Octagon May, 2016
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holes in pistons etc. A $20 fix was identified/published<br />
after the production ceased in 1960.<br />
No Twin Cam fitted with Weber Carburettors ever had a<br />
problem and a number of motors fitted with Webers were<br />
run on a test bench for 24 hours at 7000 rpm with only<br />
minimal wear on bearings. The solution being – fit soft<br />
mounts between SU Carburettors and inlet manifold to<br />
avoid vibrations in fuel bowls which caused fuel leaking<br />
out in the rear carburettor. There was seldom a problem<br />
with a burnt piston on No. 1 or No. 2, but the majority<br />
was either No. 3 or No. 4 (rear carburetors).<br />
In order to maintain reliability, performance (and peace<br />
of mind), I undertake as a minimum the following checks<br />
and or modification.<br />
1. Original exhaust valves were sodium filled. If in<br />
doubt about what you have installed or their age and<br />
condition, then replace with modern type valves (Nissan,<br />
etc.) or stainless steel (Harley Davidson motor bike<br />
manufactures blanks). Any modern blank valves can be<br />
machined to your requirements. The seats in your head<br />
should be OK as they were hardened type originally<br />
installed, but should be checked.<br />
2. The distributor should be the later non vacuum<br />
advance type (similar to those in Mini Coopers and<br />
Lotus Cortinas). Ross Kelly’s 1679 still had the original<br />
vacuum advance type before I replaced it when restoring<br />
same. Have this regraphed to avoid advancing past 32<br />
degrees at 6800 rpm. Performance Ignition Services in<br />
Melbourne is my recommendation for this work. This<br />
now allows you to set the timing at 10 degrees before<br />
top dead centre on both 8.3/1 and 9.9/1 pistons installed<br />
in engines. While you are at it, install a Pertronix LU-148<br />
Electronic Ignition and, for your peace of mind, install<br />
a Rover 2000 or Lotus Cortina rev.limiter rotor button<br />
which will not let you rev the motor past 6500 rpm<br />
3. Overhaul carburettor and install soft mounts from<br />
Weber Carburettor. I prefer the Swedish made Misab<br />
which you can reuse a number of times (cheap skate)<br />
over the American Red Line type which fall apart after 1<br />
use. (My view and experience only.)<br />
4. Replace Low Compression 8.3/1 Pistons with 9.5/1<br />
forged “Aries” American Pistons. This is the only way<br />
you may be able to show those pesky MGBs what you<br />
are made of. A good warmed-up MGA could outperform<br />
them anyway.<br />
5. Ensure the tolerance of value timing of both inlet<br />
and exhaust cams are between .072 and .083. This is<br />
critical.<br />
6. Soft mounts on carburetors.<br />
7. There are many other improvements/modifications<br />
that can be carried out but we will leave that out for now<br />
until you purchase your Twin Cam and then you can put<br />
your money on the table and all will be disclosed. (I drink<br />
full strength beer.)<br />
ITEM 13 Current known Queensland<br />
Twin Cam Owners<br />
YD3 #1035 (Coupe) Eng.No.1044 (?) Orient Red<br />
Mark Wellard (Bardon) acquired it in 2009 (?)<br />
YD2 #1672 Eng. No. 955 (?) Old English White now<br />
Orient Red Bob Inghram (Cairns) acquired it in 2008 –<br />
refer Item 2 for further information<br />
YD2 #1679 Eng. No. 1327 Old English White now Ash<br />
Green Ross Kelly (Ashgrove) acquired it in 2011 – refer<br />
Item 1 for further information<br />
YD2 #1738 - Stuart ????.(Gold Coast) acquired it<br />
in 2008 – refer Item 2 for further information and<br />
clarification<br />
YD1 #1834 (Coupe) Eng. No.1510 Old English White<br />
John Vonhoff (Cleveland) acquired it in 2012 – refer Item<br />
2 for further information<br />
YD2 #1911 Eng. No. 1594 Orient Red now Green<br />
George Lecies (Hervey Bay) acquired it in 2008 – refer<br />
Item 2 for further information<br />
YD2 #1977 Eng. No. ???? Old English White Barry<br />
Evans (Brendale) acquired it in 2013 – refer Item 2 for<br />
further information<br />
YD2 #2090 Eng. No. 1524 Glacier Blue Barry Van De<br />
Burg (Ipswich) acquired it in 1972 – refer Item 2 for<br />
further information<br />
YD2 #2122 Eng.No.2122 Glacier Blue Mal Cumes<br />
(Hervey Bay) acquired it in 1963 – refer Item 2 for further<br />
information<br />
YD2 #2147 Eng. No. 1812 Ash Green now Old English<br />
White Dan Casey (Clontarf) acquired it in 1998 – refer<br />
Item 2 for further information<br />
YD2 #2259 Eng. No. 1900 Orient Red Peter<br />
Graham (Biloela) acquired it in 2013 – refer Item 2 for<br />
further information<br />
YD2 #2260 Eng. No. 1910 Chariot Red Frank Hiscock<br />
(Noosa) acquired it in 1995 – refer Item 2 for further<br />
information<br />
YD2 #2415 (Coupe) Eng.No.2137 Iris Blue Dan<br />
Casey (Clontarf) acquired it in 1989 – refer Item 2 for<br />
further information<br />
YD ????? Refer Item 4 Wayne Kleinschmidt (Brisbane)<br />
YD ????? Refer Item 4 David Willaby (Gold Coast)<br />
YD ????? Refer Item 4 Unknown (Gold Coast)<br />
Clarification of YD2 #1738<br />
Even though this is currently running with a 1500 Push<br />
Rod MGA motor, instruments, gear box, front suspension<br />
and rear diff assembly as well as drum brakes all round<br />
and wire wheels, I consider that it should be in the Twin<br />
Cam category as the body and chassis are still united<br />
16<br />
The <strong>Octagon</strong> - <strong>May</strong><strong>2016</strong>
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