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MG MGB Technical - power gain?

im new to mgb i bought a 73 mgb that came with a wrecked 69 with weber carbs will the 69 head and carbs add any hp also i bought a header on ebay 106$ crane cam and lifter set 465 valve lift stock valve springs ok? what muffler or glasspack will make napoleon growl when i open the throttle on the highway thank you
cc perrine

Hi, welcome, I've not got a clue but others will be along that do.

Er, you sound very new to MGB and possibly classic cars(?) so I'll give my usual advice -

Buy and/or read and refer to the relevant Driver's Handbook (the one that came with the car when the car was new not a shop manual) to learn about the car and how to drive and maintain it (sample from my Midget contents page and sample only MGB). - http://www.brooklandsbooks.co.uk/product/mg-mgb-tourer-gt-drivers-handbook-3/

Also for lots and lots of info see (contributor here) Paul Hunt's excellent and comprehensive mgb-stuff website. - http://www.mgb-stuff.org.uk/hammertext.htm





Nigel Atkins

All these components have to be in happy harmony, otherwise you may not only lose performance, but also burn more fuel. It's well worth getting a copy of Peter Burgess'book How to Powertune MGB four cylinder engines. The author is the oracle on MGB tuning. I bought a copy donkeys years ago and still refer to it if doing any mods.
Peter Allen

Peter Burgess is THE MAN when it comes to MGB cylinder heads. He sometimes reads this column so hopefully he will chip in some help. Or you could try emailing him at peter@burgesstuning.free-online.co.uk You will find his web site at http://www.peter-burgess.com/indexstart.html
I know he has customers in the USA.
Mike Howlett

Kacey

You mention that the 69 car has Weber carb's', does that mean it has 2 carburettors or ---------?
Any chance of a pic

What carburettor setup is on your 73 car now

Which Crane cam did you go for

And welcome to the forum

willy
William Revit

These cars are just a tad long in the tooth now and many have had things done to them over the years so you really need to find out what you have actually got before you start messing with things.

Weber(s) don't mean more power on their own - the SUs are actually better everyday carbs - does the 73 have 2 SUs or a single Zenith?

I suggest you find a local car club and talk to people who have experience and knowledge of the marque.

Just making more noise is not an indication of power - probably exactly the reverse!
Chris at Octarine Services

I'll assume that you have SU, not Weber carbs until you post a picture.
Bill Spohn

new to british cars yes classic cars no 1973 pontiac lemans owned for 25 years godzilla went to muscle car heaven after accident bought mgb because the price was right the73 mgb has 2 su carbs the 69 has 2 carbs that are webers the cam i bought on ebay is a crane cam spec card not in the box seller said stock valve springs might be okay. just throwing parts at napoleon isnt working too good dont run good at low rpms gas mileage went down. low end is much improved top end feels the same
cc perrine

Any chance of a pic. of the webers
William Revit

Sorry I thought you were new to classics, but the relevant Driver's Handbook (the one the new owner got when the car was brand new not factory or later workshop manuals) will still be very useful to you for the servicing and settings of the stock elements on the car and help you with perhaps some British peculiarities on the car.

Webbers are a popular change on MG Bs and (MG) Spridgets (Midgets and Sprites) so some here will know them inside out (nothing wrong with SU carbs though).

You'll get a lot of information about the cars o Paul's excellent site and lots of info, and entertainment, from video number 1 of the 200+ videos of John Twist (very old skool) -http://www.youtube.com/user/Universitymotorsltd/videos

When I had a British, converted, MG V8 it had Americans Holley and Offy helping it.
Nigel Atkins

I'm a bit interested to see a pic Nigel, there's a difference between a Weber and 2'Webers'
William Revit

Yes Willy I did wonder but could be speed-typing grammer, typos, both of which I'm often guilty, or two Webers with the '69 but not necessarily on the the '69 ("I'm playing all the right notes, but not necessarily in the right order.").

I can show you a photo of my V8 conversion with Holley and Offy








... but it's a photo of the car not the engine bay.
Nigel Atkins

There's lots of maybe's about this Nigel,specially fitting a cam without knowing what it is, ,how was it timed without specs etc ,it sounds like from what has been said that if it gained heaps down low and nothing up top that the cam 'might' be way too far advanced,bht maybe not as well, or fuel starvation ,or mixture ,,or could be anything ,hence the ask for a pic of the setup to start with---maybe it's got a crossflow with twin sidedraughts-??? who knows, not me

William Revit

CC In europe Webber carbs were widely used until manufacturers were forced to adopt fuel injection. They can be jetted to match all the variants of the MGB engine (yours are unknown) but they do wear out and are not without their problems. In your shoes, I would concentrate on getting the SUs to work properly.They are easy to refit. If you fit a high lift cam, the rich needles may help.

The 69 head will need expert inspection before you spend any money on it. They do develop cracks. We used to skim them,increase compression and get more power on 100 Octane fuel. Peter Burgess may tell you that some of the later heads are better.

First off - focus on the bodywork - the terminal tinworm never sleeps.

Good luck

R
Roger Walker

Willy,
could be a hit and run merchant, needs instant reply and no time to give for detail - but did put 'thank you'.
Nigel Atkins

I found a glass pack to be much too loud and my hearing is bad enough that I qualify as having a disability. I changed to a Thrush “Turbo”2 inch in and out, decent noise and performance. I am using 2 inch from the collector back with the muffler at the back.
K Hawkins

This thread was discussed between 11/06/2020 and 19/07/2020

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