Z24 top dead center issue

[Datsun pickup]

I am having trouble setting tdc on the z24 engine head. If anyone knows how to set tdc on the engine head I need to know.

[datzenmike]

TDC on the compression stroke will see both valves on cylinder number one closed. The front cam lobe will be at about 8 o'clock an the second lobe at about 4 o'clock. Now find the timing scale on the front of the timing cover just behind the rear pulley and above the oil pump...

 

 

Now look on the edge of the pulley for a small v notch. You may have to turn the engine slightly by hand to line it up with the O at the top of the timing scale. You are at TDC.

 

Each peak or valley is 2.5 degrees. The timing for the Z24 is 5 BTDC so set on the next peak or point below the O

[Datsun pickup]

I tried to set the lobes at 8 and 4 o’clock but they would not match up. What about the numbers on the camshaft gear, do they set at tdc.

[datzenmike]

Setting 8 and 4 is just approximate. Both lobes must be pointing downward. There are 2 TDCs and you want the compression stroke TDC, not the exhaust stroke TDC, so roughly setting 8 and 4 just gets you in the ball park on the compression stroke.  You now have to look on the crankshaft pulley for the notch and align with the 0 (zero) timing mark on the scale put there by the factory. 

 

What are you trying to do? 

[Datsun pickup]

I am trying to set tdc on the head off the engine. The number 2 on the cam gear is lined up with the timing mark behind the cam gear.

[datzenmike]

 The Z series heads don't really have a dedicated timing mark behind the cam sprocket.

 

Need more info.

 

Is this so you can install the head onto an engine?

Was this engine set to TDC before removing this head?

Was the timing chain and the sprocket marked so that it can go back together in the same position?

[Datsun pickup]

What are the numbers 1,2,and 3 for on the cam gear for

[Datsun pickup]

I have the number 2 set at the mark behind the cam gear, but what are the numbers 1 and 3 for?

[datzenmike]

As wear accumulates in the chain and two sprockets, but mostly if the head is milled down to flatten it, the cam is no longer in it's timing relation to the crankshaft. Slack or milling the head will mean the crankshaft is advanced from it's original position. Each number on the cam sprocket adjusts the sprocket by 4 degrees. #2 is the factory setting and should be good for the life of the engine.

 

Again are you going to...

 

30 minutes ago, datzenmike said:

 

 

Is this so you can install the head onto an engine?

Was this engine set to TDC before removing this head?

Was the timing chain and the sprocket marked so that it can go back together in the same position?

 

 

If the cam was turned after it was removed from the engine YES, it needs to be set to TDC or close enough, so that valves do not get bent while bolting it to the bock.

 

IF the number one and four pistons are fully up and level with the top surface of the block it can be said the crankshaft IS at TDC.

 

 

[Datsun pickup]

Thanks for the help, the engine is coming together!

[Datsun pickup]

How do I adjust timing on the engine. It is 20 degrees off.

[datzenmike]

Ignition timing?

Set to TDC on compression stroke on #1 piston using the ignition mark on the crankshaft pulley and the timing scale. Remove distributor and look in hole.

 

 

You should see this...

 

 

If not you will need to drop the oil pump and the spindle above it that turns the distributor. It's driven by a worm gear on the crankshaft and has 20 teeth. Each tooth is 18 degrees so advance or retard it one tooth. Get into the same position as the picture above.  

[Stoffregen Motorsports]

20 degrees and still running?

[Datsun pickup]

Yes it still runs.

[datzenmike]

The timing for the Z24 is 3 degrees BTDC. 20 seems a bit much to actually be running so possibly operator error?

 

https://y.yarn.co/f7889fbc-b69e-4dee-9aff-231b468beb7d.mp4

 

 

To adjust the timing, loosed the hold screw on the distributor so it can be turned. Turning clockwise advances, counter clockwise is retard. I doubt that it will adjust that much though. 

[Datsun pickup]

I rotated the engine to tdc and it is at about 3-4 degrees.

 

also, my fuel pump won’t work. I think it is not getting power.

[datzenmike]

So not 20? this was corrected?

 

Check your wipers work. If they do, it's not the fuse for the pump.

 

 

 

 

[Datsun pickup]

The fuse and the relay both have 12 volts.

[Stoffregen Motorsports]

How long has the truck been sitting? Sometimes electric fuel pumps can get stuck, and a good smack with the plastic end of a large screwdriver could be all it needs to get working again.

[datzenmike]

Well unplug the pump and check for volts when someone turns the ignition on and tries to start.

 

If voltage then the pump relay is working and the pump is not.

If no reading then the pump relay is not working.

[builte]

I dread having to learn how to do timing it seems extremely complicated 

[datzenmike]

Engine running? Set up the timing gun per the instructions. The timing mark is a notch on the pulley and should show in the flash of light as it passes the timing scale here. Might help to find it and mark with crayon or dab of paint...

 

 

The very top point is ZERO degrees with 5 degrees between each peak and valley.

 

 Ignition timing is 3 degrees +- 2 degrees. To adjust there is a 10mm bolt on the distributor that is loosened and the distributor turned clockwise to increase the timing and counterclockwise to retard it. If adjusted you should check your idle speed it may go up if you advance and down if you retard the timing.

 

You should put your location in your profile saves asking if California or not.

[Stoffregen Motorsports]

4 hours ago, builte said:

I dread having to learn how to do timing it seems extremely complicated 

There are two kinds of timing. Cam timing and ignition timing. Make sure you're clear on which one you're doing.

 

Oh, wait, there's another kind that Hainz invented - timming.

[datzenmike]

 

Timming? That's what friends go do in Canada when it's too snowy to do much else...

 

 

[builte]

You guys are awesome