Which spring and needle ? – SU HS6 For Landrover series

For those who have not read my set up of SU HS6 carburetor for land rover series 3 you can read it Part 1 here and Part Two here:

As you may aware, I bought the carburetor SU HS6 as a complete unit, it comes with BAK needle and green spring, and that what I use for the initial set up… It works but may be not optimal… from the forum and discussion, they are few suggestion:

  1. Copy ACR set up with BGB needle and Black spring
  2. BDM needle with red spring
  3. BDB or BBW but not sure what spring they use..

Just to remind you on the profile of the needle, you can see below  that BGB is very rich needle, BBW second, BAK third, BDM fourth and BDB is the leanest…

needle su

Actually I want to copy ACR set up, however after having discussion with Burlen… there is no such thing as black spring for HS6, I think they do not want to be copied, and may be they change the color of the spring to hide the their set up…

Finally I ordered BDM and BDB needle and  red spring, hence I have three needles and 3 springs (one spring is from old SU)… it will be interesting the try all possible combination.. :).

Here some photos when I am tried needle and spring combination

Three springs SU HS6

Three springs SU HS6 : the Green, the red and the unknown.. (from right to left)

 

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Needle BDM and BDB fro burlen

 

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Off the Dashpot, and we can easily change the spring and needle

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Replace The spring with the another spring we want

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Off the old needle and the new needle is ready to be installed

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The needle center lead… its funny because actually the needle is slightly not centered even using this centering aid..

To make it apple to apple, first I have to make sure that the ignition timing is at 6 deg BTDC as suggested by ACR using their Cyl head.

So.. after the few tries… I finally concluded that the setup is best using green spring and BDB needle... The others also works but at high throttle it missed fire or blow back… or severely lost power compare to this one.  it is quite strange… ACR set up is using the richest needle, I am using the same head from ACR but it best using the Leanest of the option…

Bit confuse, but I find it very smooth and have more power using this set up, it capable of going uphill at 3rd gear,  previously it need the second gear to climb it… So thats it for now, any questions please write it down below.. hope it can be useful for you

 

Cheers for now..

 

Other set up is OK, but in the open throttle, I experienced a missed fire… even if I tried my best to adjust the

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Electronic Ignition – A Little Incident

Electronic Ignition can be considered as upgrade from point contact ignition, but which one…? a lot of option out there, but for me I choose the cheap(ish) option ( but not the crap by all means)… Powerspark from SimonBBC… the consideration is: the technology is already mature, the improvement will not be much different with the point breaker anyway, and I might go for Megajolt route later so I do not want to spend big money here. I ordered this item, a Chinese copy of Lucas distributor 45D4… well Lucas is well known as prince of darkness anyway, what can be worst from that…

45DsimonCut the story short, I have received the item in a good condition and installed it about two  months a go… I feel bit of improvement compare to the old distributor (not sure if this is only psychological or actual), it works.. so no more maintenance… or so I thought…

One month later, when I happily driving around the town… I heard a noise from the engine bay and the engine stopped… just like that… ooh, Dolly is playing another “guess what when wrong this time” kind of quiz again…!

I opened the bonnet and checked few things, I saw the distributor cup is no longer properly clamped or loose, and the rotor arm is not in the place it should be… ah.. this is the problem… “Common Dolly, you insulting my intelligent… this is too easy….” I said to Dolly (if you see a landy owner talking to his /  her car, consider it as normal… we do that all the time :)). Easy fix, just put it back I will be going in no time… me think… but it seems I under estimate dolly in giving a hard quiz…  the engine is not starting… it crank OK but not starting…

Another look at the distributor, it is clamped alright now, slightly loose but clamped by both clip, tried again cranking again the engine.. same result…so  this is the time more thorough investigation is needed.  I checked the inside of the distributor…

The Cup… although cosmetically no problem I found something strange… here is the pict:

cupdist

Yap the spring is broken…

So no wonder the electric current can not be transferred from coil to spark plug, because no connection to the rotor arm …  it should have something like this…

cupdistori

original 45D4 cup distributor

But what about the rotor arm..? it too seems badly “injured”… here is the pict..

rotorarm

What the hell has happened… I am checking the internet and seems no one is having the same issue, so I accept it that this might be my fault during installation, somehow it is probably not properly clamped, the cup is loose, and *Bang* the rotor may be hitting the one of the aluminum post  inside the cup, the rotor stop moving but the mighty force of the engine pushing it further and the plastic broken, and so on and so on…

I finally replaced the rotor arm and the cup from the original dizzy which I always bring for the spare… I fired up the engine no problem,  and I can go  home safely… seems that the main unit is OK…

I talk to Simonbbc and ask whether this type of “accident” is covered by his warranty… He kindly agree to send the replacement… great service… no wonder he has 100% satisfied customer in ebay. Now the original distributor cup is still being used waiting replacement from Simon…

Cheers for now…

Dissapointing dyno result – Solved..!

This few days, I can not sleep and eat.. I wish I did not do the Dyno.. :). But that is the beauty of having old car, this problem is actually a lot more interesting than problem in the office, you do not know what is wrong… it just does not work as expected but the good thing is almost everything under our control to solve it…

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Dolly at Dyno machine

So what is wrong then… if you read my previous post, you know that Dolly power is low, and peaked at 3000RPM, which should be around 4500 RPM and  lot higher.  A lot of things can be the cause, I need to check it one by one…

  1. Engine Compression, may be the compression is low and resulting low HP… checked… and the result is 165 psi across all pots. so no problem here.
  2. Fuel supply problem… how can it be..? I just replace the seal… and seems works ok
  3. What about ignition timing..? I checked using strobe and the result is 5 deg, should be no problem…
  4. The suspect  now is the carburetor SU HS6 or electronic Ignition or problem with the timing chain

The fellow land rover forum said that the Electronic Ignition can be faulty, or since I do not know the advance curve of this distributor, it may be not suitable for landrover… to prove this point, I did an exercise… set the ignition timing too advance (deliberately) and drive it full power (stopped when it start knocking), and then retard it a bit and drive it full power again, and so on and so forth until the timing is too retarded  loss power at all RPM). In this exercise, I found that no matter what, I lost power after around 3000 RPM at all ignition timing set up. So the Electronic ignition is no longer suspect.

Now how about carburetor, again little exercise in the morning, I set the jetting from too rich to too lean, again the result is the same.. loss power at around 3000 RPM. and I gave up… I am not bother checking the timing chain, the symptom is not relevant for timing chain. I just use it at low rpm, but back in my mind I always have that question… “what the hell is wrong”  something is fundamentally wrong and we can not find out what it is..? even my fellow land rover forum who usually very knowledgeable on this matter can not solve this riddle.

Finally I went to local Land rover garage and discuss it with the garage owner, I show the dyno result… just with one glance he said… ” Fuel supply problem..!”. Can not be… I replaced the seal and clean it… “Fuel supply problem..!” he said again… How can it be..? I challenge him… “FUEL SUPPLY PROBLEM.. ! DAMNED..!” he almost throw the “land rover number one tool” at me.

Ok Ok.. I said… how to solve it…? He then installed an electronic fuel pump after the mechanical lift pump… “this will do” he said. “let me know how it goes…” Why not install it before the mechanical pump..? me questioning his installation… “you fool..! you want the fuel flood your engine and blow you up…?” and it shut me down… :) here is the installation..

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Very true.. this solve the problem… I can feel Dolly is still pulling even after 3000 RPM, very happy, I say thank you to him (and pay of course) and drove home smiling… I do not bother to dyno it again… one because I have to pay, two I am afraid that I will find another problem that keep me awake during the night… may be later, but not now :)

So moral of the story is… don’t dyno even if it is free…. ah ha ha..