Determining TDC on a 4.6L

[delling3]

For whatever the reason, I am struggling to establish #1 TDC on the compression stroke. I have a compression gauge installed in the #1 spark plug hole, and have turned the crank over multiple times with a breaker bar. I am not seeing any compression reading. Maybe my gauge is bad (it's a Harbor Fraught cheapy), but it has always been sufficient for working on my motorcycles, so I presume it should work here. So, my question is, what is another way to make certain that I am at TDC on the compression stroke? I assume that if the camshaft is "off lobe" on the #1 intake valve, and the timing marks are at top dead center, I must be on the compression stroke, yes?

And to confirm, the intake valve on #1 is the forward valve, correct?

 

[lwarrior1016]

May I ask why you’re trying to find tdc?

 

[outdare]

Old school way, you can use a pencil or stick. This would visually establish TDC.

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[ttocs]

I always did it with a helper turning the key while I fingered her.

 

[outdare]

I always did it with a helper turning the key while I fingered her.

That sounds interesting and a whole other thread. [emoji102][emoji41]

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[delling3]

May I ask why you’re trying to find tdc?

In preparation to remove the harmonic balancer and timing cover (for a cam swap).

 

[delling3]

This will find TDC, but not necessarily on the compression stroke!

Old school way, you can use a pencil or stick. This would visually establish TDC.

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[lwarrior1016]

In preparation to remove the harmonic balancer and timing cover (for a cam swap).

You don’t need tdc for any of this. Put the crank key way at 9 o’clock before removing the cams so all the pistons are below the deck and you don’t smack any valves. When you go back together with it, make sure the crank timing mark is pointing straight down (6 o’clock). You’ll have to move the crank a little bit to reach that point. Then you just line up the dots. Tdc and compression stroke are not needed for this procedure.

 

[delling3]

You don’t need tdc for any of this. Put the crank key way at 9 o’clock before removing the cams so all the pistons are below the deck and you don’t smack any valves. When you go back together with it, make sure the crank timing mark is pointing straight down (6 o’clock). You’ll have to move the crank a little bit to reach that point. Then you just line up the dots. Tdc and compression stroke are not needed for this procedure.

Ok, that’s helpful. Clymer manual details the TDC procedure. Doesn’t matter what phase the cams are in?

 

[Burninriverdiver]

Listen to @lwarrior1016 he’s helped me set timing from scratch a few times I’ve had my cams off

 

[lwarrior1016]

Ok, that’s helpful. Clymer manual details the TDC procedure. Doesn’t matter what phase the cams are in?

You’re pulling the came out aren’t you? When you install the cams, they will only time the correct way. As long as you line the dots and chain links up, you will be fine.

 

[delling3]

Hey all, it's been a while. I got 1/2 way thru my cam and intake swap over the winter, and then life got in the way. As a result, the car has been sitting for months with no progress. Finally getting back in the garage, and I find myself doubting what I have done so far. Need someone to talk me off the ledge.

Cams are in the car, and the timing chains and guides and tensioners were installed. Basically ready to reinstall the timing cover. I decided to roll the engine over by hand to make absolutely certain that their was not PTV issues. I took some neon paint an marked the timing marks on the chain. Some of the paint got onto the cam gear as well. I have rotated the engine thru several revolutions, but it seems like the painted marks on the chain are no longer matching up with the paint on the gear tooth? The engine turns over fine, and aside from the bump in compression when the the cylinder is coming to TDC on the compression stroke, there is no resistance from PTV contact.

Am I going insane? Could my engine be so totally mistimed, but not have PTV contact? I was really confident that I had all the marks lined up on the crank pulley, timing chains and cam gears, but now I am completely lost.

Thanks in advance.

 

[muzzy25]

Marked chains are for installation set up
Won't be in same place after a revolution

 

[delling3]

Is this really the case? Is there no correlation of the marked links on the timing chain and the timing marks after the engine is rotated? Than seems counter-intuitive to me. Unless the chain "skips" a tooth, how does the relationship change? It seems that after the correct number of engine rotations, that all of the marks would once again line up. Can someone help me understand this?

 

[muzzy25]

Done Mark chain last week
Chain mark links will move up with every rotation. Because crank sprocket is smaller than the
size off cam sprocket
Does take alot off turns to line up again
Same as marked belts

 

[RAU03MACH]

Got to start from scratch if you can't find the timing marks
1 find top dead center
2 find the marks on the cams and position into place
Install your sprockets should fall into place of timing

 

[az97cobra]

I had trouble if i didn't start the cams in the configuration shown on pg 9 of this diagram.
Once I turned the crank it just seemed like an eternity when turning the crank to get the marks to line up again but it eventually happens.

 

[delling3]

Thanks for that. I used the same configuration shown in the ford diagram when I installed my chains several months ago. I simply wanted to confirm that I had no PTV issues by rotating the engine by hand. I assumed that the timing marks on the chains would return to alignment after a (4) revolutions - i.e. back to the same relative position (i.e. #1 piston at TDC on compression stroke). This is what was causing my concern. Sounds like what I am seeing is nothing to worry about.

 

[lwarrior1016]

Yes, you’re fine. It takes FOREVER to make the dots line back up. If they were good before you rotated, they are fine.