Cylinder Head Won't Budge

[RustyTank]

Hey guys. I'm working on my 1979 GS850G the moment. I'm trying to lift my cylinder head off the jugs but it just won't budge. Funny thing is the jugs have started to lift, but the head aint movin. I'm worried about breaking a fin if I tap it to hard with a rubber mallet. I'm looking for suggestions to help encourage this cylinder head to separate from the jugs and lift up on it's own. Oh and btw, I can report that all the cylinder head bolts have been removed, even the small one in the front.

 

[Grimly]

The studs often accumulate a collection of rusty crud between them and the barrels. A good soaking with some penetrant will help, but mechanical uppy-downy action is needed.
What about the small ones at the sides?

Fer gawd's sake, resist the sledgehammer temptation.

 

[RustyTank]

The studs often accumulate a collection of rusty crud between them and the barrels. A good soaking with some penetrant will help, but mechanical uppy-downy action is needed.
What about the small ones at the sides?

Yea, I got the end bolts out too.

Grimly, can you recommend a penetrant?

Fer gawd's sake, resist the sledgehammer temptation.

Yeah, that sh** makes me nervous :nevreness:

 

[TeamDar]

There is a bolt at the front of the head in the cam chain area that needs to be removed.

 

[RustyTank]

There is a bolt at the front of the head in the cam chain area that needs to be removed.

Yeah, I got that one off as well.

 

[fastbysuzuki]

Along with the replies already given, if you can borrow/make something like this
https://flic.kr/p/2ko2YGZ

 

[RustyTank]

Along with the replies already given, if you can borrow/make something like this

That's interesting fast. Thanks for the pic.

 

[Grimly]

Grimly, can you recommend a penetrant?

Last one had been in place a long time and had accumulated lots of crusty junk around the studs. I just soaked them in diesel and ran some thin-wall tubing down them to jiggle it loose. Definitely helped, as they came off the next day. Be aware, as you lift the barrels off, there's a shovel-ful of dirt wants to fall into the crankcase.

 

[oldGSfan]

I got a free BMW R75/5 a long time ago and the heads were stuck. I grabbed a length of cotton clothesline and stuffed it in the spark plug hole as the pistons were coming up, with valves closed of course. Popped right off. Of course a completely different engine layout and I'm not recommending it necessarily, but it sure was a cool way to solve that vexing problem.

 

[Big T]

Deep Creep for the penetrating oil

But, since the barrels are lifting, it sounds like the head gasket is stuck.
Lots of tapping with thin wood blocks along the head/barrel junction. Patience is a virtue here
You may have to pull the entire engine and remove the entire head and barrel as one, and work on it from there

 

[RustyTank]

You may have to pull the entire engine and remove the entire head and barrel as one, and work on it from there

Well, the engine is out of the frame at this point so that's not an issue. I wasn't sure if removing the barrels and the head at once was a good idea but, if that's safe to do then I may end up given that a shot if I can't get the head movin. Thanks Big T.

 

[RustyTank]

Deep Creep for the penetrating oil

But, since the barrels are lifting, it sounds like the head gasket is stuck.
Lots of tapping with thin wood blocks along the head/barrel junction. Patience is a virtue here
You may have to pull the entire engine and remove the entire head and barrel as one, and work on it from there

Got the barrels and head off this morning. They're still stuck together. I've been told by various folks to soak them in diesel to help separate. I'm sure there are other soaking solution options as well. I'm open to suggestions. That topic may be worth another thread though, I don't know.

 

[Nessism]

What about a piece of wood in through the cylinder and up to the head. Then whack it will a mini sledge? You'll need to hold onto the cylinder in some way that doesn't damage the fins. Anyway, it's the impact force that will help break it loose.

 

[Guest]

If the head was still on the engine I would tell you to screw a compression tester hose into one of the center cylinders and after placing the nuts back on the studs loosely, plug it into an air hose. In a 72mm bore 125 PSI makes about 800 pounds of force. Don't launch your head nuts loosely back on the studs if you try it. otherwise put it in a bucket of diesel oil with a pint or two of lacquer thinner in it for a few days if you are not in a hurry. It will clean the heck out of it, but it will destroy your valve seals. If you use a plastic bucket make sure it is marked PE or HDPE on the bottom so the mix doesn't eat into the bucket. You can pour the same mix into the cylinders if you flip it upside down, I would go 50/50 an the lacquer thinner and diesel mix in this case.

 

[RustyTank]

What about a piece of wood in through the cylinder and up to the head. Then whack it will a mini sledge? You'll need to hold onto the cylinder in some way that doesn't damage the fins. Anyway, it's the impact force that will help break it loose.

It's a fair idea Nessism, but man, it really makes me nervous wackin at it like that :nightmare:

 

[RustyTank]

If the head was still on the engine I would tell you to screw a compression tester hose into one of the center cylinders and after placing the nuts back on the studs loosely, plug it into an air hose. In a 72mm bore 125 PSI makes about 800 pounds of force. Don't launch your head nuts loosely back on the studs if you try it. otherwise put it in a bucket of diesel oil with a pint or two of lacquer thinner in it for a few days if you are not in a hurry. It will clean the heck out of it, but it will destroy your valve seals. If you use a plastic bucket make sure it is marked PE or HDPE on the bottom so the mix doesn't eat into the bucket.

I'm in no hurry, I know these things take time. I appreciate the info about the compression, I'm sure I can use that knowledge down the road. I think I'd rather try the soaking technique at this point.

You can pour the same mix into the cylinders if you flip it upside down, I would go 50/50 an the lacquer thinner and diesel mix in this case.

Is this an alternative to soaking the entire thing with the same result expected? If so, I suppose in this case I'd be saving the valve seals? Maybe I've got the wrong impression.

 

[Grimly]

Give up any notion of re-using those crusty old valve seals.
Total waste of time, and they're not expensive anyway. Even better is the opportunity to fit Viton seals instead.

 

[RustyTank]

Give up any notion of re-using those crusty old valve seals.
Total waste of time, and they're not expensive anyway. Even better is the opportunity to fit Viton seals instead.

Oh yeah, I totally agree Grimly. I'm def planning on replacing them. I was just curious about the process of soaking the diesel/lacquer thinner mix in the cylinders. I guess I was just trying to understand the difference between the two processes metalfab suggested. I'm 95% sure I'm going the soaking route. Currently looking for a bucket of some sort big enough that'll fit the head and block together. And I'll look into the Viton valve seals. Thanks for the suggestion.

 

[Carter Turk]

What about wood shims wedged under the intake/exhaust area between fins along with penetrating oil?

Maybe 1 on the outside of cylinder 1-4 & 2 more on each side crossways on 2-3.

Seems the wood would squish before a fin breaks.

 

[Nessism]

A wood shim aimed at the head gasket would likely work too. There are easier and cheaper ways than buying a tub and 5 gallons of some concoction that you will have no easy way to dispose of.

https://www.homedepot.com/p/8-in-Wood-Shims-12-Piece-per-Bundle-WSSHW08/300723328