Any (carbed) - Wee Startup Wear Dilemma | Technical matters | Back Room Forum

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Sun 18 Feb 2018 01:52

Any (carbed) - Wee Startup Wear Dilemma - edlithgow

Suppose your car won't start without choke in current conditions (Imagine you don't have fuel injection, if that won't give you bad dreams)

Is it better to turn it over a bit first without using the choke, to build oil pressure, or just use the choke straight away?

I ask because I read recently that "The Rover SDI launched in the UK in 1975 had a device that turned off the ignition until 3 psi oil pressure was achieved."

Assuming this is true, and that severely cash strapped BL engineers thought that worthwhile, it seems turning it over a bit might be a good idea.

I don't, however, know if the SD1 system had fuel shut-off, which would make a difference. I think most British SD1 had carbs (SU's. I rather miss SU's) so fuel shut-off might be difficult to arrange, but probably not impossible.

Not a big deal, but one likes to be optimal.

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Sun 18 Feb 2018 08:56

Any (carbed) - Wee Startup Wear Dilemma - Wackyracer

I don't know of any cars that have this and given the starship mileages that some modern cars achieve without such a system I'd say it was not necessary.

In my youth I used to take the spark plugs out during servicing and then crank the engine over without them after changing the oil and filter to get oil pressure (fill the oil filter) but, I haven't bothered doing this for years and nothing detrimental has happened.

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Sun 18 Feb 2018 15:57

Any (carbed) - Wee Startup Wear Dilemma - edlithgow

Well, yes, but I havn't had "modern cars" (apart from when I had company cars) and wouldn't much want them. I have had bangers.

My current car has lived 32 hard years in Taiwan, so I'm interested in eeking out its limited remaining lifespan.

I've done that spark plug removal thing after a long stand, say over a month, but its too much hassle for routine starting.

I can't remember doing it for an oil change, but it seems a good idea which I'll bear in mind.

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Sun 18 Feb 2018 16:12

Any (carbed) - Wee Startup Wear Dilemma - craig-pd130

I wouldn't worry about it, it's probably what the driver does AFTER the engine's started on choke which is more critical ... if the car sits there without moving for minutes while on full choke, the bores will experience fuel wash. If the driver moves off within a few seconds of starting and adjusts the choke setting to keep the rpm manageable as the engine warms up, that's better for longevity.

As you point out, if the engine's been sat for several weeks then turning it over a few times before starting might have a benefit, but oil is fairly clingy stuff and so there'll still be an oil film on the remote parts of the engine.

I wonder if the ignition shut-off applied to all the SD1's engines, or just the V8?

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Wed 21 Feb 2018 14:11

Any (carbed) - Wee Startup Wear Dilemma - edlithgow

V8 only I think (or at least that was specifically the context it was mentioned in). It was a forum post though so I can't be sure its true.

My choke operation doesn't actually involve fuel wash, because I recently replaced the (non-functional) original with a simple improvised device that uses butane.

After doing that I realised that I always give a stab of accelerator when starting the car, so I can probably avoid starting while initially turning the engine over even when its quite warm.

Been doing that this week. Whether I'll bother continuing with the practice I doubt. Possible (slight) reduction in engine wear versus probable (slight) increase in starter and ring gear wear? Hmm..

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