt be a problem with that.

strangly though sometimes for no reason it will pick up and spin round as it should too! so not sure

its just getting rather annoying as currently its being a complete bugger and not even starting and thinking it might actualy work more reliably if it was able to crank over at a normal speed.
Its got a inertia starter motor and just thinking i may well switch to a pre-engaged type if i can get a new ring gear welded onto my billet flywheel


Thanks all
(a rather frustrated and wanting to drive his mini again) Dave

[il-barba]

check the earth strap in the boot, and engine to body earth strap. make sure you have clean metal under them

[samsfern]

as above, might be worth checking and cleaning the earth straps, and cleaning where the earths meet the body, engine and battery with a bit of emery cloth, and make sure all thne bolts and screws etc that hold the earths on are tight. Unless youve got a very high compression ratio, lol.

Edited by samsernie, 18 August 2010 - 02:26 PM.

[mini93]

the earths were fine on its previous build which is a strange one tho, at that point it was running a pre-engaged starter (different billet flywheel) but that engine was running 12.5:1 its now running less than that but i cant remember what exactly

[pikey7]

tired solenoid?

what car's this on Dave?

[twodesks]

Just as a quick test - run a jump lead from the negative terminal of the battery start to the engine block. Earthing question answered in a jiffy

[Turbo Nick]

doesn't the solenoid earth through it's mounting aswell? that'd be the best place to check imo.

[mini93]

solonoid was a new-un think it would be strange that it sometimes spins freely aswell...mind its strange occurance anyhow it seems

tis on my "rally" car mike

the sol' does earth through the back plate of it, it was earthed to the body but when iv put the flip front on iv left it kinda hovering but with an earth lead attached right to it, then to suitable earth...just a bit of a bodge till i get some brace bars in there

i best get a multi meter on the sol connection and the engine earth in any case just as a check, the engines solid mounted anyhow so even if the earth strap failed theres plenty points that it would earth through

[mini93]

it started!! but then i left it idling and it stalled and wouldnt start up again, urgh annoying thing.

i cleaned up the boot earth as it wasnt looking too smart but thats the only earth which looks suspect i might bypass my fia killswitch just to rule that out as possible weak crank voltage

[Yoda]

Have you tried cranking it with the coil disconnected? i have a similar problem, done all the earths, in fact i have run a new earth cable directly to the starter mounting bolt from the battery, new solenoid, all new battery cable and terminals, and out of frustration, i fitted a coil kill switch and it spins up fine with the kill switch engaged and once spun up i can disengage the kill switch and it fires up instantly. I think my problem is high compression combined with aldon 100 fixed dizzy set at about 28 degrees. Mind you, it starts fine most times, it just seems that occassionally the engine is at top dead when i hit the starter and like yours, reacts as if its a dead battery!

Hope this helps.

[mini93]

its running megajolt lol

never mind tho, im pulling the engine to check over the crank n stuff before combe in sept anyhow, ill get some plasti-gauge on the crank and also change the starter motor type because i didnt used to have a problem on pre-engaged