O Degree Timing Mark

[Zed Head]

You mean timing challenged, right?

 

Actually, your cam timing is advanced.  The notch is on the cam sprocket and it is ahead of the groove, in the direction of rotation, which is clockwise in your picture.  I don't even try to remember what's what on rotation direction, I just know that the straight side of the chain pulls on the sprocket.  The straight side is to the right in your picture, so the chain has pulled the notch ahead of the groove.  Opening and closing the valves earlier.

 

So the pulley timing mark is at at zero now?  The advanced cam timing might explain why 34 degrees runs better.  The intake valve is closing early,  Less charge in the chamber, which would need advanced timing to burn completely.  Which plug wire is the distributor rotor pointing at, just to be sure #1 is #1.

[rossiz]

reminds me of a '68 firebird with the pontiac ohc engine - replaced the timing belt and could NOT get it to start. finally figured out the plug wires were on the wrong distributor ports. seems the belt had stretched so much over time, that the PO couldn't get enough advance and had moved the plug wires one position forward to compensate. what a mess.

 

it did run fine after i got it sorted out though...

[beermanpete]

The cam timing issue dose not have any affect on the ignition timing. You need to verify TDC without using the marks on the crank pulley to validate the timing marks on the pulley. Try using a long thin rod O(screwdriver) placed through and held by hand in spark plug hole in #1 cylinder. Turn the cracnk by hand slowly and feel the piston movement. Stop when the piston is at the top then look at the timing marks. This is not a super accurate method but should get you within a degree or two if you are careful. If the timing marks are off make a new mark and then check the ignition timing with your new timing light.

 

Also, if the marks are off it indicates a problem with the harmonic damper. Place a mark across the damper/pulley faces that spans the rubber layer. Monitor the line over time to see if the inner and outer parts move and cause an offset in the line indicating a failure of the bond between the rubber layer and the metal parts.

[siteunseen]

Thanks for the replies guys.  Number 1 piston is at TDC, it went up then back down so I pulled the cam back a hair and it hits that spot where it just kind of "floats", no movement.  I can't get a good shot of the timing mark on the pulley, I hate that A/C compressor mounted on the passenger's side behind the fuel pump, the belt and pulley make it almost impossible to do anything.

 

I did notice something good when I removed the valve cover, it was like the Exxon Valdez had ruptured on top of the head.  It has an aftermarket spray bar just like another E88 head I have that has been reconditioned, so I'm pretty sure the valve stem seals have been upgraded.

 

I've just turned my heater on downstairs.  When it gets warmer I'll take more photos, rotor position and I'll try my best to get a shot of the pointer and 0 degree notch.

 

I understand now about the sprocket being ahead of the mark on the dowel plate, thank you Zed Head.

I'm off work today and am not planning on leaving so I'll have plenty of questions and pictures for y'alls review later in the day.

It's a Bloody Mary morning!! 

[siteunseen]

I've got those questions now.  It's seems the rotor button has passed #1 at TDC.

The 0 degree notch has passed the pointer at TDC.

 

My plugs are light brown on one side.  #1 is at the right, #6 far left

and white on the other

Does that mean anything?  Maybe it's a little lean?

 

I'm going to paint that dot BeerManPete said to do now and maybe in a couple of hours I'll be able to get the thermostat to open without dieing of carbon monoxide poisoning and recheck the timing.

 

Thanks again for the help!

Cliff

 

Well hell I forgot to say my understanding to see if it jives with the issue.

I've got it so advanced the spark has happened before TDC.  The reason that happened is the 0 degree notch isn't lined up with the pointer for whatever reason, likely the pulley as it has the forward most groove for the A/C belt and by the time it gets to the timing marks it has slipped/moved.  If I paint the dot at TDC I can time it correctly and the explosion will occur at TDC??? 

[Zed Head]

Your TDC location method is a little bit imprecise.  There's play in the bearings and the piston barely moves at all as it goes over the top.  The best way to locate it precisely is with a piston stop or a dial indicator with the head off.

 

But it looks like the mark, and the crankshaft and the cam marks are all within a few degrees.  Certainly not 20 degrees off.   You can see by the distributor picture that the points of the reluctor are not close to aligned.  When those two points pass each other that's when the spark happens.  So your timing measure of 34 degrees seems in the ballpark.

 

Still odd that so many parts are right but the timing is off.  The one picture you don't have is of the #1 cam lobes, confirming that they're fully closed. 

 

It's a puzzle.  You might put the sprocket back to number 1 hole, recheck everything and see how it runs then.  

[siteunseen]

It's at number 1 on the sprocket.

After making new zero mark at 850 it reads 22 on the light. That's at the new TDC spot. 2500 rpm reads 40 at the new TDC mark.

I'm done and the dizzy is all the clockwise.

Test drive next.

[240260280z]

Rossiz's l28 had more kick with max advance 36-38 degrees so you are in the region.

[Zed Head]

So you're showing that the damper mark was off by 12 degrees.  34 - 22.  Now you have to worry about the damper and if it's failing.  Should last a while, but if the mark keeps moving that's a bad sign.

[siteunseen]

I put a scratch mark across all 3 grooves to watch and see if they separate.

 

I just drove it and it's not even noticeable from what it did before.  But the clutch is going out and I really want the 5 speed so I'm gonna drive it until I can get the E31 head ready and just rebuild the motor.

 

What do you all think about my plugs?  Should I go 1/4 turn richer?

 

thanks again,

Cliff 

[beermanpete]

The plugs look ok to me. The modern unleaded fuel does not color the plugs as much as the leaded fuel of 60s did.

[madkaw]

The latest timing figures seem right and the plugs look good, so if it runs good I wouldn't sweat it. Are you sure the dizzy/oil pump shaft is clocked correctly? Might be off a tooth.