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MG MGB Technical - trigger wheels

has anyone tried the laser cut trigger wheels, just thinking about fuel injection, with throttle bodies on my MGC
the link below has laser cut wheels, plus other brackets, etc, and powder coating.. oh and jewellery for your wife girlfriend
anyone tried laser cut parts
www.trigger-wheels.co.uk

p m watts

PM Watts

To get started in Fuel injection, you don't need a trigger wheel. You can run the fuel injection directly off the coil.

If later you decide you also want to control ignition, you can run that off the existing distributor or add a trigger wheel. A trigger wheel will allow you to eliminate the distributor and fire the plugs directly.

Check here for a cost effective DIY EFI solution.
http://www.bgsoflex.com/megasquirt.html

and here for some examples of cars with EFI installed. I'm not aware of MGC with this solution.
http://www.msefi.com/viewforum.php?f=52&sid=85de553dfc947488309e15034d72ebc6

werner
werner haussmann

Ok, now call me foolish, but other than maybe being slightly more accurate, and we're talking fractions of a degree, how is a crank fired trigger wheel better than a trigger wheel inside the distributor? essentially any aftermarket electronic ignition is the same thing. The Crane system uses an optical trigger while the pertronix uses a magnetic trigger. Unless you run multiple coil packs and a computer, you still need the distributor to fire the plugs.

That brings up another question. How difficult is it to achieve a better ignition curve with a computer than it is with a recurved distributor? It has to be phenomenally time consuming to map an ideal advance curve considering all the factors involved.
Jeff Schlemmer

A crank fired ignition is more stable. It can be more repeatable and therefore you can get a bit more advance without knock risk. A distributor has jitter that can vary the advance between cylinders due to the gears and cam chain. So you get a bit more power and a smoother engine.

Using an ECU like the Megasquirt EFI system you can fire two coils (for a four cylinder) and eliminate the distributor completely using a crank trigger wheel. This is likely the most difficult for an EFI conversion but not neccesary.

With an MGB 4 cylinder, getting a 'good' distributor is difficult. What with the many curves, unavailable springs etc. With the HIF the desirable port vacuum is even more difficult to accomplish. Using an ECU to do the ignition advance allows flexibility to 'program' any distributor curve based on rpm and vacuum (MAP). It also allows stabilization of the idle by increasing the advance when the engine slows below idle. This is done by filling out a table on a labtop. I used the recommendations from Burgess' book on what the advance should look like.

To summarize, converting to EFI with or without ignition gives some of the advantages of a modern car (at the expense of originality) My reason for adding EFI to an MGB is that it's an easy and simple way to learn all about EFI and engine management.

see here for an MGB example.
http://home.comcast.net/~whaussmann/wmgb/wmgbframeset.htm

werner haussmann

This thread was discussed on 15/02/2006

MG MGB Technical index

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