Timing Mark Dilemma

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The Dart GT

The Dart GT

1963 Dodge Dart GT Convertible
Joined
Apr 16, 2022
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On my engine reassembly, I'm stuck with the timing. The cam pin (and cam gear slot) is pointing straight up and is exactly square with the top of the block. The crank key is pointing exactly straight up. The number one (and number six) piston is exactly TDC including any adjustments for dwell. Why aren't my timing marks aligned on the gears? If I move the camshaft slightly clockwise so the marks line up the camshaft is going to be cocked slightly to the right and is no longer pointing straight up. Is it more important for the cam and crank to be in the correct position or is it critical that the marks line up too? Thanks for the help.
timing 2.jpg
 
I believe you have it in time. Turn the crank one tooth clockwise and I believe you'll find it will align the dots on the crank and cam sprockets. It will only do that ONE WAY and if it aligns, then it's correct. I think somehow you THINK it's a TDC, but it's not. Can we get a picture of the piston on #1?
 
The slants my machine shop buddy built for me where similar. He bought 3 different gear/chain sets and they were all off by a half tooth. We degreed the cam and it was dead on so he marked the gears to be aligned where it was. Yes it was a 1/2 a tooth off from the (aftermarket) factory marks. All I can say is degree it to be sure.
 
If you look at the OEM FSM photo.

The dots are on the peek of a tooth

Red and blue

Screenshot_20241227-164559.png


In the photo of your gears and chain it's peak (red) and valley (green) (1/2 tooth off)
Screenshot_20241227-164500.png

BUT.... that does not mean that the keyway in one or both gears is not adjusted to make it work right.
 
RustyRatRod said:
I believe you have it in time. Turn the crank one tooth clockwise and I believe you'll find it will align the dots on the crank and cam sprockets. It will only do that ONE WAY and if it aligns, then it's correct. I think somehow you THINK it's a TDC, but it's not. Can we get a picture of the piston on #1?
Click to expand...
Rusty, Thanks for replying. You've been a big help so far with my build. This is a 225 and the pistons are 0.1585 below the deck. I know that's a little low for some people but I believe it's within spec. I'm using the original rods so that's how the original engine ran. Believe me when I say I've rocked it back and forth and back and forth and the piston is as high as it gets.
Piston.jpg
 
The Dart GT said:
Rusty, Thanks for replying. You've been a big help so far with my build. This is a 225 and the pistons are 0.1585 below the deck. I know that's a little low for some people but I believe it's within spec. I'm using the original rods so that's how the original engine ran. Believe me when I say I've rocked it back and forth and back and forth and the piston is as high as it gets.
View attachment 1716344766
Click to expand...
Notice in this photo I can get the marks to line up but the cam is cocked to the right and NOT straight up or square to the block.
timing 1.jpg
 
The Dart GT said:
Notice in this photo I can get the marks to line up but the cam is cocked to the right and NOT straight up or square to the block.
View attachment 1716344770
Click to expand...
Where does it specify in the service manual about the cam sprocket being square with the block? If the alignment marks line up, and they do, then it's right.
 
Dana67Dart said:
If you look at the OEM FSM photo.

The dots are on the peek of a tooth

Red and blue

View attachment 1716344752

In the photo of your gears and chain it's peak (red) and valley (green) (1/2 tooth off)
View attachment 1716344754
BUT.... that does not mean that the keyway in one or both gears is not adjusted to make it work right.
Click to expand...
I have a set the same as his and my cam sprocket is marked EXACTLY like his with the dot between two teeth.
 
RustyRatRod said:
Where does it specify in the service manual about the cam sprocket being square with the block? If the alignment marks line up, and they do, then it's right.
Click to expand...
I got it out of Doug Dutra's manual. I think I'm starting to feel better already.

CAM.jpg
 
Well, as others have said, the only real way to know 100% is to degree the camshaft. It's a simple process and one that I would not leave out.
 
RustyRatRod said:
Well, as others have said, the only real way to know 100% is to degree the camshaft. It's a simple process and one that I would not leave out.
Click to expand...
Okay. I'm going with crank key pointing straight up and the #1 cylinder at TDC and leaving the marks lined up like in the second picture. On to degreeing the camshaft. Thanks again for the help....and stand by. I'm sure I'll be back!
 
Keep in mind though, that dot to dot IS 180 out. TDC for #1 is crank dot pointing at the cam sprocket and cam dot 180 degrees away from "lined up" with the crank sprocket. Dot to dot is on TDC for #6. It's shown dot to dot in all the manuals for ease of aligning. But when you go to install the distributor, you need to rotate the crankshaft ONE complete revolution to get it in the #1 TDC position.
 
Dot to dot is ALWAYS the way I do it simply because it is far easier to see when they are properly aligned. Just turn the crank one turn, and you are on TDC again, no1 ready to fire.

Another thing, and Rob maybe you know? "Back in the day" cams were often checked at "split overlap." This means when either 1 or 6 is on the opposite stroke from firing, the exhaust and intake are both equally open. That is, dot to dot, no1 valves would be "split", and 1 turn around, no 6 valves would be split. THIS MAY ALWAYS HAVE BEEN a myth and incorrect, as nowadays with the cam timing used, there "is no" split overlap that is correct so to speak, with V8s. I don't know about stocker slants, 4's, or other 6's.
 
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