Engine running problems

[53buick]

Hi All,
Well after a few (quite a few)issues I have at last got the purple moggy running but...........only just.

So, never had this engine running, it is made up of bits of lots of engines so what I know is listed below:-

1275cc austin 1300 engine bored out by 60thou to 1330cc
266 Cam fitted
Rods and crank balanced.
Head stock apart from being fully reconditioned (new guides etc).
MG Metro heated inlet manifold (with vacuum pipe blanked off)
HIF38 carb fitted with all the vizard mods including the air bypass modification to the body set up for a race 998 (AAF needle).
K&N filter and ram pipe.
3-1 manifold (1.5" pipe)
Free flowing exhaust (1.5" pipe all the way through.
Electronic ignition distributor (full recon with bearings fitted and set up for a hot 1275 profile)

So, the problem is this:-
I start the engine, it revs up to around 2000rpm for 4 seconds and then dies.
With the choke on full the engine will run at 3000rpm happily but when the choke is pushed in slowly the revs go down to around 2000rpm and then it dies.

I have set the ignition up by ear, advancing until she is reving the highest and then back it off.
Air mixture screw is very touchy, not much tolerance and she wont run at all.

I have thought the carb being set up for a race 998 would make this engine run ok but sluggish but I cant get it to tick over...
Any clues?
Cheers,
Spence

[bmcecosse]

It depends what has been done to the carb - 'racing' modifications are entirely unsuitable for road use - Vizard warns about this. The carb is also too small for your engine - you really need an HIF44, (and so would a 'racing 998!) but that shouldn't stop it running nicely at the moment. The AAF needle is FAR too weak - I seriously doubt it's for a 'racing' engine........ You need an AAA needle as a starting point - but much better with an HIF44 with a BDL needle.

[53buick]

Fantastic response, that is what I thought but would it give the symptoms I am experiencing?

[bmcecosse]

As above -depends what has been done to that carb - if the bridge has been 'airflowed' then that makes it very non-road friendly! And if the throttle plate has been thinned down too much - it may not be sealing off properly hence the high idle speed.

[53buick]

Ok, I have got an HIF44 carb and I am about to clean it thoroughly and I will give that a go, it is stock so it should be a good starting point!
cheers for your help.
;)

[bmcecosse]

Should be fine! What needle is in it ?

[53buick]

cannot tell you as the carb just fell apart, I thought it just needed a clean but on reflection I think it must have been in "davy jones locker" with extra salt in it for good measure...
so, looking for a carb again. ;(

[53buick]

Been thinking about this and my thoughts are:-
The HIF38 is used on the stock 1275.
Mine may be 1330 and cammed but looking at the needle profiles there is not much difference in the first sector which could be idle.
So...... in theory my engine should run fine but then struggle pulling the revs above 3k?
I went back out just now, started the engine on full choke (smelt mega rich which is expected).
Once the engine was circulating warm water I let go the choke and the engine runs lumpy as a bag of nails.
I adjust the mixture screw right in (no difference) right out (no difference until the last turn when it dies).
So, we have another problem I think.

Because this engine is a hybrid of about 4 engines I am almost reluctant to keep chucking money at it and I think I need to borrow a carb to isolate that area.

So, anyone near the forest of dean that can help me out with a stock HIF38 or 44 to borrow just so I can isolate the carb as the problem?
Cheers,
Spence

[bmcecosse]

The needle is very weak - and the so called 'racing modifications' may have ruined it. Can you describe exactly what has been modified on the carb ?

[53buick]

the needle is an AAL.
he has drilled a hole by the top right (looking into the inlet side of the carb) fixing hole to the inlet and fitted what looks like a jet with a 1mm hole (approx).
there is a hole drilled down into the carb next to this (1mm again) and then there is a hole going into the inlet from the carb body the same size approx.
He has crimped off the breather pipe.
the butterfly has been profiled.
the piston has been tapered.
Ram-pipe fitted and a K&N filter.

there may be other modifications I am not privy too.....

Sold to me as a high performance carb modified to "Vizzard" spec for a 998 as I was going to fit this to the 1100 prior to the 1275 purchase.

Anything else I can do to to try and isolate the problem is very much appreciated.
Cheers,
Spence

[bmcecosse]

Well - the hole drilling etc may be part of a 'weakening' device - it's certainly NOT a Vizard thing. The others are fair enough - but if the throttle plate is not right that will explain the high idle, and if the piston has been 'tapered' (??) - then I don't know what that's about - it should be nicely rounded off on the leading edge, and of course the inlet to the carb should be filed to a nice radius. You NEED that side breather tube - so crimping it is the most stupid thing in the world......try to rescue it if you can...... .and the AAL (you said AAF before ??) is still too weak........ You want an AAA.

[53buick]

Hi,
Sorry about that, AAF it is, snow blind from googling HIF38 I think!!!!!

I have un-crimped the breather and taken all the silicone sealant out of it!!!!
It doesn't seem to be running much better but it is idling (if you can call it that) lower around 1500 rpm now but lumpy and hunting,.
doesn't respond to the throttle well at all.
I think I am going around in circles here so off to look for another carb, it has to be that, I cant think it is anything else as this HIF38 has been messed with so much.

[Neil MG]

Sounds like it may also be the distributor. A lot of these recon. units are absolute rubbish! If the advance/retard isn't working properly the engine will not run well.

If the carb doesn't fix it....

[bmcecosse]

Does the carb have a spring on top of the piston?

[53buick]

OH HAPPYY DAAYySSS!!!!!!!!!!!!!!!!

Guess what.......
I remembered that 2 years ago I gave a load of Rover V8 stuff away to a mate so I recalled the favour.
He had 2 HIF44 carbs in bits ina bucket where he had stripped them down to use the throttle bodies for an LPG conversion on a 4x4....
So, that never happened so he gave the bits back.
I managed to re-assemble the bits to resemble a carb, chucked it on the car and.......... it runs bloody lovely!
A bit rich needless to say but that was to be expected.
So, now I have finished the exhaust system (including making my own silencer and manifold) and got her starting on the button.
So, next job is an air filter (the HIF38 one I have wont fit now!) and a new needle me thinks......
Cheers for all the help so far btw, invaluable!!!!!!!!

[bmcecosse]

Well done! What needle is in the carb ?

[53buick]

The needle I had was a BBU, the profile looks quite lean compared with the stock MG Metro needle which concerns me as this starts with no choke and the mixture screw right in does nothing but back it off and it dies.
Any recommendations??
;)

[53buick]

[frame][/frame]

[bmcecosse]

And how does it run with the BDL?

[53buick]

I don't have a BDL so I cannot tell, the Metro carb that was seized up broke the needle on release...
I am getting to be on a tight budget now so reluctant to buy a selection and try them, I know that is probably going to be the best way but if I selected the leanest needle available then I could re-profile it myself possibly?
Seeing this needle starts the engine nicely and the mixture screw dies when backed off, I must be close?
There is nothing I am missing here is there? seeing the carbs were of a V8 rover, the jet's are all the same size I hope?
If I can get the jet out of the metro carb then I will compare it to the one in the Rover carb and check.