52 replies to this topic

[oltonlad]

The 266 is, indeed, a lovely cam in a 998.

and a 1098...........

[mailman]

Ok, I have been off gathering some bits and bobs and I'm back for a little more guidance.

I boght a box of SU Carbs containing a pair of HS6's. Whilst cleaning these up I had a look at what else was there and I found a pair of HIF4's from an MGB. (AUD434 F/R!.

I have picked one of the HS6's and I think that the HS6 is in better condition than the HIF4's. And I have a rebuild kit for it. One of the HIF's looks pretty good and one looks good but the piston inside is stuck.

Is HS6 better than HIF4 for the build spec i'm going for? If I go HIF4 do I need them as twin's? And is it much more complicated to set up?

[oltonlad]

do you mean HIF44?........theres no such carb as a HIF4

the HIF44 will be the best compromise..............or twin HS2's will give you more torque.

its not a massive spec engine so don't over carb it or you will lose power.

if you dont have a copy of david vizards "how to tune BL's A series engine" then buy one................and read it!

Edited by oltonlad, 08 September 2012 - 07:24 AM.

[ACDodd]

Just to correct there is such a thing as an HIF4 (fitted to later MGB's) and HIF6 carbs. These look like the HIF38/44 variants but use non ball bearing suction chambers and the older HS style needle valves.

AC

[mailman]

Yea, it's definitely HIF44.

I don't have the Vizard book yet, I keep meaning to get it but it's so expensive!

I will try and borrow it and have a good read through it.

I suppose I am being a little cheeky, and perhaps asking to much, by relying on you all for advice when there is something like that book available.

I am thinking if I get my HS4 and HS6 carb's running beautifully then I can choose between the two based on the final build performance.

I think i'll try sell the HIF's then.

Thanks again guys.

[jaydee]

As above, the HIF4 is pretty much the predecessor of the HIF38 and you can find it on MGBs

[mailman]

I have managed to get my hands on a good condition HIF44, could somebody please advise the appropriate needle to order to start with and run in until getting it Dyno Tuned??

Confirmed Specs as follows:

998 +060
Kent 266
12g940 Head
Stage 1 inlet
maniflow extractors
RC40 Twin Box exhaust
Aldon Yellow Ignition

[mailman]

Also, Compression Ratio should be around 9.75:1 I think.

[jaydee]

BDL

You need to get it rolling roaded to get a custom profile needle because at a guess it will be a bit on the lean side at pick up.

[mailman]

Awesome, thanks Jaydee.

I did see your BDL recommendation earlier, i just wanted to confirm the choice based on the confirmed build.

Is it better to have a richer needle for start up and getting to the rolling road? Or will one needle do?

[jakejakejake1]

Well you can modify a needle to make it richer, but you can't make it leaner, so often people will recommend a leaner than ideal, so you can then get it profiled to suit the engine, but most good rolling roads, especially if they specialise in minis, will be able to supply a baseline needle that they will modify to suit. Although its always best to check beforehand.

[mailman]

Ok, so I had a look online and contacted the guys at Minisport about the BDL needle (and also their recommendation). They said that they had BDR, but only as a starting point as the don't recommend HIF44 with 998's.

Two questions, is BDR or BDP a good starting point (i.e. Close to BDL)? Secondly, should I stick with my HIF44?

I'm inclined to stick with my HIF carb as you guys have been nothing but extreme'y useful and accurate so far.

Thanks

[jaydee]

Difference is marginal at cruising-pick up between those three needles, the problem is they're way out at full power. At cant be adjusted at the rollers.
Forget what they said about the two needles and the HIF44, you wont have enough fuel for the 266 and the 940 with an HS4, i can guess they reccomended the HS4 for fuel economy and emissions.
I run a slightly hotter spec and with a vizardised HS4 it runs fine, but the HIFF44 actually made a difference, better bottom end, better full power.

Needle wise, if you cant get a BDL, use BFY.
Burlen or minispares have them.

[jaydee]

And the only other carb set i would reccomend is twin HS2 with probably M or GZ needles, but the HIF44 will require half the time to set up properly.

[mailman]

Awesome, thanks so much!