1.2 with 1600 cam and carb

[Leeboo]

I have a 1.2 carb engine (12nv), and next weekend I plan to fit the cam+carrier and twin choke carb from a 1.6 to it. From a 16sv carb 1.6.

I have the head from the 1600 aswell and wanted to use it on the 1.2 block as it has bigger valves but this would make it lose too much compression wouldn't it, also I don't have the square port inlet for the 1.6 head.

So basically, I will have a 1.2 block, 1.2 cylinder head, a 1.6 cam+carrier, and a 1.6 cam. How will this run? I had thought fuelling would be too much but with the 1.6 cam it should be ok?

Before anyone asks, no, I will not buy a complete 1600 engine. I am using what I've got.

Thanks in advance

[Jon_nova1]

baaddddddd

If your using the 1.2 head it should have cathedral ports? so you'd want a cathedral inlet? which would be the 1.3, the 1.6 carb fits onto this, I would have atleast got myself a 1.4 crank, I'm sure the current setup would do more harm than good?

i had a 1.4 fitted with a 1.6 carb a few years ago, it ran well, got the occasional pop from the exhaust, so i'd dread to think what you'd get lol

thats if you actually get it started without overfueling and killing the spark

[jimbob-mcgrew]

does your new cam have the same pin drive like my 16sv ? as youll need a different ignition system to match it if so. the 1.2's ignition is slot drive. i think the 1.3 cam is the only straight swap available. like jon said, youll need a 1.3sr inlet to be able to use a 2e or a 32/34 carb on it. what have u got on the exhaust front by the way ?

[Leeboo]

baaddddddd

If your using the 1.2 head it should have cathedral ports? so you'd want a cathedral inlet? which would be the 1.3, the 1.6 carb fits onto this, I would have atleast got myself a 1.4 crank, I'm sure the current setup would do more harm than good?

i had a 1.4 fitted with a 1.6 carb a few years ago, it ran well, got the occasional pop from the exhaust, so i'd dread to think what you'd get lol

thats if you actually get it started without overfueling and killing the spark

Used to have a 1300 and 1600 so have got a few parts.

I've got a 1300 inlet to match the 1200 ports, and the 1600 carb to go on that.

I thought that the fuelling wouldn't be too over the top because I have the 1600 cam which is higher lift and more suited to the carb than the 1200 cam?

[Leeboo]

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[Leeboo]

does your new cam have the same pin drive like my 16sv ? as youll need a different ignition system to match it if so. the 1.2's ignition is slot drive. i think the 1.3 cam is the only straight swap available. like jon said, youll need a 1.3sr inlet to be able to use a 2e or a 32/34 carb on it. what have u got on the exhaust front by the way ?

Its slot drive so no problems there. Exhaust wise I've got a 4 branch and bigger bore ashley system from a gte, have a 1.3 inlet lying there to match the 1200 head.

just wondering will it overfuel badly with 1.6 cam and carb, while still retaining 1.2 head

[Jon_nova1]

I thought that the fuelling wouldn't be too over the top because I have the 1600 cam which is higher lift and more suited to the carb than the 1200 cam?

Higher lift means it will dump more fuel into the cylinders, but doesn't the 1.6 have a less aggressive profile? (I'm not certain, someone can confirm)

The exact setup i had was

1.4 bottom end
1.4 cam
1.3 inlet
1.6 carb

and when i let off the accelerator you could hear the fuel igniting in the exhaust and popping flames etc, you can try it, but i think you'll flood the engine on startup

[jimbob-mcgrew]

i dont know a whole lot about fueling, but from what ive heard from others, the carb needs to be matched to the cam for the fueling to be ok, so it should be fine if there info was correct.
im sure compression has something to do with the equation too but i dont know enough about it. the 'S' engine the cam came out of is slightly higher compression than your 'N' engine.

[Leeboo]

Thanks for your replies. jonnova1, banging popping etc doesn't worry me lol, but yea seriously I see what you mean..

jimbob - thats the idea I've been going on. The 1.6 carb and cam are from one of my previous engines which ran very nicely, might just bung it all together and see what happens lol.

I was going to use the 1600 head on the 1200 block too as it has bigger valves but it would drop compression down, plus I don't have the right inlet for the 1600 head, its square port. Thats why I'm keeping the 1200 head

[mowgli]

get a decent rolling road bloke to set it up.. or it will be massively overfuelling.

[jimbob-mcgrew]

i wonder what it would run like on the stock 1b ?