Exhaust bolts, catalytic converter, rear transmission mount

[carmangary]

79 Cutlass Cruiser (4.3L)

The more I look, the more I find that needs fixing. My car was loud under the hood so I figured I would replace the exhaust manifold gaskets for a start. But, I can't get the bolts out that connect it to the crossover pipe. What's a good way to unfreeze these bolts?

Then I started looking around and I noticed that there are NO bolts in the mount that the mount to the very back of the transmission!!! It's just resting on top of the mount. I need two bolts there. Does anyone know what size they are?

Then I look at the catalytic converter and it has holes in it. That probably has something to do with the noise and fumes. Any recommendations for a catalytic converter? I would prefer a drop in replacement. It still has the original in it. I've never done exhaust work so I don't want to be fooling around with pipes that don't fit. Any advice?

Thanks in advance.

 

[Bonnewagon]

Those bolts are allways fun. Start by soaking with penetrating oil,whatever kind you prefer,PB blaster,etc over several days. Some will break anyway. Is there evidence of the manifolds leaking? Black soot tracks? Obvious blowout you can feel with your finger? Did you take a long hose and use it like a stethascope to hear any leaks? I only ask because it would suck to touch them if they are not actually leaking. If you are not handy at exhaust work I would just take it to a local shop and get a universal replacement CAT welded in, and if the other pipes are shot let them deal with it. Those transmission mount bolts are I think 3/8th by 1", but then they went metric,can't remember what year.

 

[carmangary]

Thanks for the tips. I worked with it all day and didn't get too far. I got the old catalytic converter off and ordered a new drop in replacement that should be here in a few days. I broke off the bolts that connect the crossover pipe to the right exhaust manifold and now I have to get the exhaust manifold out in order to remove the broken bolts. I got the front two bolts loose but the back 3 or 4 won't budge. They are soaking with some liquid wrench now and keep squirting it for a few days. I am not sure what I am going to do if I can't get those bolts off. There is no room to work if the break off and I have to remove them with a drill or whatever.

Car sounded like a hot rod when I backed it back into the garage without the cat though. Not bad for a 260. haha.

 

[Bonnewagon]

Can you get at the broken bolts from underneath? Does the flange point straight down, where you could maybe get a drill up in there and drill/easy-out the bastards? I know it would be a lot easier to work on with the manifold on a bench, but if any of those manifold bolts break- hoo boy.

 

[carmangary]

I'm going to try using some heat on the bolts. I searched around and that is what people recommend. Car better start cooperating or else it is going to the junkyard. lol

 

[Bonnewagon]

Yes, heat is good, as long as you don't set the car on fire. I learned the hard way! Also when you reassemble everything be sure to use anti-seize on everything, that way it'll come apart easy next time.

 

[carmangary]

I got the exhaust manifold out yesterday. I snapped the head off one of the bolts but it is sticking out 1/2" and in a very accessible place so I heated it and put Kroil on it. I'll see if it will budge this morning. If it breaks off I think I can get an angle drill in there so I am not too worried about it. I got some damaged bolt/stude removers from Sears yesterday and it helped removed on of the bolts but none of the extractors will fit the broken stud. The kit comes with sizes 2 & 4 but not 3 and 3 is the size I need. Can you belive that?

Anyway, the flange surface of the exhaust manifold doesn't look flat in all places. I think the car might have been running a long time with and cause the meatal to burn. What's the thing to do with this? Take it to a shop? Or put a new gasket on and hope for the best. I haven't been able to take a good long look where it bolts to the head but I think the head mating surface is OK.

Also, I received a new Catalytic Converter in the mail so once I fix these broken bolts and do whatever needs to be done to the exhaust manifold I should be good to go. Unfortunately, the local junkyard sent a 79 Cutlass with the same engine as mine to the crusher so I can't steal it's manifold. These 260 4.3s aren't too common I am finding.

 

[outsider_27]

I have one of those engines sitting on my garage floor waiting for me to take to the scrap heap! I have to separate it from the transmission first, won't be til spring anyway.

 

[Bonnewagon]

I have been able to resurface manifold flanges by useing a belt sander on them. Just be sure to use the flat part of the sander, not the curved edge.

 

[carmangary]

Belt sander huh? I was actually thinking about doing that. My dad has one of those non-portable belt sanders so the whole manifold would fit on it. I have a small milling machine but the manifold is a couple inches too long to fit.