mk1-forum.net

Hi.

Can someone suggest good carb needles for the following.

1071 +20 block. 544 cam. modified 940 Head. For twin 1 1/4 SU's

Thanks
Steve

From a bit of research I found Blue Springs and a No6 Needle. Does that sound right?

Haynes SU Carb Manual "Special Conversions"...

Mini Cooper 'S' 1071cc Group 2 1964-68
2 x H4
MME
Blue

From index 5 to index 9, MME is about 10% richer than No6...

Have you seen this?

http://mk1-performance-conversions.co.u ... l_carb.htm

The "Needle Selection Tool" and the "SU Needle Recommendations"
below it might be of interest.

Ian

If the blue spring is stronger than red yes and the #6 will get you close. You don't mention C/R which is hard to get up on a 1071. Do a compression test and we have an idea. If around 10 to 1 AAA spring loaded needle will be close. That type piston is common and will change out. I don't have much fixed needles any longer. Buy a needle chart book and start learning. Steve (CTR)

SU Springs:

Blue = 2.5oz
Red = 4.5oz
Yellow = 8oz
(There are others, but these are the most commonly used ones for the 'A' Series...

CooperTune wrote:Buy a needle chart book and start learning. Steve (CTR)

The Needle Selection Tool detailed in my previous post has the complete needle
chart included and is FREE. It's basically a very comprehensive multi-tab spreadsheet
and provides a serious amount of number-crunching.

You tell it which needles to analyse, and it will provide all the numbers and graphs you need.
You can make your own needle, say by entering the fat end of one known one and the thin
end of another - the spreadsheet will then attempt to find an official needle from the list that
matches.

What it will not do, however, is choose a needle for you based on the colour of your
furry dice and the diameter of your steering wheel. It won't predict your 0-60 time either
or tell you next week's winning lottery numbers, or any other bullsh!t which would be
impossible to calculate from a carb needle - Just factual numbers and graphs...


You get the whole fully featured package, FREE. No registration - Just download and use.

Ian

Steve,

An MME is for twin 1 1/2" not 1 1/4" carbs.

Steve asked about needles for HS2's not H4's.

BTW, if you were using H4's then MME's would be about right.

M

mk1 wrote: An MME is for twin 1 1/2" not 1 1/4" carbs.
Steve asked about needles for HS2's not H4's.
M

Sorry, but my first post was for H4 as well...

Ian

Hi Guys.

Yes Mark beat me to it. Mine are HS2's.

I went off David Vizard's book and ordered Blue springs and '6' Needles from my mates at mini spares.

They arrived today and we gave it a try. I do not know what the old needles and springs were as they came with the car. I just know that it seemed to be running quite lumpy (rebuilt engine) Anyway, after fitting the new gear it made a hell of a difference. The engine sounds pretty sweet considering everything is not had a final set up yet.

My car is getting very close to its first drive in 11 years.

Thanks for the help and links.

Took the car for its 1st proper drive today. I need alot more work on the carbs I think! The no6 needles and blue spring combo had the car running very rich.

The car bogged down VERY badly up to 3k revs. The car would hardly move in 2nd gear. I put the old needles back in and its better but still not good until 3k revs then flys.

It has a modified 544 Cam. Perhaps the cam is the problem?

I'll make sure carbs are set up right before doing anything else.

Steve, Some more updated photos of your S pls!
Why not go for a pair of H4 as Mark since you use a 544?
What mod you got exactly on your cam?

Al

SteveG wrote: The car bogged down VERY badly up to 3k revs.
<SNIP>its better but still not good until 3k revs then flys.

I had EXACTLY the same symptoms on one of mine before Aldon re-curved the distributor.
It would hardly run below 3000 and even on a slight incline I had to drop a gear...

Do I dare say that this is more likely to be a timing issue then?

Ian

I'll look at everything. Timing could be the cause. On a slight incline 2nd gear didn't get me up and I had to stop and select 1st!

To be honest, When I bought the Engine it came with the 'near new' Cam 544 'slightly modified. I was told it was fitted to a 970s for only 50 miles until they had to pull the engine out. He said it went very well and would be perfect in my 1071.

My mechanic that's been helping me reckons the 544 is a Full race cam and too big for my 1071 but i'm not so sure as most people on this forum say the 544 is perfect for a 1071. That's why i'm hopeful its in the timing or carbs area.

hi Ian

What spec is your car?

This is at the mechanics house next to his 67 S replica. Its a 1380 and goes very well (no bogging down!)

I still have paint to flat and Buff on my car.

It's the combination of a short stroke and a biggish cam, a 544 in a 1275 or a 1380 is only a fast road cam. Because of there longer stroke, these engines produce more lowdown torque.

A 544 isn't going to be a problem if its timed in right and everything else is right.

the only 1071 ive ever had that bogged down like described above runs a 649 and twin h4's

that suffers from horrific carb standoff, you either have to 'tickle' it away from the traffic lights, or simply mash the throttle to the floor - anything inbetween makes it stutter like a good one!

my gtm is running twin 1 1/4's and a evo 2 cam, its like a pussy cat (and to my shame its been no where near a rolling road, I simply swung the dizzy and tickled the carbs so its stoich at 60mph)

It's not a problem it's just how a 544 works.

What angle you time in your 544?
Mine planning to fit in a 1275s I will time it at 107deg.
While the factory stated the LCA is 110 deg.
Sounds it is off time a little!

Al

I have 544 in my 970 and you are familiar with how that drives.

Has the dizzy been calibrated? Timing checked and re-checked?

My offer still stands to check the carbs over, you may have to leave it over here for a bit though...

J