intake exhaust gasket help

[grantf]

I am planning on replacing the manifold gasket on my 77. Any advice from those who have done this before? I plan on giving all of the bolts a liberal soak with PB blaster the day before. What brand of gasket is best? What snags should I expect? ect.

[240260280z]

I did this when I changed the head a long time ago. If I recall I applied anti-seize to all mating parts of the gasket. I think Norm or someone on Zcar.com suggested this. Maybe use the higher temp copper blend. My memory is poor so I vaguely recall a metal side to the gasket and I think I put it against the head so that water/rain does not cause it to rust.

Take your time with the bolts on the studs and note where all of the thick compensating washers go. There are some related photos in this post that can help: http://www.classiczcars.com/forums/showthread.php?42420-77-280z-head-removal-step-by-step-photos

Also drain some rad fluid if you have to take off he thermostat housing.

[grantf]

Funny, I already saved that article you wrote to my favorites two weeks ago. I was wondering about anything that I may need to apply to the mating surfaces. I used a copper spray when putting head gaskets on my Kh400 but that was a two stroke motorcycle.

Edited August 4, 2011 by grantf

[240260280z]

Just read a few other tips:

The copper spray is permanent and not necessary.

Some have used the Nissan Gasket with a sealer that is built in/on it. they report they could remove manifold many times w/o problems (post race inspections for porting)

Many recommend changing studs and nuts (I believe Ace hardware has studs in their metric section if you are stuck).

[grantf]

Changing the mounting hardware makes sense especially the exhaust. looking up the Nissan part now.... cannot find genuine Nissan gasket. Nippon Reinz?

Edited August 5, 2011 by grantf

[240260280z]

Felpro seems OK for most unless you compete and need stockers.

[chaztg]

I used a FelPro gasket with no metal inerts for a stock intake/exhaust manifold refit on my '75 280 (no headers) with a little spray-on copper gasket sealer, lightly applied around the port openings. I let it set up for a few minutes to get tacky. It worked great. I've found that 12mm Toyota exhaust manifold bolts are good replacements for the stock nuts & lock washers. They have a flared base & notching around the top. I don't why the design seems to work so well, but it's a great fastener for high temp areas like the exhaust manifold. I use a little locktite, which I'm not certain is needed because it might get baked away. Those Toyota fasteners don't seem to get "cooked" or rust as much as the stock nuts do. They could made of a different alloy or something?

[FastWoman]

I'm in the camp of replacing all hardware whenever possible. If you don't, then it will continue to rust/corrode/fossilize in place, and a stud that is merely difficult to remove now may be impossible to remove later -- at least without drilling, helicoiling, or whatever.

MSA sells a stud/bolt/nut set that worked quite well for me. I also used whatever gasket it was that they sell. I sprayed with Copper spray and rimmed the intake and exhaust holes with a tiny bit of Permatex sealant, per ZTrain's suggestion. So far everything is tight and happy. It's been about a year now.

If you do decide to extract and replace studs, you'll probably need to blow-torch the more stubborn ones, spray with PB Blaster as they cool, and then turn them out CAREFULLY with either two nuts jammed on the stud or with a SHARP/NEW pair of vice grips. It's essential that you take your time. Chase out all the threads with a tap. Use Nickel Antisieze on the new hardware. You might also pull off your thermostat housing while you're doing work there.

When chasing out threads, beware that the forward thermo housing bolt screws into the timing chain area just beneath the backside of a timing chain guide. You shouldn't chase out those threads unless you've got the valve cover removed and are watching the backside of that hole. You don't want to bend that guide! Also, when chasing out the threads, remove the tap frequently to clean it. Take your time. You don't want a jammed tap because you were too lazy to pull the tap out frequently enough!

Oh, finally, you need to know that 1 day soaking with PB Blaster isn't enough. You probably need to be soaking that stuff for a week or more. Also I've seen some test results, and Kroil is a much better penetrant. The BEST penetrant seems to be the home brew of 50% acetone and 50% ATF. I've never used it, but the test results I saw were very persuasive.

It's a heck of a job to do, but if you take your time, you can do it. :-)

Edited August 7, 2011 by FastWoman

[grantf]

Thanks fastwoman, I am familiar with tapping holes in steel and aluminium. We use Kroil at work, Great stuff but it seems a can stops dispensing after 1/4 use. I don't know why.

So now I am getting ready and I am F%&%&CKing stuck. the @$#%#!$% heat shield is in the way and it appears to be bolted to the underside of the intake. Any suggestions? my hands are not large but I can only just get them in far enough to touch the bolts.

[Zforce]

I just did this yesterday on my carburated Z. There are no snags to worry about, it's just time consuming, it took about four hours including picking my kids up from school. The gasket I got was the stock gasket for a fuel injected Z so I did not use any sealer. If it was a paper gasket I would use copper spray, the old one was like that and it lasted for about 6 years.

[grantf]

I think this is more difficult as my Z is fuel injected and there is no way to get at the heatshield bolts. :angry:

I was thinking of using copper spray, still thinking....

[Zforce]

If you can remove all of the hold down washers and the bolts on top of the manifold you should be able to remove the intake manifold with heat shield still in place.