Stubborn Heat Exchangers

[bigel]

Here's my situation...

I've recently dropped the engine on my '87 Targa to replace the head studs. I'm in the process of dissassembling the power plant and am having difficulty separating the heat exchangers from the heads.

I have removed all fasteners from my old, rusty exchangers and I can't even budge the suckers, let alone remove them from the heads. I've given them a few raps with the dead-blow hammer, but have been hesitant to really hall-off on them.

Any words of wisdom/compassion from anyone who has encountered the same situation?

My exchangers are in decent shape overall (save one 'ding' from road contact), but the mounts (flanges) and fasteners were super rusty/nasty.

Please help! Otherwise I'll be forced to take the pry bar to them!!!

Thanks in advance.

Steve

[michael lang]

Heat is your friend!

[911pcars]

Assorted heat exchanger nuts from one engine (3.2) treated with an alternating application of oxy-acetylene heat and Kroil. At some point, the internal hex will no longer have that geometrical shape. In such cases, a slice into the internal hex area with a Dremel-type tool and small dia. cutoff disk will either expand the nut ID and/or provide an opening to insert a long pry bar.





Surprisingly, all nuts removed and fortunate no studs were injured in the course of filming this procedure.

Suggestion: Red hot parts are soft and will bend and deform. Let heated parts cool down a bit before applying loosening torque. Easy on the muscle. I had less luck on the heat exchanger crossover tube connections and cat. Fasteners in the outer extremities are usually worse off, typically petrified and not connected to expensive engine pieces.

Sherwood

[bigel]

Thanks for the replies, but maybe I wasn't clear...my fasteners have all been removed and I still can't lift off the exchangers.

Is there a pry point of some kind that I can 'get under' to start the exchangers moving off the heads?????

[Flat6pac]

Pull the cams, then the cam carrier, at this point you have the exhaust tooled to the heads. Pull the heads from the block. Now each head is standing on its own attached to the heat box and much easier to individually tap and remove.
There is about a 5 mm heatbox insert into the head which is what is holding it to the heat box.
Bruce

[Amstaff]

Just to be Caption Obvious are you sure that it is completely unbolted and that you didn't miss one?

[911pcars]

Originally Posted by bigel

Thanks for the replies, but maybe I wasn't clear...my fasteners have all been removed and I still can't lift off the exchangers.

Is there a pry point of some kind that I can 'get under' to start the exchangers moving off the heads?????

Are the heat exchangers free of all other exhaust components (crossover tube, muffler, cat.)?

If so, I wouldn't pry. If not careful, there's a chance of breaking a fin or bending sheet metal or other engine part.

I would apply the same penetrating oil to each exhaust flange and tube connection to the heads and flange studs. Let it soak overnight, then try again with the deadblow.

An application of heat could help oil penetrate deeper into the tube connections.

Sherwood

[bigel]

Thanks to all, I have my marching orders...

[michael lang]

I fully understood you that all the fasteners have been removed. You indicated that in your original post that you tried tapping the exhaust manifolds but you were hesitant to hit it too hard. What I meant by "heat is your friend" is try heating the flanges and give those a good whack to free them up. Then make sure you have all the fasteners removed including those at the back of the engine where the muffler attaches to the belt/pulley housing. Maybe that will help you get the heat exchangers freed up.

[porschetub]

Heat is your friend no question here,the downside is galling of the threads which in turn starts another problem later,you can use heat and a fair amount then chilling the nuts with cold water works a treat.
This method breaks the corrosion between the stud and nut,spray the nut with cold water after heating with a butane torch ...it works.

[tom1394racing]

The problem with the late SC and 3.2 exhaust manifold is that the insert from the thick flange heat exchangers rusts itself into the exhaust port on the head.

I have used the method described by Bruce where the heads and heat exchanger are removed as a unit without the cam tower. This provides better acess to the manifold/exhaust port junction for application of heat and penetrant.

The last one I did had one stubborn head that would not come loose. I ended up having to cut the heat exchanger off at the manifold pipe and then very carefully remove the manifold pipe from the head.

Good luck

[bigel]

They're off...heh, mess with me, will ya?!

[bigel]

The exhaust side of the heads (exhaust valves) are ugly...some carbon, etc.

I guess this is to be expected though. I really wasn't planning to replace/rework anthing that wasnt' visibly damaged/shot. The fuel lines are surprising great shape, but he oil lines to the timing chain tensioners are looking a little oxidized on the aluminium parts and the hoses look a little aged and brittle.

Thanks for the works of wisdom and encouragement.

Love this forum.

Steve