Timing question(s)

[one1]

I want to ask questions about timing that will give me the proper understanding of the timing, not just reading the idiot marks. My first question however is about one of the idiot marks. LOL.

Diamond on the cover above the oil pump sprocket and the notch on the sprocket. This is correct for TDC?

Second question, if I remove the timing cover with the marks on bottom how do I know where TDC is without the cover marks? I have the number one piston up (and number 4 of course) at the top so I'd like to know if that is all I need to be where I need to be or if I rotated it again the marks on the harmonic balancer would change position when the #1 piston comes to TDC again? (like a 2:1 ratio)

I have the head ready to go back on the engine so I can set the head anywhere I want before I put it on. What is the way to make absolutely sure it is at TDC just like the oil pump and harmonic balancer?

 

[Insanejughead]

The harmonic balancer is keyed. It's mark can't get messed up. Same with the oil pump sprocket.

Since you have the head off, the number one piston being at top dead center is good as it is right now. Remember, the pistons are TDC once per rotation, but one rotation is for the compression stroke (the TDC you need) and once for the exhaust stroke (the TDC that's opposite what you need). However, without the head on the block, TDC is like you have it with the #1 cylinder at the top of it's stroke.

Now, when you put the head on the block, you'll want to have the camshaft sprocket aligned to the 5 o'clock position (looking at it head on). You can align it that way on, or off, the block. It's a non-interference head, so you won't have to worry about hitting pistons and bending valves or anything like that.

Once you do get it on the block and torqued properly, etc. etc. etc. You will need the plastic cover put on the front of the block. It has the alignment mark that you need to have the sprocket line up to.


The good thing is this, if you're off by a bit, you'll probably only be off by one tooth on the belt and sprocket. That is easy fixed, but it's good to always rotate the engine crank bolt by hand to make sure that, with each two turns of the crank, the cam sprocket lines back up to the exact same 5 o'clock position while the crank and the oil pump line up with their timing marks exactly.

Once you get all of them double checked, tighten your timing belt tensioner and you're good to go.

 

[4b316]

If you look at the bottom gear on the crankshaft,you will see a keyway slot,put this at 12 o'clock and you are at TDC.You will also see a little notch in the front seal cover,this lines up with a dot on the bottom gear for TDC.Your timing marks are on the back cover so just line the diamonds and triangles on the upper gears.The notch that you have pictured is not a timing mark,there will be a diamond and a triangle stamped in the flat surface.Both oil pump and cam gear are the same.Here is a good read if you haven't all ready http://www.therangerstation.com/Magazine/Summer2010/4cyl_timing_belt.shtml

 

[Insanejughead]

4B, if he has the head off, he doesn't need to refer to the marks on the crank sprocket or the harmonic balancer. The piston being at the top of the cylinder is all that is necessary to know that it's at TDC.

 

[one1]

Thank you, I'll have to read that a few times and let it soak in. I've always had to do the engine with the idiot marks because I have never had the head off, but with it off I really want to understand it and the mechanics without referring to the marks as my only guide. I'm expanding my horizons a bit with this opportunity I have. The head just got back today so I am ready to tackle this.

When I pulled the head off there was a mark on the camshaft that was up at 12 and the lobe was facing 9 o'clock at the time the block was at TDC. This is the mark and here is where the sprocket is at that mark.

 

[Insanejughead]

Could you post a picture of the sprocket, looking straight on at it, simply for my sake.

Your engine is a '95-'97, right?

 

[one1]

Yes. I will.

Here's where the block is for now. So the oil sprocket up there and the block here. Now just get the head set.

 

[one1]

Here ya go. I'm goin in and gettin her done.

 

[one1]

 

[one1]

As long as I am on the TC mark I should be in the spot, right? I'm trying not to be a tooth off and having to redo it.

So the oil pump notch at the diamond is supposedly right, but that's not the case for the cam which the key is tdc and the notch is 10 o'clock. Confusing because when I took the engine apart and the block and head were at tdc the oil pump sprocket was also at 10 like the cam sprocket. The key for the oil pump sprocket is in the identical position as the cam so which is right. Put the notch at tdc or the key? As stated for the record the key on them was tdc when it came off. (Why even put that notch there?)

This leads me to believe I should have the oil pump sprocket notch and cam sprocket notch at 10 o'clock then put the mark on the harmonic balancer pulley to TC.

SOUND RIGHT?

 

[Insanejughead]

Okay, you have missed one VERY important concept about this whole issue.

Top Dead Center ONLY refers to the #1 piston being at the top of the cylinder. The camshaft keyway is NOT supposed to be facing "up". So don't even use the key slot to determine TDC for the camshaft.

The alignment mark for the camshaft (or that stamped piece of metal that sits directly behind it) should point at the 5 O'CLOCK POSITION for the timing to be correct.


So, turn your camshaft clockwise until that alignment mark gets to the 5 o'clock position as you are looking at it from the front of the motor.

 

[Insanejughead]

Oh, and don't confuse CRANKshaft with CAMshaft...


After reading 4b316's post, I feel you may have accidentally made that mistake. However, with the harmonic balancer still on the front of the crank, you can't see the key slot and sprocket that he is referring to.

 

[one1]

I'm not confusing them, I want to make sure they weren't guided by the key as well.

You can see the key on the harmonic balancer with it assembled, you just have to look close. It is tdc when the mark reads TC.

You can see the key in this pic.

 

[Insanejughead]

Okay, but I'm just trying to stress the point that you don't need to talk about the key slots on any of the shafts.

In fact, don't do it in the future because people will get confused and think that you are referring to the keys as the way to figure out timing.

Go off of the marks on the sprockets. They are larger, which allows for a smaller margin of error when checking timing, and can only be wrong if they are badly damaged (which would take a LOT considering they are spun by a rubber band belt.)


So as to make this NOT confusing to anyone in the future, here is the position of each of the aligning marks on the sprockets.

CAMshaft = 5 o'clock
Aux/Oil pump shaft = 12 o'clock
Crankshaft = 1 o'clock

 

[one1]

Let me show you why this has been confusing for me.

Here's a thread showing the timing marks on the cam:

http://www.therangerstation.com/forums/showthread.php?p=679878

Now here's my timing cover:

What are the freaking odds?

That's why I have been so confused. This could only happen to me.....