Opening a Port

I run an Accurite electronic ignition which is housed in the distributor but does away with the points and condenser.

It has been extremely reliable so far, but I do carry a spare distributor just in case. !!

It makes for a much smoother running engine with the added bonus of better fuel economy as well.

Some purists would not entertain the idea of electronics on a classic car though.

Why do you ask ?

Phil

The time and effort spent in matching ports, manifold and joint will be well repaid on any engine.

A 1565cc Renault 16 given this treatment would match a 2 litre Vauxhall or Ford for acceleration or top speed!

Don't overdo the hot spotting, to maximise charge density. BUT if overdone, you could suffer icing, which will bring things to a halt, until it thaws out. DON't ask!

You need just enough heat input to match the latent heat of vapourisation of the petrol.

Heating from the coolant will provide the most easily adjusted and controlled method, if possible.

Sharp edges in the tracts, cause turbulence, and impede flow.

Someone once said "Getting the gas into, or out of an engine determines whether it is a pig or a horse"

So don't forget to ensure that the exhaust system does not cause too much back pressure, but remember that a little may be beneficial in preventing loss of charge on the overlap.

If you want improved performance, you can tune the exhaust system, but remember that what works at one speed could work against you at another!

Howard

This thread is very changeable. First we start with exhaust manifold porting, the induction porting, then gas flowing heads, now electronic ignitions!

A question on electronic ignitions: I have encountered Accuspark electronic systems but not Accurite. Please can you provide a link? I’m not overly enthusiastic about the reported reliability of the accuspark versions. I have made made a better electronic system in the past - but it either lacked starting energy or real high end power (due to inverter limitations at the time).

Richard (Islip Minor on the morris minor forum) has a far better electronic system on his minor (which really goes like - -ink).

NDIY

You are correct, I was getting my Accu's muddled up with the DRO system I used to have. It is an Accuspark unit on the car.

I too have heard about some folks having reliability issues with them, but so far mine has been excellent, like I said I do carry a spare just in case.

Phil

Yes that's the one, a typing error on my part. I ran a single 1 3/4" SU carb and 1 3/4" 3 branch stainless exhaust with this set up.

I've used the 12G295 or the near identical 12G206 Cooper 998/MG1100 head in the past on 1000cc 'A' series motors, One of the issues (other than rarity) with these heads is the large amount that needs skimming off the head if you're not using flat top (or 'pop up' pistons) a .070" plus skim often results in a break in to the rocker feed oilway drilling that runs across the face of these heads. Nowadays I use the 12G940 head from the 1275cc motors, It has bigger valves, less volume in the combustion chamber, so needs less skimmed off to attain a decent compression, the rocker oil feed drilling doesn't run across the head face, and if it's a late (1987 onwards IIRC) head it will have factory fitted hard valve seats suitable for unleaded petrol.

When this head goes on a small bore (i.e. 850/950/998/1098cc) motor it needs to be fitted along with the 1275 rocker gear and head gasket as the valve spacing is different on the 1275cc head. The 1275 exhaust valve opens over the edge of the cylinder on the small bore motors, so if the head has been skimmed, or you are running a high lift cam, reliefs need to be cut into the block.