9 replies to this topic

[AzMaN]

Time to let my fustration out on you lot me thinks.

Today was MOT day, first time in about 3 years for the mini so i got it there it all went fairly well apart from the rear left cylinder wasn't opperating and the track rod ends were loose (this was due to needing the tracking doing). So off i went home to fit the space cylinder i had and halfway home it died just like that. Traced fault to balast resistor on the coil being nackered, so made the coil into a 12v for a while.

Got home, changed cylinder, went back to mr MOT man, and mini was running like a bag of nails didnt like any load kept cutting out then not starting (found dizzy was loose).

Nowfor the bit i need help on. I time it to 8deg BTDC at 1500rpm like the manual says, and still it runs poor, i also turned the mixture up about 2 turns because it was reading very lean on the MOT machine (0.04). Im running a HIF38 with an AAM needle, LCB & cone air filter.

Am i doing something wrong here, its rearly annoying me

[dansalter]

just a suggestion, my car was bugging me for days with me trying to figure out what was wrong with the timing
mines a 998 with the same carb and needle as you.

it would run and revv beautifully on the drive but out on the road it was hirendiously bumpy. i thought it was the timing at first

anyway, after a few days i discoved that a wire fron the dizzy had become bare and everytime i went over about 3,000 rmp on the road the wire would shake and earth itself on the body of the engine, this would obviously cut the spark for a split second untill it jolted n shook the wire back off.

fixed the wire and it ran beautifully.

but it definatly felt like timing.

i guess its a long shot but hope this helps.

[bmcecosse]

Well done passing that MOT! It's going to need a good tune -up. Are the valve gaps all correct ? Start with inspection of the dizzy - all cables connected ok - is it now back to 'ballast' operation ? Is it all in good order? Bob -weights free to move and springs connected ? Vacuum advance unit connected - and does it move the dizzy plate when you suck the pipe ? Then set up the timing to give best idle - swing the dizzy by hand until it's smoothest/most steady. Then adjust the idle mixture to give best idle too - test by lifting the piston. may have to re-adjust timing. Add some 3 in 1 oil to the dashpot. Take it for a road test - then switch off after a hard run and take the plugs out for a look at the colour. They should be light beige - not too white!

[AzMaN]

Well done passing that MOT! It's going to need a good tune -up. Are the valve gaps all correct ? Start with inspection of the dizzy - all cables connected ok - is it now back to 'ballast' operation ? Is it all in good order? Bob -weights free to move and springs connected ? Vacuum advance unit connected - and does it move the dizzy plate when you suck the pipe ? Then set up the timing to give best idle - swing the dizzy by hand until it's smoothest/most steady. Then adjust the idle mixture to give best idle too - test by lifting the piston. may have to re-adjust timing. Add some 3 in 1 oil to the dashpot. Take it for a road test - then switch off after a hard run and take the plugs out for a look at the colour. They should be light beige - not too white!

new coil is on order, but ill check all the valves and dizzy internals tomorow. Im using proper SU dashpot oil in the carb, is that better than 3in1 or not.

Im itching to drive it properly, not just urge it here and there hoping it dosnt brake down.

[bmcecosse]

Much the same - it's fine.

[AzMaN]

ok an update, new coil fitted, timed to 8deg BTDC like manual says, valve gaps checked ok.

Currently it idles lovely, but put my foot down and it all goes pear shape it just sound like a bad of nails. I know the vacum is working due to the timing changes on looking at it with the stobe light. i was thinking though that maybe its too lean, i have the carb turned down to minimum, anything over that and it sounds like is kinda missfireing but i know its too lean, the MOT man said it was hardly reading on his machine.

I plan to rolling road it but like i say i need to be able to drive it to get it there

I was also thinking maybe the fuel is geting too hot? i have an LCB fitted and the pipe runs quite close to it.

[valve bounce]

i had a similair prolem when i upgrade to a hif 38 and apperently it was the needle valve (there sopose to be a bit tempramental) but i could on get mine to run about 3000rpm any low nothing anything higher nothing.

also i think you should be using a aaa or aau needle.

hope it helps
rob

[CobraV8]

You might want to check your fuel pump / filter - you may not be getting enough flow.

[lrostoke]

You really want a CO reading of 2.5 - 3%.
If you have a strobe with advance, try turning the revs up to 4000 and set the timing to show 32 degrees.
Then see how she runs, put it under heavy load, if it sounds like its pinking then knock it back to about 30 degrees.

Also long shot, check out your HT leads, just had an issue where mine was struggling rev over 4000 rpm, turned out be a bad connection on the coil to dizzy HT it was burning out.

Edited by lrostoke, 21 July 2009 - 11:08 AM.

[AzMaN]

right then, instead of opening new thread ill update this one.

After fitting a electric fuel pump, and after the carb pumped all the fuel out the overflow i got a bit anoyed, so i took the carb off, borrowed a hs4, and bingo started first time on the button - problem sovled or so i thought.

bonet and grill put back on, pull off and it stalls and wont re-start. inspected components and realised that i hadnt tightened the dizzy up, went to static time it and the blub on off method wouldnt work so now i think the brit part ignition module is up the *melon* to be honest im not haveing much luck atm maybe i should have just brought a already rebuilt mini atleast then i may be driving it