18 replies to this topic

[rasputin22]

Model: very standard metro, i'm afraid, except the air filter is not currently attached. (For autograssing). Blocked off the crankcase breather on the carb and there is no vacuum for the dizzy and again this tap has been blocked off.

998 engine, factory standard high compression
Year: 1989ish

Description of problem 1:
The carb is a HIF38, obviously, with a rubber pipe going from just next to the fuel inlet to just before the the carb meets the manifold spacer. Think its for some sort of lean off device??? Can this be removed??

Now i have taken it apart to make sure there was not much grit/dirt on the inside and clean out the inlet filter. I'm sure i put it back together ok as i have a little experience on a hif44 and they are very similar, except this lean off device thing.

Right, tried starting it after rewiring the car and it was difficult to start. Only managed to get it to start if i lifted the carbs piston. Once my finger was taken away it stalled. Tried this a few times to the same result.

Looking at the exhaust there was quite a bit of black smoke coming out, not clouds as though oil was the problem.

Once i got the engine to idle by screwing in the idle speed adjustment screw on the throttle spindle i played with the piston again. I could lift it quite away, the revs would increase and the engine sounded alot better. To me this sounds like its running dead rich????

Anyone know what i am missing???

Description of problem 2:
On the distributor, where the vacuum goes to, i tried sucking on it and i was getting a constant suck of air, not as i would expect it getting harder and harder to suck. Now i guess the diaphragm is past its best.

I have spare dizzies, but not sure what off. Does it matter if i fit another one on to the current dizzy or are there different rates of vacuum??

I was thinking of leaving the vacuum completely off as people do and run it as a staic advance. So does anyone know what advance to have???

Any help would be greatly recieved

Ryan

[rasputin22]

Had another look at it today and got it running a little better.

The worst thing now is back firing through the carb when the throttle is depressed and there isn't much power when driving.

I'm not overly convinced on the quality of the petro, may have been stood for a while, could this be the major factor??

[rasputin22]

Right i have used fresh petrol and its still backfiring, everytime i add/blip the throttle i get a backfire thorugh the carb and there is still not much power.

At the moment i am finding that the engine is running better with an airleak. Plus when i took the spark plugs out they were really black and sooty. So this is overfueling right???

I've tried adjusting the idle mixture to no avail, it doesn't seem to change anything at the moment.

I've tried adjusting the timing to no avail.

I have shortened the exhaust by removing the backbox and having the exhaust come out just before the rear wheel so may have less back pressure and there is no airfilter on it at the moment as i'm trying to get it setup correctly.

The needle is currently an ASD if that means anything to anyone which i'm guessing is a std needle for a 998 hif but not 100%

Any help would be great please

[Grayedout]

Confused. The pipe next to the fuel inlet as far as I know is the fuel overflow which should just be piped to the floor and not to a vacuum feed which it sounds like you have !

What happens if you feed the overflow to the floor and then just block the vacuum for now?

Also had a look in my very long list of needles and can't find an ASD listed so afraid can't help with that one. An AAA or AAU might be a good start for a Class 1.

Edited by Grayedout, 01 July 2009 - 09:39 PM.

[rasputin22]

Not an ADS, may have been a ASD then, oops.

I have ordered an AAU needle so hopefully the fueling should be about right.

In the pictures i have the top carb and i've figured out i have connected it up wrong according to this feed.

http://www.theminifo...x...01&hl=hif38

Thanks for the help, will try this.

[Grayedout]

Be worth getting it on a rolling road !!! In Class 1 you need every horse you can get !!!!

[rasputin22]

Thats very true, at least i don't have the power sapping rad fan attached to the water pump though, but i do have the extra body weight. Should be fun to see how i comare against mini's.

[rasputin22]

Been looking into this some more and have seen opposing evidence with the lean off pipe. Is anyone out there currently using a hif38 with a lean off pipe and knows
exaclty where does it go.

The things i have seen so far is:-

previous topic with lean off at top outlet
http://www.theminifo...x...01&hl=hif38

ebay with lean off to top outlet, granted its a 44 but surely works the same

http://cgi.ebay.co.u...n...3A1|294:200

with lean off tapped next to fuel in

http://cgi.ebay.co.u...O...3A1|294:200

As you can see they contradict each other. I have also seen the haynes manual with the overflow filter at the top so the pipe must go next to the fuel in.

I haven't been to my car to try changing it, just after some confirmation. I'm trying to do some research at the moment and have ordered a different needle.

Edited by rasputin22, 04 July 2009 - 09:34 PM.

[bmcecosse]

You should keep the vacuum advance - just use one from another dizzy as long as it will hold a vacuum! Yes - there are slightly different specs - but it won't matter in this case. And yes - block off the weakening device!
You may want to consider weakening the spring inside the carb - to make SURE the piston rises right up, and use the thinnest of oil (3 in 1) in the dashpot. You may want to try it without the dashpot damper fitted - my old Sprint Mini when running in the 'single carb' class ran best like this. It would have been hopeless on the road - but was great on the track!

Edited by bmcecosse, 04 July 2009 - 09:40 PM.

[Ethel]

The weakening device only operates on part throttle ( it feeds some manifold vacuum to the float chamber to work), Hifs have a separate choke so if it's over fueling it could be that, especially if pulling the choke out has little or no effect.

[minipac]

hi rasputin have you got a rule book for class 1. because as for as i know your not allowed to use a hif38. class 1's use the hs4 with an aau needle. you are best to ask your league Scrutineer before spending to much money on this one

[rasputin22]

The rules state:-

Cars must be of a model originally fitted with 1 only single choke carburettor, max 2 valves per cylinder, with engines of up to 1000cc front wheel drive or 1100cc-rear wheel drive. No Cooper S, GT., Rallies, Sports, Special Editions, Or engine parts permitted etc:

No modifications to engines permitted except as listed.

Production drivers please note: -all cars must be as were produced by the manufacturers, except for permitted modifications.

If a driver refuses to allow SEGTO to fit a ECU they will be deemed illegal.

If not stated that it can be done then it cannot be done.

1. 60 thou (0.060") maximum overbore permitted and any other renewal or replacement of worn components.

2. No reprofiled or remanufactured camshafts, manufacturers original or manufacturers replacement ½" wide lobe, 3/8" lobe cam is allowed but must be within the manufacturers tolerances. Camshaft Nos 6267 or 4717 are permitted. 4717 can be identified by 1 ring between lobes of cylinder no 3, 6267 can be identified by 1 or 2 ring between lobes of cylinder no 2. Other vehicle camshafts will be checked against manufacturer's Technical Data.

3. Manufacturers dowel or woodruff keys must be fitted as standard.

4. Engine balancing is permitted, No machining of pistons except for balancing purposes and this can only be carried out on the inside surface of pistons, and they must not protrude above block face, but some manufacturers have pistons that protrude as standard, so particular vehicles will be checked on their merit, according to manufacturers tolerances, for that specific vehicle. One piston and one con rod must remain as standard. Competition pistons are not permitted.

5. No centre main crankshaft straps.

6. When closed the valve head must protrude into the combustion chamber and not be recessed.

7. Valve springs must remain standard to the engine used.

8. No matching or machining of carb to inlet or manifold to block. Inlet and exhaust manifold must remain as standard.

9. Head numbers 12A 1456 2A 629 Minis or "A Plus" CAM 4810. Cylinder heads may be skimmed, but no modification to oil ways. Lead free inserts & 3 angled valve seats may be used.

10. Oil pump pick-ups may be relocated, sumps may be baffled.

11. BL "A+" 1000cc engines or running gear are permitted. Crank, rods & pistons must remain as standard to block.

12. No "S" type distributors on BL."A" series and A+ engines. Distributor must remain as standard to the engine used, and fitted with a vacuum capable of working..

13. Electronic ignition permitted if fitted as standard. A+1000cc camshafts, heads and springs may be interchanged with A series 1000cc or vice versa.

14. Fitting of dynamo/alternator optional.

15. No duplex timing chains.

16. Air filters free. No ram pipes, air scoops, turbo nor any other forced induction.

17. Carburettor butterfly must not be modified or removed.

18. All cars must retain original carburetion. 1½" maximum. S.U. Needles must remain round.

19. No twin specialist carburettors

20. Casting and or forging marks must remain


So i think i'm in the clear with that one

[minipac]

The rules state:-

Cars must be of a model originally fitted with 1 only single choke carburettor, max 2 valves per cylinder, with engines of up to 1000cc front wheel drive or 1100cc-rear wheel drive. No Cooper S, GT., Rallies, Sports, Special Editions, Or engine parts permitted etc:

No modifications to engines permitted except as listed.

Production drivers please note: -all cars must be as were produced by the manufacturers, except for permitted modifications.

If a driver refuses to allow SEGTO to fit a ECU they will be deemed illegal.

If not stated that it can be done then it cannot be done.

1. 60 thou (0.060") maximum overbore permitted and any other renewal or replacement of worn components.

2. No reprofiled or remanufactured camshafts, manufacturers original or manufacturers replacement ½" wide lobe, 3/8" lobe cam is allowed but must be within the manufacturers tolerances. Camshaft Nos 6267 or 4717 are permitted. 4717 can be identified by 1 ring between lobes of cylinder no 3, 6267 can be identified by 1 or 2 ring between lobes of cylinder no 2. Other vehicle camshafts will be checked against manufacturer's Technical Data.

3. Manufacturers dowel or woodruff keys must be fitted as standard.

4. Engine balancing is permitted, No machining of pistons except for balancing purposes and this can only be carried out on the inside surface of pistons, and they must not protrude above block face, but some manufacturers have pistons that protrude as standard, so particular vehicles will be checked on their merit, according to manufacturers tolerances, for that specific vehicle. One piston and one con rod must remain as standard. Competition pistons are not permitted.

5. No centre main crankshaft straps.

6. When closed the valve head must protrude into the combustion chamber and not be recessed.

7. Valve springs must remain standard to the engine used.

8. No matching or machining of carb to inlet or manifold to block. Inlet and exhaust manifold must remain as standard.

9. Head numbers 12A 1456 2A 629 Minis or "A Plus" CAM 4810. Cylinder heads may be skimmed, but no modification to oil ways. Lead free inserts & 3 angled valve seats may be used.

10. Oil pump pick-ups may be relocated, sumps may be baffled.

11. BL "A+" 1000cc engines or running gear are permitted. Crank, rods & pistons must remain as standard to block.

12. No "S" type distributors on BL."A" series and A+ engines. Distributor must remain as standard to the engine used, and fitted with a vacuum capable of working..

13. Electronic ignition permitted if fitted as standard. A+1000cc camshafts, heads and springs may be interchanged with A series 1000cc or vice versa.

14. Fitting of dynamo/alternator optional.

15. No duplex timing chains.

16. Air filters free. No ram pipes, air scoops, turbo nor any other forced induction.

17. Carburettor butterfly must not be modified or removed.

18. All cars must retain original carburetion. 1½" maximum. S.U. Needles must remain round.

19. No twin specialist carburettors

20. Casting and or forging marks must remain


So i think i'm in the clear with that one

hi you did say you race autograss. as class 1 is as follows.
mini 998 leyland/austin rover/rover
it is not permitted to use or convert an 850cc or 1100cc or 1298cc engine to 998cc
you can also use the citroen ax 954cc or the fait cinquecento 899cc
and i think this year they are testing the peugeot.
class 1 is front wheel drive only.
as for as i can remember the last rear wheeled car the was allow to run in class 1 was a imp 848cc i think but thats going back some years.
as for carb rule book states
type number and size is restricted
the standard production carburettor must be retained in its standard production form.
modification to carburettor prohibited.
the carburettor must be fitted with a throttle return spring.
carburettor needle - free.
i have raced in autograss for about 6yrs and have done class2 for 1yr class1 for 3yrs and the last 2yrs class4.
and have built all my own cars.

[Ethel]

The weakening device links into the float vent so you may see various arrangements. With the device there's a small orifice (great word ) in the lower (vent) pipe so when the weakening thing is providing vacuum it doesn't quite keep up at letting air in and the pressure in the float chamber is reduced. Without the leaning device either of the vent pipe locations can be used.

[rasputin22]

mini pac - i was going by segto rules http://www.standlake...orules_2009.htm and didn't see any mention on carb types, although i think i have heard/read it has to be only 1 1/2 inch wide carb and no mods. When i've finished building it, haven't started racing yet, i'll be sure to get it scrutineered by a member proir to racing to make sure all is ok.


Ethel - right i think i get a basic understanding of it, thank you. I will have another look when i take it apart again and see if it all becomes clearer. I can just block these off though right, as i doubt i'll be needing it to lean off at any point, lol.