Just finished installation of a new block in my 66 Alpine and all went well. Set the timing using the light bulb method. Find now I must have done something wrong as the timing is off. Looking for suggestions on how to see the timing marks. Have tried a mirror find it difficult to see what is really going on. Used a timing light, find light is blocked by fanblade, belt, etc. so I can't see marks. If anyone has a mirror configuration or whatever, would be appreciated. How about using a vacuum gauge, have seen it suggested. In my youth in the 40s, we just rotated the distributors until she purred! Suppose that is too crude for these days!
-
Welcome to the new SAOCA website. Already a member? Simply click Log In/Sign Up up and to the right and use your same username and password from the old site. If you've forgotten your password, please send an email to membership@sunbeamalpine.org for assistance.
If you're new here, click Log In/Sign Up and enter your information. We'll approve your account as quickly as possible, typically in about 24 hours. If it takes longer, you were probably caught in our spam/scam filter.
Enjoy.
Distributor timing
- Thread starter Clark
- Start date
sunalp
Diamond Level Sponsor
How do you know your timing is off? What I do when setting TDC is pull the spark plugs,
take the valve cover off and turn the engine over , by hand, and watch the valves. Then you
see #1 intake go down, watch it come up and watch where it stops. If you go a little more
you'll see the exhaust valve start to go down. Just back it up and wiggle the rockers. You should
be able to wiggle them ( as long as they're gapped correctly) both. Check the #1 cylinder as to where
the piston is. At the top, you're there, if not you're 180 out ( check #4 piston position)
What you said about rotating distributors still works!
Hope this helps,
Cheers!
Steve
take the valve cover off and turn the engine over , by hand, and watch the valves. Then you
see #1 intake go down, watch it come up and watch where it stops. If you go a little more
you'll see the exhaust valve start to go down. Just back it up and wiggle the rockers. You should
be able to wiggle them ( as long as they're gapped correctly) both. Check the #1 cylinder as to where
the piston is. At the top, you're there, if not you're 180 out ( check #4 piston position)
What you said about rotating distributors still works!
Hope this helps,
Cheers!
Steve
Yep, vacuum guage will take out the guess work. I hook my vac guage up to a fitting I insert into the manifold drain port, look for around 22" vac and take it for a drive.
Barry
Diamond Level Sponsor
Timing at peak torque RPM (both partial and WOT) and above is much more important than timing at idle. Cranking in 3-4 degrees of extra base timing at idle to get maximum manifold vacuum could result in too much total timing (base + mechanical advance) at WOT and maximum torque RPM and cause a major detonation problem. Think about it.
Last edited:
Collectively, the combination of throttle setting, ignition timing, compression, fuel mixture and all the other dynamics that occur with a running engine will produce a given manifold (vacuum) pressure. Things like air temperature and pressure can significantly alter these outcomes on any given day.
For our purposes the ideal vacuum reading for an idling engine is around the 22" mark, moving the timing or mixture will change this number and worn engines might struggle to get to there.
There are some factors which could lead to detonation if manifold pressure gets too high, particularly if you've got a high compression engine or performance cam and if you are contemplating racing or running full throttle for extended periods, that's why in my previous statement I recommend going for a drive after setting the timing to listen for pinging; find a good hill and put your boot into it..
I have a standard S1 with 1600 running on 95 octane and find it likes about 20" at idle, any more and it will ping at high engine loads.
Whilst years ago manufacturers specified a number for timing at idle, the fuels we use today are pretty far removed from back then, our distributors are probably quite a bit off from factory specs just to put a few other variables into the mix, that's why I find it's better to set timing by vacuum rather than specific numbers.
With my previous reply, I realise that I didn't actually describe how to go about it, assuming that you have the distributor correctly installed, it's simply a matter of hooking a vacuum guage to the manifold and with the engine running at idle, move the distributor around until you get about 22", just be cautious with this number as it could give you some pinging under load, aim for the 20 - 22" mark.
The vac guage needs needs to be connected to the manifold at a point such as the brake booster port or, as I do, the manifold drain port.
In my younger days I have always learned that the procedure with the help of a vacuum gauge is as follows:
1.Aim for the highest vacuum (engine being hot and idling);
2.Then back off the vacuum a little (about 0,5 up to 1,5 inch).
Finding the right amount of backing off is a matter off test driving the car until the engine is not pinging.
This will resul,t as Beamdream says, in 20-22 inch.
Regards,
Peter
1.Aim for the highest vacuum (engine being hot and idling);
2.Then back off the vacuum a little (about 0,5 up to 1,5 inch).
Finding the right amount of backing off is a matter off test driving the car until the engine is not pinging.
This will resul,t as Beamdream says, in 20-22 inch.
Regards,
Peter
Tim R
Silver Level Sponsor
If I were you, before I do anything else I would set the timing to where you THINK its should be, then swap the leads around 180* on the distributor. The way that the WSM is written people often end up lining the timing marks on the timing wheels up without rotating the engine 360* before they instal the oil pump. This step is crucial but is often over looked. This means that you are timed to fir eon No4 cylinder instead of No 1.
We have 'cured' numerous non-running, post engine rebuild Alpines by doing nothing more than swapping the leads by 180*.
There is a video on the Sunbeam Alpine Channel on YouTube showing one of our engine rebuilds.
Good Luck,
Tim R
We have 'cured' numerous non-running, post engine rebuild Alpines by doing nothing more than swapping the leads by 180*.
There is a video on the Sunbeam Alpine Channel on YouTube showing one of our engine rebuilds.
Good Luck,
Tim R
First up if your guage is reading 24" at idle (say around the 8oo rpm mark) I suspect that the guage is in error, some vac gauges have a zero facility, check that first.
A genuine 24" reading on an average engine would put you into the potential detonation zone; to lower the reading you need to retard the timing.
Reading your original problem again I assumed you had the distributor installed correctly, because what Tim said is very true for initial setup, many of us have stumbled on this one. However seeing where you're at right now it seems you have passed this stage.
A genuine 24" reading on an average engine would put you into the potential detonation zone; to lower the reading you need to retard the timing.
Reading your original problem again I assumed you had the distributor installed correctly, because what Tim said is very true for initial setup, many of us have stumbled on this one. However seeing where you're at right now it seems you have passed this stage.