I can tell you from first hand experience that using the short bodied carbs
on the earlier short manifold is not a good idea. I had a similar thought
and tried it. Some of the logic at the time suggested that the larger
diameter of the short manifold would ease the breathing as well. After
converting and finding the engine sluggish at best (with fully retuned
carbs), one of the local club members remembered that the reason the later
TR-4s had the longer, slender manifold was to increase the flow velocity
and hence create a ram effect to increase flow past the valves. Some
enterpising soul could likely take the short manifold, short carbs, a flow
bench, and lots of tubing, and come up with a workable solution but I
sincerely caution anyone against the common sense, logical approach. It
isn't quite as simple as one might consider. (I'll step off the soap box
now...)
At 04:14 PM 5/6/98 -0900, Robert Alexander wrote:
>Tony,
> I was faced with the same problem in general last fall when I was
>trying to find some way to put air cleaners on my 67 +4 with a TR4
>engine. Got all sorts of good advice about women's underware (remember
>that, John B.?) and finally found an answer at my local LBC mechanic. He
>suggested swapping my long-tube TR4 manifold with a shorter TR3 (which
>he just happened to have) and stay with my short-body SU's (you have the
>short manifold, but longer-bodied SUs). He then suggested using RamFLow
>air cleaners. They have a crushable expanded steel cover over a foam
>filter, and with just a little reshaping I got them to fit under the
>existing bonnet. If you don't need air cleaners (we do in New Mexico)
>then your that far ahead, but I think they look very vintage, almost
>like they came off an old British bike, and fit the Morgan character.
>Just an opinion.
>
>Bob Alexander
>67 +4
>
>On Wed, 6 May 1998 tjsouz@epix.net wrote:
>
>> Date: Wed, 06 May 1998 08:11:50 -0700
>> From: tjsouz@epix.net
>> To: FPS3@aol.com
>> Cc: morgans@Autox.Team.Net
>> Subject: No-scoop bonnet
>>
>> Hi Fred et al,
>> The subject is choice of carburetor(s) for my flat rad 4 seater
>> project. Having progressed to the point of being able to hang the
>> radiator and temporarily clamp the firewall and original scuttle, I can
>> now see how thw bonnet will fit. The good news is that new chassis
>> length and engine position have worked out and the bonnet will fit fine
>> in length. The bad news is that the decision time to chop the right
>> hand bonnet half for carburetor clearance is now at hand. You see I
>> have upgraded the engine to a TR-3 with its twin side draft SU
>> carburetors and intake manifold. The old Vanguard engine used a single
>> downdraft which fit well inboard the bonnet.
>>
>> I would like to keep the original bonnet intact, thus hiding the engine
>> upgrade to the casual observer.
>>
>> Now the engineering question. Is there another manifold and carburetor
>> combination for a TR-3 engine that will fit inside the bonnet? And of
>> course not sacrifice the added power capability of the TR-3. Maybe a
>> downdraft 2 bbl Weber a la Ford Cortina or something. A new intake
>> manifold could be welded up from tubing. Maybe there's a manifold
>> available? Has anyone pondered this problem or seen a solution? I
>> understand from Craig Seibert that Melvyn Rutter's flat rad four seater
>> +4 (Beryl) goes like stink with its engine and suspension improvements.
>> Craig might have a picture of Beryl showing the starboard side, but so
>> far hasen't been able to find it. Perhaps Melvyn might have a published
>> picture or account showing the bonnet/carburetor interface. A photo in
>> the M. Rutter ad shows a front 3/4 of Beryl but unfortunately for me
>> it's the left front.
>>
>> If worse comes to terrible, of course, a hole could be punched and a
>> SS-type scoop faired in, and although perfectly acceptable to Morgan
>> standards, I would like to at least explore options that leave the
>> bonnet intact, maintain the vintage flat rad look and hide the "boiler
>> room".
>>
>> Any suggestions, hints, references comments greatly appreciated. It's
>> a wonderful thing to have so many good Morgan people netted together
>> with which to share these ideas.
>>
>> Regards, Tony Souza
>>
>
>
"Entropy Happens!"
Michael D. Miles, PE Consulting Design Engineer
(503) 292-1234, FAX: (503) 292-1105, email: mdmiles@teleport.com
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