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Old 23-08-2020, 07:51   #1
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Exhaust manifold stuck?

Hey,
Another post while working on some engine issues and learning many new things in the process..
I managed to pull the head of my engine, I noticed the exhaust manifold is super gunked..
I tried to take it off but seem to be missing a bolt or something.. no play at all and all visible bolts are out..

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Anybody got an idea?
Not much to find about this engine except for a very basic owners manual
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Old 23-08-2020, 08:13   #2
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Re: Exhaust manifold stuck?

Welcome to the forum.

Why not set that assembly into a freezer overnight, then remove it and quickly heat the manifold around the attachment stud holes, but not the studs, with a MAPP gas torch to see if that will permit removal of the manifold.
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Old 23-08-2020, 08:21   #3
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Re: Exhaust manifold stuck?

Thanks!
I was hoping to get it off today.. but I guess some things can't be rushed..

I'll try to gently wiggle it loose some more but if that doesn't work I'll take it back home and try the freezer method.

Edit

It does seem to have some room around the studs but I guess this might be different on the inside
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Old 23-08-2020, 08:23   #4
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Re: Exhaust manifold stuck?

Congratulations on the head removal. On to the exhaust manifold.

Forcing: Take a thin, sharp blade such as a paint spatula or scraper, and tap it into the crack. Don't use a pry bar or chisel. You can put a whole bunch more pressure separating the parts that critical tiny fraction of a millimeter with a thinner blade- it concentrates your tapping on it with a mallet or hammer. If it's bolted together, nothing will happen. If it's not, the crack will get just a tiny bit wider.

By the ned of the day, you're going to have a pile of parts. Good luck.
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Old 23-08-2020, 08:26   #5
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Re: Exhaust manifold stuck?

thanks you! Did feel like an accomplishment when the head started to slide up
Ah perfect I have some of those on board! I'll give that a try.

And yep the pile of parts is starting to get bigger and bigger haha, doing my best to keep everything nice and organized
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Old 23-08-2020, 16:06   #6
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Re: Exhaust manifold stuck?

The second image appears to shows studs which hold something onto the head. These are most probably the reason you cannot get it apart and if you could remove them it may come off more easily. If you put two nuts on the stud, tighten them against each other and use a spanner on the bottom one you may be able to screw them out.
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Old 23-08-2020, 16:40   #7
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Re: Exhaust manifold stuck?

Often times they are just stuck and it takes a sharp rap with a rubber mallet or other tool like maybe a piece of wood to break it loose, don’t use a steel hammer as many manifolds are cast and break rather easily.
I would be very careful with the pry it off method, it’s very easy to damage the mating surfaces, so if you do it be very careful, and don’t pry, back to manifolds can be brittle.
Never tried the freezer method myself, but why not give it a go, a lot less aggressive than most anything else.
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Old 23-08-2020, 17:37   #8
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Re: Exhaust manifold stuck?

I'd be a bit careful of the freezing and heat technique on cast engine parts, they are crone to cracking from thermal shocking.
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Old 24-08-2020, 00:52   #9
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Re: Exhaust manifold stuck?

I managed to carefully tap it off with a piece of wood and a hammer going back and forth from corner to corner!
Man the water flow was definitely very obstructed!
Any suggestions what to soak it in for cleaning?

Edit

The gasket was faulty and because of that one of the studs corroded and that why it got stuck so badly
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Old 24-08-2020, 04:37   #10
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Re: Exhaust manifold stuck?

Good news.

The best option is mechanical scraping for everything that may be reached.

My preference is my 4,000 psi / 3.5 gpm pressure washer to blast things like this clean.

There are dangerous chemicals, like pool acid that will clean parts, but I avoid using them.
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