Q: MGB GT 69' dashboard layout
jerry
I would like to buy a 69' MGB GT.
The present owner made some modifications on the dashboard, so i don't know,
which parts of the board are original or not.
1. There is a own switch for the gaspump(fuelpump).
2. To start the machine you have to turn the key to position 'ignition' and
push a startbutton on the left side of the dashboard like on my Series 1
Lancia Fulvia.
3. There is a Weber carburetor mounted on the machine. As far as i know the
original carburetor is an SU-type.
If anybody knows something about it, please let me know.
Thanks in advance, jerry
je...@ping.at
FruitBat
Sounds like a racing modification. The fuelpump switch and start button
are non-standard, as will probably be the ignition switch and all sorts
of other things under the bonnet.
The Weber (45 DCOE 13 twin choke) may have been supplied by British
Leyland Special Tuning Department as part of the official Stage 5 Tuning
kit. (gave 122 horses at 5,500rpm, rather than the standard 95 horses
with twin 1 1/2" HS4 SU carburetters, at 5,400rpm - but with some slight
loss at lower-to-mid revs).
Special Tuning Stage 1 - port polishing and sometimes stronger valve
springs, added about 3 horses.
Stage 2 - different Camshaft for mid-range acceleration.
Stage 3 - Stage 1 plus half-race camshaft, 1 3/4" SUs,
1/16" machined off head to raise
compression ratio to 9.7:1
took output to 108 horses at 6,000rpm.
Stage 3a- Compression 9.6 to 9.8:1 by fitting competition
flat top pistons instead of head
machining as at Stage 3.
Stage 3b- Stages 3 plus 3a raised compression to 10.5:1
took output to 115 horses at 6,000rpm.
Stage 4 - Stage 1 plus, bronze Hidural valve guides,
high-duty Nimonic valves, high-lift
wide-period camshaft, block machined so as not
to bend the exhaust valves, steel
timing chain sprockets (standard are cast iron)
and other minor engine mods, and
Lucas 40943A competition distributor. 1 3/4"
SUs. Compression ratio 9.8:1
took output to 121 horses at 6,000rpm.
Stage 5 - Stage 4 but Weber in place of SUs. Gave similar
max output, but dipped
marginally between 4,000 and 5,000 rpm
and maintained maximum output therefrom, up to
6,500rpm.
Stage 6 - As for 4 or 5, but compression raised to 10.6:1
by machining head as at Stage 3.
took output to 129 horses at 6,500rpm.
Stage 7 - Stage 6 plus larger inlet and exhaust valves,
2" SU carbs and very wide overlap camshaft.
Used for sprinting - zero low end power and
torque but higher max output,
in consequence, ate clutches.
98 Octane fuel is the recommended minimum standard up to Stage 3,
with 100 octane or higher from then on.
For normal road use with a standard engine, Champion N9-Y plugs are the
norm, but cooler N3 for hard driving.
Stage 4 recommendation varied with type of racing circuit from N3
through N62R to N57R.
For stage 5 tune, the recommendation was for N3 in cylinders 1 and 4
with N62R in cylinders 2 and 3 for short circuits and, N62R for 1 and 4
with N57R in cylinders 2 and 3 for long circuits. The centre cylinders
are inclined to run hotter due to the proximity of the two exhaust
valves.
If you've read this far, you probably realise that you need more
information about the car as, if there is a Weber carburettor, there are
bound to be other modifications that you need to know about.
However, the most important bit of an MGBGT is the state of its'
bodywork, which can be very much more costly to put right than anything
mechanical.
regrads,
--
donlad.
Dave Plowman
<donald...@virgin.net> wrote:
>
> If you've read this far, you probably realise that you need more
> information about the car as, if there is a Weber carburettor, there are
> bound to be other modifications that you need to know about.
Ahh memories. Takes me back to the BMC special tuning book!
Interesting the power output claims from the factory, compared to a
commercial tuner.
I also remember the DCOE making the engine smoother than (perhaps worn)
SUs, but /much/ less torque at low revs.
--
Dave Plowman dave....@argonet.co.uk
RIP Acorn
Leroy Curtis
>Hi!
>
>I would like to buy a 69' MGB GT.
>The present owner made some modifications on the dashboard, so i don't know,
>which parts of the board are original or not.
>1. There is a own switch for the gaspump(fuelpump).
Non-standard. Owner's modification
>2. To start the machine you have to turn the key to position 'ignition' and
>push a startbutton on the left side of the dashboard like on my Series 1
>Lancia Fulvia.
Non-standard. Owner's modification.
>3. There is a Weber carburetor mounted on the machine. As far as i know the
>original carburetor is an SU-type.
>
Twin SU carburettors were standard.
--
Regards
Leroy Curtis
Please replace "nospam" with "baram" in my address if you wish to
reply by Email
jerry
lower price ;-) ), its great.
Bye, jerry