Help with rebuild and tuning my HIF 6 SU

[Nigelpugh7]

Hi Guys,

Could do with some help on the su carbs fitted to my 3.5 v8 in my land rover defender.

I believe they are su HIF 6 units, but might be wrong.

After fitting a new distributor and plugs and leads etc the v8 is still running rough with a misfire, and keeps flooding with fuel coming out of the float overflow pipes.

I would like to buy some rebuild kits for the carbs as the jets and needles seem well worn.

Could someone give me advice on what needles I would need for these carbs please?

At the moment it is fitted with BGC needles but these seem very rich.

Thanks in advance.

Nigel.

[DaveEFI]

First thing to do is sort the flooding and get the fuel level in the float chamber correct, as this effects the overall fuelling.

[Nigelpugh7]

First thing to do is sort the flooding and get the fuel level in the float chamber correct, as this effects the overall fuelling.

Thanks Dave,

Should I just disassemble the carb and float unit, and reset back to std settings as per my Haynes su carb manual?

The previous owner did not know anything about v8 engines and I suspect he had been messing with the mixture levels.

What should l be looking for that might be causing the flooding?

Do you think I should get some new floats on order too?

[kiwicar]

Hi
If the engine is stock then stock needles and set up is the best place to start.
Flooding is often just a worn out float needle, or a float that has become puntured and full of petrol (and no longer floats )
If you suspect you have had a prize fiddler the return everything to stock, check especially the needle mounting into the piston, check it is in the correct indent, get the jets to the right starting point (haynes procedure) If it has the poppet valves (over run valves) on the throttle plates then cut them off the springs and solder then shut, the things are a pain and will not be working now anyway. Once rebuilt and cleaned (including the linkages) check the pistons are free to rise (engine off) correctly (MK 1 finger here) and ballance the 2 carbs. Now start up and check they will rise on the throttle and that they reach the top of their travel about 5200 5400 revs once this is done it is just a case of tweeking it in on the main jet.
Best regards
Mike

[DaveEFI]

First thing to do is sort the flooding and get the fuel level in the float chamber correct, as this effects the overall fuelling.

Thanks Dave,

Should I just disassemble the carb and float unit, and reset back to std settings as per my Haynes su carb manual?

The previous owner did not know anything about v8 engines and I suspect he had been messing with the mixture levels.

What should l be looking for that might be causing the flooding?

Do you think I should get some new floats on order too?

V-8 SU carbs are no different to Mini ones, in principle.

Where there are signs of flooding, I'd replace the valves regardless. The floats should be checked for signs of damage or leaks. And the fuel level set as per the manual.

[Nigelpugh7]

Hi
If the engine is stock then stock needles and set up is the best place to start.
Flooding is often just a worn out float needle, or a float that has become puntured and full of petrol (and no longer floats )
If you suspect you have had a prize fiddler the return everything to stock, check especially the needle mounting into the piston, check it is in the correct indent, get the jets to the right starting point (haynes procedure) If it has the poppet valves (over run valves) on the throttle plates then cut them off the springs and solder then shut, the things are a pain and will not be working now anyway. Once rebuilt and cleaned (including the linkages) check the pistons are free to rise (engine off) correctly (MK 1 finger here) and ballance the 2 carbs. Now start up and check they will rise on the throttle and that they reach the top of their travel about 5200 5400 revs once this is done it is just a case of tweeking it in on the main jet.
Best regards
Mike

Thanks Mike,

I will follow all of your advice later today, when I can get to the Landy.

The real problem with my defender and the engine is we don't know what the engine came out of, as its not a standard v8 defender more a conversion at some time in its life.

We believe the engine is a rover p6 engine, looking at the rocker covers, but it could have been from anything.

I have tried to look at the engine number, but it's too hard to read, will try again later and then hopefully cross reference the v8 to a vehicle using the references on sites like Rimmer brothers.

Also we know the carbs are HIF, but don't know what type as the ident tangs are broken off.

When I changed the distributor this week the old one had a date on it of 1976, but that could have been the dissy and not the engine.

The other annoying thing about this v8 is it has the detox, emision pipes fitted to it. I think it will be best to just blank them off, do you agree?

[kiwicar]

Hi
Could it be an ex military engine? out of a wolf/101fc 109 ambulance? easy way to tell is is it painted snot green?
Does not make a huge differanc as to what you do though, certainly not to start with check for fault around the float area, fix them (as Dave says replace the float valves new ones are always better than old) and get it set up as standad as a starting point.
I would dump the emisions stuff as it is junk anyway, it would be a good idea to try and find out exactly what it is because some of the variants are in a very low state of tune.
Best of luck
Mike

[Quagmire]

I believe that the older P6 era engines have the engine number on the rear of the block where it meets the bellhousing (my first engine purchase was like this), the later ones have the number on the top of the block face on the passenger side near the dip stick, where is yours?

Once you get the number you will be able to find out exactly what it is

[DaveEFI]

Assuming it is a complete engine, P6 used points in the dizzy, SD1 electronic.

[Nigelpugh7]

Hi
Could it be an ex military engine? out of a wolf/101fc 109 ambulance? easy way to tell is is it painted snot green?
Does not make a huge differanc as to what you do though, certainly not to start with check for fault around the float area, fix them (as Dave says replace the float valves new ones are always better than old) and get it set up as standad as a starting point.
I would dump the emisions stuff as it is junk anyway, it would be a good idea to try and find out exactly what it is because some of the variants are in a very low state of tune.
Best of luck
Mike

Thanks Mike, I will look at doing that.

It's not painted snot green though, so I don't think it's out of a 109!

Will definitely dump the detox stuff too!

[Nigelpugh7]

I believe that the older P6 era engines have the engine number on the rear of the block where it meets the bellhousing (my first engine purchase was like this), the later ones have the number on the top of the block face on the passenger side near the dip stick, where is yours?

Once you get the number you will be able to find out exactly what it is

Yes this engine does have it on the top of the block by the dipstick.

When I get it cleaned will check the number.

[Nigelpugh7]

Assuming it is a complete engine, P6 used points in the dizzy, SD1 electronic.

Thanks Dave,

Well the dizzy I took out was electronic, but I can't guarantee that it was the one the came with the engine.

One other thing i notice that I have not seen before is that it has the normal temp sender location by the water manifold where the thermostat housing is, but it also has another temp sender by the top of the intake by the centre of the inlet manifold too.

Don't know if that is significant at all?

[harvey]

One other thing i notice that I have not seen before is that it has the normal temp sender location by the water manifold where the thermostat housing is, but it also has another temp sender by the top of the intake by the centre of the inlet manifold too.

Don't know if that is significant at all?

If the extra sensor is retained by 3 small bolts it's an Otter switch for a choke warning light, which if the HIF6's are the original fitment would make the engine from a P6B. Engine number would confirm that.

[Nigelpugh7]

One other thing i notice that I have not seen before is that it has the normal temp sender location by the water manifold where the thermostat housing is, but it also has another temp sender by the top of the intake by the centre of the inlet manifold too.

Don't know if that is significant at all?

If the extra sensor is retained by 3 small bolts it's an Otter switch for a choke warning light, which if the HIF6's are the original fitment would make the engine from a P6B. Engine number would confirm that.

Thanks Harvey,

I have managed to get to the number on the engine now.

It is a 15DxxxxxA , which from the Rimmer bros website tells me it's a range rover 1981-1985 , carb pulsair.

Good news I guess as it is also a 9:35 to 1 compression ratio and from a similar year as the defender it is now fitted in too!

Does that also help me to identify what needles and jets I will need for the su carb rebuild kits?

[Nigelpugh7]

Guys,

A quick update for you.

I looked at the costs to service the su carbs, and in the end went for a brand new pair of HIF 6 carbs that were on eBay, ready jetted for a range rover.

I have now fitted these, and the engine runs lots better, just need to spend some time now tuning them and getting the co correct.

I have also fitted a new dissy, as the old one had a broken vacuum, this has also helped with the running improvements.

I will keep you posted.

Thanks for the help and advice so far.

Nige.