Moss Motors, Ltd

I have a Spitfire MKIII with a single Zenith-Stromberg Carb and a newly installed optical points (electronic ingition).  Money is an object.  I'd like to work on improving perfomance.  I'm considering starting with Weber Carburetor.  I am looking for recommendations for the best Weber/manifold combo to choose as well as any other great ideas to sup it up.

Nuke,

 Check out PIERCE MANIFOLDS  (piercemanifolds.com) They have all the conversion kits, Good folks to deal with. 

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"Cogito ergo Zoom"
"Love your freedom? Thank a Veteran"

I purchased my Weber manifolds from Moss in the UK, and fabricated the linkage. I bought my Webers used and rebuilt them. I'm using twin 40DCOE's, but I have extensively upgraded the cylinder head (larger valves, ported and polished head, upgraded springs, fast road cam) to optimize their performance. I do NOT have any problems (no hesitation, no "typical" flat spot, etc) with them. The key is in the jetting. Unless you plan on significantly modifying the head, however, you will probably not realize the real value of the carb(s). The machine shop and parts charges for my cylinder head improvements were about $1700 in 2005.

Not knowing what your budget is, I can tell you personally that tuning Webers can be expensive, re the cost of "experimenting" with different jets, venturis, etc. to optimize the value of the carbs. Although the standard Weber carb set-up sold by many suppliers is usually a good baseline, getting to the problem-free point will most likely involve trying different combinations.

If you are working on a strict budget, I'd focus on modifying the cylinder head and consider upgrading to dual 1.5" SU carbs, a setup that was offered in England/Europe. Periodically, you'll find these used on eBay for a reasonable price. I love the look and sound of the Webers, but from what I hear the 1.5" SU setup is very good. Add a good quality tubular header and appropriately sized exhaust system, and I think you'll be pleasantly surprised.....

Great information.  Thanks.  I've played some with carbs and elecrical and transmissions, but I've not dealt with upgrading the cylinder head.  Can you recommend where I can get some information on how do approach this?  I'd like to do as much of the work as possible myself.  I also don't want to go off and spend my resources on upgrades that don't add much value.

 Thanks again for the insight.

 

Nuke

 

Mike,

Thanks I'll check it out. 

By the way, I thank veterans every day.  Father's a WWII vet, both brothers have served, both my son's intend to serve (1 doctor/1 marine) and I'll be retiring soon after 26 years as a Nuclear Submariner.  Thank you. 

Nuke

Kas Kastner wrote a book on racing modifications for Triumphs, including Spitfires. In addition, there are some pretty helpful web sites to consider:

http://triumphspitfire.com/

http://teglerizer.com/triumphstuff/index.html

You'll find, as you peruse these and other sites, some talk of "bolt on" modifications. Yes, something will add a little (bigger carb jets, fast road cam, header), but taking full advantage usually involves getting the cylinder head to breath better. The good thing is the MKIII Spitfire motor is normally seen as the best Spitfire motor to work with in getting power increase 

I'd leave the machine shop work on a cylinder head to the professionals. I'm currently having to have (expensively!)repaired a rare Mini Cooper S cylinder head (AEG163 casting) because the previous owner attempted to port and polish the head and ground through the lift rod tubes!

Nuke,

Thanks for the kind words, and Thanks to your Dad and you for your service! My Dad was a 20 year man in the U.S. Army, a paratrooper with the 11th. Airborne ( three combat jumps in Korea, and a VietNam vet too.) I served from '77 to '81 as a 63H10 ( wheeled vehicle mechanic)

Gotta admire a member of the Silent Service..........

 

Thank you!!!!

 

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"Cogito ergo Zoom"
"Love your freedom? Thank a Veteran"