Help! with Exhaust Manifold on '83 280zx

[wickman10]

Anyone have any advice on getting the exhaust and intake manifolds off. I have read some of the other threads and they were helpful but any additional info would be appreciated. I am looking for process pics and diagrams as it is difficult for me to see what needs to be taken off. I am halfway there but stuck on the heat shield which has rusted out bolt heads so I cannot get a socket to spin them. Help please!

[HKSZ]

Intake manifold has to come off first,top 4 bolts are easy to get at, bottom is held with 6 fat washers on studs so you only have to loosen the nuts off then the intake manifold lifts out, shouldn't have to take the heat sheild under the intake off to get at the lower 6 washers just need a socket & extension bar, except for the first one you reach down behind the exh manifold with a 12mm spanner and turn it 1/8 at a time.

[peterc]

You can't access the nuts/bolts necessary to remove the manifolds without first removing the heat shield. Believe me, I've tried. If they won't loosen off you're only option is to break off the heads of the heat shield retaining bolts. Which means that you will have to ream out the broken studs in order to be able to re-attach the heat shield later. A combination of cold chisel, dremel tool and lots and lots of swearing worked for me. If you're lucky some of the bolts will ratchet out and you should be able to salvage the heat shield.

Good luck,

p

[wickman10]

Thanks for the replies guys! That has been exceedingly helpful!!

[zbane]

You can actually get to the lower 6 bolts needed to remove the intake manifold without removing the heat shield. I tried to remove the shield thinking it would make life easier (and it would have) but I couldn't get them all off (rusted, then rounded). I tried the dremel solution, but couldn't get it to where it needed to be-very hard to do without seeing what you are doing, and I wasn't going to use my finger as a guide...

You will bust a couple knuckles, you will curse up a storm, but you will get them off. Knowing where they are helps quite a bit, and I was very unhappy with my FSM for not even mentioning that the lower 6 had to come off/be loosened in order to get the intake off.

Attached are photos showing where the bolts are/should be.

Hopefully your intake manifold won't be as hard to remove as mine was (I needed to utilize a hydrolic jack to break mine loose from the head once the bolts were off)

[peterc]

David

I may be mistaken but I think that the heat-shield on the '79 is different from the '83. I know where all the intake/exhaust bolts are located but could not access them with the heat-shield in place. Couldn't wrench them from below, and couldn't snake even a 1/4" drive socket extension past the heat-shield.

My hat is off to you for managing to remove them without first removing the heat-shield. What did you use?

p

[wickman10]

yeah the 83 must be different, I was (indeed after much swearing) able to access the bolts without taking the heat shield off, I just used a 10inch extension and a mirror to see them. They came off ok once I found them. THere are notches in the heatshield on the 83 that allow the extension to go through. Heatshield would have been horribly difficult to get off anyway. I could see that after I got the manifold off. Problem now is I broke an easy out in the stud of the outer exhaust manifold bolt.(The main reason, beside gasket replacement, why I took the manifold off to begin with was the two outer bolts were sheared off) I can't remove it now and am wondering if I can get by with just replacing the gasket and not worrying about the mess on the outer bolt?

Edited December 31, 2008 by wickman10

[peterc]

I don't think that you will be happy using that head with two broken manifold studs. Sooner of later exhaust leaks will develop. The stock exhaust manifold is pretty solid, so may resist leaking for a longer period of time, but a header will allow blow-by fairly quickly...at least in my experience, .

Replaced a stock exhaust manifold (broken manifold/downpipe studs) with a header, with engine in-vehicle. Unable to access one of the inner manifold bolts and it leaked right from the get-go. The car's in the garage for the winter, and Im pulling the engine this spring to over-haul it so no big deal. But pretty frustrating to replace one exhaust leak (header/downpipe) with another (engine/header) .

Good luck

p

[zbane]

My hat is off to you for managing to remove them without first removing the heat-shield. What did you use?

I used extensions and a lot of swearing. My biggest problem was finding the bolts, and then finding them again with the socket as my hand got in the way, and I couldn't contort my fingers out of the way...