15 replies to this topic

[WillMini]

heyyy, so, i was looking to find out what head i have on my engine (1978 mini 1000). i just took the head apart, and someone back in the day redid the valves BUT they put all the exhaust valves in cylinder 1 and 3 and the intake valves into 2 and 4! anyways, the head is casting number 16m7. i haven't found a mini head with that number. maybe its just a Canadian thing, i dont know. does anyone know this head???

[Dan]

Does it have fresh air injection ports?

[miniboo]

pics needed i think. but i also think it may be one of teh fresh air heads like Dan says

[WillMini]

yeahhhhh, it does. should i plug them up, or used the fresh air injection. i heard its useless and does nothing for the environment.

[miniboo]

just plug them up. as long as it can pass a smog test without the pumpp etc.

can you do me a pic or 2 of the head?

[WillMini]

thanks, yeah fore sure, cameras at a friends house. ill get it fridayy.

[miniboo]

any pics yet?

[Jammy]

Fresh air injection ports? What are they?

[Ethel]

I have some of those - nostrils

[Xiao_Bin]

Fresh air injection ports? What are they?

Canadian minis have an air pump that inject air in the exhaust (i think) to (as claimed) reduce the emissions

[samwell]

just dilutes the output, surely the same amount of C**p comes out???

[WillMini]

sorry about the long reply, got my camera back, but my internet was done for a few days. BUT here are the pics



i think they are fresh air ports, but i think they are useless. ill just plug them up.

[miniboo]

plug them up. the one i took off a few months ago had them plugged up. not a problem at all. just make sure you get the car properly tuned afterwards

[Dan]

Ah well that's not the casting number for the head, it's some other tool maker's number. All the heads have a number there and it doesn't seem to mean anything. The casting number is normally in the middle of the rocker area but then again maybe it's different on Canadian heads.

Yes the fresh air injection head is unique to Canada I believe, certainly it's unique to the air injected cars and wasn't used on any others with the ports plugged. Don't know much else about it I'm afraid.

just dilutes the output, surely the same amount of C**p comes out???

No, the air is injected into the port as the valve is opening and so the gasses are still very hot. Given a supply of fresh oxygen any leftover unburnt fuel or part burnt products will readily react at these temperatures. It is a system meant to ensure more complete combustion of the fuel so the emissions will be less noxious. It does exactly the same thing that a catalytic converter does but in a different, cheaper way (cheaper in the '70s when cats cost a fortune anyhow). Lots of bigger performance engines use the same basic system today to protect the cat from getting large lumps of unburnt fuel spat into it only now the system is controlled by electronics rather than vacuum valves. Ford and GM both use a system called pulse air injection in large engines and it's the same thing but with an electronic pump. The main drawbacks with the ancient BL version are that running the air pump from a belt drive costs a lot of power, the tune of the engine is limited by the reaction speed of the valves driving the system, the head is poorly laid out and the whole thing is very heavy. What it does, it does well but it has a heavy price in terms of performance.

[WillMini]

Ah well that's not the casting number for the head, it's some other tool maker's number. All the heads have a number there and it doesn't seem to mean anything. The casting number is normally in the middle of the rocker area but then again maybe it's different on Canadian heads.

Yes the fresh air injection head is unique to Canada I believe, certainly it's unique to the air injected cars and wasn't used on any others with the ports plugged. Don't know much else about it I'm afraid.

just dilutes the output, surely the same amount of C**p comes out???

No, the air is injected into the port as the valve is opening and so the gasses are still very hot. Given a supply of fresh oxygen any leftover unburnt fuel or part burnt products will readily react at these temperatures. It is a system meant to ensure more complete combustion of the fuel so the emissions will be less noxious. It does exactly the same thing that a catalytic converter does but in a different, cheaper way (cheaper in the '70s when cats cost a fortune anyhow). Lots of bigger performance engines use the same basic system today to protect the cat from getting large lumps of unburnt fuel spat into it only now the system is controlled by electronics rather than vacuum valves. Ford and GM both use a system called pulse air injection in large engines and it's the same thing but with an electronic pump. The main drawbacks with the ancient BL version are that running the air pump from a belt drive costs a lot of power, the tune of the engine is limited by the reaction speed of the valves driving the system, the head is poorly laid out and the whole thing is very heavy. What it does, it does well but it has a heavy price in terms of performance.

SO, really would the car be less efficient and burn more fuel if it is using all this power to turn a pump???


also my casting number(the number in the rocker area) is 66am4004. still cant seem to find any info. im assuming its the same as any mini 1000 head but with those fresh air ports.