Improvement ideas

[Stephen Aitken]

I’m sure this has been covered but wanted to get some opinions on what improvements on the B are really worth doing?
I’ve done a few cosmetic things, LED dash bulbs and headlights, new wheel, walnut dash, magnolia gauges, leads, hoses, air filter, carbs stripped, rocker cover with a better seal, fuel hose upgrades, brakes. They have all made a small difference but what else is really worth it. For example power steering, better exhaust, lowering suspension, central locking kits etc
Would be good to hear from others. I’m aware that some don’t like moving away from stock which I understand.
thanks
S

[steveshepstone]

In order to receive some really helpful advice, you might like to specify what area(s) you would like to improve: Looks, performance, handling, ride comfort, reliability? I'm sure you'll get lots of suggestions but I bet they'll differ, especially if you give some idea of budget.

[Stephen Aitken]

Main areas for me are looks and performance but open to any ideas. In terms of cost might be best to have a scale cheap modest expensive?

[Vic Butler]

My priority when I bought my rubber bumper BGT in 1979 was to improve the performance as compared to my previous 1967 BGT (succumbed to rust- it was gutless. So, a pair of SU HS6 carburettors, a better cylinder head and exhaust has made all the difference. Cosmetically it's had a glass sunroof and LE alloy wheels and now I have a B with good performance. The instruments etc are good enough as they are.

[Paul Hollingworth]

Its not as easy to tune the B series as the A. You tend to have to do a whole package of things to get an improvement in performance. It depends on what you want. Most of us want more bottom end torque rather than top end power. Things like K&N filters, sports exhaust and longer period cams tend to only do the latter and all need to be done altogether to see a real improvement. My first and only step was to take my head to Peter Burgess for his Econotune treatment and I did see a significant boost to low end torque. You could go for his large valve head but then you will need the other mods as well. I don't like Weber carbs as in my experience the A and B series with their Siamesed intake ports don't run smoothly on them. As Vic says bigger SU's are a better solution. I have a friend who is fitting the 1 3/4 inch SU carbs and manifold off a Austin 1800S. He's already done the other stuff. I wait to see the result.

[Stephen Aitken]

What’s the benefit of the HS 6 over stock?

[Vic Butler]

They need to be fitted with a freeflow exhaust and a gasflowed and ported head. I am fortunate in knowing the man who was Downton Engineering's ace cylinder head expert and he ran a business near me with his son. He built me a bespoke head from the 12H2709 casting which had to have MGC inlet valves fitted due to valve seat damage.
With a larger bore inlet tract I would have expected to lose bottom end torque but no. The car is easy to drive in traffic and pulls well at lower revs but give it its head and it will reach the red line quickly. This tractability was a known trait of Downton heads. Ideally it needs a rolling road session to fine tune it.
It's no good slapping on a pair of HS6's and expecting better performance without head and exhaust modifications. My HS6's are fitted with MGC K&N filters and stubststacks.
The Distributor Doctor recalibrated the distributor to suit the tuned engine.
Simply letting the engine breathe better will release more power.

[Peter Cresswell]

The biggest advantage of the HS carbs over the HIF is the ease of tuning them. On a mildly modified engine (Stage 2 tune) a pair of HS6 carbs release quite a bit of bhp at the top end at the expense of the bottom end torque, but this can be negated by having a larger bore. Even +060thou (1860cc) gives quite a bit more torque over 1798cc. A 45DCOE weber will release more power at the top end over a pair of HS6 (usually 3 - 4bhp) but at rev ranges most people would be uncomfortable with on the road.
I have recently finished my engine which has a self modified head based on 12G2705 casting with race valves and 3 angle seats. Compression ratio is 10.5:1 and the camshaft is a Piper 285 magnum, with Maniflow rally exhaust manifold and system. Carbs at the moment are still HS4s with richer (No.6) needles. It is certainly a much quicker car than it was and pulls very strongly in 3rd gear and top, but I now find 1st and second gears are too low. A close ratio gear set would make things better but at nearly £2,400 for the set plus gearbox build costs, it isn't going to happen. This also would throw up another problem as this would give a near 60mph first gear with the standard rear axle ratio, and a lower ratio of 4.1 or 4.3 are quite expensive by the time the cost of having them built into the tube axle is taken into account. The car is also quite a bit noisier than before!
I point these things out so you realise that modifications are quite expensive and you don't get many horses per pound spent, and also they might throw up the need to modify other areas which can be as expensive as the engine.
It is quite difficult to get real power increases from the B-Series engine and it always seems to me that a lot of money has to be spent to get an extra 5bhp. It should be remembered that BMC Competitions Department managed 135bhp for the Le Mans MGBs (around 100bhp at the wheels) when they had 1293cc Cooper S' giving the same or more in race trim. This has been improved on with modern knowledge to around 170bhp for race cars, although Huffaker in California were getting 180bhp in the 1960s from MGB racing engines without many special parts for their SCCA spec cars.

[Vic Butler]

Near where I live is a fairly steep hill with an S bend at the bottom and a hairpin bend halfway up. The hill cannot be approached at speed because it's in a 30 mph zone. My Stage 2 BGT will go up this hill in 3rd with 2 up without any problem and is capable of exceeding the speed limit before it ends. If the road was better at the top I could leave the car in 3rd up to the red line.