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MG MGB Technical - Stage 2 conversion

Where can I get info re all parts required / recommended to perform a stage 2 conversion on my '76 roadster ? Also any handy hints etc. Would like to perform most of the work myself.
Iain

Iain, you shold get hold of the book "How to Power Tune MGB 4-cylinder Engines" by Peter Burgess. It has the info you need.

/Jesper
Jesper Akesson

Stage 1, stage 2 etc, mean different things to different people. The original BMC Special Tuning stages were extrememly mild, and you would have had to use a dynomometer to notice any difference after stage 1 tuning. The biggest gains are to be had by modifying the cylinder head.

I agree with Jesper, buy Peter Burgess' book. He is THE expert on these old engines, and is also easy to talk to if you want to discuss anything. I have a Burgess "Fast Road" head on my car, and it is excellent.

Mike
Mike Howlett

Thanks for that guys, I'll pick up a copy. Does it cover necessary modifications to braking system / suspension etc ??

Iain
Iain

Mike

What are the gains like lower down the rev range with this head eg for pulling away from lights/2nd gear junctions.

I am considering a fast road or ecotune head but can't decide between them. I think ecotune has more power up to about 3500rpm then fast road takes over.

Just wondered what its performance is like vs stock
Matt k

Mike, I have a fast road head and a 285 cam ,which is a rather spirited cam, and I am perfectly happy with my lower rev characteristics. The idle is just a tad lumpy.
My car is sligtly stronger now than before my change.

This is what I wrote to Peter after I sorted out my engine:
After putting on AZ needles my car really runs well. I started out with #6 then i mounted #7 that is a little bit richer, the change was barely noticable. Thet is noticable for me as a layman, remember that my experiences are an amatueres. I test ran my car with an wideband O2 sensor, and the results (leaning out a lot above 3500), made me order AZ from burlen. AZ needles are a lot richer from midrange and up. I have mainly used a software called WinSU in my search of needles and this software use the term midrange, which I guess is around 3000rpms.
Now I can use whole revrange in a very positive way. My idle is ok, it pulls well from 1500 and comes alive at around 2500-3000. But I like it the most at around 3500-4000. I can rev it to 6000 without problems (well except for the noise then). My kidbrother who regularly likes to punish my car has no problems notice the huge difference and compared (concerning accelleration) it to his Peug 206 with 110 hp, a good thing.
Jesper Akesson

Matt,

My Fast Road head is now several years old and has done many thousands of miles. It runs perfectly on ordinary unleaded with no pinking and very little run-on. My engine is otherwise standard apart from K&N filters and richer needles (can't remember which ones Peter used - I'll have to look it up when I get home). The cam is standard, as is the exhaust manifold. On Peter's dyno, the measured bhp at the wheels went from around 67 before to around 90 after changing the head. On the road the car feels very little different at low rpm. It still pulls solidly from 1000 rpm if you want to. The most difference is noticed between 2500 and 4500 rpm, when the extra power is really noticable. Don't get me wrong, it's still no ball of fire, and modern hatchbacks will leave you behind when they are well driven, but it has made a nice car better (and cheaper to run!).

Mike
Mike Howlett

Hello Mike,


Not so bad to shift from 67bhp up to 90!!
Modern hatchbacks are still quicker yes, but they often benefit still less power losses and much better
gearboxes and suspensions with four independant wheels all around!
For K&N conversion HIF4's require AZ needles as mentionned by P.Burgess.
SAfety fast.
Renou

I missed to say that I run the AZ needles in my HS4's.

/jesper
Jesper Akesson

Iain,

For suspension and brake mods etc - see How to Improve your MGB, MGC & MGBV8 by Roger Williams. ISBN 1-901295-76-1/UPC. It's published by Veloce in the Speedpro Series (as Peter Burgess's book). List price £15.99 but I bought my copy remainsered at about £6.

It's an excellent book but I can take no responsibilities for you wanting a V8 after reading it!

Peter
P L Hills

I READ THE THREAD every day when I have time and enjoy it. MY ? is what do you mean by fast road head . I have Peter book but I am new to the Mgb game

A 79 Mgb was giving to me 3 years ago need anew top
rust on both sill Su need rebuilding and needed a air compresser But it did start up, rev wide open so I stop it notice oil leaking form the back of the motor on the floor .So I took the motor apart for rebuilding. How do I get the max form this motor and driver it daily
lfinklea

lfinklea, on Peter Bugess website you can read about his different stages of head porting.
http://www.mgcars.org.uk/peterburgess/

/jesper
Jesper Akesson

Peter, Thanks for that. Must admit my ultimate fantasy would be a V8 (how easy is the conversion ?) Basically I've got a 76 roadster in pretty good nick, was rebuilt early 02 so body sound etc. I was thinking a stage 2 (maybe a 2 litre) would make a suitable alternative. What do you reckon ? Go the whole hog and go for the V8 ?
Iain

Earlier in this thread Matt asked about anyone's experiences of the Ecotune head as oppose to a Fast Road. Seems like there's feedback about the Fast Road but we'd appreciate how the Ecotune fairs as the alternative. Like Matt I'm deliberating as to what to install.
Thanks
Ron
Ron Goodrum

Ron,

The Econotune head is cheaper because the shaping of the ports concentrates on the easier parts to reach - the fast road head has more work done to the inaccessable parts of the ports and this takes more time and skill so costs more money but flows more mixture.

With all performance work, an initial increase in power is relatively easy and cheap - the more power you want the more expensive it gets - until squeezing out the last drop of power costs as much again as all the work to date!

I am sure Peter won't mind me reproducing part of his price list here:

Standard Leadfree £185
Econotune £280
Fast Road £360
Fast Road Big Valve £415
Fast Road Plus £475
Rally (from) £525
Full Race £830

(all exchange and plus VAT)

and the econotune head sits somewhere roughly in the middle between the standard head and the fast road head in terms of performance.

But this is only part of the equation - you have to consider cams and compression ratio, carburation and timing as a package together with the head - and the result can vary from producing an out an out power house that won't idle below 3000 rpm and would be undriveable in a road car - to an engine producing much less peak bhp but being very torquey and a delight to drive in town and on twisty country roads.

So - the answer to your question is probably that you are asking the wrong question!

First decide what you want the engine to do - then ask people like Peter or me what spec of engine will deliver that - the answer is not always what you would expect!
Chris at Octarine Services

Iain,

In my book there is no comparison between a 2 litre 4 cylinder and a V8.

The V8 is a superb drive even in standard form, because of the huge torque. No 4 cylinder can match that, even if it has more overall bhp at max.

However the costs of V8 conversion are high - because of the body, caburation, exhausts, brakes and suspension mods needed. I would budget on around £7000 to do the job properly - more if someone does it for you. The actual work is straightforward and there are lots of parts available to help with the job, like the special oil pump cover to enable the remote oil filter and special engine mountings.

The cheapest route to V8 ownership is to sell your car and buy one already done!

A good driveable 1950cc stage 2 will cost around £2500 and produce much the same peak bhp as a standard MG V8.

Chris at Octarine Services

Chris, if I was to go down the 1950 stage 2 route, what modifications would you recommend to suspension ??
Iain


Ian
I too have been thinking about improving the performance of my GT and like you would prefer to improve what I've got rather than ditching it in favour of a V8.
Since it is my daily drive I can be without it over the weekend, but that's about it. The idea of improving what is basically under the bonnet is appealing and the comments of experience going down this route so far are very useful. Thanks so far for the thread, if there are anymore out there who have modified in a similar fashion and can relate what were the pitfalls as well as the advantages all the better.
Gary
G Roberts

Iain, Gary,

I have gone the 1950cc performance engine route.
(it has a crossflow cylinder head, but most general remarks will go for a classical cast iron head as well)

Things I did before deciding final specification etc: dig through the archives of this site, read Peter Burgess' book, ask people questions (mainly Chris Betson).
In the end, Chris (and I) decided to go for an engine with 1950cc Accralite forged pistons, 10.8:1 CR, big valve head modifications by Peter Burgess (this part might differ as we have different cylinder heads), Piper 285 cam and some more goodies (all of which can be seen on Chris' website!).

The main thing is: be sure you get what YOU want. There are people who bought a rally cam just because they thought it would be ok, but eventually they didn't like the on/off character their car had developed.
On the other hand, there are people like me who are totally and utterly thrilled with the new engine, but to achieve that, it is of the utmost importance you have the right combination of parts and settings, as Chris mentioned.

For what it's worth, my suspension mods are: uprated lever arm dampers up front, Koni telescopic dampers at the rear (were installed when I bought the car, so can't really comment on the difference), 185x15x65 tires on 15x5.5 72 spoke wheels (the power was too much for the 60 spoke wheels I had before) and a 3/4" front anti-roll bar.
This results in a car that's not a lot harder than a standard MGB but handles a lot better, imho.

hope this is what you were looking for,

Alex
Alexander M

Iain,

Assuming you will use the extra power to go quicker, you need to uprate the brakes to stop quicker! V8 thickness discs plus the calipers will help resist fade under heavy braking but not increase stopping power. A set of EBC brake pads will increase stopping power by up to 30% but they wear out faster.

Increase the diameter of the antiroll bar to 3/4 inch.

Uprate the front dampers, but retain the lever arm type. You can use telescopics at the back but they need to be set soft.

Springing is a matter of choice - stiffer springs will improve roadholding but the ride will suffer.
Chris at Octarine Services

This thread was discussed between 04/10/2004 and 22/10/2004

MG MGB Technical index

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