Thread: Will a '83 model dizzy be a drop in fit for a '75?

The oil pump drive changed somewhere in between. You may need to swap the drive cogs over but study the later dissy carefully to see that you retain the oil pump drive. Failing that fit the later oil pump gear and short drive shaft that matches the 83 dissy. You need a 3/16" pin punch to drive out the roll pin. Be careful how you support the dissy while driving out the pin. Not too hard.

Today I drove down to visit DiscoPete who has a 1977 2 Door.
Pete kindly removed the distributor for comparison, finding the same drive as the (actually) 1982 model intended donor.

Now, if someone could answer, when did the changeover of the oil pump drive gear on the end of the distributor occur? Hopefully before the SuffixD 1975.
My engine is a 356 series, original to the car.

Pete's pretty sure the '77 is original (sure looks to be), it even has what is supposed to be the earlier of the vacuum advance units, which is non-operable.
The 1982 distributor is the same body casting number, but does that mean anything?

Here are some images showing the 1977 and the 1982 distributor.
For all intents and purpose, they're the same.

Note the early vacuum advance unit. Disregard the Crane pointless conversion on the 1982.



Oil pump drive bases the same.


From the top they look similar, apart from the slotted screw in the top of the 1977.



Will the '75 be the same? I'd just like to know before removing the distributor from the 1975.

Thanks again.

Cheers,
Richard

I am firmly convinced that it would have taken you less time to remove your '75 distributor and check it, than the time it took you to take the photos and put up a post about it!

Perhaps so.
However, my experience and familiarity with RR is not quite 4 weeks old.
Perhaps I should've known better without realising. No biggie.

Maybe, this information will assist another novice in the future.

Removed the '75 distributor, it had a different oil pump drive at the base, no drop straight in. Doesn't fit at all. The difference is the base of the distributor shaft.

The change between the drive types can be narrowed down from between 1975 and 1977.

Back to the hunt for a working vacuum advance. Perhaps a new one.
Then the farnarkling with the disassembly of the top plate to attach the unit.

Unless I could use the vacuum advance unit from the later distributor, which does work. Anyone know?


Cheers,
Richard

Originally Posted by jackafrica

Perhaps so.
However, my experience and familiarity with RR is not quite 4 weeks old.
Perhaps I should've known better without realising. No biggie.

Maybe, this information will assist another novice in the future.

Removed the '75 distributor, it had a different oil pump drive at the base, no drop straight in. Doesn't fit at all. The difference is the base of the distributor shaft.

The change between the drive types can be narrowed down from between 1975 and 1977.

Back to the hunt for a working vacuum advance. Perhaps a new one.
Then the farnarkling with the disassembly of the top plate to attach the unit.

Unless I could use the vacuum advance unit from the later distributor, which does work. Anyone know?


Cheers,
Richard

Why don't you just whip it out and check I'm sure you can get it all to work. The later dizzie is pretty simple ( don't ask me how I know ). I'm sure if you dismantle both, you'll be able to assemble something out of the two of them that works (infact I'd just use the vacuum advance and crane unit in yours .... even if I had to drill different mounting holes for the advance unit in the dizzie body).

seeya,
Shane L.

POWERSPARK RANGE : Electronic Ignition, Home of the Powerspark electronic ignition and electronic distributor

Check out this place. This is where i purchased my replacement dizzy from. They also sell the vac advance for a reasonable price.

Originally Posted by Jazzman

POWERSPARK RANGE : Electronic Ignition, Home of the Powerspark electronic ignition and electronic distributor

Check out this place. This is where i purchased my replacement dizzy from. They also sell the vac advance for a reasonable price.

Thanks for the link and trying to help. I looked at their Lucas vacuum advance units, but not quite the same as the early Range Rover one. The linkage arm appears different.

I've ordered a correct one according to part number from another mob in the UK and it will arrive in due course, hopefully correcting the problem with the advance.

Cheers,
Richard

Originally Posted by DoubleChevron

Why don't you just whip it out and check I'm sure you can get it all to work. The later dizzie is pretty simple ( don't ask me how I know ). I'm sure if you dismantle both, you'll be able to assemble something out of the two of them that works (infact I'd just use the vacuum advance and crane unit in yours .... even if I had to drill different mounting holes for the advance unit in the dizzie body).

seeya,
Shane L.

Shane, the challenge is in the oil pump drive gear between the two units. The difference is the shaft and the slot, as well as the depth of the oil pump gears, early 22.5mm v late 27mm.
In short, they don't fit.
My 1975 is NOT the same drive as the 1977, nor interchangeable, as I've worked out.
It has been suggested that perhaps pressing the gear off the shaft I need for the later drive might work. Could also involve machining the oil pump gear drive shaft.
Only trying to replace a non working vacuum advance unit, not re-invent the wheel and build a car around it ;-)

Whilst you might drill into the original body, I won't.
Like my stuff as original as I can where possible. I'm probably deluded by the notion that these early 2 doors, before 1979 are worth saving in their original state.
Certainly the year or suffix specific parts for them are difficult to locate if they weren't used on something else. But I digress in the dream bubble.

The advance plates and points mounting plates are also different between the two units, even though the bodies share the same casting number. They have different model numbers, for a number of reasons. The linkage arm on both units is also different.

I don't live only a few minutes from a choice of parts sellers and people who salvage Range Rover parts.
There aren't any people wrecking 1975 model 2 doors that I've been able to find, anywhere. Locally (50ks distant), there is but one bloke and he's difficult/quirky most times.
I've already driven 130ks today looking for a new or decent oil pump gear.

Will stick with what I have, replacing the vacuum advance unit with the correct one.

Cheers,
Richard