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Finishing rebuild, head back on, setting timing...


caltanian

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What will you see under the timing chain cover that will tell you more than what you can see now?  There's nothing under there.  All of the marks you need are visible under the valve cover and on the damper and timing tab.  There's no need to pull the cover.  If you want to be exact, better to get a dial indicator down the #1 bore and verify TDC that way.  That's the basis of your questions.  Everything revolves around piston position.

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I know this is common knowledge to builders but I just figured it out.  The key in the crank nose and the dowel on the front of the cam should be straight up.  You can remove the pulley and the valve cover to check that.  I made the mistake of pulling my front cover for no reason just because the shiny links on the timing chain weren't lining up with the dimples like they did when I set it up.  Zed Head set me straight on that, thank you Zed!  They only line up every so often.

DSC01265.JPG

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https://drive.google.com/file/d/0B4m9tctEf-4SbzFTQ0VPbTQ0clE/view?usp=sharing

https://drive.google.com/file/d/1hR6Ip4684fNpfuo9QZhHDLppq-yMbqwCfg/view?usp=sharing

well. I know that the adjuster had popped out on me, so I had no choice but to pull the cover off again. 

Cover is currently off, and ready to be put back on once I know the chain is on right.. 

7021a3ac-c354-420d-8a09-a6822ace2dd0

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Yep. Im going to in the morning double check that its 100% tdc, get the head torqued down, and then get the chain on the front. IF at that time, the balancer notches do not line up, there has to be something with the balancer itself yes?

 

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Don't mean to get all pedantic and I hope I'm not irritating - but the chain's only purpose is to spin the camshaft and keep it oriented properly to the crankshaft.  That's why I focus on the crankshaft and the camshaft and ignore the bright links.  You have the cam and crank properly oriented, now you just have to put the chain and sprocket on so that that orientation is maintained with the straight side of the chain tight, like it will be when the engine is turning. 

If the damper and tab marks are off when you're done then change the damper and/or tab.  Not the chain or sprocket or anything else.  The damper marks and tab are just external indicators.  If the parts aren't indicating what you just confirmed as correct, the problem is with them.  Only reiterating to be sure.   

One place you can get screwed up on when confirming cam orientation is to not have the straight side of the chain tight.  It has to be tight. 

Still wondering about the "straight up and down" part though.  You're in the eyeballing it regime, there are no marks to go by. "With the crank key slot is straight up and down."

Here's a thought - if you have an old damper try it and see if the marks are still off.  Two identically bad parts would be unusual.

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Zed head-

Im not eyeballing the block. That TDC was found with a micrometer. So I am confident in the fact that it is. 

Thank you all for the help. Going to get back at it tomorrow and see what can be done. 

Edited by caltanian
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13 hours ago, Zed Head said:

 That's why I focus on the crankshaft and the camshaft and ignore the bright links.  You have the cam and crank properly oriented, now you just have to put the chain and sprocket on so that that orientation is maintained with the straight side of the chain tight, like it will be when the engine is turning. 

 

Still wondering about the "straight up and down" part though.  You're in the eyeballing it regime, there are no marks to go by. "With the crank key slot is straight up and down."

 

Okay, now you've lost me.  How do you line up the crank and the cam without using the bright links and the dimples on the crank drive gear and the cam sprocket?  When I install the chain's bright links onto those dimple marks the key slot is straight up and down.

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set the crank w/#1tdc (use a dial guage or other measuring device if you want to get dead nuts) then set the cam (both lobes on #1 up, cam mark at tower mark) then you're good. the chain links are completely irrelevant at this point - they are just there as a quick aid when doing setup. once chain is on, tighten the right side by rotating crank clockwise a few degrees, then turn the cam ccw to line things back up and see if you're chain stretch requires a different setting for the cam sprocket (1,2,3).

if the harmonic balancer is not lining up w/the pointer, either the balancer has slipped or there is a mismatch between the pointer and the pulley (different years)

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The bright links help you get started.  But when you're done, the check is to look at the notch and the groove on the chain sprocket and the cam shaft retaining plate.

How do you find TDC with a micrometer?  I haven't seen that method.

Added the picture from the FSM of the notch and groove.  Still doesn't tell you if the crank is at TDC, but it's something.  

Overall though, the problem here is that you're trying to figure out which indicator is wrong - your micrometer method, or the damper marks and tab.  If you know that your micrometer method is right, there's no need to look at the chain, sprocket, or cam at all.  The damper just indicates TDC.  The damper mark should be correct even with the head completely off of the engine.  No cam, sprocket, chain.  Actually, that would be the very best time to check your damper and tab since you can easily measure TDC then.  The damper mark and tab mark's only purpose is to show you where piston #1 is.

 

1976 notch and groove.PNG

Edited by Zed Head
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Or! you can take the depth slider on a micrometer and stick it #1 cylinder. Get the highest mark of the piston top. I've done it both ways with the head on trying to get my timing right when I first bought the car and switched to a zx dizzy. Ended up dropping the oil pump then pulling the motor which is still on an engine stand after a year. Brahahahaha!

Skin comes off a cat many ways. 8^)

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