Marcos Maniacs

Hi Donny,

There isn't sufficient room under the bonnet to fit downdraught carbs on the
B30 engine and there would be no means of attaching an air filter in any
event. Those marine engines typically don't have air filters. My
side-draught Solex carbs came with plastic trumpets and no air filter so I
had to manufacture some aluminum tubes onto which I attached the round K&N
filters, one per port.

Regards,

Paul Dransfield
3 litre Volvo

-----Original Message-----
From: indigo33050 [mailto:indigo@...]
Sent: Saturday, January 26, 2002 2:24 AM
To: MarcosManiacs@yahoogroups.com
Subject: [MarcosManiacs] Re: Anyone done carbs/injection on a 3 litre
stra ight 6 volvo engine?


--- 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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