timing nightmare

[westy64]

Hello gentlemen

I am on the process of timing the car, after a timing belt replacement session that did not happen as expected.
The engine is a Fiat 2L abarth, euro specs.

The fiat workshop manual of this engine says I have to put cyl #1 at TDC,
then check that cyl #1 is in explosion phase and cyl #4 in "rocking phase" (is that correct in english ?)
then check that distribution rotor is pointed to cyl #1
then time it with a strobe lamp at 10 degrees before TDC.

When I turn the crankshaft by hand to put cyl #1 at TDC (using a screwdriver in the sparkplug hole to determine exact position), crankshaft pulley mark is aligned with the belt cover marks (and camshaft holes and marks align to the marks).
And these belt cover marks are on the left side of the pulley (driver side), while most of the marks that I can see on this forum are on the left side (passenger side).

When I look at the rotor position inside the distributor, it faces the plug that is under the wire going to cyl #4.
I will check this evening if the plugs go direct from inside to outside or if they play hide and seek.

So ?
I read all the threads, and they all recommend that timing should be done on cyl #4 and not on cyl #1, which is contrary to my fiat manual.
Is my engine so specific ?

what should I do ?

thank you in advance for your help.

[TX82FIAT]

The dizzy/rotor needs to be set to fire #4 first. Some people start at 0 degrees and move to 5 degrees and then 10 degrees to get the timing the way they like. just make sure the marks line up. Most people find the car runs better at 10 degrees. But to answer your question about #1 and #4 for TDC, I'm not sure it really matters (but i could be wrong). When #1 is TDC #4 should be in full compression. But then again, I have not changed a timing belt on a spider in about 12 years. The last time the belt was changed was when the engine was rebuilt and they set the timing for me.

[joelbert2k]

For reasons that I have never understood, when you line up all the timing marks, as you have done, then #4 is in firing position. That is to say the cams are lined up for the compression stroke.
Most people set the ignition/distributor timing using #1 plug but you can use #4 just as well.

[redcars]

+1 on the ignition timing with #1 or #4 it makes no difference at all. One and four are at top dead center together. The cam must be timed with #4 at the dizzy ready to fire.

[azruss]

Even though the pistons are the same, the cam timing is not. Voice of experience. The car will barely run with the timing set to #1. Purrs like a kitten on #4.

[garion]

If you timed it on cylinder #1, wouldn;'t the firing of #2 and #3 be reversed? #1 and #4 would be ok, but the other two would be messed up wouldn't they?

[djape1977]

Hello gentlemen

I am on the process of timing the car, after a timing belt replacement session that did not happen as expected.
The engine is a Fiat 2L abarth, euro specs.

The fiat workshop manual of this engine says I have to put cyl #1 at TDC,
then check that cyl #1 is in explosion phase and cyl #4 in "rocking phase" (is that correct in english ?)
then check that distribution rotor is pointed to cyl #1
then time it with a strobe lamp at 10 degrees before TDC.

When I turn the crankshaft by hand to put cyl #1 at TDC (using a screwdriver in the sparkplug hole to determine exact position), crankshaft pulley mark is aligned with the belt cover marks (and camshaft holes and marks align to the marks).
And these belt cover marks are on the left side of the pulley (driver side), while most of the marks that I can see on this forum are on the left side (passenger side).

When I look at the rotor position inside the distributor, it faces the plug that is under the wire going to cyl #4.
I will check this evening if the plugs go direct from inside to outside or if they play hide and seek.

So ?
I read all the threads, and they all recommend that timing should be done on cyl #4 and not on cyl #1, which is contrary to my fiat manual.
Is my engine so specific ?

what should I do ?

thank you in advance for your help.

cyl n'1 on TDC, cams on marks, aux shaft mark on the pulley pointing at bolt that holds distributor in place, rotor arm pointing at n'4 on distributor cap. tighten everything, rotate engine 3-4 complete turns by hand (you'll need a spanner or a rachet and remove sparkplugs), release tensioner and retighten the belt. fire up!

[131]

I read all the threads, and they all recommend that timing should be done on cyl #4 and not on cyl #1, which is contrary to my fiat manual.
Is my engine so specific ?

Is it a "factory" manual or haynes rubbish? The ignition is timed on number 4. Following the instructions you have will work, but it's easier to do it on 4.

[westy64]

Is it a "factory" manual or haynes rubbish? The ignition is timed on number 4. Following the instructions you have will work, but it's easier to do it on 4.

Here is what I have :











note that the TDC mark is on the right in pic #1

[westy64]

cyl n'1 on TDC, cams on marks, aux shaft mark on the pulley pointing at bolt that holds distributor in place, rotor arm pointing at n'4 on distributor cap. tighten everything, rotate engine 3-4 complete turns by hand (you'll need a spanner or a rachet and remove sparkplugs), release tensioner and retighten the belt. fire up!

thanks Djape.
It took me a while to understand that 3-4 complete turns IS NOT 3/4 complete turn.
But why does this bloody book mentions cyl N°1 ?

[azruss]

Jean,
Get #1 piston at TDC. get cam gears and idler on their marks. Install the belt. Do not rotate the motor without the belt. You probably have an interference motor and you will bend valves. After turning the motor by hand, recheck the positions of the crank and cam timing marks. Now set the distributor to #4 and you are good to go.

[westy64]

A quick question :

When pistons 1 and 4 are at TDC in the same time, are the valves of both cylinders also in the same position ?
The little text on the picture deals with cylinder 4 that needs to be "in rocking phase", while #1 is in "explosion".
What does this mean if they are strictly in the same position ?



Sorry for insisting.
I need to understand.
Thanks in advance.

EDIT : I got it.
I was confused by the text which deals with a control on the valves (explosion, etc...).
I thought it was an extra control and I did not understand it.
In fact this control is done when you align the cams on the marks.

[majicwrench]

When 1 & 4 piston are at TDC, the valves for one cylinder are on the firing stroke (both valves closed-explosion) and on the other cylinder on the overlap stroke (both valve just barely open- rocking phase).
So, no, valves are not in same position. Your rotor now has to point at the cap terminal for whichever cylinder is on the firing stroke.
Checking ignition timing, like with a timing light, you can use either #1 or #4.
Keith

[westy64]

So here is the explanation...
You all are right, rotor has to be on #4.



I mixed different procedures.
This small procedure from Fiat does not tell to align the cams.
It does not because it is not its purpose.
It's purpose is to time the distributor.

So it tells to put cyl1 in firing phase and then check that the rotor points to cyl1.
Basic.

When you (and I) follow the whole timing procedure, we align the cams, the crankshaft, the aux pulley, and then cyl4 is in firing phase and then the rotor is to be on cyl4.
Both procedure are true.
They are simply two different ways, when I thought it was the same story that was told.
My apologies for insisting so much.
Thank you all for your help.
It will be done next week and no doubt it will fire !

[jkn070458]

There seems to be some confusion on what #1 is. The book I use says that #1 is by the firewall but the intake has numbers 1,2,3,4, front to back. I can tell you that it doesn't matter if you time it from the firewall side or the radiator side as long as the rotor hits #1 and the wires follow to the appropriate cylinders. I know this because I've timed mine both ways to reduce deceleration popping.