Talk Morgan Forums Morgan Sports Cars Morgan Aero 8, 2012< Plus 8, SuperSports, Coupe & Aeromax Starting after a lay up?

Personally I wouldn’t worry.

I’ve had cars stand for months and even years.

Certainly wouldn’t be starting it up every 4 weeks causing condensation etc

I wouldn't worry personally, starting it up and letting it idle multiple times will give the most wear as its the slowest warm-up cycle, and it can cause condensation to form in the exhaust and oil.
Modern oils are so good I would just start it when you want, but don't go mad on the throttle till its circulated.

If you remove the fuel pump fuse you can crank it over without it firing if you wish to do so, if it helps I wrote a guide on oils a while back - its fallen down the page list somewhat but might be useful if your interested.

http://www.talkmorgan.com/ubbthreads.php/topics/534284/re-aero-8-engine-oil-guide#Post534284

As said above , crank engine but don't let it fire initially !

The map on my engine specifies a minimum of 3 seconds cranking before ignition is fired, seems very sensible to me as it helps to build up a bit of oil pressure.

Nick, thanks for taking the time to provide an insight to the complexity around something as "simple" as choosing the correct oil for a machine... (-: Oh for a return to the simple life..(-: But wait climate change will perhaps take us back there... (-:

There are two sides to every coin, though perhaps more these days..(-: One amongst us reckons he may have wrecked a Stag engine perhaps with low or no oil pressure start ups..? Whereas another seems to hint at engines can lie for years.. but then what..?

Condensation vs dry bearings, be they in the engine or the cooling fan in older Mogs... You chose, but as I suggested I doubt lengthy lay-up was ever part of the initial design criteria of motor vehicles...? Sure you can go to Youtube and find folk firing up old engines for the first time in many a year.... ME..? I think I might be inclined to try to introduce some pressure into the lube system and more, call me mechanically sympathetic..(-:

Digitisation in terms of engine protection..? Ign circuit inhibited for three seconds of the engine spinning on start up request, prior to sparks being generated, seems entirely reasonable if not programmed to allow oil pressure build up then what...?

As an alternative, "modern" design criteria, I think that a Porsche 997 runs the fuel pump for 3 seconds when the drivers door handle is operated on entry... quite the opposite of the expectations of others perhaps..? My guess is that with specific modern oils tighter engineering tolerances Porsche think was to ensure minimum battery drain and quick fire up, given all the electrical consumption that modern digital machinery places upon the battery when the car is not in use, even for short periods...?

Of course as Nick put together a comprehensive guide as to the criteria relative to oil types and their design function, it does indeed seem that modern engineering requirements may differ from that of the past, and Morgans span a considerable period of engineering advance..? I suspect the lean burn engines run hotter thus around that time design of much changed, increased reliance of cooling fans etc.etc. I suspect oil design was in the mix too..? These days it seems some oils are designed to last for the life of some machinery, thinking some Ford gearboxes fitted to Morgans may have no drain plugs..? How many new vehicles have grease nipples anywhere...(-:

I guess it helps to try to understand that which you might wish to achieve, and what YOUR priorities might be relative to the well being of your Morgan.....

If my carb fed Morgan lies for a while as it has done for much of it`s existence, it is likely that the fuel in it`s carbs may have evaporated, and it can take quite a few seconds of the fuel pump ticking merrily to refill the float bowls... BUT.. the fuel pump does not run unless there is oil pressure and to create oil pressure takes the engine being turned over for some period of time until the oil pressure switch detects that pressure build up and closes it`s contacts... all this after a lay up period of time enough for the fuel to evaporate.... Poor old battery... what are the chances of loosing out on that first run in the sun after Winter.if your Mogs wiring operates as does mine..?

I would be grateful if any other early +8 owners out there, know the wiring and operation of their fuel pump could describe it`s method of operation and how it might be wired, or provide a link to the appropriate web page, GoMoG or otherwise..?

If you send me your email address i will send you a copy of the wiring diagram from the +8 owners handbook for a carb fed engine.


David Byrne

David/B3MOG Thank you very much for your very kind offer of scanning the +8 owners handbook... I have one such that came with my mid 80`s +8, and it seems the wiring diagram in mine is generic at best, and does not have an electric fuel pump, or an oil pressure switch or any associated circuitry included...It seems this may be the norm for trad +8 handbook wiring diagrams..? There is a number on the page that may well relate to the diagram W 549 553 81.

Greetings Luddite, Apologies for not replying earlier. If you go to the Gomog site and go to +8 specific , then Oil and Oil Pumps, then Pressure Isolator switch which leads you to Rover SD1 3500 Oil Pressure isolator Switch by Bill Beddows with a small imputes from myself. That should explain things. My 4/4 with a 45DCOE needs an electric fuel pump in the fuel line turned on by a switch just before starting to fill the float chamber. At the moment I unscrew the top hat on the DCOE and pour in a small amount of petrol when the car has not been used a while.
Doug
from deep deep downunder.

Doug/Mogdriver, many thanks for taking the time to reply to my request for further info. Coincedance or what, I found a wiring diagram drawn to depict operation exactly as you initially described on in this thread as per GoMoG.

I found a diagram in the Haynes manual for the Rover 3500 V8 No 356 of the Haynes manual series. There is also a drawing of the oil pressure switch connections on page 131 and wiring diagram on page 140 of the same manual, though the diagram also contains a lot of kit not fitted to a Morgan.

Beamed up the GoMoG site and used your directions to find the appropriate page http://www.gomog.com/allmorgan/Plus8isolatorswitch.html

Early hours of the morning here, thus not dressed for the cold garage..(-: Seems that my issue may be that my oil pressure switch is not fully functioning internally as it should. While it does provide voltage to the pump when the ign switch is in the RUN position, engine running, oil pressure is present, by closing two of the contacts on the three contact pressure switch, and thus disconnects the same voltage when there is no oil pressure present.

My issue would seem to be that the third contact which should supply voltage to the fuel pump when the ign key is held in the START position does not do so.

The three connection oil pressure switch would seem to be configured to have two of it`s contacts connected internally when there is no oil pressure....and in that situation the white and brown wire will be connected to white and purple wire through the switch.... Thus when the ign key is held in the START position the white and brown wire becomes live, supplying voltage to the switch and thus passing voltage on to the white and purple wire causing the pump to run and fill the carb float chambers with fuel.

Once the engine starts and the oil pressure builds the internal switching action of the oil pressure switch breaks the connection from the white and brown to white and purple, and simultaneously makes a connection from the white wire to the white and purple wire that is connected to the pump, thus the pump continues to run providing the carb(s) with fuel for as long as there is oil pressure present as detected by the switch.. thus all is running normally.

Should there be some sort of accident where the ign is left on but the engine stalled there will be no oil pressure thus the fuel pump will stop operating.

I noted the by-pass suggestion on GoMoG Doug, I had contemplated something along similar lines using the starter button switch I had in my kit that once graces an old S Type Jag...(-: Though some years back had wired in "temporary" by-pass to achieve the same aim, having picked up voltage from the rear sidelight near the pump passing that through an unmounted switch from the switch to the pump, providing a temporary supply when the sidelights were switched on and the temporary switch ON.... Thus for the by-pass to operate two switching actions had to be performed, side light switch had to be on and the temporary by-pass too...which could be done prior to engaging the starting process if required... I had planned to use the starter button in place of the temporary switch, to add a degree of safety should the button be held on in an accident situation, but how far does it seem reasonable to take this stuff....I think your idea of manually filling your Weber carb float bowl works fine.... Not so easy on Strombergs or SUs though.. (-:

Of course there is a balance to consider... IF the three connection oil pressure switch is operating normally then the battery may well have enough power to fill the carbs while the starter is spinning the engine though after a lengthy lay up perhaps less so..at which time the by-pass circuit may seem a reasonable idea may be fire up the engine pre filling the carbs should provide a quicker fire up of the engine, which may not be ideal as the oil will perhaps not have time to begin to build pressure.. thus allowing the engine to turn over without firing up for at least a few revs, before activating the by-pass or manually topping up a Weber may seem reasonable...?

More than happy to read alternative thinking, and thanks again Doug.

It does sound like you need a new oil pressure switch Luddite with single pole two way contacts, assuming the wiring is intact.

The additional switch sounds like a good idea if your car is used infrequently. A push button momentary switch could be wired across the normal run (oil pressure present) contacts of the oil pressure switch. This would allow priming of carbs prior to starting providing ignition was in normal run position.