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MG MGB Technical - Unleaded in Ontario

I'm sure there's been lots of discussion on this topic so I'm hoping someone can supply the definitive answer. I have a '72 roadster that's pinging badly. Had it tuned by two different mechanics, one specializing in Brit cars, the other not. Still pinging badly under load (when accelerating).
So the questions: would a lead substitute or additive assist in resolving this?
And I've noticed that Canadian Tire has a product call Formula 1. Any experience or comment on this product?
John M

My experience with octane boosters is that they're pretty much worthless. Going back into the foggy past, it seems to me that in '72, high test fuel was still a common product. About that time frame, I owned a '64. Under heavy load it pinged even using the highest octane I could find. Things to consider: it's a high compression engine, you may have to retard the spark advance a bit to reduce detonation, or, there may be a carbon build up in the cylinders that can cause pre-ignition. Over the years, someone may also have replaced the distributor with one that has an incorrect advance. You don't say whether you've had this car for a while, or if it's a recent aquisition. It's hard to know the exact maintenance history of a lot of our cars, having been passed through many hands over the course of the years.
R. L Carleen

Hi John, can't give any specific advice about your pinging. I do, however, own a 73B, and live in southern Ontario. I use the Canadaian Tire product on all fill ups. I use about half a bottle. I also use the Sunoco 94 octane fuel. I don't have any pinging. I don't know if this would cure your situation, but I figure it can't hurt. Hope this at least narrows the possible reasons for your pinging.

Cheers,
Stu
Stu Cameron

I stumbled across this wesite the other day. Can't vouch for the accuracy, but it's something to consider:

http://www.mgparts.co.nz/combustion.html
Rob Edwards

In the UK I find the octane boosted lead replacement additive does nothing for the pinking that I get with the lower octane unleaded, so have to use the higher octane with an unboosted additive.

Check the vacuum and centrifugal advances are working correctly and not stuck on max or going to max at too low an rpm or you *will* get pinking when adjusting timing to the book value. At the end of the day if everything is working correctly you will just have to back it off until it stops doing it.
Paul Hunt

This thread was discussed between 22/03/2004 and 23/03/2004

MG MGB Technical index

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