Changing Carberettor

[spacebass]

I want to change the carb on my Suzuki Jeep from stock to an SU , (I know there are others) the recommended size is 1 3/4" Called an HIF44 but as you have to fabricate a manifold adaptor anyway what would be the effect of fitting an 1 1/2" or 2" model instead? would the 2" cause big increase in petrol consumption?

[Thetyim]

When you increase the carb size you will get a better top end a slightly poorer bottom end.

Fuel comsumption will depend on the jetting you use.

[Bung]

You would want to be carefull here, you could end up with a pig.

As said jetting is important and you shoud fit extractors and a free flowing exhaust to get the most out of it.

I would look around on the internet, (try google) Those old jeeps are pretty popular and there will be something about doing that sort of thing and probably somewhere to buy everything as well.

I knew someone who put a mazda rotary engine in one, it really flew!

Let us know how you get on

[spacebass]

You would want to be carefull here, you could end up with a pig.

As said jetting is important and you shoud fit extractors and a free flowing exhaust to get the most out of it.

I would look around on the internet, (try google) Those old jeeps are pretty popular and there will be something about doing that sort of thing and probably somewhere to buy everything as well.

I knew someone who put a mazda rotary engine in one, it really flew!

Let us know how you get on

Dear Bung and Thetyim,

Thanks for your help, I have looked all over the web and am now looking at Ebay to buy in England and bring back to Thailand where I am now. I know how to do it, (least I can show someone who has skills in that area!!).

There are Five carbs talked about weber 32/36 and others, SUs HIF44 and HS6 all these need manifold adaptors, then there is the Nikki (from VW) and Diatsu Charade and Hyundai Pony that bolt on.

Reading all the bumpf I have come to the conclusion I will put on an SU because thay are the most plentiful on ebay and actually the best when you get them on.

I only want the engine to work efficiently and some mpg, as I believe all these carbs achieve. Not any mind boggling performance (Suzuki Jeep?).

But when I get on Ebay there are many cheap 1.5inch SUs which basically come off a mini, MGs etc some quite big 1275cc similar to Suzuki which is 1298cc, and there is at the moment a 2" said to be from a Jag.

My question is a simple one and that is although a 1.75" is ultimate would I actually know any difference pottering round Pattaya and occasional jaunts to Rayong on motorway if I fitted a 1.5" or for that matter a 2" SU all other things being equal. Minis after all have been fitted with both 1.75" and 1.5" models.

The other thing is of course what is the breakers yard story in Thailand, anyone know what happens there? Is there one in Pattaya? If there was this might move interest to Diatsu or Hyundai.

[Thetyim]

Finding the right size jets here in LOS may be a problem.

I think you are right to go for an SU.

SU's are good for economy, have an adjustable jet and no diaphagms to split. If the dashpot is worn you can work around it by using a thicker oil until the parts arrive.

[highonthai]

Jet, jet, jet!

People often go right ahead and spend $500 for a carburetor, bolt it on, and seem "pleased" with the results. Others are upset by a backfiring, or smoke belching monster. In either case, spending the time to properly jet a carburetor is a very worthwhile task, since recieving a "perfect out-of-the-box" carburetor is one of the biggest myths in the Business.

In addition, proper jetting is different depending on the size engine, elevation, cam overlap, etc. I have even seen the SAME engine combination require different jetting (same carb) on two different engines! So, for someone to say "this is what you need" is ridiculous. They can get you CLOSE, but not exact. To get exact you need to spend time and patience, and dial it in.

Why Jet? If it's too rich, the extra fuel will wash the fuel off your cylinders and wear out your pistons, cylinders, and rings quickly (no oil), in addition to building up deposits on your valves, heads, and piston tops. If it's too lean, the engine will run very hot, misfire, and can eventually lead to a burnt valve(s).

Here is a link to a suzuki BBS lot of good info for you. http://www.pirate4x4.com/forum/archive/ind.../f-13-p-23.html

[spacebass]

thanks hionthai for your input which will come in handy , once i know: whether a 1.5" and 1.75" SU carberretor are interchangeable on a 1298cc suzuki engine, given they are both used on mini engines which must be similar to each other.

Thanks again

[mraitchison]

DO you really want to go much faster in one of those Suzuki jeeps?

Is it and SJ413 Samurai or SJ410 Santana - the old tip overs.

[Gary A]

What's wrong with the Suzuki OEM carburetor? The engine and the original were obviously designed for each other. I wouldn't want to try to outguess the Japanese engineers. Bigger carburetors will only give better performance if the engine has been altered.

[spacebass]

for the benefit of mraitchson I quote a line from earlier in the thread that he obviously hasn't read:

I only want the engine to work efficiently and some mpg, as I believe all these carbs achieve. Not any mind boggling performance (Suzuki Jeep?).

And Gary it is indeed odd that suzuki engineers who are generally held in high esteem have put such a dog carb on this jeep in Europe and Asia but it is in general regarded as such on the various suzuki boards (the aisan carbs that is, in the U.S. they used a Hitachi carb which seems OK) apparently changing it makes the vehicle feel much nicer, improves MPG and solves many potential idling / tickover problems, bigger is not the name of the game, the question stems from the availablity of sustitute carbs in slightly different sizes as yet no one has answered the question I have asked regarding this and some seem not to have even read it.

[mraitchison]

Woops

There should be a compulsory summary of every thread so I don't miss things.

The ex used to have one of these in the UK. Shit MPG and terrible iddling - must be what you are talking about.

I know a local has one here witha diesel engine fitted to it but not sure what size.

If you wanted to improve its mpg etc wouldnt a diesel engine transplant be cheap enough?

[Gary A]

It is apparently not a simple thing to convert the drive train to diesel power. It's a matter of getting the transmission and transfer case to work with a different engine. A company in the USA offers a kit to change to a Volkswagen diesel but it is expensive, must be imported and the Volkswagen diesel is scarce here if available at all.

Woops

There should be a compulsory summary of every thread so I don't miss things.

The ex used to have one of these in the UK. Shit MPG and terrible iddling - must be what you are talking about.

I know a local has one here witha diesel engine fitted to it but not sure what size.

If you wanted to improve its mpg etc wouldnt a diesel engine transplant be cheap enough?