Removal of heat exchangers on sc engine

[hughc]

I'm in the process of removing the heat exchangers on my sc engine. I am deathly afraid
of snapping studs and I've been lucky so far with 3 nuts and 2 cap nuts removed with no broken studs. But I have 7 more to go.
With the thousands, tens of thousands heat exchangers removed on air cooled engines, has anyone come up with the fool proof method of removing nuts without breaking studs?
I'm using a combination of torch, induction heater, penetrating oil, and even candle wax and lots of patience.
Can anyone suggest something that I haven't done?
Thx
Hugh

[john walker's workshop]

One at a time, heat bright red all around, with OXY ACET, wait a few secs so they get dull red, so the metal isn't so soft and give it a bit of a snap with your ratchet. If it doesn't crack loose, do not continue, just repeat the above. Done hundreds that way and can't remember the last one I broke. You will need a looong 8mm 3/8 drive allen socket for the allen nuts and a medium or long 3/8 extension and 13mm wobbly socket.

[Flat6pac]

I’ve used propane for years the nuts get cherry red then they unthread easily
Remember the sockets stay hot too
Bruce

[MichaelSJackson]

Remember that when an object with a hole is heated, the hole gets larger. (We use this fact when we use a freezer to create more slop before pressing a bearing?)

So ideally, try to heat the nut or the casting more than the bolt/stud.

The difference in expansion helps to break the weak oxidation weld. (This reinforces John's point about not forcing it, if the weld did not break.)

[theiceman]

For me the secret was what John said. I was fortunate enough to have the engine out and heads, cam housing and exchanger on the bench. I purposely used tools that i could not have enough mechanical advantage to break the stud, just a regular 8mm allen key and a 13mm wrench i think it was.
As they were short if i couldn't remove it with just those tools it wasn't ready and reheated it again cherry as John said. Once they were ready they just came out with those tools.

[thsupernge]

This is such great info. When reinstalling do you guys all cover threads with Anti-cease?

[AlistairWallace]

I did the following which worked like a charm. Mine were extremely rusty.

• I bought 12 pipe caps - metal caps that screw on to the end of steel pipes used in plumbing.
• Filled each cap with PB Blaster Penetrating Catalyst.
• Jammed the caps up to each bolt using wood shims
• Left it over a two day period to work its way in
• Used the correct tool for the ones that are difficult to get too, cannot remember where I got it from. Either way, use good quality sockets, quick snap, not slow wrenching.

This worked for me, but each car is different, good luck

[hughc]

Thanks guys. Lots of great instructions/ideas.. I have one exchanger removed and will report back on my progress.

The main reason for removing the exchangers was to be able to completely clean the engine after determining where the oil leakage was originating.

I was hoping to go with Dry Ice Blasting but that was crazy expensive so I will be looking for another alternative.

Anyway, one step at a time. Thanks to those that replied.

[john walker's workshop]

No brandon here. Keep it classy.

[mike sampsel]

Originally Posted by thsupernge

This is such great info. When reinstalling do you guys all cover threads with Anti-cease?

I did, and on all the exhaust bolts too.

None anywhere else on engine, none on my spark plugs.
Change your plugs every 3 years or so ... plugs and anti seize cause a rousing discussion here.

[70SWT]

I do the same thing as Mr. Walker describes, but I only have a MAPP torch. I also presoak using Kroil for days before the first try, and then respray frequently during the work. I like Kroil better than PB Blaster, but have used both with success on most projects.

My experience says that the key is not to rush it. Work a nut/stud a little, and if it's not moving, respray it and try the next one.

I recently took a couple of days of periodic attempts to get all 12 of mine off without breaking any. And I have several that are pretty corroded and could have snapped easily if overworked, so this careful approach works. Take your time and be very sympathetic.

[mikedsilva]

I'm using a small oxy/acetylene setup very similar to theiceman. I don't worry about PBblaster etc.

Get them cherry hot, then apply pressure with the tool. It's amazing just how much easier they undo after they have been red hot.

Once you've used this type of heat, you won't need to use anything else.

[WP0ZZZ]

Originally Posted by mike sampsel

I did, and on all the exhaust bolts too.

None anywhere else on engine, none on my spark plugs.
Change your plugs every 3 years or so ... plugs and anti seize cause a rousing discussion here.

Is a copper-based anti-seize a good choice for the exhaust bolts?

[tperazzo]

I just posted a video on my YouTube channel of heat exchanger removal.

I've never done it before and it went well for me as rookie, but I ended up buying a big boy torch (oxy/acetylene)

One commenter said its easier to remove the exhaust as one complete unit after the hex and barrel nuts are removed from the head studs. I tend to agree this would work even better than the way I did it.

Here's the vid:

https://youtu.be/tmXnd47CA8U

You can do this! I didn't have any luck with the mapp gas crap that is available today!

[john walker's workshop]

Yup, all in one piece, muffler included.

[G450X]

Originally Posted by 70SWT

I do the same thing as Mr. Walker describes, but I only have a MAPP torch. I also presoak using Kroil for days before the first try, and then respray frequently during the work. I like Kroil better than PB Blaster, but have used both with success on most projects.

My experience says that the key is not to rush it. Work a nut/stud a little, and if it's not moving, respray it and try the next one.

I recently took a couple of days of periodic attempts to get all 12 of mine off without breaking any. And I have several that are pretty corroded and could have snapped easily if overworked, so this careful approach works. Take your time and be very sympathetic.

Exactly what I did, I only broke one stud and was very happy. The stud broke off long enough to put my stud puller on it and more MAPP gas & Kroil and it came out. Good Luck, SSI’s and M&K 2/1 was worth it!

[hughc]

Fait accompli Finished that job this am. no broken studs. What a relief. Now to clean the engine. Thanks guys for all the assistance.

hughc

[john walker's workshop]

Tres bien!

[oscar94]

Is there any risk of damage to the magnesium engine cases or even getting one to ignite if using oxyacetylene? I need to replace my exchangers, but kind of worried about a hot flame under there.

A quick google search has O/A temp at 3000C and magnesium ignition at 480C.

Apologies if this is a dumb question.

[SoCalSK8r]

Is it common to replace the all the studs?


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