Find your P6's base unit number:

NickDunning

Active Member
The base unit number is the number your P6's body had when it was produced at Pressed Steel, before being shipped to Solihull or elsewhere for assembly.

All cars should have one, although they do go missing or get painted over.

They can be very revealing of the date your car was made, and we have sadly uncovered more than a few 'ringers' in recent times in the UK due to people swapping identities between good post Jan. 1st 1973 cars and nasty tax-free ones.

Don't get cought out, if you're in doubt about a car you're looking at we can help, and Mark Gray has extensive records now which enable us to identify the approx changeover dates from a base unit number as well as a chassis number.

There are several different flavours of base unit:

Manual 4 cylinders are all numbered consecutively, starting, in late 1962 with M 000001.

Automatic 4 cylinders start with 'A' - A 000001.

Automatic V8 cars start at BA 000001

Manual V8's BM 000001

This is the base unit plate on Paul Birch's summer 1973 2000SC.

6thJanuary201224.jpg


The plate is situated under the carpet/rubber inside the boot in lip in front of the spare wheel (when viewing from the rear of the car).

baseunit.jpg


In the case of this car the spare wheel is mounted on the boot.

Here's a few interesting ones:

23rdJanuary201121-1.jpg


This is the plate from CHA14T, one of the last batch of 2200TC's built in January 1977. (initially LHD, then converted to RHD before being sold on the UK Market in 1979). I think this is the highest number we have. There's no such thing as Series 1 or Series 2 in the world of base units. They start at 000001 and finish, in the case of manual 4-cylinders, at somewhere just ahead of M 215629.

If I remember correctly, Brenda's gold Earl's Court show 1963 car, chassis number 40000100A, has base unit number M 000142.

29thJanuary20117.jpg


This the plate (BA 000542) from our Mr. Rockdemon's PAE, showing what a lovely early V8 it is indeed.

1stSeptember20109.jpg


Last one here is an example of a ringer. This was the base unit plate (BM 013829) on a particularily dead 'K' registered 3500S with a very low chassis number (48100454A) we were offered a couple of years ago. The car, on the surface, looked to correctly be a 1971/1972 car. A little digging revealed that it was actually a 1974/1975 car. They only actually built 17000 3500S's. The owner wasn't aware and was sold the car by his motor dealer friend! oops!
 
NickDunning said:
Automatic V8 cars start at BM 000001Manual V8's BA 000001


Nick - Are you sure you don't mean:

Automatic V8 cars start at BA 000001

Manual V8's BM 000001

The M standing for manual, the A for automatic, and of course the B standing for Buick.
 
Adam Birch said:
NickDunning said:
Automatic V8 cars start at BM 000001Manual V8's BA 000001


Nick - Are you sure you don't mean:

Automatic V8 cars start at BA 000001

Manual V8's BM 000001

The M standing for manual, the A for automatic, and of course the B standing for Buick.

Well spotted Adam. I was in too much of a hurry. I've now corrected the post :shock:
 
Rubythursday said:
My 2200TC has 214958, it was registered Jan 1977

Rover built 1159 manual 4-pots in 1977, plus another 216 autos - a lot of cars.

Yours would have been built November/December 1976, probably. CHA's base unit was obviously one of the last off the pile as it's about a thousand ahead.
 
Rubythursday said:
671 behind CHA. That is quite a lot of cars made in the death throws of the model. Were Rover just using up stock?

Sorry, my arithmatic is lacking at this time of night :oops:

The SD1 2300 and 2600 didn't go into production until May/June 1977, Rover were building stocks to keep going and to use up parts.

They over-did it as a lot of the last batch (the approx 200 originally-intended-for-export LHD 2200TC's) sat for a long while in a field before being sold on to UK dealers at a cheap rate, together with the kit of parts to convert them to RHD. They are fascinating cars (German shin bins, anti-glare dashboards, oil cooler, and the controls left in the LHD position, so they're confusing to get used to if you're used to UK market cars).

Actual last day of production was 19th March 1977, with a handful of 2200TC's being finished off-line after that point.
 
NickDunning said:
GrimV8 said:
I can hear lots of people drilling off their plates now they know where they are :LOL:

Well then it becomes moody because of the lack of plate Mr. Grim :)

I can tell you are not from Tottenham Nick :mrgreen:

You'd put one it its place, not leave it looking dodgey :wink:
 
There's no numerical relationship that could give you an equation to get from body number to chassis number (eg base unit # + 356 = chassis #). But bodies are used broadly in manufacturing order, although there are wild exceptions, particularely towarsds the end of production. So if you know your chassis number then Nick and Mark Gray can usually find an adjacent chassis number and body number pair to compare. That way you have reasonable confidence in originality of yours.

But don't forget that the Rover Co Service Department regarded a base unit as simply another component of the car and it was not uncommon for them to change one. They were even known to send out a couple of fitters and do it on site!

So I am much more laid back about whether base unit and chassis no (and hence registration) match than Nick or Mark are. I see a new (or 2nd hand) base unit as a perfectly valid way of rebuilding a car. Where it does get slightly questionable is when the resulting vehicle owes far more to the donor than just the base unit - which registration are you going to carry over? That dilemma is going to be pretty rare nowadays, as almost all base units require welding! But you can be surprised by a historical event. And then there are the folks that only change the chassis number plate over - I really do frown on that!

Chris
 
GrimV8 said:
NickDunning said:
GrimV8 said:
I can hear lots of people drilling off their plates now they know where they are :LOL:

Well then it becomes moody because of the lack of plate Mr. Grim :)

I can tell you are not from Tottenham Nick :mrgreen:

You'd put one it its place, not leave it looking dodgey :wink:

Nearly - born at City of London Maternity Hospital, Tollington Park, N4. But I appreciate what you're saying Mr. Grim.
 
Rubythursday said:
Is there any correlation between body number and chassis numbers? or did Rover just pick bodys randomly from the pile?

It's random, to a point - the chassis numbers were stamped by Rover when the car was being produced. Rover had hundreds of base units sitting about waiting to be built up at any time. There is a certain logic though - My early 2000 is chassis number 40006745, base unit BM 007777. This points to there being very approximately about a thousand export cars produced (using the same base unit) by Sept. 1st 1964, when my car was built, as well as the UK models.
 
Interesting, shame it's not actually stamped into the base unit, as Grim says, wouldn't be much trouble to take that off your old rotten tax-exempt unit and screw it onto your new unit.

Still at least it's another thing to look out for. From my experience most of the "ringers" aren't anywhere near that clever anyway, leaving much later interiors in etc.... :roll:
 
None of the nonsense about changing cars identities would have come about if the government had left the rolling date for exemption in place. I have 2 P6s, one I pay tax on and the other I don't, it's just daft!!!
 
webmaster said:
Interesting, shame it's not actually stamped into the base unit, as Grim says, wouldn't be much trouble to take that off your old rotten tax-exempt unit and screw it onto your new unit.

Still at least it's another thing to look out for. From my experience most of the "ringers" aren't anywhere near that clever anyway, leaving much later interiors in etc.... :roll:

And sometimes the original chassis number still there under dust under the rear decker! seen that a couple of times :shock:
 
on mgbs and triumphs reshelling is common isnt it?

if you could buy a new base unit would that be better or worse than reshelling around a ringed base unit?

For me conceptually the problem is 1, honesty and 2, legality. The actual operation itself is fine but should be documented, and this silly tax situation needs sorting once and for all.
 
Amazing how things crop up, my Brother and I found that number last weekend whilst assessing the repair to the boot floor and wondered what it was for.

Nick, if ok will be calling on you sometime Friday afternoon to collect boot floor as arranged.


Martin P
 
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