Dwell Angle, Timing, and CHT sensor questions, Timing way off (well above 27 Deg) but runs...??? Options

[NJ914]

Looking for inputs from those who know...

Situation: Engine runs but timing is way off. 27 degrees is at 1800rpm[b]. 3500rpm is in the mid to upper 30's. When attempting to adjust the distributor to spec, engine dies. Only runs at higher timing angle. Not sure what the cause is.

1: Distributor gap is currently at 0.018" and dwell is 50-51 degrees through speed range.
Per the Haynes book, 1 degree of dwell can change the timing by 3 degrees.
Spec is 44 to 50 degrees.

Is this correct?

If I open the gap larger to bring the dwell down to 44 degrees, will this help bring the timing closer to spec?

2: Measured the CHT sensor cold and it was 3100 ohms. I believe it is supposed to be more in the 2000 - 2500 ohm range...?

What is the correct range for the CHT sensor cold?

It is supposed to drop below 100 ohms when up to temp. Is this correct?

Could the higher than spec resistance of the CHT sensor be contributing to the timing issue?

[GregAmy]

(IMG:style_emoticons/default/agree.gif)

Where I was going with this...you have not yet verified that the timing mark on the fan is in the actual correct position or is the correct one. You could be looking at the wrong mark, or (sorry, I can't resist) the fan hub has spun on the crankshaft.

On my 2L - what engine is yours? - I have a notch on the flyhweel at #1 TDC that's visible from an access hole at the top of the transaxle; you might have to push the sheet metal back to see it. Compare that mark to the fan marks, see if they agree.

http://www.914world.com/bbs2/index.php?showtopic=339759
http://www.914world.com/bbs2/index.php?showtopic=342133
http://www.914world.com/bbs2/uploads/post-...-1565184944.jpg

And rechecking proper valve clearance is easy enough.

http://www.914world.com/bbs2/index.php?showtopic=28758

I can't see how the cam was mis-dialed-in and yet "[e]ngine ran without issue until a few years ago when it was removed to correct oil leaks." So I think it's something simplier. - GA

[NJ914]

(IMG:style_emoticons/default/agree.gif)

Where I was going with this...you have not yet verified that the timing mark on the fan is in the actual correct position or is the correct one. You could be looking at the wrong mark, or (sorry, I can't resist) the fan hub has spun on the crankshaft.

On my 2L - what engine is yours? - I have a notch on the flyhweel at #1 TDC that's visible from an access hole at the top of the transaxle; you might have to push the sheet metal back to see it. Compare that mark to the fan marks, see if they agree.

http://www.914world.com/bbs2/index.php?showtopic=339759
http://www.914world.com/bbs2/index.php?showtopic=342133
http://www.914world.com/bbs2/uploads/post-...-1565184944.jpg

And rechecking proper valve clearance is easy enough.

http://www.914world.com/bbs2/index.php?showtopic=28758

I can't see how the cam was mis-dialed-in and yet "[e]ngine ran without issue until a few years ago when it was removed to correct oil leaks." So I think it's something simplier. - GA

Since the fan only has one mark, I was not using it for reference. I use three references.

1: The distributor rotor is pointing toward the #1 plug wire in the cap.
2: The notch in the Flywheel is at the 12 o'clock position.
3: Remove the #1 spark plug and confirm the piston is at the top.

Does this sound like I have it covered?

[Dave_Darling]

1: The distributor rotor is pointing toward the #1 plug wire in the cap.
2: The notch in the Flywheel is at the 12 o'clock position.
3: Remove the #1 spark plug and confirm the piston is at the top.

Does this sound like I have it covered?

No. The piston will be at the top of the cylinder both at TDC and at 180 out from TDC. To make sure you're not 180 out, you need to check the position of the rocker arms. For TDC#1, both rocker arms will have some slack in them. (Assuming solid lifters and stock pushrods.)

--DD

[NJ914]

1: The distributor rotor is pointing toward the #1 plug wire in the cap.
2: The notch in the Flywheel is at the 12 o'clock position.
3: Remove the #1 spark plug and confirm the piston is at the top.

Does this sound like I have it covered?

No. The piston will be at the top of the cylinder both at TDC and at 180 out from TDC. To make sure you're not 180 out, you need to check the position of the rocker arms. For TDC#1, both rocker arms will have some slack in them. (Assuming solid lifters and stock pushrods.)

--DD

Had some time over the holidays to do some more investigation. The first go round I rotated the dist. rotor toward the #1 plug, removed plug #1 and confirmed the piston was at the top of the cylinder. BUT, the Flywheel notch was not visible at the 12 o'clock position. I rotated the engine 180 degress and then had the rotor pointing toward #1 plug, piston at the top, and flywheel notch visible at 12 o'clock. It sucks not having a TDC mark on the fan. I went ahead and put a black mark on this position for the future.

Felt confident I was at #1 TDC, so I went ahead and removed the exhaust, heat exchangers, etc.. (76 2.0 can't access valves without removing) and opened up the valve covers. Checked valve clearance on all 4 cylinders. Found the following:

#1: Intake closed. Exhaust 0.008"
#2: Intake closed. Exhaust 0.009"
#3: Intake 0.006" Exhaust 0.008"
#4: Intake 0.002" Exhaust 0.008"

Checked them twice. Based on these findings I'm surprised it ran at all.

Adjusted all Intakes to 0.006" and Exhausts to 0.008". Checked them twice.

Reassembling the exhaust now and praying this will solve the problem.

[NJ914]

1: The distributor rotor is pointing toward the #1 plug wire in the cap.
2: The notch in the Flywheel is at the 12 o'clock position.
3: Remove the #1 spark plug and confirm the piston is at the top.

Does this sound like I have it covered?

No. The piston will be at the top of the cylinder both at TDC and at 180 out from TDC. To make sure you're not 180 out, you need to check the position of the rocker arms. For TDC#1, both rocker arms will have some slack in them. (Assuming solid lifters and stock pushrods.)

--DD

Had some time over the holidays to do some more investigation. The first go round I rotated the dist. rotor toward the #1 plug, removed plug #1 and confirmed the piston was at the top of the cylinder. BUT, the Flywheel notch was not visible at the 12 o'clock position. I rotated the engine 180 degress and then had the rotor pointing toward #1 plug, piston at the top, and flywheel notch visible at 12 o'clock. It sucks not having a TDC mark on the fan. I went ahead and put a black mark on this position for the future.

Felt confident I was at #1 TDC, so I went ahead and removed the exhaust, heat exchangers, etc.. (76 2.0 can't access valves without removing) and opened up the valve covers. Checked valve clearance on all 4 cylinders. Found the following:

#1: Intake closed. Exhaust 0.008"
#2: Intake closed. Exhaust 0.009"
#3: Intake 0.006" Exhaust 0.008"
#4: Intake 0.002" Exhaust 0.008"

Checked them twice. Based on these findings I'm surprised it ran at all.

Adjusted all Intakes to 0.006" and Exhausts to 0.008". Checked them twice.

Reassembling the exhaust now and praying this will solve the problem.

Finished putting everything back together yesterday and attempted a start.
No Joy!! (IMG:style_emoticons/default/sad.gif) (IMG:style_emoticons/default/mad.gif)

Would only run (and not well) with the timing advanced into the high 20's low 30's.
Wondering if the TPS could be a problem? Running out of ideas...
Is it possible for TDC to not be in alignment with the notch in the flywheel?