ignition timing :(

Started by alfa331.7, May 30, 2012, 06:31:24 PM

Previous topic - Next topic

alfa331.7

hey all

iv just done a top end rbuild on my alfa 33 1.7 carby 8v

as i was taking it to get it 2inch sports xhaust this morining  ...the car seem very powerless and keeping knocking and it was just a terrible drive with a few backfires

i remember a family member playing with the dizzy well turning it and its hardd to get it started and going aswelll

im 99% sure its my ignition timing how do i go about this ???
cheers alfio

colcol

Timing is running retarded, to set it properly, take off distributor cap, take out spark plugs, put car in 5th gear, push car forwards, until rotor arm points towards no 1 spark plug lead, then shine torch into no 1 cylinder, and see if you can see piston at top, if all ok, take plastic cap off the top of the bellhousing, and you should see timing marks, you will see a 'T', this is Top Dead Centre, and this 'T' should line up with a pointer, if not rock car forward, until it lines up, if all ok, rotate distributor until the rotor arm lines up with no 1 spark plug lead, there is usually a notch on the distributor, then, go and put car into neutral, put handbrake on, put spark plugs in and leads back on, put distributor cap back on, put timing marks cover back on bellhousing, then start car, if it starts ok, take it for a drive, go up a hill, and if it slightly pings, [makes noise like marbles are rattling], if not, you need to advance timing, to do this loosen off distributor and slightly turn anti-clockwise, and go for a drive up a hill, you have to keep doing this until you get a slight pinging up up a hill or when you labor the motor a bit, ie 5th gear at 50klms, then floor it and listen for pinging, you could use a timing light, but it would depend what petrol, distributor, carbys, state of tune and driving style etc, i use this method, and it seems to work good, Colin.
1974 VW Passat [ist car] 1984 Alfa 33TI [daily driver] 2002 Alfa 156 JTS [daily driver]

Frank Musco

Remove the plastic plug at the rear of the engine, next to the distributor, closest to the drivers side. Might be missing, so just look for the hole.
Loosen the distributor clamp bolt so you can move the distributor by hand, not too loose that it moves by itself.
Remove the vacuum advance hose, and plug up the carby end.
Put the timing light onto the battery and No.1 spark plug lead. (Front drivers side)

On the flywheel there are three marks. Good idea to clean them before you start, some even put some paint on them to make it easier to see, although be accurate!

Start her up, warm her up, then shine the light down the hole.

The first is 0 degrees (TDC)
The second is 8 degrees (BTDC) between 850 -1000 rpm
The third is 36 degrees (BTDC) at 4500 rpm

Some have 4 marks, so you want to look for the second mark being 8 degrees and the fourth being 36 degrees.
The third is 22 degrees (BTDC), intermediate timing at 2000rpm.

Shine the light down the hole and match up the second mark with the point on the rear engine cover, down in the hole. Set the timing at 8 degrees and check the engine revs are not over 1000 rpm.
I suggest you move the distributor with the car OFF, then start it to check, then again turn OFF to move distributor so you don't get a shock, and so on until you get the correct timing.
Then get a mate to hold the revs at 4500rpm to check the total timing of 36 degrees. THIS IS VERY IMPORTANT!! too much total timing and she pings and gets hot and eventually gives you major grief. Even more critical if you have machined the surface of the heads, which increases compression.

IF YOUR TIMING IS CORRECT AT IDLE AND HIGHER THAN 36 AT 4500RPM, THE DISTRIBUTOR NEEDS TO BE RE-CURVED. TAKE IT TO YOUR NEAREST ALFA MECHANIC.

If it all looks good, turn the engine OFF, and tighten the distributor, replace the vacuum hose, remove all tools and take it for a drive. Now recheck the timing and idle speed and fuel mixtures. Incorrect fuel mixture will cause the car to ping/detonate with the correct timing.

Most important, give the bloke who played with your car, a clip over the back of his head, and hide your keys from now on!


alfa331.7

ahh i get it now cheers colin and frank ill let you guys know how i go

im a rookie to the timing light never used one  but im sure it wont be complicated if i follow your guys steps :)

alfa331.7

just a few fotos :) i using diffrent rims on it now they are replicas of the v4 simons

Sheldon McIntosh

Quote from: Frank Musco on May 30, 2012, 10:18:05 PM
If it all looks good, turn the engine OFF, and tighten the distributor, replace the vacuum hose, remove all tools and take it for a drive.

That's very specific advice Frank.  Speaking from experience?  (I think we've all been there) 

I once drove to Sandown and was wondering what the slight rattle was from the front left wheel.  I needed to bleed brakes before I went out on track anyway, so was wondering what I'd find when I took the wheel off.  Found a 25cm long wrench left on the chassis rail from the wheel alignment a few days before (imperial size too, naughty wheel aligner).  That could have made a mess as I braked for turn one....

Frank Musco

Quote from: Sheldon McIntosh on May 31, 2012, 05:03:18 PM
Quote from: Frank Musco on May 30, 2012, 10:18:05 PM
If it all looks good, turn the engine OFF, and tighten the distributor, replace the vacuum hose, remove all tools and take it for a drive.

That's very specific advice Frank.  Speaking from experience?  (I think we've all been there) 


;D Yep...Usually during the mad rush to check as many things as possible before getting to the track. Then looking in my toolbox and wondering... where did I put that fricken tool...somewhere on the Hume highway!!

colcol

Timing light, whats a timing light?, actually have 3 of them, sometimes use them to initially set the timing, and then use the slight pinging up a hill technique, to suit, when its right, cars starts easy, good torque up hills and doesn't use too much fuel, all my timing lights won't work with modern spark plug leads, as they are too well insulated, have to drag out original Alfa Romeo red leads that came with the car, Colin.
1974 VW Passat [ist car] 1984 Alfa 33TI [daily driver] 2002 Alfa 156 JTS [daily driver]