12 replies to this topic

[Timini]

Hi all
Need some basic advise on needles and springs on twin 1 1/2 hif4 sorced from an mgb.
The engine is 1330, stage 3 head, a plus rockers, 276 cam. The needles in at the moment are ACD with blue spring. I would welcome any input as to what needles to use as base before taking to the rolling road. Also if anyone has a suitable manifold they wish to sell? I'm having troubles getting one.....stock issues
Many thanks
Tim

[whistler]

I think you mean HS4 carbs.

[Shooter63]

I know what you mean, not that I've actually started the engine yet, but I've got AAV needles which seem pretty close to the old fixed needle no3, the taper is almost spot on but a touch leaner all over so a jet adjustment should sort it out.

Shooter

[Timini]

Thanks
They are hif4 but I am led to believe the needles are the same as HS4 floating type needles.

[FlyingScot]

Moved to non fuel injection PQT

FS

[carbon]

Timini, try this link for comparing needles. You can compare fixed with swing as long as both are for 0.090 jets: http://www.mintylamb.co.uk/suneedle/

 

For fixed needles your spec would probably run OK using number 7 needles with blue springs or number 3 with red springs. With the HIF you can't buy anything lighter than the red spring, and the number three looks reasonably close to the ACD apart from just off idle where it is a bit weaker.

 

Out of interest do the pistons on your HIF4's have the recessed groove where the needle sits? This may have effect of richening up the mixture at part throttle, in which case the ACDs could be a reasonable starting point.

 

But you will only know for sure by setting up on a rolling road.

[Dusky]

I ran quite a similar spec on ABD needless. Twin hif4 as well

[Spider]

I know it's not what you'd like to hear, however unless it's a track car, I'd suggest to you that twin HS4's are too big for a road car on that engine spec. You will be able to get them to work ~~ OK ~~ but you'd get better results with something like a single HIF44 or twin HS2s.

[Timini]

Thanks guys.
The pistons do have the recessed groove.

Moke spider It's interesting that you recommend twin hs2 as I have a pair but was advised to go for 1 1/2s as the 1 1/4s would strangle it. I also have an hif 44 with, I believe, BDL needle. Would rather use twins as I've always liked the pickup on sprites I've had. If 1 1/4s will be sufficient I'll rebuild and use them.

[carbon]

I'm running twin HS2s on 1293, MD266 cam giving 10.5mm valve lift (probably about same as your 276?). Works very well with QA needles and old red springs (these are not so strong as new red springs).

 

A few areas which are worth attention:

- use K&N or similar high flow filters

- flow the spindles as detailed by Vizard

- flow the inlet manifold (if standard type) as detailed by Vizard

 

If you do all this it won't be giving much away to a standard HS4 set-up, and will also look pretty original.

[Spider]

Moke spider It's interesting that you recommend twin hs2 as I have a pair but was advised to go for 1 1/2s as the 1 1/4s would strangle it. I also have an hif 44 with, I believe, BDL needle. Would rather use twins as I've always liked the pickup on sprites I've had. If 1 1/4s will be sufficient I'll rebuild and use them.

 

According to SU, twin HS2's suit engines up to 100 HP and respectfully, with your spec, you'd be looking at around 70 - 80 HP range. The single HIF44 has a similar HP rating.

 

Twin HS4's are good for up to 115 HP.

 

'Gains' allowed for at the top end, usually take away from the bottom end, which for street cars, is where they tend to 'live' most of the time. The smaller carbs will make the engine more responsive.

[Timini]

Thanks again for the replies.
My hs2s are 998 Cooper. If i use them am I better off getting another manifold as I've read it's not very good or just modify as vizard?
Thanks again
Tim

[nicklouse]

I would fit a single HIF44 myself.