My Robin Hood has a 2 litre Pinto engine with a moderate street camshaft (262 degrees). The rest of the engine to my knowledge is standard although it seems a little worn.

I always felt that the engine lags when accellerating with the ignition set by by the book to 8 degrees before tdc. I read that some sports cams need more advance, so I attempted going forward step by step and by now reached 16 degrees before tdc. I then got a little spooked and do not dare to set more. But the engine seems to run a lot better now ...

I checked with vacuum attached that the total pre-ignition does not exceed 45 degrees before tdc (that's what I found as max one should not go beyond). To all I can say, the engine does not pling or knock.

Is that setting ok to your experience or is this too much and I risk to wreck the engine with it? Thanks for your help.

Edited September 29Sep 29 by Amateur

I run a 2 litre pinto which is a BRISCA F2 race spec and that runs on 2 degrees timing.
My previous stock engine with twin weber 45s was also running at 2 degrees timing.

The best way to set the timing (in my experience) is to do it by ear.
Turn the dizzy to the point that it is idling smoothly at the lowest rpm it can. when you achieve this, it will be running OK without pinking (detonation).

Also, don't go by the book as the book was written for (proper) fuel back in the 80s/90s and todays fuel can't have as much compression and they ignite faster than they used to (you can thank Ethanol for this and all the rubbish they mix in).

Edited September 29Sep 29 by ThanasisPolitis

12 hours ago, ThanasisPolitis said:

I run a 2 litre pinto which is a BRISCA F2 race spec and that runs on 2 degrees timing.
My previous stock engine with twin weber 45s was also running at 2 degrees timing.

The best way to set the timing (in my experience) is to do it by ear.
Turn the dizzy to the point that it is idling smoothly at the lowest rpm it can. when you achieve this, it will be running OK without pinking (detonation).

Also, don't go by the book as the book was written for (proper) fuel back in the 80s/90s and todays fuel can't have as much compression and they ignite faster than they used to (you can thank Ethanol for this and all the rubbish they mix in).

Thanks. But 2 degrees? Hmm.
When I researched right, with too late ignition the engine runs sluggish and uneven. And the closer one gets to the sweet spot (towards advance) the engine picks up rpm and runs smoother. At 8 degrees advance my engine still runs uneven in idle and increasing pre-ignition increases the rpm and everything seems to run better.
But I will do the test. Next weekend I will twist the dizzy around just by ear. Let's see where I will end up. :-)

Yesterday evening the TV program was no good, so I decided to try the timing thing. Guess what...

I drove around the block to warm it up, lossened the dizzy and pushed it toways tdc. The engine choked and died. I tightened the idle screw a little bit and then tried to find the sweet spot just by ear. When done, I took the strobo light and checked: I was at 20 degrees before tdc ... :-) With vacuum attached, ignition however goes well into the 40s, so I went back to the 16 degrees I started with.
That seems to be the solution for my engine. At that point the engine idles smooth. My (Weber DGV) carburator also turns quite rich when accelerating. I already tried to fix that but have not yet found a way to do so. The rich mixture does not go away with the increased pre-ignition, but the engine seems to be able to cope with it better (more time to burn the fuel). So I guess I will stick with that value. Thanks for your help.

Edited October 1Oct 1 by Amateur

Awesome! good to hear that you have found the sweet spot for your engine!

"My (Weber DGV) carburator also turns quite rich when accelerating. I already tried to fix that but have not yet found a way to do so."
You might have to take the car into a tuner with a rolling road so they can re-jet the carb so it will have a more consistent fuel delivery across the RPM range.

57 minutes ago, ThanasisPolitis said:

[...]
You might have to take the car into a tuner with a rolling road so they can re-jet the carb so it will have a more consistent fuel delivery across the RPM range.

Thanks. I have a lambda gauge built into my dash to see the mixture in real time when driving (a gadget I no longer want to miss). So I can do my own field tests by driving around the block... :-)
When holding speed, the mixture is at a perfect AFR 14 and that works at all rpm. Only when I push down the pedal, the mixture turns rich (AFR 11-12) and stays there as long as I accellerate. The slower I accellerate and the less I push down the pedal the richer it gets. The moment I stop accellerating, mixture goes back to normal. A smaller main jet would fix that but it would also make my holding mixture too lean. So that is not an option. And the air correction jet is only active at higher rpm, where the rich mixture issue is actually less than at lower rpm.
There is a thing that came to my mind today: A year or two ago, I my engine choked when accelerating because the floating chamber basically fell dry. I then drilled an extra hole into the floater valve to increase the fuel flow when it opens before I found that by fuel pump was broken. That extra hole might actually be the cause. I will check if an original valve changes anything. If that's not it, I will (have to) cope with it. Too rich is better than too lean. And holding mixture is fine anyway. Without the lambda gauge I wouldn't even know that the mixture is too rich :-)

Tbh the first thing you have done wrong is check the timing with dizzy vacuum still attached, usually the timing would be @12 degrees before tdc , That’s at the start get the engine to normal running temp then disconnect the vac pipe from the dizzy check the timing with no vac pipe on move the timing to zero degrees , then reattach your vac pipe to the dizzy and it should be correct when you throttle up the timing will move up to accommodate the request for more fuel and air , also running rich will only over a period of time burn out ,plugs, valves, and piston crowns.

Edited Friday at 11:14 AM5 days by Daveo

20 minutes ago, Daveo said:

Tbh the first thing you have done wrong is check the timing with dizzy vacuum still attached, [...]

Sorry, I probably didn't write it up propperly. But that is exactly what I did.
1) Remove the vacuum hose
2) set the timing by ear (turn the dizzy back and forth) to the sweet spot
3) check the timing result with the strobo light (=20 degrees without vacuum).
4) then re-attached the vacuum hose and checked the total timing advance when reving: No substancial change (within <2 degrees) in idle when vacuum is attached. At mid to high rpm I got a max of about 46-48 degrees.

With that I hear no pinging or such.. But to be safe, I went back to the 16 degrees idle advance, which gives me a max advance including vacuum of about 42-44 degrees.

Concerning the (too) big floating chamber valve I mentioned above: I changed that back an hour ago to the 200 size valve that was originally in the DGV. First impression from around the block says that it didn't change much. But it takes a bigger tour to really check that.