280z L28 setting engine timing

[fairladyz432]

Im about to install my newly rebuilt head onto the block but before i removed the head prior to the rebuild i didn't set my timing to TDC with the cam lobes pointing upwards. The picture i attached is where it sits currently. I do know that the engine goes through tdc twice during the cycle so i think another turn will make it the correct TDC. Right now my head cam timing is in the correct position with the front lobes pointing upwards. Do i simply just install the head and then crank the engine slowly till it reaches the next tdc cycle? Any help would be great lol. 

[Zed Head]

Set the damper pulley ignition timing mark on zero, it's almost there now.  Install the head with the cam lobes up on #1 as you described.  Then install the cam sprocket so that the notch and groove are aligned as shown in the FSM.  You'll probably have to turn the camshaft slightly to get the sprocket on.  Since your timing chain is worn you might have to use the #2 hole on the sprocket.  Make sure that the driver's side of the chain, the straight side, is tight, and the damper pulley mark is on zero, when you compare the notch and groove positions. Once you get those three marks lined up you can spin the engine with no fear.

That's the basics.  That's why the marks are there.

[fairladyz432]

THANK a lot for the help, looks like I’m not too far. Do I have to remove the chain blocking tool (keeps the tensioner from falling out ) before I can crank the engine? 

Edited October 19, 2018 by fairladyz432

[Zed Head]

Yes.  Once the sprocket is on it's not needed.  But if you need to adjust the sprocket put it back in.

It can be difficult to get the sprocket on even if everything is right.  Good luck.

[fairladyz432]

Sorry I meant to say do I leave in the chain block tool on right now as it sits to align the damper pulley to zero before I install the head? 

[Zed Head]

I forgot about that.  I'll bet your timing mark is within a few degrees of zero right now.  I'd go ahead and put the sprocket on, remove the chain holder, then rotate the engine slightly by hand to get timing mark to exact zero and to get the chain tight, to see how your marks line up.  I can tell by your piston positions that the timing mark is close.  Your valves will have plenty of room.  Just go slow.

[Zed Head]

Just thought also that you can put the sprocket on to the head temporarily to line up the notch and groove.  A little more precision than just having the cams pointed up.  If you're worried.

[fairladyz432]

Yep got the sprocket installed on the cam as well. Here’s a pic of the damper pulley with notch mark close by the zero marker. Do I rotate crank to line up the notch from the pulley to the 0 mark and that’s it? 

[madkaw]

DO NOT ROTATE THE ENGINE YET! 

You should have lined up the crank sprocket on 0 first before putting on cam sprocket . It will be tricky to keep tension on the chain , but you should be able hold the tension tool in place and move the crank that small bit. THEN install the sprocket 

[Zed Head]

He could also turn the camshaft the few degrees to match the damper pulley.  The key to not damaging a valve is that the cam timing matches the crankshaft timing.  If he's 30 degrees advanced on the crank the cam should be 15 degrees advanced.  Then install the sprocket and chain.  The chain is what actually controls the cam and crank relation.

There's basically two steps involved here.  1. Get the head on with the valves in the proper position to not hit piston tops.  2. Get the sprocket and chain on so that the crankshaft can be rotated without valves hitting piston tops.

Keep those two things in mind and come up with a solution.  People have used a pipe or lever to hold up the sprocket and chain while they moved the crankshaft.  The big risk now is having the tensioner pop out.  Then he's in a whole new world.  The tensioner really really wants to pop out of its hole.

Many possibilities.

[Patcon]

I will muddy the water, even if I shouldn't. I'm a measure twice cut once kind of person. If this were my engine, I would just remove the cover and set the chains. It's not very hard as long as you don't brake a bolt. I had to do this recently when we lost the tension on the chain. I guess I wouldn't want to end up a link or two off. Might not destroy anything but might not make good power either. It seems like the only way to know for sure at that point is to remove the front cover

[madkaw]

5 hours ago, Zed Head said:

He could also turn the camshaft the few degrees to match the damper pulley.  The key to not damaging a valve is that the cam timing matches the crankshaft timing.  If he's 30 degrees advanced on the crank the cam should be 15 degrees advanced.  Then install the sprocket and chain.  The chain is what actually controls the cam and crank relation.

There's basically two steps involved here.  1. Get the head on with the valves in the proper position to not hit piston tops.  2. Get the sprocket and chain on so that the crankshaft can be rotated without valves hitting piston tops.

Keep those two things in mind and come up with a solution.  People have used a pipe or lever to hold up the sprocket and chain while they moved the crankshaft.  The big risk now is having the tensioner pop out.  Then he's in a whole new world.  The tensioner really really wants to pop out of its hole.

Many possibilities.

Why do more guessing than he needs to. If he turns the crankshaft slowly and carefully while holding the chain he can get it to O. It wouldn’t take hardly anything to get to TDC, then figuring the camshaft location is much easier since you have the alignment marks to judge where to put the sprocket. I just went thru this because I forgot to mark the link when I removed the sprocket. I knew it was on #3 when I removed the sprocket , but dummie me forgot to mark the link. I was able to locate sprocket properly by using the factory alignment marks ( the - and the v) Logically if you are TDC on the crankshaft that is just one less thing to guess.