Marcos Maniacs

--- Hello all! I am a new subscriber to your Marcos group. I bought 
my car from a gentleman in central Florida who had 5 Marcos 
available at the time. I seriously considered a Volvo B-30 powered 
car with an automatic transmission he was offering (the Road and 
Track Magazene car featured in the 1970 road test). Though I didn't 
end up with this particular car, I considered improved carburation 
for it when I was looking at it. Years ago, I rebuilt a pair of 
Volvo B-30 marine engines (170 hp if I recall)that had three one-
barrel downdraft carbs (Solexes, I think) mounted on a short, 
compact "log" manifold. I never fully checked on the frame and 
bonnet clearances for the Marcos, but thought this setup might fit. 
I have since located one of these marine B-30s in a nearby marine 
salvage yard., but not having aquired that particular car, had no 
interest is pursuing the conversion. If anyone knows if they will 
fit, I would be happy to see if they are still available. E-mail me 
and I will check on them.   Donny Lang  - Florida Keys


In MarcosManiacs@y..., pauldransfield@i... wrote:
> Hi again Martin,
> 
> I have triple Solex 45 carbs on my beast. They are essentially the 
same as
> Weber 45 DCOEs for all intents and purposes, with one choke per 
cylinder.
> The Volvo competition inlet manifolds that I have allow the carbs 
to fit
> without modifying the bonnet but the right side of the engine has 
to be
> raised about half an inch to allow room for them above the frame. 
Mind you,
> those inlet manifolds are extremely rare so you would probably 
have to have
> something made up. The standard exhaust manifold is just as bad, 
being a 6
> into 1. The best solution there is to search out a pair of exhaust 
manifolds
> and downpipe from a Volvo 164E (the fuel injected version), which 
are threes
> into 2 into 1, and are actually very good. You'd probably have to 
replace
> your exhaust system as well.
> 
> However, if you're going to go to the expense of upgrading the 
carburettors,
> you'd be wasting time and money if you didn't tackle the head 
first. It
> should be properly ported and polished, and fitted with 48mm inlet 
valves
> rather than the standard 46mm, because just adding better 
carburation will
> not in itself give you much extra power. The standard head is very 
rough
> with smallish, angular ports and great improvements can be 
realised. 
> 
> If you want a hotter cam, you should consider fitting double valve 
springs
> but if you do, make sure they're the right ones because fitting 
the wrong
> ones will prematurely wear the cam lobs. The head would need a 
small
> adjustment to allow them to be fitted. I got a cam reprofiled at 
Kent Cams
> in England for a very reasonable fee and they also supplied my 
competition
> cam followers.
> 
> The standard engine also comes with a fibre timing gear which 
eventually
> breaks down. If you're going to soup up the engine, it's essential 
that you
> replace the current gears with a steel set, otherwise you could 
ruin the
> engine. I'd also convert to electronic ignition and fit an 
electric fan in
> place of the mechanical one. And while you're at it, you probably 
could use
> a better distributor. 
> 
> Done properly, you'd get about 230+ bhp and blow the doors off 
practically
> everything else on the road. 
> 
> On the other hand, I know of one individual in England who 
converted his 3
> litre Volvo to fuel injection by using the components from a Volvo 
164E. I
> gather it was quite an extensive conversion and a lot of re-
engineering and
> adjustments had to be applied to get it to work properly. It was 
written up
> in a Marcos Owners Club magazine quite some time ago. The fuel 
injection
> engine puts out a little more horespower than standard but I 
wouldn't
> consider it worth the time and expense.
> 
> If you would like any more info or clarification, let me know.
> 
> Regards,
>         
> Paul Dransfield
> 3 litre Volvo
> 
> -----Original Message-----
> From: martin_easterbrook [mailto:martin.easterbrook@v...]
> Sent: Thursday, January 17, 2002 6:05 PM
> To: MarcosManiacs@y...
> Subject: [MarcosManiacs] Anyone done carbs/injection on a 3 litre
> straight 6 volvo engine?
> 
> 
> Hi, I'm new here.
> 
> My father has a 1973 3litre Volvo Marcos.  He has totally restored 
> it (re-trimmed, resprayed, rewired, twin round headlamp conversion 
> and round rear lights).
> 
> I set the twin carbs up as best as I could, but wasn't happy with 
> it, so we took it for a rolling road session.  The dyno guy 
managed 
> to get the car running a bit better, but the main problem seems to 
> be the nasty inlet manifold/carb layout, with two carbs for 6 
> cylinders.  Cylinders 1 and 6 look like they will probably run 
lean 
> because of the tortuous route the fuel has to take to get to them.
> 
> We had to set the car up quite rich to get it to run nicely - we 
> measured 136hp at the rear wheels.
> 
> I wondered whether anyone has ever tried to fit triple carbs to 
this 
> engine in a Marcos - looks like it might be quite tight, but it 
may 
> just go.  Alternatively, has anyone fitted injection?
> 
> Long-term, we will probably tweak the engine a bit, aiming for 180 
> to 200hp (flywheel) - any tips appreciated.
> 
> Martin
> 
> 
> 
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