dotdat Posted June 13, 2013 Report Share Posted June 13, 2013 Am replacing the Head Gasket on my 1974 - 620 PU. The PO had repl'd the HG and got a poor seal resulting in a coolant leak near #4 cyl. The shiney link on the time chain is off from the #1 mark on the cam sprocket. The chain must of been off a link down on the crank sprocket. My Question is: Can I go ahead and Place the chain onto the Cam sprocket in a manner that gives me a correct line up with the V and dash indicator? My crank pulley is on zero and the #1 cyl. is TDC on the compression stroke. I sure don't want to pull off the front plate if I don't have to. Thankz.... 1 Quote Link to comment
Eagle_Adam Posted June 13, 2013 Report Share Posted June 13, 2013 if the bright link on the crank is on point then you need to make sure the cam sprocket is on point too but if you didnt reinstall the timing chain yourself them it could be one tooth off on both sprockets due to the motor rotation. Ive set the timing correctly then set the valves and never been able to get them to line up again, still got the motor running. Quote Link to comment
Eagle_Adam Posted June 13, 2013 Report Share Posted June 13, 2013 did it run before you took it apart? Quote Link to comment
datsunaholic Posted June 13, 2013 Report Share Posted June 13, 2013 The shiny link only ever lines up on initial install. After that, it moves around. Key at this point is be DAMN sure the crank is at TDC, not "close", using the TDC indicator on the timing cover/crank pulley, and them making sure the V notch on the cam sprocket is right. Quote Link to comment
Silky_Johnson Posted June 13, 2013 Report Share Posted June 13, 2013 Can I go ahead and Place the chain onto the Cam sprocket in a manner that gives me a correct line up with the V and dash indicator? My crank pulley is on zero and the #1 cyl. is TDC on the compression stroke. I've done this before. Marking your timing chain before removing the sprocket is the best though. Once I ran into a situation where, in a bonehead move, I popped out the tensioner and then managed to get it back in without taking the front cover off. To do so, I had to move the chain around and thought I was going to have to pull the front cover off to reset the bright link. Instead, I set the crank to TDC, put the sprocket in the chain, and adjusted the cam and tried different teeth until I got the V notch just right. I turned the crank around until I hit TDC again, and everything lined up perfectly. The engine ran fine after that. Quote Link to comment
Silky_Johnson Posted June 13, 2013 Report Share Posted June 13, 2013 I'm not saying it's optimal or anything, just that I've done it before. Quote Link to comment
dotdat Posted June 13, 2013 Author Report Share Posted June 13, 2013 did it run before you took it apart? No, it had set outside for about 7 years. Then the PO had worked on it before I bought it. Quote Link to comment
Z-train Posted June 13, 2013 Report Share Posted June 13, 2013 Not what you want to hear,but.......with what you've found up top,the bottom is a giant question mark that's gonna fester in the back of your head.Take it apart. Quote Link to comment
Eagle_Adam Posted June 13, 2013 Report Share Posted June 13, 2013 strip the timing cover off and start over man.... i know you probably dont want to but its for the best Quote Link to comment
dotdat Posted June 14, 2013 Author Report Share Posted June 14, 2013 Sheeeet...... Not what I wanted to hear, but I do trust your experience. To all, I DO appreciate your time and advice. Quote Link to comment
datzenmike Posted June 14, 2013 Report Share Posted June 14, 2013 Like Doug said. Set TDC accurately. Look through the top hole in the cam sprocket. The notch on the back of the sprocket should be just below or slightly to the right of the tiny horizontal etch mark on the cam thrust plate behind it. Like this.... The horizontal mark is about 4 degrees wide. You may be able to adjust by moving from the #2 hole to the #3 hole. If the notch is more than that, carefully block the chain to prevent the tensioner falling out and move the sprocket one tooth. This will give 9 degrees of change. Install by turning cam slightly to get the dowel into the cam sprocket and take another look. As long as you are at TDC and the notch is like the picture it's timed perfectly. Quote Link to comment
Eagle_Adam Posted June 14, 2013 Report Share Posted June 14, 2013 It may be too late.... But if you can check amazon or eBay for a Nissan timing chain wedge. $10...... 2nd best Datsun specific tool I have 1 Quote Link to comment
Buzzbomb Posted June 27, 2013 Report Share Posted June 27, 2013 It may be too late.... But if you can check amazon or eBay for a Nissan timing chain wedge. $10...... 2nd best Datsun specific tool I have That thing is the SHIZNIT, isn't it? I used it when I replaced my headgasket. I found it at Checker on closeout for LESS than $5! What a life saver and totally worth it even if it broke during use. Thanks for taking that pic. It's pretty apparent just how effective that sucker really is! BTW- if that's the 2nd best Datsun tool you have, what's the first?! Quote Link to comment
Z-train Posted June 27, 2013 Report Share Posted June 27, 2013 Here's another type: Quote Link to comment
Eagle_Adam Posted June 27, 2013 Report Share Posted June 27, 2013 That thing is the SHIZNIT, isn't it? I used it when I replaced my headgasket. I found it at Checker on closeout for LESS than $5! What a life saver and totally worth it even if it broke during use. Thanks for taking that pic. It's pretty apparent just how effective that sucker really is! BTW- if that's the 2nd best Datsun tool you have, what's the first?! my snap on torque wrenches come in the #1 slot 1 Quote Link to comment
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