So I had a feeling that I had a crack in my headers since recently my exhaust noise has gotten a lot worse. I pulled the intake manifold off to find a crack in my rear cylinder header that is cracked almost completely around. My intake ports on the block also have an 1/8 - 1/4 inch of black (carbon?) buildup and the inside of the intake manifold is filthy.
My question is there any way to clean the intake ports on the block without taking apart the whole motor? I am debating weather or not too do a full rebuild anyways because I just recently picked up a new car I drive everyday. Also best case scenario if I did a rebuild whats it gonna cost just for gaskets and such?
Thanks I have pictures too if need be I can post

 

this is what the intake port looks like

 

That on your 1991? Serious problem with intake deposits there - what's the manifold look like? I'd expect that on RENIX (damned EGR system...) but not on HO.

If you're going to clean the ports out, you'll want to unscrew the rocker arms (just loosen them so the valves close,) bend a hook into a flat screwdriver, and pull the deposits into the hose of a running Shop-Vac - you don't want them left where they can fall in through the intake valve!

If carbon had leaked past the gasket, the gasket had failed on you and wants replacing anyhow. I find that a thin, even coat of RTV copper won't go amiss - put it on both sides of the gasket. Replace the manifold screws - if you can't get bronze, then use SAE5 carbon steel. If you're stuck using carbon steel, they get replaced every time they come out! Be sure to reuse those little dish-shaped washers, they're there for a reason.

New studs may be cut from 3/8"-16 threaded rod, I like to use brass. Be sure to get new nuts as well, since the OEM studs are usually threaded 3/8"-16 going into the head and 3/8"-24 where the nut goes on.

If you suspect collector cracks as well (you can usually see a carbon track where the crack is, if it's been there for a while,) replace your engine mounts as well. I'd say that all but one or two of the several dozen cases of cracked header collectors I've heard of have been accompanied by failed/failing engine mounts - so just replace all three.

The usual test for engine mounts? Take a knitting needle about 1/4" in diameter (I just use the demo block punch on my Multi-Plier, but the knitter will give you the same thing) and put the tip against the "rubber" block. Gently press it with your thumb. If the rubber more than dimples, it's gone soft and will want replacing - failure of one mount indicates replacement of all three is required.

If the point of the needle actually penetrates the rubber, replace the mounts soonest.

If the dimple does not recover, replace the mounts straight away.

I've been able to replace all three mounts in an hour or so using a floor jack, so it's pretty simple. Easier for you, since you already have the manifolds unscrewed...

 

Replace the transmission mount, or you will crack the header again.

 

Ya all my mounts are toast, should i just pick up some stock ones or are there some you guys recommend?

 

intake

 

After taking off the headers and welding up the cracks I just decided to do a full exhaust job as well. My muffler had a bowling ball sized hole in it from a rock a while back. I am going to be buying a builders mandrel bend kit off ebay and go from there.
as far as the engine mounts I know I have seen on a couple builds some yellow motor mounts with an american flag on them but I cant seem to find the name of them right now? Bomb proof or something?

 

Hopefully this link works for you, I am in the same boat, I also have a craked header and need new motor mounts. Not sure how much carbon has built up in my intake yet.

http://www.google.com/imgres?imgurl=...26tbs%3Disch:1

 

Thank you very much I will order a set as soon as my check comes through!
I decided to just do a top end rebuild after talking to my ASE mechanic friend. This will be great to do while I have everything apart.

 

Let use know how much something like that cost. Are you doing it all yourself?

 

Ya have no job right now and have a lot of free time and just cleaned my garage so its time to make a mess again.