12 replies to this topic

[mvahora]

Hi everyone, 

 

Wanting some opinions or experience from anyone who has had this sort of spec engine using twin HS4 carbs and what needles you have used/started with. In the process of getting my mini back on the road after years of it sitting. I have purchased twin hs4s with stub stacks and K&N filters to upgrade my twin hs2s. below is the spec,

 

1310cc, Block drilled for 11studs, 1.5 roller rockers, Piper 285/2 cam + modified head ported and polished to suit 285/2 cam, S/S race valves inlet 1.401 (35.6/29), aldon yellow, maniflow st2 LCB single box, NGK BP7RES plugs.

 

thank you

Edited by mvahora, 16 December 2020 - 01:16 AM.

[Steam]

CP4 or #6 with blue springs are what was used in the police S with twin 1 1/2. Should give a starti g point at least.

[imack]

Years ago I had a 1380, Avonbar 36/31 head, 10:1 CR, piper 285/2, 1.5:1 rockers maniflow LCB, twin hs4's with k&n's and stub stacks.
Ian Hargreaves of Avonbar suggested AAR needles. It ran well but from memory they were to lean at the top end.
Good enough for run in prior to rolling road session though. Never did rolling road it.

[mvahora]

Years ago I had a 1380, Avonbar 36/31 head, 10:1 CR, piper 285/2, 1.5:1 rockers maniflow LCB, twin hs4's with k&n's and stub stacks.
Ian Hargreaves of Avonbar suggested AAR needles. It ran well but from memory they were to lean at the top end.
Good enough for run in prior to rolling road session though. Never did rolling road it.

 

AAR looks like a decent needle to start with, but yes, as you mentioned mintylamb shows it to be a quite a bit leaner at higher revs when compared to the needles listed below

 

keith calver suggests AAA for a 276 kent cam or the AAM or ABY for a 286 cam. MED also sell the AAA with their twin hs4s...  Thoughts on the AAA needle?

 

 

 

 

Attached Files

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[Arthy]

I'm running AAA in a 1330 with an SW8 cam, 1.5 rockers, stage 3 head and the usual exhaust/dizzy mods. Running the BP7RES plugs too!

 

It runs well with AAA, although I've never had it on the rolling road (hopefully next year!)

 

Pulls strong and doesn't seem to be struggling to lack of fuel at the higher revs - plugs are a good colour too after a very spirited drive.

 

 

Hope that helps!

 

Regards,

Arthur

[imack]

My engine was set up on a rolling road by Peter Baldwin and runs AAU needles
1380, 11:1 cr, MED 37/31 offset valve head, 1.5:1 roller rockers, MED FIA15 (649 derived cam) Vizarded twin 1.5" su's on steel maniflow intake with MED stubstacks and ITG filter, maniflow large bore long 3:1 manifold with single box rc40.
It ran well prior to rolling road session on the AAR needles from my previous engine but I knew it was lean higher in the rev range.
I tried AAM and ABY, AAM was the better of the two but still way to rich in the 4000 to 5000 rpm range to the extent of black smoke and misfire. Wouldn't take more than about 1/3 throttle below 5000rpm.

[Arthy]

My engine was set up on a rolling road by Peter Baldwin and runs AAU needles
1380, 11:1 cr, MED 37/31 offset valve head, 1.5:1 roller rockers, MED FIA15 (649 derived cam) Vizarded twin 1.5" su's on steel maniflow intake with MED stubstacks and ITG filter, maniflow large bore long 3:1 manifold with single box rc40.
It ran well prior to rolling road session on the AAR needles from my previous engine but I knew it was lean higher in the rev range.
I tried AAM and ABY, AAM was the better of the two but still way to rich in the 4000 to 5000 rpm range to the extent of black smoke and misfire. Wouldn't take more than about 1/3 throttle below 5000rpm.

 

You think I should try AAU? We're running quite similar specs besides the cam! - even down to the vizarded twin HS4's and inlet manifold.

 

I have noticed since fitting 1.5 rockers recently, it won't take anything more than 1/3 throttle in 3rd below 2.5k revs. 

[Dusky]

Swinging or fixed? Aau singing, AH2 fixed on a similar setup.

[imack]

My engine was set up on a rolling road by Peter Baldwin and runs AAU needles
1380, 11:1 cr, MED 37/31 offset valve head, 1.5:1 roller rockers, MED FIA15 (649 derived cam) Vizarded twin 1.5" su's on steel maniflow intake with MED stubstacks and ITG filter, maniflow large bore long 3:1 manifold with single box rc40.
It ran well prior to rolling road session on the AAR needles from my previous engine but I knew it was lean higher in the rev range.
I tried AAM and ABY, AAM was the better of the two but still way to rich in the 4000 to 5000 rpm range to the extent of black smoke and misfire. Wouldn't take more than about 1/3 throttle below 5000rpm.

You think I should try AAU? We're running quite similar specs besides the cam! - even down to the vizarded twin HS4's and inlet manifold.

I have noticed since fitting 1.5 rockers recently, it won't take anything more than 1/3 throttle in 3rd below 2.5k revs.

All engines are different, all I can really say is that ABY and AAM were way too rich in the 4-5000rpm range.
It's really a case of trying to find a suitable safe needle until you can get on a rolling road.

[mvahora]

I'm running AAA in a 1330 with an SW8 cam, 1.5 rockers, stage 3 head and the usual exhaust/dizzy mods. Running the BP7RES plugs too!

 

It runs well with AAA, although I've never had it on the rolling road (hopefully next year!)

 

Pulls strong and doesn't seem to be struggling to lack of fuel at the higher revs - plugs are a good colour too after a very spirited drive.

 

 

Hope that helps!

 

Regards,

Arthur

 

 

My engine was set up on a rolling road by Peter Baldwin and runs AAU needles
1380, 11:1 cr, MED 37/31 offset valve head, 1.5:1 roller rockers, MED FIA15 (649 derived cam) Vizarded twin 1.5" su's on steel maniflow intake with MED stubstacks and ITG filter, maniflow large bore long 3:1 manifold with single box rc40.
It ran well prior to rolling road session on the AAR needles from my previous engine but I knew it was lean higher in the rev range.
I tried AAM and ABY, AAM was the better of the two but still way to rich in the 4000 to 5000 rpm range to the extent of black smoke and misfire. Wouldn't take more than about 1/3 throttle below 5000rpm.

 

 

 

My engine was set up on a rolling road by Peter Baldwin and runs AAU needles
1380, 11:1 cr, MED 37/31 offset valve head, 1.5:1 roller rockers, MED FIA15 (649 derived cam) Vizarded twin 1.5" su's on steel maniflow intake with MED stubstacks and ITG filter, maniflow large bore long 3:1 manifold with single box rc40.
It ran well prior to rolling road session on the AAR needles from my previous engine but I knew it was lean higher in the rev range.
I tried AAM and ABY, AAM was the better of the two but still way to rich in the 4000 to 5000 rpm range to the extent of black smoke and misfire. Wouldn't take more than about 1/3 throttle below 5000rpm.

 

You think I should try AAU? We're running quite similar specs besides the cam! - even down to the vizarded twin HS4's and inlet manifold.

 

I have noticed since fitting 1.5 rockers recently, it won't take anything more than 1/3 throttle in 3rd below 2.5k revs. 

 

 

 

The AAM and ABY as you both mention are richer from 4-5rpm onwards range hence why I assume they are suggested for the 286 cam profile by keith calver and others. 

The AAA is richer at the lower RPM range and is suggested for a 276 cam....

 

I think wev nailed it down to 2 options. AAA or the AAU which seem quite similar.

Edited by mvahora, 21 December 2020 - 03:41 AM.

[mvahora]

Swinging or fixed? Aau singing, AH2 fixed on a similar setup.

 

 

 

i just got the pair of hs4s today, checked them and they take the swinging type needle. I opened up the twin hs2s and they have been running red springs with fixed AH2 needles. Surprising as that's what you mentioned.. my hs2s were running quite well with fixed AH2s.

 

do you know if there is there a swinging needle which has a profile that's similar to the fixed AH2?

Edited by mvahora, 21 December 2020 - 04:48 AM.

[Dusky]

Swinging or fixed? Aau singing, AH2 fixed on a similar setup.

i just got the pair of hs4s today, checked them and they take the swinging type needle. I opened up the twin hs2s and they have been running red springs with fixed AH2 needles. Surprising as that's what you mentioned.. my hs2s were running quite well with fixed AH2s.

do you know if there is there a swinging needle which has a profile that's similar to the fixed AH2?

You can convert your AH2 to swinging. Burlen SU sells the tophats separately, I converted mine a few years ago too

[mvahora]

 

 

Swinging or fixed? Aau singing, AH2 fixed on a similar setup.

i just got the pair of hs4s today, checked them and they take the swinging type needle. I opened up the twin hs2s and they have been running red springs with fixed AH2 needles. Surprising as that's what you mentioned.. my hs2s were running quite well with fixed AH2s.

do you know if there is there a swinging needle which has a profile that's similar to the fixed AH2?

You can convert your AH2 to swinging. Burlen SU sells the tophats separately, I converted mine a few years ago too

 

 

can that be done? Is this the kit your talking about? http://www.sumidel.c...-bush-and-screw