more timing questions

[Wayne G.]

Ok this one may be a bit over the top, But I have been reading and well can't figure this one out...

I have a 60 FI the original cam, the injection is off her and is the original distro, the distro is from a 62 and has no vacumm advance she is a dual point setup...

Some simple (maybe not questions)
I read initial timing is 18 on the FI motor? But is that with the original distro? is so then what should I shoot for a total timing? And if so at what RPM should I set it at and what degrees? say something like 32?

And the second major question what points should I use in the distro, and what gap and dwell settings if setting up new ones, and at what base timing and RPM should I set them at...

I guess the best way would be dyno and or plug reads maybe even a Wideband O2 and take some readings and logs here and there at different settings. But I am leaning towards more a 62 FI settting usage overall, I have not look to see what they are, but I am thinking it may or may not have used the same camshaft?

HELP!

Right now at 18 base and 29 each point and 34 total @ 450 RPM she runs fine OK, I can feel more power over 1000RPM a much smoother motor and all, but just not to happy with the idle, would not say a miss as much as a noticable roughness to the idle... not the normal loppy I should be getting...

I can set timing by feel and see what happens as that can't hurt all to much, but the DWELL and GAP may be a issue... for sure its a 62 cam and coil and I would assume points also...

The distro was all cleaned up and checked no end play good and solid and oil as should be. Wires all clean and all contacts, even checked the Voltage reg and all is good. It tunes well no issues there, just seems a bit off the dwell when I first checked it was at 29 one set was 19 I do not recall what the other was but going to 29 on each one at a time then both I got 34.8 so I just fined tuned it... that made a hudge noticable difference... seemed to bump the timing up just about 2 so I lowered it back to 18 and well just seems a bit say loaded up at ilde... I am running a 6.5 power valve on the holley and the air idle scews adjust out fine... at about 13 on the vacuum gauge she seems a bit rough if I put idle at 15 on the gauge she much smoother and about 760-800 idle rpm, but still seems rough, If I hit 1000rpm its a night and day smoother motor?

Car was rebuilt, No air leaks, the vacuum gauge is steady and no needle bounce. New plug wires, new rotor and cap (ACdelco)...

I can easily figure total timing now that I think about that, so what is total timing on a 60 FI I know I seen that listed somewheres...

Just the way it should be, or am I being really picky, smooth idle is something I have come to be used to? Maybe I am shooting for too smooth a idle... She seems better at a much lower base timing but then seems to loose the snappy throttle respone... maybe just a trade off...

thanks all in advance...

[Duke W.]

Re: more timing questions

Which FI engine? There were two, and their characteristics are very different!

Duke

[Wayne G.]

Re: more timing questions

Which FI engine? There were two, and their characteristics are very different!

Duke

Oh yes this is true but I assumed there is only one to have - hehehe
290HP vin is 8627 and for sure a CS matching motor...

[Duke W.]

Re: more timing questions

If you have a '62 distributor, it should have a dual window cap and use the same points as the single point system. See recent threads for a discussion of the six different point sets and advice on which one to use.

In order to set "total WOT timing" one must know for certain the speed at which the centrifugal advance is all in, and this must be verified by observation with a timing light.

If you look up the '62 distributor specs you should find that the maximum is 24 degrees at 4600 revs. Therefore, unless the advance has been modified to come in quicker, the total WOT timing must be set at over 4600!

In order to achieve 34-38 degrees total WOT advance, the initial must be set in the range of 12-16. Idle quality and off-idle torque will generally be better the greater the initial timing on non-VAC distributors, but if you go too far the engine might detonate at higher revs.

It's a matter of experimentation to see what works best for the specific engine and driving conditions.

Duke

[Wayne G.]

Re: more timing questions

If you have a '62 distributor, it should have a dual window cap and use the same points as the single point system. See recent threads for a discussion of the six different point sets and advice on which one to use.

In order to set "total WOT timing" one must know for certain the speed at which the centrifugal advance is all in, and this must be verified by observation with a timing light.

If you look up the '62 distributor specs you should find that the maximum is 24 degrees at 4600 revs. Therefore, unless the advance has been modified to come in quicker, the total WOT timing must be set at over 4600!

In order to achieve 34-38 degrees total WOT advance, the initial must be set in the range of 12-16. Idle quality and off-idle torque will generally be better the greater the initial timing on non-VAC distributors, but if you go too far the engine might detonate at higher revs.

It's a matter of experimentation to see what works best for the specific engine and driving conditions.

Duke

I see, very nice "right" up on the points, I will select the ones I need for 6500rpm and set them up, it may be hard to find a gauge for the spring to check that, not sure if my old Burroughs Carb tool gauge kit still has the pull spring gauge in it... I read what you said about the total coming in and all, I also read were it says advance comes in around 1000 on the wieghts sort of why I am thinking around 1000rpm she smooths out so so much more... I guess I will have to get my kids advance light and do some revs and see... I thought that total timing was lower than what your saying on the stock 290hp motor? Maybe I read that wrong 18 base and 24 total from the distro would be about 42? I may just to as always and get it all fixed up, points set up... and do a tank of 94 octane and just take it up a hill and adjust till she don't ping? Its not like I am gonna drive it 0-60 real hard, its a cruzer....

Again real nicely done on the points... thanks...

[Joel F.]

Re: more timing questions

Hi Wayne,

Duke's advice is good but I would not rely on your old distributor actually adhering to factory specs. A lot could have happened to it in the past 50 years, someone may have changed the springs, the weights, altered the amount of advance by using a bushing. Without using a timing light with advance capability, you will never know you are working with. You can buy a decent timing light at Sears and get a set of springs and weights for your distributor from places like Summit, Jegs, etc. This should give you what you need to get to the total 34-38* advance as well as to tune how quickly you get to that advance (I would suspect that the factory spec of 4600 rpm is not ideal).

[Wayne G.]

Re: more timing questions

Hi Wayne,

Duke's advice is good but I would not rely on your old distributor actually adhering to factory specs. A lot could have happened to it in the past 50 years, someone may have changed the springs, the weights, altered the amount of advance by using a bushing. Without using a timing light with advance capability, you will never know you are working with. You can buy a decent timing light at Sears and get a set of springs and weights for your distributor from places like Summit, Jegs, etc. This should give you what you need to get to the total 34-38* advance as well as to tune how quickly you get to that advance (I would suspect that the factory spec of 4600 rpm is not ideal).

Oh no not a chance buying a timing light, not when the kid has a sweet snap on one and does the dwell and rpm all in one.. hehehe anywho I can see the distro is not all redone... It was bought brand new from GM as a service part back in the day, and this car has been in family since 68 when this was all down, (remove the FI) as that was a pain back in the day. also as I have stated she has a 1966 Impala or Chevelle 396 GM part carb ordered right from GM back in the day, so at least I do not have to deal with those unknowns. I know that would suck... I will tackle this all soon enough - Your guys know your stuff! Much thanks all around!

[Duke W.]

Re: more timing questions

Hi Wayne,

(I would suspect that the factory spec of 4600 rpm is not ideal).

True. OE centrifugal advance curves were usually conservative because they had to work from the southwest desert to the arctic.

Any car guy worth his salt recurves the distributor with lighter springs to get the advance in more quickly, which yields better low end torque. This is especially important on torque-shy SHP engines.

Even with the slightly lower octane of today's best premiums (If you don't understand this search RON, PON and MON.), most OE engines can handle more aggressive curves without getting into detonation.

HUGE DIFFERENCE when I installed the '64-65 SHP/FI weights and springs (along with a 236 VAC) into my 63 340 HP distributor circa '65, which brought in the 24 degrees at only 2350 vs. 4600. Pulling a 3.08 axle through a CR trans really showed the low end torque improvement, better fuel economy, and more stable idle. The OE 201 VAC didn't deliver full advance until 15", but the engine only pulled 12" at idle. Duh!

Duke