MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Rally MGAs

Hi everyone

I use an MGA Mk2 for Regularity rallying, exclusively European events.

It's been extensively modifed, mostly to BMC competition spec so as not too cheat, (the 5-speed box was removed when I bought it!) It now has a CR box (original 1622 reinforced unit) and a 4.55 diff.

engine has standard carbs, but hi comp, gas-flowed head, lightened and balanced bottom end, and competition free-flow exhaust.

It came with a very odd cam that only came in at about 3200. Some weird rally cam of uncertain parentage. It got 108 bhp on a rolling road at about 5800, which was impressive. But when mated to the CR box it was hopeless, just impossible in hairpins, leading to much slipping of clutch, slamming into 1st on the move, and copious swearing. So out it came (it should have been whipped out much earlier...)

As a consequence of reading posts on this thread, particularly by Peter Burgess, I have installed a Piper 270. The car is still being put together, so I will report back on its performance when it's running.

If anyone else uses their MGA for rallying, I would be interested in swopping notes and modification experiences.


R Bunn

Very cool car. Enjoy the Rallying.

Cheers, David
David Honness

Nice car

Interesting choice with the 4.55 Diff, but I have to agree the close ratio box and a hot cam do make it hard work especially around town and pulling away.
J Bray

First impressions:

Marginally less power, but more torque. To be expected with a Piper 270. Power pick-up out of a 90 degree bend not spectacular, but doesn't bog down either. One has expect steady acceleration. I still expect the car to struggle on an uphill hairpin with the CR box and 4.55 Diff, but it that context one would slam it into first and rev it hard to maintain a consistent speed through a sequence of hairpins.

Now I need advice on modifying distributor advance. In order to remain period as possible I don't want to replace the unit with a 123 version (it already has electronic ignition - my only concession to modernity.)

So let's see what it's like once the timing has been sorted. But overall it seems to reinforce the oft-found conclusion: higher comp ratio, hotter cam, more power: less driveability. Milder cam, slightly more conservative CR: slightly milder performance, but the power that's there can be used more.

Any advice on ignition advance and advance curve much appreciated.
R Bunn

This thread was discussed between 05/02/2012 and 11/02/2012

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.