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Timing Mark Dilemma
https://slantsix.org/forum/viewtopic.php?t=68040		 Page 1 of 2
Author:  1963ddgt [ Fri Dec 27, 2024 2:28 pm ]
Post subject:  Timing Mark Dilemma
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. (I added a photo. Hopefully it uploads ok)
Attachment:
timing 3.jpg
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Author:  Rick Covalt [ Fri Dec 27, 2024 3:28 pm ]
Post subject:  Re: Timing Mark Dilemma
Quote:
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
I don't know that it matters about the slot being straight up? But you need to degree the camshaft and check it that way. Most new camshaft / gear sets do not line up. They can be 5-15 degrees off. You are going to need a offset bushing installed in the cam gear and correct the timing that way. Your next problem is the gear has a slot instead of a hole that can be drilled to accept the offset bushing. I never use those gears.
Author:  Will [ Fri Dec 27, 2024 4:19 pm ]
Post subject:  Re: Timing Mark Dilemma
Correct Rick
See this kind of thing a lot.
Will
Author:  1963ddgt [ Fri Dec 27, 2024 4:47 pm ]
Post subject:  Re: Timing Mark Dilemma
I can get the marks to line up by rotating the cam slightly to the right. The key in the crank is still pointing straight up and the the #1 piston is still TDC. Does it matter that the cam is cocked slightly to the right?
Attachment:
timing 4.jpg
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Author:  Rick Covalt [ Fri Dec 27, 2024 6:05 pm ]
Post subject:  Re: Timing Mark Dilemma
You won't know if it is correct until you do the cam degreeing process. All you know now is that the dots line up. You do not know if the valves are opening at the right place.
Author:  SlantSixDan [ Fri Dec 27, 2024 8:02 pm ]
Post subject:  Re: Timing Mark Dilemma
1963ddgt, The advice you are getting is maybe not the answer you wanted—you have more work to do before you button up this engine—but it is the answer you need. If you don't follow it and just throw the engine back together with the dots kinda lined up, it'll run, but not as well as it should. Performance, driveability, and fuel economy will be off, and you'll regret it every time you drive the car.

An engine rebuild is a once-in-an-almost-never event. Take the time and make the effort to do it all the way right.
Author:  1963ddgt [ Sat Dec 28, 2024 11:07 am ]
Post subject:  Re: Timing Mark Dilemma
Thank you all for the help When I degreed the cam, my intake is 0.037 higher that the exhaust. I think I've got a problem. I just don't what my problem is.
Author:  Rick Covalt [ Sat Dec 28, 2024 12:20 pm ]
Post subject:  Re: Timing Mark Dilemma
Not sure what you are measuring? If you have already degreed the cam, what was the Intake centerline number on the cam card, and what was the number you had when you checked it? This would be in degrees. .037 sounds like you were measuring valve lift? That difference could be in the cam, adjustment bolt...etc. Post some more numbers from the cam card and we should be able to guide you better.
Author:  CNC-Dude [ Sat Dec 28, 2024 1:24 pm ]
Post subject:  Re: Timing Mark Dilemma
Quote:
Thank you all for the help When I degreed the cam, my intake is 0.037 higher that the exhaust. I think I've got a problem. I just don't what my problem is.
That is showing the intake is advanced, which may be correct if the cam is ground with advance made into it. Just confirm the intake centerline is correct from what the cam card says....Cam grinders have been grinding advance into their cam profiles for decades for many reasons, mostly because it enhances cylinder scavenging and gives the engine more throttle response down lower in the RPM...
Author:  Greg Ondayko [ Sat Dec 28, 2024 4:08 pm ]
Post subject:  Re: Timing Mark Dilemma
Do you have the stock camshaft for your year and model car?

If It is a stock rebuild you will not have a cam card, but we can refer to the FSM for the intake centerline info.

Rick rebuilds most if not all of his engines with a non stock cam.
Author:  1963ddgt [ Sun Dec 29, 2024 7:26 am ]
Post subject:  Re: Timing Mark Dilemma
When I rotate the engine 180 degrees, TDC #1, my lifters are dead even (up/intake and exhaust open?). I think I'm good, correct?
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timing 6.jpg
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lifters 2.jpg
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Author:  Rick Covalt [ Sun Dec 29, 2024 9:13 am ]
Post subject:  Re: Timing Mark Dilemma
Quote:
I think I'm good, correct?
You are not measuring what needs measured to tell you what you want to know.
You said you degreed the cam, correct? What number did you check it at for the Intake Center Line. That will tell you if you are advanced or retarded or just right.
Author:  CNC-Dude [ Sun Dec 29, 2024 3:43 pm ]
Post subject:  Re: Timing Mark Dilemma
Looking back at his post, he never stated that he actually degreed the cam. And given his confusion with comments made further in the post, it sounds like he needs further help to make he gets off on the right foot...He says degreed, but I actually think he means "lined the dots up", and not actually used a degree wheel which is a huge difference between the two terms...
Author:  Greg Ondayko [ Sun Dec 29, 2024 3:50 pm ]
Post subject:  Re: Timing Mark Dilemma
We mean this for degreeing the cam:
Image

Greg
Author:  kesteb [ Fri Jan 03, 2025 10:23 am ]
Post subject:  Re: Timing Mark Dilemma
He also has slop in the timing chain. Is this a new timing chain?
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