Morris Minor Owners Club

I have fitted a 1 3/4" su HIF44 carb.to my 1275cc.Marina engined Moggie.Can anyone help,please,with advice on the correct needle to use? I am prepared to experiment but need a point to start from.Thanks,David.

Welcome to the forum! First off - we need to know what other modifications have been done to the engine - what manifold the carb is on - and what needle is in it at present!

Kent 266 Megadyne camshaft,moderately gas-flowed head(std.valves) Falcon large bore exhaust and waiting on high lift (1.5)rockers.Toyota 5-speed box.Present needle unknown-will check.Bags of power up to 4000rpm.then it doesn't wan't to go any further.Used to rev.happily to 5000 with the old HIF38 but not so much torque.Will advise on needle asap.Many thanks,David.

The high lift rockers are a mistake.......... They 'may' give you 1 extra bhp at the top end - but will lose you plenty low down, and cost you in fuel too. Also much higher wear/tear on the valve gear - my advice - forget them! As for needle - the 'standard uprated needle for the 44 is the BDL, but as with any SU modification - it is just a starting point.

I know we've discussed high lift rockers before but why would they lose bottom end power? Surely it's large overlap angles in the cam rather than higher lift that reduces the bottom end power.

Speaking as someone who's actually using high lift rockers I found a noticeable increase in the low end and no drop in fuel economy.

Aye - but are you using them with an already high lift cam ? The problem is - at TDC the two valves on overlap will be even further open - with inlet gas going down the exhaust pipe. They just don't represent value for money - power gain against cost - it's the worst 'benefit' you can buy! But - each to their own!!

Thanks for the advice.The existing needle is a BCZ so I shall start with your recommended BDL and work from there.Regarding hi-lift rockers,David Vizzard (who designed the 266 Megadyne cam) states that although the cam will give a good power increase with std. rockers it was designed to give max.power using the high ratio.Any further comments are welcome as you are now causing me to have second thoughts! Regards,David.

The rockers are up to you - I wouldn't touch them with a barge pole! You will get far better results with a large valve head - the standard inlet valve is quite restricting on a 1275. Fine on a 1098 etc. The BDL is slightly richer than your BCZ after mid point , so should help at higher revs.[frame][/frame]

But do run a plug test after fitting it!

That neat graph is available by Googling "minty su compare-o-rama" (honest!) Its an excellent needle comparator website for SU's. Or get "winsu" for £10, type in all your variants and it will spit out the best fit needle.