5 replies to this topic

[alexw89]

Hi Guys,

Right i have a 1984 mini 25 which has a 1989 1275 Metro engine Fitted, The engine number is 12HD09 which from what i can gather cross references to a Leaded big valve head , 9. something compression ratio, it has a 3 into 1 tubular manifold, aftermarket heated inlet manifold, Hiff 44 and a K&N cone filter.

My problem is when i first got the car it would barely run/rev so i removed and cleaned the carb set the timing with no vacum to 6* BTDC and after a fiddle with the mixture screw it would tickover lovely and rev pretty cleanly,

However when i connect the vacuum pipe it shoots to over 25* btdc and sounds like its pinking and doesnt run as well but only on idle, so i turned the dizzy until the pinking noise stopped and then when i took it for a drive its super flat and doesnt want to accelerate really at all, But setting the timing to 6* BTDC with no vacum again and despite the Pinking kinda noise on idle it pulls very very well and its impossible to boot it in first without spinning the front wheels!!

so im pretty stuck as to what to do i mean i could live with the pinking noise but pinking is a bad thing and i dont want to damage the engine!

Any help would be greatly appreciated, Cheers.

[Ethel]

Have a look at the vacuum can, it'll have the advance stamped on it somewhere.

[racingbob]

i have my mg metro engine timed at 10 - 12 deg at 1000 revs ( lucas electronic )

it doesnt seem to change when the vacum advance is on or off

try another dizzy

[ACDodd]

First thing to do is check the accuracy of the TDC mark on the engine.

Secondly check the timing dynamically at idle then at 1000 rpm then at 1500 and then at 500 rpmn increments till you reach the point of max advance, or 6krpm, whichever is sooner. Do this with the vacuum disconnected and post back the results. Mind you don't get anything caught up in roating pulleys and wear eye protection (things can fly out of the fans at alrming speeds).


AC

Edited by ACDodd, 20 March 2012 - 07:28 PM.

[alexw89]

Thanks for the replies I will check the timing st set tons and post the results tomorrow, however got a quick question can I do away with the vac advance and rely on the mechanical advance?

I've heard it helps economy at low throttle openings but not much else, I mean if I can do away with it and the only ill effect is economy I'm happy to get rid!

[alexw89]

At set rpms* is what I intended to put stupid predictive keyboard!