I am in need to advice on removing the OE manifolds off my 83' Z28. I have a bad head gasket on the drivers side (coolant in the oil and a steady oil drip onto the Y pipe on the drivers side as well). My car's rusty manifolds have not been off the car since new I
am assuming, I have owned it since 1992.

Since the I would like to do some gasket matching/bowl work/new springs while the heads are off does anyone have any suggestions on getting manifolds off in the car or should I look at pulling the engine?? I am reasonably competent but do not have the full array of usual
tools a full time technician would have. I have a engine stand and hoist's are readily available to rent and a air compressor and basic air tools.

Thank You in advance!!
Scott

 

Remove the bolts from the Y-pipe and the cylinder heads...

 

I get that part, they are all solid rust. I would start with PB Blaster and soak the crap out of them. Should I expect them to break and if they do what then??

 

Well, if they break, they break. The head is coming off anyway, so no real advantage to pulling the motor, just more work. Once the heads are off, if there are broken bolts that you can't get out, bring it to a machine shop and have them do it.

The driver side manifold is pretty accessible. The passenger side is a little more challenging to get to the rear bolts because of the Heater/AC box, but it's still doable. No particularly special tools needed. Just the typical ratchet/socket set with short and deep sockets, extentions, universal joints and a wrench set with open and boxed ends. Also, a boxed end "S" wrench is helpful for the rear passenger bolts.

 

First obstacle will be, some of them will be studs, not bolts, and have little brackets and things held onto them with nuts. Murphy being the bearer of truth that he is, the nuts on ones that have them, will be loose in the heads, while the nut will be stuck solid to the stud; butt, since there's a bracket or whatever (oil dipstick comes to mind), the act of turning the stud while the nut is still tight, will destroy the piece bolted to it. You'll need a THIN open-end wrench to get behind the extra piece to hold the stud still while you try to bust the nut loose... you'll probably have to make one by grinding it down. And also consistent with Murphy, the feature I mention next will be absent or ineffective on those, but just enough will still be there to make getting a wrench on the stud near impossible.

Next will be, if they're actually still untouched from the factory, is that the locking retainer things the factory used, will be in the way. They were a little sheet-metal deal that went between the bolts on each port, and had 2 little tabs that folded up against hex flats of the bolts/studs. With those still there you can't get a socket onto the bolts. They come off easy with a screwdriver or something, except that you can't get one in there from any angle you have access from.

Next will be, the bolt heads are probably rusted to the next metric size down from the original. (9/16") 14mm might get on them better than 9/16". Use 6-point tools.

And of course, they might be rust-welded in there, they might break off when you try to move them, etc.

It would be nice if the heads could be removed with the manifolds still attached, since it would be SO MUCH eeeeezyer to deal with them out of the car; butt being a small block Chevy, the whole lower row of bolts is completely blocked by the manifold.

It'll be fun no matter what.

 

If they break, as mentioned since you gotta remove the exh manifold anyway. Take them to a muffler shop or anyone/anyplace you know with a welder, if enough stud is left then a nut can be welded on and the heat should help loosen it up. If those aren't options, then you can drill them n use a nut & bolt.

 

Obviously I can't predict what your experience will be, but when I removed the H.O. exhaust manifolds from the '84 305 they were on, every nut, bolt & stud came out with no problems.
So unless you have some serious rust going on, you probably won't break anything...