Progress

[280ZManiac]

Ok,

I was finally able to remove my drive-shaft and replace the real oil seal in my 4 speed. No more leak

I also spent some time on pressure washing the underside with engine degreaser to try and track down my oil leak. Well I have now determined that I have what looks like a leak from my head gasket

The leak begins behind the intake and exhaust manifold and runs down the side of the block to drip on the floor of the garage. I also may have a leak in my oil pan gasket but not sure still checking. I am about to start pulling the top off my engine but wanted to ask a quick question.

If you remember from my previous posts I am having an issue with backfiring, black smoke and loss of power on acceleration. Would a leaking head gasket cause this?

Thanks for all the advice as I am not a mechanic but ohh can I take things apart

280Z on its way to becoming a daily driver

[sblake01]

Depends on how bad it's leaking. How's your compression? A bad temp sensor or throttle position switch or bad connection at either can also cause black smoke and loss of power on acceleration since they both affect the fuel mixture.

[280ZManiac]

Alright,

I have removed the intake manifold and the fuel rail. I am now attempting to get the exhaust manifold off. I have one bolt that is welded tight. I am afraid it is also rounded off so I might have to cut it off and tap it out. I have never tapped a broken bolt before. How difficult is this?

Thanks for the help

280Z on its way to becoming a daily driver

[Nissanman]

Exhaust manifold studs are a real beach to service.

The metal tends to crystallize due to the heat and it makes them very brittle.

Do what you have to do to remove the manifold.

When all clear you will be left with a stub of the stud protruding from the head.

If it has any thread on it, you may be able to lock two nuts on it and attempt to unscrew.

If no thread, you can try to unscrew it using vise grips, penetrating oil, and lots of patience, but I think I know what is going to happen:disappoin

After it has snapped off, your only option is to use a drill bit on it.

Drill a small hole down the centre of the stud, right through to the base of the hole in the head.

8mm stud, try a 4mm drill bit.

This hole is now ready for a dose of penetrating oil which will treat the threads from the bottom of the hole.

Repeat the treatment for a few days, patience here is a definite virtue:devious:

Then, if the Nissan Gods are smiling, use an EZY-OUT very carefully, to unscrew the stud.

If you don't like using EZY-OUTs, and I don't, the alternative is to drill out with a larger bit, so that when done you can re-tap the head for the correct stud size.

If you can get it, use a LH drill bit in a reversible drill so the drilling action will assist in unscrewing the stud.

Don't just do the one that is broken, consider re-newing all of the manifold studs while you can get to them.

It is only a matter of time before deja vu sets in:tapemouth