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How do I adjust my cam sprocket for chain stretch?


Milenko2121

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The distributor only goes in one way. The distributor drive is from the oil pump. As long as you intall the oil pump correctly the distributor will be fine. When everything is correct the top edge of the distributor drive tang will be at about 11:30 and the distributor rotor will point towards the vacuum advance diaphragm. The 5 degrees BTDC is fine tuning. You adjust it by rotating the distributor slightly while the engine is running using a timing light.

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Yes. Good advice from beerman.And refer to the the Haynes manual. Don't rush. Line up the marks on the pump and the shaft, and you need to keep the pump and its shaft in the correct alignment as you install it.You need to keep the pump straight as you install, so the shaft can enter through its guide hole. If you are not happy when you look at the position of the tang at the top, pull the pump and do it again.

Edited by olzed
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Yes. Good advice from beerman.And refer to the the Haynes manual. Don't rush. Line up the marks on the pump and the shaft, and you need to keep the pump and its shaft in the correct alignment as you install it.You need to keep the pump straight as you install, so the shaft can enter through its guide hole. If you are not happy when you look at the position of the tang at the top, pull the pump and do it again.

the main question I have is do I install the pump and dizzy at TDC or when the pulley is pointing to the 0 which is just before TDC. Or is my pulley off?

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How are you determining TDC, to figure the pully is off. How far do you think it is off.?

To establish TDC.---

Turn the crank clockwise until #1 piston is at the top of the bore, and both the cam lobes on #1 cylinder are pointing up like ears.

Both valves will then be closed.

Turn the crank till the mark on your pulley aligns with the 0. This will be TDC.

Edit. You can also determin TDC by aligning the cam timing marks through the hole in the top pulley. Always turn the crank clockwise to allow for chain slack. If you go past the marks, then turn the crank back and start over.

Edited by olzed
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How are you determining TDC, to figure the pully is off. How far do you think it is off.?

To establish TDC.---

Turn the crank clockwise until #1 piston is at the top of the bore, and both the cam lobes on #1 cylinder are pointing up like ears.

Both valves will then be closed.

Turn the crank till the mark on your pulley aligns with the 0. This will be TDC.

Edit. You can also determin TDC by aligning the cam timing marks through the hole in the top pulley. Always turn the crank clockwise to allow for chain slack. If you go past the marks, then turn the crank back and start over.

i determined TDC by having the cam at 12oclock (both lobes were up) and the crank at 12oclock(marker was at 3-4oclock).

the mark on the sprocket is also correct

however

when I installed the pulley, the mark was about 5-10 degress off from the 0(it wasn't even on the marker)

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If you have any doubt about the accuracy of the timing mark on the crank pulley you should locate TDC independently of the timing mark.There are several methods to do this. The quick and dirty method is to use a probe that fits into the spark plug hole (i.e. screwdriver). Holding the probe as vertically as possible, place it into the cylinder through the spark plug hole while turning the crankshaft in the normal direction. This may require a helper. Be careful to stop if any resistance is felt. You don't want to damage anything by trapping the probe between the piston and head. As the piston rises the probe will be pushed up. Allow the probe to rise with the piston. At TDC the probe will stop moving even though the crank is still in motion. After you past TDC the probe will begin to fall. Stop and reverse the rotation to a few degrees before TDC. Now go forward again to the point at which the probe is the highest. Make sure to be turning the crank in the normal direction so there is no slack in the drive side of cam chain. This method will get you within a degree or two. If the timing marks are not closely aligned at this point you have a problem with the crank pulley and/or timing mark on the timing cover.

Since you have already installed the cam make sure the lobes for the #1 cylinder are pointing up. If not, you are at valve overlap on the exhaust stroke. Turn the crank 1 full turn and relocate TDC as described above. The cam lobes should now be pointing up. With the crank in this position the other timing marks used for the camshaft installation should all be in their correct places.

There are certainly more accurate methods for locating TDC but they require tools you might not have. This is just an attempt to identify, or rule out, a gross error with the timing mark accuracy.

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got everything put together, however i'm having a few issues.

the car idles, but the exhaust is quiet, and the idle keeps bouncing.

the only way I can get it to idle fine if I raise the idle to over 1k, and with the idle screw all the way in, I can't get it lower than 800rpm.

I installed the oil pump to at the 11:30 position at TDC. what am I missing? before I redid the chain, it idled fine.

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