General Questions

Q. Did the additional power of the V8 mean that the standard brakes were found wanting?

A. Not for me personally, once uprated front pads were fitted, but some keen owners were soon asking for even more braking efficiency. By 1975 (before the advent of affordable alloy calipers) I discovered one easy front brake upgrade that was available from the Austin Princess parts bin. The Princess 4-piston cast iron caliper was a direct bolt-on swap for the original MGB 2-piston unit. I subsequently found that even more swept area could be had by using the more readily available Rover SD1 4-piston calipers - latterly the Vitesse ventilated type with bespoke AP ventilated discs. I fitted cars with all three alternatives.

However, the SD1 ventilated calipers were a little on the heavy side, required bespoke mountings and discs, and the dual inlet versions were often awkward to bleed - so I stopped using them unless the customer insisted. Solid type SD1 calipers were slightly lighter and an easier fit, using late Triumph GT6 shouldered mounting bolts (as used with that car's M16 caliper) and factory specification MGB V8 discs. The only non-standard parts you will need are the brake hoses which require a 10mm metric fitting at the caliper end. Stainless braided hoses are recommended and can be made up to suit at reasonable cost by a brake specialist. The only modification required for the conversion is minor surgery to the brake back-plate in order to clear the slightly larger caliper. Pedal feel will be much improved by changing the standard brake master cylinder to one with a bore of 22.2 mm. (7/8"). An AP version of the OE cylinder, but with the larger bore (Part no. CP2623-94) is available ex-stock from the ever-helpful BG Developments on 01527 8673176.

 

I'm told that the Princess calipers are hard to come by these days, but back then they were available new and were comparatively cheap. I'm also told that the solid disc version of the SD1 caliper is now available again in limited quantities (See News, 01 December 2009) but you should be aware that using them may create clearance problems with some types of 14" road wheel, necessitating a change to a larger diameter, usually 15". This potential problem is more likely to occur with the vented version of the caliper, which requires the use of a thicker disc. It is therefore advisable to check wheel clearances before embarking on this upgrade. (See next answer).

 

Of course, you could opt for the Frontline Costello front disc/alloy caliper conversion, but the point about the upgrades detailed here is that none of them affects the originality of your car (if that is your concern) since they were optionally available during the original production run. You may also wish to upgrade your discs to grooved or drilled ones whilst changing your calipers, but this is not strictly necessary if your current discs are in A1 condition and are to V8 specification. These are 14mm rather than 11mm thick and were fitted to some cars. Modern brake pads are certainly worth using though, whichever path you take. Please note that clearance problems may preclude the use of this caliper with some 14" wheels.

 

Q. What about wheel and tyre options?

A. The 14" Dunlop wheels originally specified on the Costello were similar to those later used on some Reliant Scimitar SE5 models, which had a slightly different offset and a 5-and-a-half inch rim as opposed to a 5" rim on the Costello. The factory V8s also used a variation on the same wheel, but with an alloy centre and a steel rim. Both cars were shod with 175/70 HR 14 tyres.

Some Costello owners preferred different, all-alloy alternative wheels - mostly Minilite, but occasionally Wolfrace - especially in the 15" size with a rim width of either 6" or 6.5" usually with 185/60 or 195/60 section tyres. Cars which began life with wire wheels invariably ended up with centre-lock Minilites. The clearance needed for an SD1 front caliper conversion made the change to 15" alloys even more likely. Still larger rim widths with suitable tyres to fit required 'Sebring' flares (which I have never thought particularly attractive). However, without some flaring - and even restricting rim and tyre sizes - rear wheel fouling of the inner arch could be a problem.

 

A simple solution for 6" or 6.5" wheels and tyres was to fold away the inward projecting flange at the top of the rear wheel arch - or to add subtle flares of the kind seen on Helen Massey's car. (See Gallery) Further improvements could be had by fitting a Panhard rod to improve lateral location of the rear axle under acceleration. (Note that while the Panhard rod does improve axle location, it cannot be expected to correct an axle which sits in an offset position - a production anomaly from which many MGBs suffer and one which is exacerbated when wide wheels and tyres are used.)

 

Flaring the front arches to accommodate anything larger than a 195/60 section tyre on a 6" or 6.5" rim is not really recommended. Except for race use larger tyres aren't needed, and producing an aesthetically acceptable flare is difficult - and well nigh impossible if you choose to retain the original car's chrome side moulding strips. What's more, in my opinion, wheels larger than 15" with very low profile tyres are not in keeping with a car from the seventies and, in any case, significantly degrade ride quality.

These days, 195/65 or 60 x 15 radial tyres are a good choice - and some owners on 15 x 6 or 6.5 rims have successfully used an asymmetrical arrangement with 205/60 or even 215/60 section tyres at the rear. (Only with wheel arch modifications though, and probably a recalibrated speedometer as well) As to the choice of tyre brand, I tend to favour Bridgestones, Michelins or Pirellis - HR rated at least - but it's really a matter of budget and personal choice.

 

Q. I've seen some cars with big American downdraft carburettors rather than SUs or Webers - do you approve?

A. I thought the Weber option was an elegant and reasonably economic European solution, but remember, the Buick which spawned the Rover V8 was an American engine and well-proven 4-barrel Holley 390 cfm conversions from the likes of Offenhauser or Edelbrock were already available in the early 1970s - so why not? The Costello bonnet bulge left plenty of room for those whopping pancake air cleaners too! Indeed, some of the early Buick-engined Mk I cars had Carter 4-barrel carburettors as standard. I'm told that the current favourite for this application - and the natural successor to the Carter - is the 4-barrel Weber/Edelbrock 500 cfm carburettor.

 

For those who have the Weber/Edelbrock fitted already, here are the correct jets and settings, which will suit 3500cc and 3900cc engines in standard tune. Anything outside those parameters will require specialist advice, followed by fine tuning on a rolling road.

 

Primary MainJet - 80 CHG

Secondary MainJet - 95 (Standard)

Fuel Needle - 62/52 CHG

Fuel Needle - Spring Orange (Standard)

Float Height - 11/32 (Standard)

 

And for those owners who would like to retro-fit the Weber 500cfm, the most commonly used inlet manifold is the readily available Edelbrock Performer, but I reckon that the best for optimum gas flow is the Wildcat single-plane alternative. That aside, if you'd like the whole lot in a box, Webcon have developed a complete kit of their own, with the correct jets already fitted.

If you're sticking to your original HIF-6 SUs and P6 specification engine, for the record, here are the correct needles and jets:

BBG needles with AUD 521 jets (left and right) or BBV needles with AUD 623 jets (left and right).

If they are still attached, the tags on the carburettors should tell you which variant you need.

 

Q. I know you've been asked before, but what about those corroding radiator expansion tanks?

A. There's no easy answer other than to have a new one fabricated in either stainless or aluminium (mine was done in brass by Feltham Radiators - Lawrence. Mine too! - Alan Worth. I sent mine to Malaysia! - Oliver Marchant). For the latter, the correct filler neck and cap are available from the likes of Merlin Motorsport. However, later cars (or those which have had tired original engines replaced) often ended up with a different configuration on the front of the engine. This did away with the need for the fabricated tank (and the top hose passing underneath the fan belt) and enabled the use of a standard inner wing mounted expansion tank from the MGB parts bin.

 

Q: I have a rather reluctant starter motor. Any ideas?

A: I'm not an auto electrician, but your first course of action is to check that you have the starter properly earthed. If you still have problems, then it might be that it is on its last legs. The right hand exhaust passes close by the starter motor and if the latter is not fitted with some sort of heat shielding, it can suffer adversely over time. Difficulty with hot starting (where the starter motor sounds as if the battery is flat) is an indicator of heat damage. Consider a Lucas service exchange unit - or purchase a smaller, more powerful, geared starter motor from the likes of Moss Europe or Cambridge Motorsport. And don't forget the heat shield. Factory ones are available for the standard starter motor, but you could do just as well yourself with something like Aerotech aluminium shielding - which you would have to use anyway in order to protect the smaller alternative starter, for which no ready-made shield is available.

 

Q: Have you any suggestions for improving the light output of my standard headlamps? I have been advised against using some of the aftermarket bulbs, because they apparently draw too much current which can damage the wiring loom - and they may not even be road legal.

A: You could try PIAA Platinum White bulbs (which I have used) Phillips Extreme or Osram Night Breakers. All these bulbs claim to be road legal and compatible with original wiring. All produce significantly higher light levels - but only if your reflectors are in very good condition. The other, though more expensive option is to go for one of the new bi-xenon High Intensity Discharge H4 headlamp conversions now on the market. These produce around 300% more light than a standard halogen bulb while actually consuming less power. However, you should ensure that whatever you buy carries E mark approval, since some of the cheaper options do not and cannot be recommended. If you are offered a choice of colour temperature and wish to avoid the ultra white boy-racer look, go for a conversion rated at 4300 degrees Kelvin rather than 6000 degrees.

 

Poking about under other people's bonnets during the inaugural gathering obviously got some of you thinking on the way home.

 

Here's a subsequently emailed question from Richard Fairclough:

 

Q: What choices are there to replace a tired distributor?

A: There are firms doing reconditioned OE distributors and you might find even a new one on eBay, but I think you can do better. Mallory make two versions of their 'Dual Point' distributor, for pre and post vacuum advance applications - to which you can fit an electronic contactless module. The Mallory 'Unalite' is the one for injected engines. I have fitted several Mallory kits with good results and no problems. However, you must ensure that the distributor drive is not worn or no new distributor will work properly. Another supplier worth looking at - but of whom I have no experience - is a firm called '123 ignition' in Holland. They have recently introduced a fully digital distributor for the Rover V8 which certainly looks good. I believe that 123 products are now available in the UK via Southern Carburettors or SC Parts Group.