timing gear alignment.

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Onus Gumboot

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A strange question. I am putting a new timing chain on my 225. A 1976. not the original motor, so it's 76 or newer. It has the peanut plugs. Anyway. the timing marks on the gears are not right across from each other The crank gear has the mark at about 10 oclock which should be right. But the valve gear is also at 10 oclock. It was running pretty good, but the compression on no. 1 cylinder is low, so I am in the process of doing a valve job, and while I'm waiting for parts, I decided to do the timing chain, since I already have that. It looks like the original timing chain and gears, since it has the nylon teeth on the valve gear. But that seems like it's 180 degrees out. Would it even run like that? Anyway happy fourth for those who see this today.
 
That sounds correct for being timed on #1.
 
What does the factory service manual say?

Free download at MyMopar.Com
 
Dana67Dart said:
What does the factory service manual say?

Free download at MyMopar.Com
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The manual says the marks should be facing each other. Which is what I expected to see when I took the cover off, with the #1 cylinder up, and the rotor in the distributor facing #1 terminal. But it is opposite of that. So I am not sure if I should put it back together like it was, or turn the cam gear so that the marks face each other like it says to do in the book. I don't know if I'm missing something here, or someone worked on it before, and got the marks off. You wouldn't think it would run if that was the case, but it ran fine, really. Starts right up every time. Just a problem with #1 cylinder compression, which I suspect is a burnt valve. I have a gasket set ordered for that, but it won't be here until next week. Until then I am doing the timing chain, which was real sloppy. No broken teeth on the nylon gear though, so I've seen worse.
 
Onus Gumboot said:
The manual says the marks should be facing each other. Which is what I expected to see when I took the cover off, with the #1 cylinder up, and the rotor in the distributor facing #1 terminal. But it is opposite of that. So I am not sure if I should put it back together like it was, or turn the cam gear so that the marks face each other like it says to do in the book. I don't know if I'm missing something here, or someone worked on it before, and got the marks off. You wouldn't think it would run if that was the case, but it ran fine, really. Starts right up every time. Just a problem with #1 cylinder compression, which I suspect is a burnt valve. I have a gasket set ordered for that, but it won't be here until next week. Until then I am doing the timing chain, which was real sloppy. No broken teeth on the nylon gear though, so I've seen worse.
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It says that for ease of timing it up. With the marks facing each other, it is timed up on #6, not #1. All manuals show to time on #6 so you can have the marks right there together and make it easier. Once you get it aligned in that position, rotate the crankshaft once and you will now be in the #1 firing position and you can drop the distributor in. This is why when you bring the engine to #1 compression stroke with the rotor pointing to #1, the timing marks are both at about the 10 O'clock position. Your engine is timed correctly.
 
RustyRatRod said:
It says that for ease of timing it up. With the marks facing each other, it is timed up on #6, not #1. All manuals show to time on #6 so you can have the marks right there together and make it easier. Once you get it aligned in that position, rotate the crankshaft once and you will now be in the #1 firing position and you can drop the distributor in. This is why when you bring the engine to #1 compression stroke with the rotor pointing to #1, the timing marks are both at about the 10 O'clock position. Your engine is timed correctly.
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Thanks. That's what I missed. I didn't see where it says to time it to #6. I new there was something. I have a '67 ford that worked differently. Timed to #1. Runs great.
 
Onus Gumboot said:
Thanks. That's what I missed. I didn't see where it says to time it to #6. I new there was something. I have a '67 ford that worked differently. Timed to #1. Runs great.
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It doesn't. No manual on the face of the planet includes that tidbit, as far as I know. It screws a lot of people up.
 
RustyRatRod said:
It doesn't. No manual on the face of the planet includes that tidbit, as far as I know. It screws a lot of people up.
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I've daily drove a Few of them, all over FL, over the years. Good thing I never had to do a chain. I'd have had some issues! Lol
 
Many V8s are this way. You have to understand the timing sprocket (they are not gears) turns 1/2 the speed of the crank, so every time the crank rotates once, the cam is "1/2 a turn off" It's all "magically corrected" LOL the next turn of the crank.
 
I have come to the conclusion for V8 engines....

The crank rotates 360 deg.

If the timing mark is pointing at 12:00 it is in the correct location. No need to check tdc

The camshaft rotates 360 deg.
If the timing mark is pointing to 6 o'clock it is in the correct location.

No need to check anything else.

I have seen engines that reference 12:00 for both but that's seems to be the exception.

If you think I'm wrong, look at the lobes on the cam to the gear mark, the lobes will be in the same position as long as the dot is in the same location. Same for the crank.
That's why the FSMs don't need to tell you how to index other then align the dots.
 
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Dana67Dart said:
I have come to the conclusion....

The crank rotates 360 deg.

If the timing mark is pointing at 12:00 it is in the correct location. No need to check tdc

The camshaft rotates 360 deg.
If the timing mark is pointing to 6 o'clock it is in the correct location.

No need to check anything else.

I have seen engines that reference 12:00 for both but that's seems to be the exception.

If you think I'm wrong, look at the lobes on the cam to the gear mark, the lobes will be in the same position as long as the dot is in the same location. Same for the crank.
That's why the FSMs don't need to tell you how to index other then align the dots.
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Then you align the dots, install the distributor in pointing to #1 and get back to me on how well it runs, because it will NOT.
 
RustyRatRod said:
Then you align the dots, install the distributor in pointing to #1 and get back to me on how well it runs, because it will NOT
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Explain!

I don't see how it can be any other way.

The crank gear can only go on one way.

The cam gear can only go on one way.

With the dots aligned per the FSM you are good to go.

(Timing the distributer is a separate matter)

If you set the crank to have the #6 ( your words) cylinder at tdc then that would make the dot at 12:00. There is no other position that the dot is at 12:00 on the crank.

Same holds true for the cam. There is only 1 position that the cam gear dot will be pointing to 6:00 and I assume based on your statement that #6 is that position, then the cam will be on the #6 compression stroke.
 
Dana67Dart said:
Explain!

I don't see how it can be any other way.

The crank gear can only go on one way.

The cam gear can only go on one way.

With the dots aligned per the FSM you are good to go.

(Timing the distributer is a separate matter)

If you set the crank to have the #6 ( your words) cylinder at tdc then that would make the dot at 12:00. There is no other position that the dot is at 12:00 on the crank.

Same holds true for the cam. There is only 1 position that the cam gear dot will be pointing to 6:00 and I assume based on your statement that #6 is that position, then the cam will be on the #6 compression stroke.
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I have explained in both my previous posts. Let's see if I can do it again. You're assembling a new engine. Let's say since the OP's engine is a slant 6, that's what we have. You align the crank and cam sprockets with the marks facing each other. Cam sprocket dot at about 5 o'clock and crank sprocket at about 10 o'clock. Dots aligned. With me so far? Now you continue on assembling. Put the distributor in pointing to number 1. Right? WRONG! Because when you time dot to dot at the cam and crank you're timed on #6, not #1. Understand?
 
RustyRatRod said:
Now you continue on assembling. Put the distributor in pointing to number 1. Right? WRONG! Because when you time dot to dot at the cam and crank you're timed on #6, not #1. Understand
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I'm not, nor was I talking about timing the distributer.
Dana67Dart said:
(Timing the distributer is a separate matter)
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I was talking timing the valves.

And yes I forgot the op was on a slant so 6 and 12 dont apply.

But having the dots align does (about 10 and 5)

Timing the dist requires the engine to be at tdc on the compression stroke of the #1 cyl.
 
Dana67Dart said:
I'm not, nor was I talking about timing the distributer.


I was talking timing the valves.

And yes I forgot the op was on a slant so 6 and 12 dont apply.

But having the dots align does (about 10 and 5)

Timing the dist requires the engine to be at tdc on the compression stroke of the #1 cyl.
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Since the OP included the distributor in this discussion, I felt it was necessary to include it in my responses.
 
I think you still need to line the dots up whenever you install a new chain. Set the distributor timing later. Reason being it is really easy to get a slant six chain one tooth off if you don't carefully line the dots up. Happened to me once with a rebuilt slant six long block that I bought because I needed a quick replacement (by which I mean the old motor died and I needed to get it back on the road the next day). Ran smooth but was way low on power, played around with it, finally bit the bullet and removed the timing cover and found out the dots didn't quite line up and the chain was one tooth off. I'm thinking that issue would not be readily seen if the marks were at ten and ten.

Now if you're leaving the old chain on, and the motor ran well, no need to worry about it.

Edit PS: I think I jumped in a bit too quick, assuming the OP was going to replace the chain. I agree that seeing the marks at ten and ten does not indicate a problem.
 
65 Cuda 340 said:
I think you still need to line the dots up whenever you install a new chain. Set the distributor timing later. Reason being it is really easy to get a slant six chain one tooth off if you don't carefully line the dots up. Happened to me once with a rebuilt slant six long block that I bought because I needed a quick replacement (by which I mean the old motor died and I needed to get it back on the road the next day). Ran smooth but was way low on power, played around with it, finally bit the bullet and removed the timing cover and found out the dots didn't quite line up and the chain was one tooth off. I'm thinking that issue would not be readily seen if the marks were at ten and ten.

Now if you're leaving the old chain on, and the motor ran well, no need to worry about it.

Edit PS: I think I jumped in a bit too quick, assuming the OP was going to replace the chain. I agree that seeing the marks at ten and ten does not indicate a problem.
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I agree! I just wanted the OP to know that with the dots facing each other, he's 180* out.
 
RustyRatRod said:
I agree! I just wanted the OP to know that with the dots facing each other, he's 180* out
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Your statement has got me confused...
According to the 73 FSM cam gear and crank gear dots should face each other.


Screenshot_20220705-183257.png
 
Ok again you are focusing on timing the distributer.

I am ONLY talking about timing the cam to the crank. And that is irrelevant to distributer timing.

If the op times the cam to the crank at 10 and 10 you are saying the cam will be timed correctly.

I will take your word for that.

I find it easier to align two dots when they are facing each other.

I get that you are saying that then if you rotate the crank once after 10 and 5 timing you are then on tdc of the compression stroke for the #1 cylinder.
 
Dana67Dart said:
Your statement has got me confused...
According to the 73 FSM cam gear and crank gear dots should face each other.


View attachment 1715952068
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Read further. Somewhere after that page, before the distributor installation instructions it will tell you to rotate the crank one revolution. 1 and 6 are running mates, so both will be at TDC at the same time. One of them will be on TDC compression and one of them on TDC exhaust. I’m not sure why this is so confusing.
 
Dana67Dart said:
Ok again you are focusing on timing the distributer.

I am ONLY talking about timing the cam to the crank. And that is irrelevant to distributer timing.

If the op times the cam to the crank at 10 and 10 you are saying the cam will be timed correctly.

I will take your word for that.

I find it easier to align two dots when they are facing each other.

I get that you are saying that then if you rotate the crank once after 10 and 5 timing you are then on tdc of the compression stroke for the #1 cylinder.
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ALL OF THIS is exactly what I said in post #5. You act as if you have a learning disability.
 
You can throw the distributor in the ditch. That engine in the FSM is STILL 180* out. The distributor really hasn't anything to do with this. I don't know why your so fixed on it. The CAMSHAFT is what's important here. The cylinders only see the valves closed for compression ONCE in 4 cycles. With #1 at TDC the valves are closed. With it timed up like the FSM says, the valves on #6 are closed, not #1. So, if you time the distributor to #1 you will be WRONG. Yes, all you have to do is turn the crank ONE revolution from the FSM picture and you're on #1 TDC. I've only seen a scant FEW manuals make that point. The bottom line? If that FSM says the engine is timed to #1 TDC with those sprockets as they are in the picture, it is WRONG. Plain and simple.
 
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