HIF carbs

[ndevans]

Morning. Is there a way of identifying a carb, apart from measuring the inlet size? Are there any markings I should look for? I have a HIF carb and want to know whether it's a 38, a 44 or a 6.

[bmcecosse]

You need to measure the outlet side of the carb. More simply - look at the needle markings - if they begin with an 'A' then it's an HIF38. Otherwise ( ie Bxx) it's a 6 or a 44 - there's not a huge difference between them.

[ndevans]

44mm or very close across the port on the engine side, needle is a BDL. I guess that makes it an HIF6 or 44?
ok, next problem-it's on a Howley inlet manifold, but that is 38mm across the ports. Ok to run with this, or not?
It will go on a 1275 Marina engine, when I get round to doing it.

cheer N

[bmcecosse]

NO - a step down like that is terrible for air flow. You either need to open out the manifold (if there is enough 'meat') - or get a 44mm manifold. BDL is a good 'starting point' for a modified 1275 engine - probably too rich for a standard 1275 engine.

[ndevans]

Thought you'd say that! A quick search on ebay hasn't thrown up any 44mm Howley inlets, but there are a few standard Metro cast iron inlets. Are they any good?
As for the engine, I've only just got it, haven't stripped it yet, so no idea of cam etc. Assume standard.

[panky]

I opened up a Minisport manifold, it was simple to do as there was a lip on the inlet that filed away easily, I suspect they use the same casting for both carbs.

[bmcecosse]

I would open it out - indeed Vizard tells us how best to do it - to maximise flow round the bends to left and right - he opens the manifold to more than the 44 across the L-R axis - and then uses the phenolic spacer to make a nice blend from carb to manifold. Actually - your 44 is on the 'large' size for a standard 1275 and maybe the easy answer is to source a 38 meantime. The 44 is always 'money in the bank'.

[ndevans]

Ok, only gone and got myself a HIF38! Needs a good clean and new gaskets, but otherwise looks fine.
The needle is marked ADS-is that the standard for a HIF 38? It'll go onto a 1275 ex-Marina engine. No idea what cam is in it, but I'm assuming a standard cam.
Cheers N

[panky]

The ADS needle would have been fitted to a small bore engine, ADE was 998 Metro and it's quite close to the profile of the ADS. An AAA would be more suitable for a 1275 engine

[ndevans]

OK ta.

Next question-I still have the HIF44 in the bank, so what sort of mods would make it worthwhile on a 1275? Different cam?

cheers N

[bmcecosse]

Big valve head for a start - and yes a slightly better cam - A C Dodd RS cam gets great write up - but there are many others - and unless you plan spending a fortune on lightening/balancing/main strap etc - you want a torque' cam - not a revvy cam. And of course - a decent larger bore (but not huge) exhaust system. It all adds to the cost..... and be sure to tell the Insurance Co,

[ndevans]

Ah well, happy days then! I happen to have a big valve head in the bank too!

Of course, I don't actually know what head is on the 1275 yet, but again, I assume it's just a standard 12G940. It's definitely ex-Marina, the engine number checks out.

I could try the 38, then the 44 & see which I like the most. Roll on springtime!
(& seeing off this damn pneumonia which has prevented me from doing meaningful work in a cold garage).

cheers N

[bmcecosse]

Get well soon! The bigger carb just gives you more 'full throttle' - so unless you find yourself constantly 'foot on the floor' with the smaller carb - the larger carb won't make much difference - and perhaps poorer fuel economy.

[ndevans]

Ta, feeling much better than I was, but still not right.

Ok, next question-is it prudent to replace the jet as well as the needle on an HIF? I've usually replaced both in the past on my HS2.
Also, is there anything in the float chamber that may be worth replacing? Both carbs are unknowns having been sat for years. Might be ok, who knows, but it seems prudent to overhaul and replace potential worn items at this stage.

cheers N

[bmcecosse]

I would leave well alone !