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Correct use of overdrive on a Mk3 Spitfire


Jonah
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Hello all

i took my Mk3 Spitfire for it’s first run of a few miles today to test among other things the overdrive operation. I’m not sure what I should have expected or heard when I flicked the switch in 3rd or 4th gear to know whether it’s working or not.

the solenoid was changed as part of the restoration and the system was checked  electrically to be working.

Any guidance welcome

thanks Julian 

 

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Is it an original D-type unit? Has it been in there since before the restoration? Sat unused for a few years? If so it may just take a while to come back to life. I had one that I fitted to my first Vitesse that did nothing at all on my first test drive, to the local town for some shopping. I assumed I'd got something wrong and let it be. On the way home from shopping, though, I tried it again. Still nothing, but this time I left it switched in. Two miles down the road it suddenly engaged. After that it worked fine for many miles (until the gearbox failed but that's another story).

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Yes it was in the car when bought it 10 years ago and I’m embarrassed to say that I’ve only just finished the restoration work, business got in the way!

So it has been sitting idle for a long time, I’ll take it for a longer drive tomorrow and will hope for a bit of your luck 

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Just sitting with the engine off and the igniton on,  in thrid/fourth gear, you should hear a click as the servo engages when you turn on the O/d.

If that doesn't haappen, then an external, electrical fault can be corrected.     If not then  the problem is internal, may solve itself, may not.

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I've just been through all this; check for electrics by turning the ignition on then moving the O/D switch. You'll see the green oil and red ignition warning lights flicker if the O/D is getting power, or try it in the dark with the headlights on and you'll see them dim slightly. This will at least tell you there's power getting to the system.

On the road you'll definitely feel if the O/D kick in, and certainly when it goes off. Try a drive with it turned on and just leave it on, as the guys have already said it might just be reluctant to kick in and if you can possibly clear what's sticking either by heat from the engine / exhaust or the pressure of the oil, so it may free up.

Have you checked the oil level?

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if all the electrics pan out ok on aD type take off the cover plate and operate the OD the solenoid pulls a lever inside here, in the lever is a 3/16" hole , when the sol pulls it should align the lever hole with a test hole in the case behind the lever  a  3/16" drill will make a useful alignment checker

any adjustment is by the locked nut on the front end of the pull rod , do not adjust the cap nut stop cap in the front of the case 

have you checked the gearbox oil level ???

pete

 

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8 hours ago, Julian Jones said:

Yes it was in the car when bought it 10 years ago and I’m embarrassed to say that I’ve only just finished the restoration work, business got in the way!

So it has been sitting idle for a long time, I’ll take it for a longer drive tomorrow and will hope for a bit of your luck 

10 years is nothing to be embarrassed about 
A few of us have restorations starting last century.

Well done.

Adrian

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1 hour ago, thescrapman said:

Some of us are continuing rebuilds started by friends in the early 80's

I still haven't properly got my Mk3 road-ready from a restoration that started in 1989. The latest problem I have is that, when we welded the new boot floor in (1991) we managed to fit the front of it a good half inch too high, which means the spare tyre won't fit below the fuel tank or clear the lock striker when being removed.

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2 hours ago, NonMember said:

I still haven't properly got my Mk3 road-ready from a restoration that started in 1989. 

Herald Estate started in 1995, almost complete in 2003, and restarted again in 2020. Never been on the road in between...! Apologies, Julian, I'm hi-jacking the thread... but it happens to us all, and I'd like to think it'll hit the road eventually... just like yours.

  chassis3.jpg.569c6ce08696ca2af97e3ae3ed27a010.jpg DSCF0930.jpg.cba82aeeb66449630a993faee8216ab6.jpg 01C6CC88-A5A1-4EDB-AE26-20051B31F18F_1_105_c.jpg.2d6622289cc7750b95f399e1e64ff8bc.jpg

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 Thanks everyone for your reassurance!

ive just checked the relay wiring and the power connections were reversed, with the ignition on and in 3rd I can hear the relay kicking in when I switch on overdrive. The relay is quite loud and with carpets and sound proofing I can’t hear the relay.

when the hurricane stops I’ll take it for a test drive

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Colin when I set out to restore ‘Wreckie’ I was full of enthusiasm to fulfill a lifetime ambition. I hadn’t bargained for over 40 years of Barney Bodger and a previous owner who was a genius with filler, and concrete in black plastic bags!

this was such a daunting project for when I started I had no real tools and no knowledge, there have been highs and lows but I wouldn’t change a thing, I’ve loved it 

there will be more threads from me to tap into the wealth of knowledge you guys have as I tackle my ‘snagging list’, door gaps, window glass gaps..................

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2 minutes ago, Julian Jones said:

Colin when I set out to restore ‘Wreckie’ I was full of enthusiasm to fulfill a lifetime ambition. I hadn’t bargained for over 40 years of Barney Bodger and a previous owner who was a genius with filler, and concrete in black plastic bags!

Are you sure that wasn't ME? Chassis above from 1995 just getting its' first coat of white Hammerite and if you look very closely you'll see that the side rails are boxed in, which was recommended to me to keep rust at bay and must have doubled the weight. The diff was full of sandblast grit and the engine was badly worn. By 2003 when the roof wouldn't fit I gave up; the bulkhead was fitted incorrectly to the chassis. So now 17 years later I'm doing it all again properly. I hope. No Hammerite, anyway. :)

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Pete I glibly said I’d  check the gearbox oil today and then as I’ve never checked it since filling the gearbox before the body went on I realised..........

how do I do this without taking out the tunnel etc?

is there a straightforward way to do this?

 

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from under its not easy , someone puts the chassis in the way and if you use a trolley jack  do have a axle stand in place or you risk a squashing 

big hole in the tunnel up near the side of the  clutch pedal 

no key hole  more a 3" hole saw , make a simple cover to keep the noise out .

Pete

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Thanks Pete, I’ll do it tomorrow. I have axle stands but struggle to lift the car high enough to get good space underneath.

i have a 2 tonne engine crane and have been trying to come up with a way of lifting the car safety onto ramps to get access to the chassis.

When  I had the body off I used Rust buster epoxy made in laurel green on the chassis, but in many places it’s peeling off, so dark green hammerite beckons if I can get underneath

best Julian 

 

 

 

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12 hours ago, Julian Jones said:

i have a 2 tonne engine crane and have been trying to come up with a way of lifting the car safety onto ramps to get access to the chassis.

Not by the engine, anyway! The problem is that most good solid lifting points are hidden by bodywork, so once you identify one you have to work out how to get a chain to it so that, once it takes the strain and becomes vertical, it doesn't crush body panels or bend any components. 

If you don't want to bother of buying extending ramps, that jack up once the car is on them, you could jack the car up then position the ramps one wheel at a time; but make sure everything is securely chocked and not likely to slip or move as you're lifting.

Changing the oil from below is easy enough; cramped access I know but if it's easier - and safer - to cut the tunnel then go for it.

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