Conversion to Carb

kimwan · **Joined:** Sat Apr 25, 2009 11:07 am **Posts:** 25

Hi Guys,

I am converting my engine to carburetor.

Pl advise -

1/ what are the PARTS that need to be changed.

2/ what are the Step by Step Process of the
conversion to be done by the mechanic to
perform the BYPASS?

3/ what will be the estimated cost of Parts and
Labour?

Currently an SU HS4 + Manifold has been installed but engine could not run properly and the next step is to change the DISTRIBUTOR.

I am worried that once I take back the car and the complete conversion has not be done, car will troubleshoot again.

Tks

RedBaron · **Joined:** Fri Jul 25, 2008 5:27 pm **Posts:** 35

kimwan,

has your mechanic not finished your conversion yet? i thot that you started this more than 4 weeks ago!!!

anyhow, this is my account of my spi to carb conversion experience
1. kept the spi fuel tank
2. prepared a Y joint for the fuel return, as the pressure of the injection petrol pump is too great for SU carbs
3. spi removed
4. carb and manifold installed
5. dizzy changed
6. kept all the original wiring of the spi intact for the moment, in case wanted to revert back to spi. (now all traces of spi wiring removed)
7. bob's your uncle, conversion completed

I hope that this will help. This was my experience. and I never looked back, after the conversion to carb...

rB

kimwan · **Joined:** Sat Apr 25, 2009 11:07 am **Posts:** 25

Hi RB,

Just curious why you converted to carb?
Are you also having fuel injection troubleshoots like mine?

You kept the spi wiring and later decided to remove it so I conclude that carb is a smoother experience than spi in terms of maintenance and less problems?

Keeping the spi fuel tank does not cause you problems so far?

When we buy carb, does it mean together with manifold as as set or have to buy seperately?

Is it necessary to to change both carb and manifold for conversion?

What's a dizzy? Is it the distributor?

What's SPI? Is it necessary to remove the spi or I heard my mechanic says have to 'cut off' the spi but do not know what he means...

Asking you these questions so I can understand when I communicate with the mechanic who seems to want to just convert without having to go through the whole process and doing minimum work by just changing carb with manifold and distributor only. He is reluctant to have to work on the cramped engine compartment and have to modify here and there to fit in the distributor.

I shall have to convince him to work on the Y joint as well. He seems to think that as long as the car runs and does not stop, should be ok but in my case, scared of further troubleshooting and have to resend back to him to diagnose and repair with no end in sight...

Thanks for sharing RB

RedBaron · **Joined:** Fri Jul 25, 2008 5:27 pm **Posts:** 35

Quote:

Hi RB,

1. Just curious why you converted to carb?
Are you also having fuel injection troubleshoots like mine?

2. You kept the spi wiring and later decided to remove it so I conclude that carb is a smoother experience than spi in terms of maintenance and less problems?

3. Keeping the spi fuel tank does not cause you problems so far?

4. When we buy carb, does it mean together with manifold as as set or have to buy seperately?

5. Is it necessary to to change both carb and manifold for conversion?

6. What's a dizzy? Is it the distributor?

7. What's SPI? Is it necessary to remove the spi or I heard my mechanic says have to 'cut off' the spi but do not know what he means...

Asking you these questions so I can understand when I communicate with the mechanic who seems to want to just convert without having to go through the whole process and doing minimum work by just changing carb with manifold and distributor only. He is reluctant to have to work on the cramped engine compartment and have to modify here and there to fit in the distributor.

8 I shall have to convince him to work on the Y joint as well. He seems to think that as long as the car runs and does not stop, should be ok but in my case, scared of further troubleshooting and have to resend back to him to diagnose and repair with no end in sight...

Thanks for sharing RB

Kimwan,

I will try my best to answer you, however, I must stress that this is from my experience of my conversion and I do not profess that it is the best, but it worked for me. And I will have to live with my choices.

1. My reasons for converting to a CARB system was that I was not getting enough fueling from the SPI system, ie my Air/Fuel Mixture was not sufficient for my setup

2. I decided finally to have the sections of the SPI part of the wiring loom removed, because it was too untidy in the engine bay.

3. Keeping the injection tank has not caused any problem for me thus far. As I have the Y joint for the return to the petrol tank.

4. Buying a CARB does not necessarily come with a manifold. The manifold is required, as it is the only way for the carb to be attached to the cylinder head.

5. Yes

6. Dizzy is short for distributor

7. SPI = single point injection

8. I believe that the Y joint is necessary, the injection system petrol pump has much higher pressures than the carb fuel pump. Thus WITHOUT a petrol return which is facilitated by the Y joint, the fueling pressure will be too high for the CARB,

I hope that this helps.

rB

kimwan · **Joined:** Sat Apr 25, 2009 11:07 am **Posts:** 25

Hi RB,

Thanks so much for your simple and clear explanations.
I have been from confused uplifted to clarity.

Now I know, that for a complete bypass from spi to carb conversion I must at least do 3 things -

1/ Fix carb w manifold
2/ Fix Distributor compatible to the carb system
3/ Get a Y Joint fixed

With the 3 steps above I should be able to enjoy a smooth carb system up and running and once confirmed I am ok with the carb sys I can get the mechanic to remove the unsightly spi wiring.

Just beats me why a long experienced mechanic is not familiar w conversion:(

Fortunately I hve you good samaritans to offer so much useful guidance.

Thanks again fren

fatboy_my · **Joined:** Thu Jul 10, 2008 10:58 pm **Posts:** 209

Kimwan,

Just be aware that RB's system was done by a competent mechanic. Not some under 'pokok chery' type mechanic. An improper conversion to this system can result in damaged carburettor internals.

A safer route to take is to find a proper carburettor fuel tank and carburettor based electric fuel pump. This minimises the risk of something going wrong.

Most mechanics just want to get it running but do not solve the actual problem. Doing something wrong repeatedly does not make it right or be counted as experienced.

Good Luck.

Cheers

kimwan · **Joined:** Sat Apr 25, 2009 11:07 am **Posts:** 25

Hi DD,

Thanks so much, for the tip I am really scared of further trouble shooting that's why I have no option but to convert to carb at 1K+ but now due to not understanding the mechanics involved, I am now victim of possibly having to pay more....and not having assurance that all is ok...

Sigh, my quote for parts of carb kit is Rm750/- from 1/2 cut and labour at 350/- so I tot in a week or two I will enjoy a trouble free car.

Now 4-5 weeks have passed and mechanic told me he bought a new manifold while I tot complete kit supplied at agreed price for a bypass to be done being carb + distributor + Y joint

Now I have to contend with carb compatible fuel tank and fuel pump and who knows perhaps more and if not done, scared of further damage to carb which could be worse off than my Fuel Injection trouble earlier experienced.

Sigh, what a rollercoaster Mini journey for me but I am thankful for all you guys giving me advice to make my journey smoother.

Salute and thank you


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