Help understanding my odd timing?!?!

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myasylum

myasylum

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O.k. First... I'm not real good with this timing stuff I know.

Now that I got that out of the way... Let me explain what I find to me odd...

I have a 408 stroker motor wit a lunati voodoo 60403 cam, and a stock Distributor.

Just tiring to set the inital timing doesn't seem to make sense. (we'll start off there).

It won't even run at 0 degrees, and it wont run at 12 degrees. It will first run at about 20. It seems to run best at about 30 degrees initial timing. When I went to check total timing by increasing the rpm's the timing doesn't move. It stays at 30 degrees.

I did have a "mechanic" look at it, and he said it didn't make any sense to him. He just looked at me and said... "Well??? It runs!" That's as much as he could tell me.

Could someone go a little further into this please?

Thanks!
 
So that timing could actually be correct? What might be "locked out" on it?

It does turn over a bit weird though, like it is a bit too advanced, it's hard to really find "the spot". I guess I could just take off the distributor wire, and play with the timing from that point to see where it might turn over correctly? Or is that just not right?
 
pull the dist cap off and try to turn the rotor just a bit maybe a 1/2" or so is all., let us know what it does..
 
Well, it turns to the left about a 1/2" and you can hear a spring move. It doesn't turn at all the other way.

One of the things the "mechanic" did is that he moved to hose on the carburetor for the advance to the "full vacuum manifold port" that I had it capped. (I have a Holley Street Avenger). He said I'd get more vacuum from there rather then leaving it at the vacuum advance port. So he then capped the vacuum advance port instead.

Is this correct?

Thanks!
 
have you simply raised the idle speed by turning the screw clockwise?

What compression ratio and what duration @.050 ?

and the mechanic is wrong, last I checked there was no bleed off hole in the vac diaphragm.
 
myasylum said:
Well, it turns to the left about a 1/2" and you can hear a spring move. It doesn't turn at all the other way.

One of the things the "mechanic" did is that he moved to hose on the carburetor for the advance to the "full vacuum manifold port" that I had it capped. (I have a Holley Street Avenger). He said I'd get more vacuum from there rather then leaving it at the vacuum advance port. So he then capped the vacuum advance port instead.

Is this correct?

Thanks!
Click to expand...



well if it has full vac at idle then your advance is in from the second you start it. put the vac advance back where its supposed to be and see what happens...
 
abodyjoe said:
well if it has full vac at idle then your advance is in from the second you start it. put the vac advance back where its supposed to be and see what happens...
Click to expand...

That is what I was thinking when he did that, but since he was the "mechanic" I thought I'd give him the benefit of the doubt. I'll go try that now...
 
Another thing too, I'm assuming your checking the timing by the timing marks on the crank simply because I know of no other way (I'm 16 1/2 so, no big surprise) ensure that the 0 mark on the crank is indeed TDC for #1 cylinder. This can be acheived one of two ways.

Method 1. Remove number one cylinder's spark plug and place a finger in the whole trying to acheive the best possible seal. Now either turn the engine by hand if you can, if not disconnect the secondary wire which runs from the coil to the center of the distributor and have an assistant "bump" the ignition. If no assistant is available, it is much easier to turn an engine by hand when all the other spark plugs are removed, this way no other cylinders create compression thus making the engine easier to turn. With your finger in the spark plug whole, try to feel for the moment when the cylinder no longer developes pressure on your finger, remember to get the best possible seal. The moment in rotation at which you lose pressure, you've found #1's TDC. Check to make sure the 0 on the plate near the crank lines up with the timing mark on the crank. If not there's your problem.

Method 2. This is exactly the same procedure as number one, only you are replacing you finger with the end of a coat hanger that's been bent relatively straight. Make sure that at some point in the engines rotation the end of the coat hanger makes contact with the piston, for the coat hanger will cease to move up and out of the spark plug whole upon TDC. I personally do not recomend this method because common sense says that the coat hanger might damage something inside the combustion chamber. You can however substitute the coat hanger with a stiff insulated wire. And BTW, this method is most easily accomplished by hand turning the engine.

Good luck!
 
Well... It's difficult to check the timing now because it's getting late. (I have cranky neighbors)

However I did switch the hose and the cap (to where it was originally) and it runs A LOT smoother now at idle.

I'm not sure what the timing is yet, but it sure fixed something!

So much for the "mechanic". I wish I could find one that knew what he was doing around here. He did say that "he didn't understand why I was using vacuum advance at all."

Don't ask me????

Thanks! I'll check the timing again tomorrow! Car runs great!
 
I do have a question though!

When you do the initial timing, do you cap the distributor, or the carb? Or neither?

When you check total timing is it still capped or plugged back in as normal?

Thanks!
 
Well, I'm glad you've got things sorted out and I totally understand the whole neighbor dilema. The way I could justify your "mechanic's" comment on your use if vaccum advance, maybe he didn't know or forgot that said car is a street car. At least I'm assuming it is, for that is the only reason I could see having vaccum advance.
 
myasylum said:
I do have a question though!

When you do the initial timing, do you cap the distributor, or the carb? Or neither?

When you check total timing is it still capped or plugged back in as normal?

Thanks!
Click to expand...


yes unhook the vac advance. initial it shouldn't matter if ya cap it but total it would be a leak un hooked so cap it.
 
Initial is checked with the vaccum hose disconnected from the distributor and plugged, the hose is still attached to the carb. Total timing has the the vaccum hose attached to the distributor.
 
/6 Matt said:
Initial is checked with the vaccum hose disconnected from the distributor and plugged, the hose is still attached to the carb. Total timing has the the vaccum hose attached to the distributor.
Click to expand...


should check both total mechanical advance then the vac advance .
 
Agreed, I kind of confused myself. Check initial with the hose plugged anyways then check total mechanical advance. Then hook the hose back up and check FINAL advance.
 
So plug the distributor for the Initial timing, not the carb?
Then plug back in for total?

Sorry, I tend to make things harder then they are...
:dontknow:
 
You unplug the hose from the distributor end and put in a screw (or something that plugs the hose up). It doesn't matter beans if the distributor is plugged or open. What matters is the carb vacuum port is plugged.
 
Ah, ok. I get it! Thanks! May I ask why the vaccum gets plugged? I'm learning here. :) :read2:

Thanks!
 
here read through these articles. it explains what is needed to do pretty well.

timing1.jpg


timing2.jpg


timing3.jpg


timing4.jpg
 
abodyjoe said:
here read through these articles. it explains what is needed to do pretty well.





timing3.jpg
Click to expand...

Those articles have some good info but also one thing that is totally wrong. I cut the first page out as all in it is correct. The incorrect part is right at the top of the middle column. He states "Advance cans are adjustable. Insert a 3/32" allen wrench through the vacuum advance nipple. You'll feel it lock in. Turning counterclockwise retards, clockwise advances timing". The vacuum advance is adjustable but the adjustment is just a spring that affects how much vacuum it takes to pull the can in so it does not affect how much timing the can produces. There is a fixed amount of timing advance in the can. With this adjustment you can tailor how fast the vacuum advance timing will come in and that's it.
 
O.k. I have initial set at 35 degrees. The problem is that I don't know what it's suppose to be set at? It starts to die at 25, and 45, so 35 degrees seemed "safe".

When I plug the vacuum advance back in, it stays at 35 degrees. When I go up in RPM for total, it goes up 10 degrees at 45 degrees.

Does that seem right?
 
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