The Triumph Dolomite Club - Discussion Forum

Hi guys.
I'm wondering what sort of cranking speed I should expect for an 1850 auto? The Spitfire 1500 (rebuilt starter and new battery) winds over at a fair speed even though the engine has great compression.
Although I've had no trouble starting the dolomite it cranks over at a much slower rate. I'm wondering if it's a symptom of worn brushes in the starter, or just what I should expect from a larger engine coupled to an auto box?

Cheers,
Sam

Just tried my Sprint auto and it was difficult to count but approx 20 turns in 5 seconds. No choke otherwise it would have started, good battery just topped up, old starter. It is close to 30C here today so warm oil would put up less resistance than I sure where you are!

However, as you say you have no trouble starting, and it is the coldest time of the year, I wouldn't lose any sleep. Once you have difficulty starting, they you may have cause for concern.

I would just put a charger on the battery until it is fully charged and try again. It can make a big difference.

Geoff

Thanks Geoff, I'm reasonably confident it's not battery related - James replaced the battery with a new quality one (and the alternator) prior to me owning the motor.
I'll stick it on the charger though and see what's what.

Cheers, Sam

It is close to 30C here today so warm oil would put up less resistance than I sure where you are!


Geoff
[/quote]


We really dont wish to know............

Sam, it is turning the torque converter and probably some of the gearsets. Have you tried it with the spark plugs out?

Toledo Man wrote: ↑Sun Jan 28, 2018 2:02 pm Sam, it is turning the torque converter and probably some of the gearsets. Have you tried it with the spark plugs out?

Now that is something I actually did on a Rover 2200 SC. By removing no1 and no4 plugs I had just enough juice in the battery to spin the engine fast enough to get it started. Had no jump leads,charger or any other way of boosting the battery.

Problem is though I could not get the plugs back in without turning the engine off. It was a long time ago, I think I put no4 back in and then no1. That was when I bought myself a battery charger from Halfords.

Also at this time of year batteries tend to get run down. As Geoff suggested, Colder days= slower cranking, heater blower, HRW,lights on etc put a heavier load on the battery. If it is doing short and infrequent runs then the battery may not be getting enough charging time to put back in what starting up took out.

RUK, sorry, Binny gets taken on long runs by Sam.

I put in a new 45ah Bosch battery with 330A cold cranking capacity, I also upgraded the starter wire and bus box so Binny will be getting the full power of the battery on startup. When not in use the battery was always connected to a ctek conditioner.

As for cranking rate Binny cranked at the same rate as DTR and the other slant engine I have.

Nothing to do with the auto box. Fluid does drain back into the sump when it is left standing and being in park when you start there isn't a huge amount of load on the starter when turning the auto box, about same as a normal manual. I turned the TC when the engine was out and it actually spins very freely, once the TC is spinning the pump will draw oil back into it and it will then take little effort to keep it rotating.

I have a reconditioned 1850 starter on the shelf here.

I'd def get that from Alun, then you have a spare for the RBRR!

James467 wrote: ↑Tue Jan 30, 2018 10:33 am I'd def get that from Alun, then you have a spare for the RBRR!

Starter is not an issue on the RBRR - you don't stop, so you don't need to restart! (joke.... you stop for fuel, breakfast, etc)

James467 wrote: ↑Tue Jan 30, 2018 10:22 am Nothing to do with the auto box. Fluid does drain back into the sump when it is left standing and being in park when you start there isn't a huge amount of load on the starter when turning the auto box, about same as a normal manual.

going off topic for a moment, I thought there was a non-return valve in the auto box the prevent the oil draining back to the sump?

as for cranking speed, my 1850 and sprint autos only spin at about 200 RPM, if I remember correctly, the gear ratio between the starter ring and the starter pinion is 10:1 or 11:1 but I am prepared to be corrected, so if the engine is cranking at 200 RPM the starter is probably doing 2000 RPM.

on my 1300 I knew when my starter was on the way out as the cranking speed was slow and it also drained the new battery very quickly. the carbon dust inside was almost causing a dead short.

Malcolm

going off topic for a moment, I thought there was a non-return valve in the auto box the prevent the oil draining back to the sump?

Good point, not sure. When I pulled the engine I drained the sump and box as I wanted to replace the oil in it with decent stuff not the CarPlan rubbish which the box didn't seem to like. The car had been sitting for a week or so and not a lot of fluid came out of the convertor and a lot came out of the sump. All fluids were level and correct before the engine came out.

Thanks all - sounds like I'm just paranoid and used to a motor that cranks over a bit quicker.
I'll stop worrying!