Ahh, yes - it's that time of year again. Just successfully passed emissions testing, so I get to now attempt to retune the car so it runs again!

I always try to follow the recommendations of the timing posts I've read & loved for so long, but am never fully satisfied with how it turns out.

I just played with it again tonight, and here's what I found:

With my 2 silver (Heaviest I think) springs in the distributor, I get 36 degrees at 2200RPM on the digital tach on the timing light.

At this point, the initial timing is 21* at 850RPM in park, 16* at 600RPM in Drive.

When I attach the vacuum canister to Manifold vacuum, the timing goes to 39* @ 850RPM in park, and 44* @ 600RPM in Drive.

The vacuum canister has a 57 stamped into the flat part near the diaphragm, and 233 printed toward the other end.

When the vacuum canister is fully deployed, the timing jumps by a couple of degrees, and you can hear the engine hunting a bit. Without the vacuum advance, it's pretty stable.

So I pretty much don't know what I'm doing from here. 20* seems pretty high for initial timing, but I don't know how to get 36* without going that high initially. Also, I don't like how it drops 250RPMs when shifting into drive.

Oh, It's an 81, but the computer has been disconnected & the Distributor replaced with a "normal" HEI, and the Carb is now a holley 3310-3.

Once I get this straightened out, I'll start asking about tuning the carb again.. ;-)

Anybody have any suggestions? Thanks!
Dan

 

Have you read the sticky at the top of the Page?

 

You are kidding right?

 

RHD - Yup, Read the sticky more than a couple of times.

Kevinator - Kidding about what?

Basically, the sticky says to adjust the springs until you get 36* at 2500-3000 RPMs. With my heaviest springs, I get 36* at 2200. At this point, the Initial is 20*. Also, I get a 250 RPM drop when I shift into drive.

Doesn't seem right to me, but I don't know what to check. That's why I'm asking.

Also, the sticky is directed more toward Points than HEI, but there shouldn't be much difference about where things end up.

Thanks!
Dan

 

use a different combination of spring. try one heavy and one light or medium spring. You want the 36º total timing in between 2500-3000. 2200rpm is too quick.

Once you get the 36º dialed in with the right springs you should be ok. Most HEI distributors came with a 20º mechanical advance so your initial timing at idle should fall around 16º.

Yes, rpm's will decrease when you put the car into drive. don't worry about it. set for proper idle speed (probably around 700-800rpm) when it's in park. when you shift into drive it WILL decrease the rpm's some because you have now just engaged the transmission and have started to put a load on the motor.

except for not having to set dwell on your HEI, the sticky at the top covers you on the info you need

 

Thanks Barry. I did have one silver & one gold spring in, and I got 36* at 2000rpm. That's why I went to 2 silvers.

The silver & gold are the same diameter wire, but the silver has fewer coils = heavier spring.

I know this ain't the original distributor, were there any made that didn't have 20* of mech advance? Maybe I've got one of these and actually need to use the weights & stuff from the kit.

Thanks again,
Dan

 

Danno,
When you get 36*, are you going any further to make sure it is all in?
remove the springs completely and disconnect the vacuum.start the motor and set the distributor to 36* at about 1200rpm. This sets the total advance.
Replace the springs (without moving the distributor) and see when it is all in by, this will give you the curve.

 

Yup, I'm sure it's all in. I just double checked - plugged the vac advance, put in the lightest springs I have, and they were all in at 1500. I went up to 2500, and it didn't move any further. I set the distributor to give 36* all in.

I tightened the distributor bolt, and put the 2 silvers (heaviest) back in. They came all in ~2200-2300. When I went back down to idle ~800rpm, I was at 21*.

So my distributor is giving 15* mechanical advance. Seems low. Everything's moving freely through it's full range of motion, so either the distributor slots aren't long enough, or the weights & center piece are designed to give a short advance. Maybe it's a truck distributor or something? Dunno, I'm stumped.

Anyhoo, that's the update. Any other ideas??

Thanks!
Dan

 

does it ping?

 

It's been a while since I've seen a timing thread, so...

 

I don't think so. I've never heard an honest to goodness ping that I know of. I've read a lot of descriptions of "coins on glass" and "Spray paint can rattles". I haven't heard any of these while I'm driving. I don't know how loud it would be either. The fan & engine in general ain't too quiet, so maybe it is, and I just can't hear it.

Anybody have a recording of a ping?

Thanks,
Dan

 

i set my cars 2 degrees LESS than audible ping.
my cars are not too loud.
Loud? get a knock sensor, like MSD sells