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…

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..


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..

Everything About Tuning The 2.25 Petrol Engine – ACR, Turner & others perspective

engine2.25petrolWarning: Long article but worth it..! There are a lot of information about how we upgrade our old engine… some says.. : drop in the 2.5 cam, milled the head by 0.02 inch, ported and polish etc etc.. all is good advise but I read this discussion (or debate) with great interest and decided to put it here in case we need  reference lets start (I deleted conversation that are irrelevant), and unfortunately, I can not see the poster names unless it stated at the end of the post.

Someone: I think that these engines have a specified max rev limit of 4600. Though going over 4000 for anything short of a few seconds is probably not a good idea. My tachometer has the occasional misbeat but in no way does it wander like yours does. If its something to do with the ignition and not a bad connection it’ll show up on a vacuum guage as well, they’re cheap, easy to fit and very useful.

Roland (ACR): We set the Power Plus engine red line at 5200RPM this will give plenty of safety margin as they will run to 5700 on an intermittent basis with no problems. There is little to be gained by running much over 4800 as the power falls off rapidly over this point. However if you enjoy using the power e.g. racing rush hour traffic, off road competition etc it is useful to be able to run past maximum power so that the engine drops into a more favourable part of the power band on changing up a gear as the spacing between gear ratios on the 4 speed box is large. Regarding oil temperature the red line is around 250 however Mobil 1 will work safely well beyond that . We would keep the 250 as the upper maximum it is very unlikely even desert temperatures will push the temperature this high.


Carburetor SU HS6 Set up for Land rover series Part 1.

In search for the best replacement of original Zenith carb, I found few alternatives, again Internet is helping me a lot. In the spirit of sharing, I would like to share my carburetor set up. I have written: possibly the best carburetor for land rover series few days ago, so I will not cover why I choose SU (skinner union) carb. Here I will explain about the set up, lets start…

Installation is the most complicated one

  1. It requires you to fabricate the manifold / bracket to attach SU carb to your inlet manifold
  2. It needs us to alter the current linkage (to pedal) set up
  3. SU HS6 comes with many type: Left fuel bowl, right fuel bowl, 90* (up right position) and 30* (slightly tilted like in V8 rover)

Those three combination of complexity need us to think, the best placement for the carb. Is it facing to engine, is facing the bulk head or is it facing the radiator fan etc.. Undeterred by this complexity, I go ahead and by second hand SU HS6 and hell broke loose.. :)

Installation: The relatively easy part is buying… I am lucky to get New Old Stock SU HS6 quite cheaply,  so that is good..


Now lets make the manifold / bracket or anything you called to attach the carb to inlet manifold. The easiest way is go to a garage that have access on lathe and ask them to set it up for you. for my case I have to go to two different special garage, one is to make the base (two bases as you can see here: one goes to carb and one goes to manifold) the the other garage (exhaust specialist) to make the connection pipe and set it up in the landy. Here is the manifold ready to be installed.


And finally here is the installed carb… Picture explain better than word.. :)

SU HS6 set up

With this set up I still retain part on the throttle linkage, just in case if I want to change it to zenith again, I still have the parts in there… Hence it installed away from bulkhead and closer to radiator fan. The oil bath filter is still there, although currently it is redundant… but yes you can use the oil bath filter again if you will cross Sahara desert… :)

So that’s all folks… if you have question please ask down below… stay tuned for part two I will talk about setting up the needle, jetting and spring and how it different with Zenith… see you later..

Possibly the best Carburetor for Land Rover Series

The original carburetor is Zenith, and from what I read is the best suited for land rover series. But the Zenith now is on the phase of extinction, the old one is mostly beyond repair, and it will be lucky if you can get new one at decent price. I am trying to order new Zenith from the manufacturer and they said that they produce no more…

So what is the 2nd best option for our pet..? Landy lovers around the world have tried many things with various success, the following brands are frequently mentioned as the best replacement for Zenith and Solex, not in particular order:

  • Rochester BV : for those who live in US seems prefer this option.. you can read it here: http://www.expeditionlandrover.info/landRoverFAQ/FAQ_rochester.htm  from Terry Ann Wakeman one of the land rover guru.
  • Weber : There are few types of Webers: usually 34ICH and 3236 again you can read it here: http://www.expeditionlandrover.info/LRpartNumbers.htm#carbs from terry wakeman site.
  • Skinner Union (SU): The other side of continent, Europe, they seems prefer this option (using SU HS6), a lot of Land rover forum is talking about this type of Carb to replace Zenith or Solex
  • Various Japanesse carbs : I’ve seen few landy  in Indonesia use japaness carbs and it si going OK..

All in all, I think land rover will take any Carb for its heart transplant, but the question is… what is the best carburetor for her.

I have no means of testing each of the brand, but what I can do is searching online, and  read comments about it and asking around in few forums. Now I will give few rating on each of the brand with few attributes (NOTE: this is personal opinion based on reading some online articles or user comments in forums)

Rochester BV Weber 34ICH SU HS6
Availability Difficult Very easy Easy
Easier to install Easy Very easy Difficult
Easier to set up Easy Difficult Very easy
Fuel Economy Good good Very Good
Reliability Very Reliable Reliable Very Reliable

So which one is the best for our landy…

Weber 34ICH, is a good all round carburetor, its plenty and easily available, easy to install etc. But it is more  more susceptible to dirt and water in the fuel and can frequently cause problems if the fuel is not clean and well filtered. Not easy to set up and a bit more sensitive to altitude change.

Rochester BV will be more reliable and easier to set up than Weber, but availability is difficult to obtain and expensive… I was quoted US$ 300 for NOS Rochester BV and the second hand is also quite expensive.

SU HS6, it is very reliable and very simple design, less moving parts hence the reliability. Availability is equal if not better than Rochester BV. Used in many British cars hence second hand are plenty and easier to get… the tricky part is, we need to make some kind of adapter to fit in landy series.

Simple test on the availability, go to ebay and type each type of the carburetor and which one is more readily available.

All in all, if I have access to those threebrands easily, I will say that my choice for the best carburetor for land rover series is SU HS6… I know I simplify a lot of things but that is my conclusion, if you have other opinion.. please write down below.

Second hand well used SU HS6

Will post the set up later