Thread: I really am idling with 40 degrees advance

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After thinking that my timing marks were off, I discovered using a piston stop that they were right on.

My Small block chevy with mild cam and Qjet is running quite well. No pinging (that I can hear, but loud muffler), staying about 200 degrees with 180 tstat, and generally all seems ok. BUT at idle, the timing shows 40 degrees. When I rev the engine when sitting still to bring in all of the centrifugal weights, I get to 58 degrees, and it seems to be doing fine. I drove 50 miles last week this way (25 miles to and from work).

I have an adjustable vacuum canister, including a limiter plate set at about 16 degrees max vacuum. It starts well too, even when hot (a bit tight, but not too bad).

Should I be worried? When I reduce timing, the power goes down. When I get to 12 static, 26 (or so) with vac, and 38ish max with static, vacuum, and centrifugal idle, it spits pops and runs poorly. It acts like the timing marks are off, but I know they are not!

Are you certain the cam and crank are phased correctly?????

Dave, I'm with you on the cam part. Very suspicious.

Believe me, your engine is NOT idling with 40 degrees advance. You are timing it on the wrong cylinder, or something. It would kick back and blow the starter off before it ran like that.

IF you have your idle RPM set above 800 and you are running FULL manifold vacuum to the vacuum advance , then you may be running 40 degrees advance at that idle. This would depend on how much mechanical advance and vacuum advance is being added to the initial at your idle RPM.

The correct method to check/set the timing is to disconnect and plug the vacuum advance hose from the vacuum advance cannister. You should also have the trans (if automatic) in drive (be sure to set the emergency brake and block the wheels and do NOT rev the engine up when checking this way. Also would be a good idea to have someone with their foot applying the brakes.) and the idle should be in the 650-750 RPM range.

Checking at a higher RPM will cause an incorrect reading as the centrifugal advance weights will have begun to open and will cause some additional timing.

Checking with the vacuum advance hooked up will also cause an increase in the timing since their is no load on the engine the vacuum advance unit will also increase the timing.

You are checking the timing incorrectly.

40 degrees is WITH vac advance. I'll post up each component tonight, but I think that's about 25 static. I was idling at about 700 when checked, so below where the centrifugal comes in. With centrifugal all in, it shows about 56-58 (all 3 full in).

Attached is a picture of the timing chain alingment marks when I did the cam swap this winter (before I bent the locks over).

Denny, you answered "absolutely". Do you mean I should absolutely be concerned?

My timing (just measured) is:
24 degrees static at 700rpm
40 static + vacuum at 700rpm
60-62 static + vacuum + centrifugal at 2800 rpm

The cam is Lunati Voodoo 60101
Advertised Duration IN/EX: 256/262
Duration @ .050 IN/EX: 213/219
Gross Valve Lift IN/EX: .454"/.468"
LSA / ICL: 112/108
Valve Lash IN/EX: Hyd/Hyd
RPM Range: 1000-5500

By the way, I was extremely careful to follow the break in to the letter. I'm learning alot, but now I know why people go and buy turn key crate motors. What the hell? It seems just fine, but the numbers just don't add up. I'm losing my motivation real fast with this damn motor.

Now what?

The engine idles ok at the higher advance rate because it takes a while for the lean idle mixture to burn.

Do you have an amplified ignition box
Something along the lines of an MSD6al?
And are you using a dial-back timing light?
Perhaps one of the Penske ones from Sears?

I found when timing my 462" Buick engine (455 series engine) with a Penske dial-back it was off about 20 degrees.
The original timing light - also a Penske - a non dial-back style showed the timing where it should have been.

I've discussed the dial-back timing lights being used with an MSD 6al box on another site (HAMB).
Most of the guys reported that their dial-back lights read the timing correctly and compare favorably with a non dial-back light.

The readings taken on my - owned for a short while, took it back - light was with the dial set at zero and getting the degrees off the degreed dampener.

A couple things you could do.
Take a reading with a standard timing light and see how it compares to the dial-back light if in fact that's what you're using.

The other, time the engine statically at your desired initial advance figure.

The manuals show centrifugal timing starting as low as 430 rpm in some cases so your 700 rpm idle probably has part of the centrifugal timing in.

Timing the engine statically would show you where you're at there.

As far as your cam timing goes, I'm not seeing a crank gear mark other than the yellow or black line in the pic.

Is that a 350 or a 305? They take different timing tabs and yours sounds like it may be a 305

The timing mark on the lower gear is a small circle obscured by the paint pen. I put in a better pic, you might be able to see it. Black mark is the keyslot I marked.

I have only an HEI with integrated (high voltage) coil. No MSD or dial back light. Using a standard timing light with the marks on the balancer up to 50(double checked against an 8" timing tape).

You may be right about the centrifugal, but would be surprised if it was that much difference down that low. I will try to get it to idle even lower.

On a separate note, I noticed my fuel pressure was very low (recent change showing 1-2PSI). I just thought I would mention it in case that had any impact on this. It might even be a bad gauge.

350 engine. Not 305 (pretty sure).

i cant remember if im right or not but i think u install the stop in the spark plug hole, rotate the engine with the degree wheel on the crankshaft, when it stops set the wheel and pointer to 0 then counter rotate the crank till it reaches TDC again then whatever the difference is from 0 to the counter rotated number, find the half of that number and that is your True 0 mark it and then retime

oh and make sure that when u r degreeing that the wheel is securley tightend down

I just swapped cams in my 400 and it runs great. Your cam is installed correctly, no question. The outer ring on your harmonic balancer has probably slipped on you. Common problem. If so it's trash, get a new one. If you use a piston stop and find zero tdc and your dampner doesn't line up to zero tdc, then your dampner ring has slipped or your timing pointer is attached in the wrong place on your front cover.

Originally Posted by K5BlazerGuy

I just swapped cams in my 400 and it runs great. Your cam is installed correctly, no question. The outer ring on your harmonic balancer has probably slipped on you. Common problem. If so it's trash, get a new one. If you use a piston stop and find zero tdc and your dampner doesn't line up to zero tdc, then your dampner ring has slipped or your timing pointer is attached in the wrong place on your front cover.

Don't know how relevant this would be, you're responding to a post from May---hopefully the dude has resolved these issues by now!!!!

So far the TDC has been determined and I guess a pointer was added to point to TDC when the crank was rotated to it. Now by using a timing tape the balancer can be degreed. Attach the timing light, remove the vacuum advance hose and plug it. Run the motor to max advance, probably around 3000 rpm and set it at about 30 deg. Now go back to low idle. You should see an rpm where no further movement of the timing happens or where it just begins if you are going up in rpm. Observe this number on the tape. Subtract this number from the 30 (or what ever you used) This will give the amount of advance in the distributor.

Now you have a set point which is the max rpm before mechanical advance starts. You can set the static timing at this speed. What ever number you choose. The other way is to set the total timing at a speed where all of the advance is in. Say 3000 rpm. Set the total desired at this speed or greater. Either way you must leave the vacuum advance plugged. It will be around 15 degrees additional. Some units are adjustable. The vacuum advance is primarily for MPG. When you tromp on the gas the vacuum advance retards to its 0 point leaving you with your mechanical advance.

One more thing. I spoke with MSD just recently and the man told me to get a cheapo timing light as some of the new ones are so sensitive the will pick up all or most of the multi spark duration and give incorrect timing value. For a change cheapo is better. IE. the cheapo does not pick up the multispark length.