hi hi have got a datsun 120y and just bought second hand extractors and was wandering what people do with the inlet manifold heater valve thing because its attached to the origional exhaust manifold so do u just block it of with a piece of stell plate also will this affect the operation of the car????

Thanks

it doesnt go all the way through to the inlet from memory does it? so you can just leave it.

its just like a revese heat sink to heat the inlet manifold to get better fuel atmorisation in colder climates i thought.

o thanks yer just realised its just a heat sink not right through!

yeah there's no hole in that valve thingy.. you can just change the extractor. that stuff is used for better cold operation, and for better fuel atomisation.

On my 1st 1200 (with headers), I only had a problem (carb started icing up, and ran like crap) when the outside temp was 32f (0c) or less. I took a couple of hose clamps and attached the stock metal thingy to one of the extractor tubes. Not the prettiest, but it worked.

So it has been noticed that for normal street driving, inlet manifold heat, from the exhaust manifold, has a positive effect on driveability & fuel consumption while extractors/headers/flows [pick one] can have a negative effect due to removal of the heat source.

They were clever little buggers those Datsun engineers.

Water heated inlet manifolds are the way to go when extractors are used & I'm trying to remember if the manifolds from the round port 'thrift' versions of the A14 & A15 can be fitted to the earlier A12 type head.

Hopefully someone here will know.

The worst carb icing will occur in temps a little above freezing in high humidity conditions, ... like fog. Particularly in high vacuum cruise mode.

I have had my GX carbs freeze to the point that the throttle shaft stuck & would not close when I lifted the foot from the 'power pedal'.

No dramas though & the throttle closed after about 10 seconds but it was an interesting experience. Covering the lower half of the radiator core with cardboard ensured that a repeat never occured.

So covering the radiator partially is to keep the engine compartment ambient temp from falling too low?

I've wondered how that would help coolant temps, which are controlled by the thermostat anyhow.