Help! replaced head gasket car runs rough

[rickl750]

Hi Guys,

I just replaced the head gasket on my 1978 280Z. I started the engine and it's running very rough and it's smoking like crazy. I tried adjusting the timing and it helps a little but not enough. I was very careful with the timing chain and hope that's not the issues. Does anyone have any thoughts?

If the concensus is the timing chain, what's the best way to adjust it?

Thanks in advance for your help.

Rick

[MikeW]

What color is the smoke? What made it necessary to replace the head gasket?

[rickl750]

Gray smoke and the head gasket was blown.

[Tim 76' 280Z]

Did you have the head shaved? There might have been a problem with your head. If so you will still have the problem you have no matter how many times you replace the gasket.

Edited February 22, 2009 by Tim 76' 280Z

[racebird1]

A rough way to see if your timing is close is to take out your plugs and carefully turn the crank and using a wooden dowel bring the #1 cylinder up to top dead center of the compression stroke and check to see if the rotor in the distrubetor is pointing to the #1 wire position. Also still may have head issue possible water still getting in cyl. Sometines it may pump air into cooling system so look for air bubles in the radiator. Do a comp test in each cyl. Good luck.

[stevef1972z]

Smoke can be from left over water in the oil system if the head gasket blew and allowed water into the oil system. Even after an oil change you will have milkshake looking stuff in the pan and all over. If you just removed the head and cleaned it and put everything back together there is a lot of water and antifreeze left in the oil passages of the block. That stuff can ruin plugs as well. Check the condition of your plugs and what the oil looks like again.

[rickl750]

I just took it apart and checked the timing chain. The piston at TDC, distributor pointing at #1 wire and the notch on the sprocket aligns with the one on the cam plate, the valves also seem to be closed. The only strange thing is that the bright link on the chain is lined up with the #2 mark on the sprocket (that's the way it was before disassembly). Anyway, I'll crank it over in a little wile and see what happens. Btw, I did go over all the vacuum lines, wires, etc. )I had labeled everything)

Thanks,

[rickl750]

Guys,

one quick question. On TDC the long part of the lobe (the toe) on the cam for #1 piston should they be pointing up or down?

Thanks

[sblake01]

Up........

[racebird1]

Correct lobe up on #1 when at TDC. Both valves are supposed to be fully closed when the #1 is supposed to be firing. Remember there are two revolutions to each cycle. TDC should always be on the compression stroke. Turn the engine slowly you will see the exhaust valve open then the next rotation the intake valve will open this is coming up on the compression stroke when it reaches the TDC both valves should be closed so the engine will fire.

[rickl750]

Hi Guys,

I confirmed the timing, put it back together and started the engine. It ran very rough but after 10min it smooth out and she now idles on her own. She’s still smoked allot for about an hour and then cleared up. She’s good now, running a little rough and I’m sure once I tune her up she’ll be fine.

Thank you all your help,

Rick