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How do you remove the cylinder heads R50/5
- Thread starter briana
- Start date
Brian -
Here's a typical picture of the "business area" of the head under the valve cover...taken from a recent post on valve clearances:
http://forums.bmwmoa.org/showpost.php?p=468534&postcount=12
Steps are:
- remove valve cover...two 10mm nuts forward and aft and an acorn nut in the middle
- remove 6 nuts...see picture. Two, top and bottom for each rocker arm, intake and exhaust. And one at the 12 and 6 o'clock position. Hopefully the broken spark plug doesn't create problems getting to the one at 12 o'clock. You should remove them in stages...don't take one completely off, but back them all off in even increments.
- as you remove the rocker arm nuts, be ready to remove the rocker arm and the upper and lower pillow blocks. Try to keep them all together and oriented the correct way.
- remove the pushrods from their tubes. Again, keep the intake and exhaust separate and note which end goes on the cam follower and which into the rocker arm
- if you're lucky, the head will come off with a little light tapping with a rubber hammer or dead blow hammer. Be careful about the fins as they could break. Avoid prying off the heads.
That should get the head off. You'll have some cleaning to do.
Here's a typical picture of the "business area" of the head under the valve cover...taken from a recent post on valve clearances:
http://forums.bmwmoa.org/showpost.php?p=468534&postcount=12
Steps are:
- remove valve cover...two 10mm nuts forward and aft and an acorn nut in the middle
- remove 6 nuts...see picture. Two, top and bottom for each rocker arm, intake and exhaust. And one at the 12 and 6 o'clock position. Hopefully the broken spark plug doesn't create problems getting to the one at 12 o'clock. You should remove them in stages...don't take one completely off, but back them all off in even increments.
- as you remove the rocker arm nuts, be ready to remove the rocker arm and the upper and lower pillow blocks. Try to keep them all together and oriented the correct way.
- remove the pushrods from their tubes. Again, keep the intake and exhaust separate and note which end goes on the cam follower and which into the rocker arm
- if you're lucky, the head will come off with a little light tapping with a rubber hammer or dead blow hammer. Be careful about the fins as they could break. Avoid prying off the heads.
That should get the head off. You'll have some cleaning to do.
R
racegun
Guest
i highly recommend you get a repair manual if you are a newby wrench. Airheads are easy to work on, but ya must know what you are doing!
Brian -
You may be interested in the top end manual written by Oak Okleshen. It's a very thorough step-by-step process for how to completely remove the top end, of which removing the heads is a part. People usually get this manual when they want to change the pushrod tube seals. Oak sells it for $25. He can be contacted at his email - askoak at aol dot com.
One of the situations you'll need to deal with when reassembling is the alignment of the rocker arms. The /5s needed some special alignment in order to assure proper operation. Oak covers it in his manual. Duane Ausherman also speaks about it on his webpage:
http://w6rec.com/duane/bmw/valve/index.htm
Note the "H" looking tool near the top of the page. This is the item that's needed to get the rocker arms and pushrods aligned.
You may be interested in the top end manual written by Oak Okleshen. It's a very thorough step-by-step process for how to completely remove the top end, of which removing the heads is a part. People usually get this manual when they want to change the pushrod tube seals. Oak sells it for $25. He can be contacted at his email - askoak at aol dot com.
One of the situations you'll need to deal with when reassembling is the alignment of the rocker arms. The /5s needed some special alignment in order to assure proper operation. Oak covers it in his manual. Duane Ausherman also speaks about it on his webpage:
http://w6rec.com/duane/bmw/valve/index.htm
Note the "H" looking tool near the top of the page. This is the item that's needed to get the rocker arms and pushrods aligned.
stevesgarage
New member
Um..., Duane calls the H-looking tool "completely useless". Don't bother with it. Instead use his techniqure for pinching the blocks while tightening. Or you can also use a pair of big c-clamps and 4 short sections of 1/2" emt (thin-wall electrical conduit). You get a little more control that way. (Too tight and the rockers won't rock - big problem!. Too loose, and you get a little too much clatter -a very small problem.)
Definitely replace the pushrod tube seals while you are there. If they don't leak now, there are going to eventually.
--Steve
Definitely replace the pushrod tube seals while you are there. If they don't leak now, there are going to eventually.
--Steve
Well, Duane does have a dim view on certain things. My understanding is that the two rocker arms must be parallel to each other and they should be aligned with some sort of "axis" of the head. That's what I understood the tool to be used for. The /5s had those degrees of freedom where as the later versions of rocker arms took most of that out. Maybe it can be done without that tool.
stevesgarage
New member
Kurt has a point about strong opinions. And Duane is not the most opinionated one out there!
For Brian's benefit - a few things to keep in mind:
1) It is not rocket science. Read the book, take your time, and double check your work and you will be fine.
2) Don't worry about finding the H-tool (my opinion -see below). However, this does not mean you can just toss them on and go. Watch the alignment of the blocks and watch for any play that could cause them to cant.
3) Watch the position of the pushrods when you start to tighten things down. They need to be seated AND centered in the pushrod tubes. Nothing worse than starting to torque things down and finding the pushrod end has dropped out of the little cup....
4) Pinching the blocks together (per Duane's website) is optional. It will likely reduce valve clatter if you do it, but nothing will be ruined if you don't do it. On the other hand, if you make them too tight, so that the rockers can't pivot, then you have a problem.
5) I prefer to torque everything down gradually. e.g., take them all down half way, then all down fully. That way I can also double-check that nothing has shifted before I do the final tightening. I torque down in the order specified in the manual. (Yes, I actually disagree with Duane on this one!)
O.k., to explain and qualify my opinion. I have only worked on bikes with less than 50K miles, so I have no experience with higher milage rockers (insert favorite pun here!). However, in my experience, I've not seen enough play in the pillow blocks to worry about them canting. That doesn't mean it doesn't happen, just that I've not seen it. I also don't see how the simple H-tool could be precise enough to impart such a small adjustment to the blocks. Again, just my opinion.
Good luck!
--Steve
For Brian's benefit - a few things to keep in mind:
1) It is not rocket science. Read the book, take your time, and double check your work and you will be fine.
2) Don't worry about finding the H-tool (my opinion -see below). However, this does not mean you can just toss them on and go. Watch the alignment of the blocks and watch for any play that could cause them to cant.
3) Watch the position of the pushrods when you start to tighten things down. They need to be seated AND centered in the pushrod tubes. Nothing worse than starting to torque things down and finding the pushrod end has dropped out of the little cup....
4) Pinching the blocks together (per Duane's website) is optional. It will likely reduce valve clatter if you do it, but nothing will be ruined if you don't do it. On the other hand, if you make them too tight, so that the rockers can't pivot, then you have a problem.
5) I prefer to torque everything down gradually. e.g., take them all down half way, then all down fully. That way I can also double-check that nothing has shifted before I do the final tightening. I torque down in the order specified in the manual. (Yes, I actually disagree with Duane on this one!)
O.k., to explain and qualify my opinion. I have only worked on bikes with less than 50K miles, so I have no experience with higher milage rockers (insert favorite pun here!). However, in my experience, I've not seen enough play in the pillow blocks to worry about them canting. That doesn't mean it doesn't happen, just that I've not seen it. I also don't see how the simple H-tool could be precise enough to impart such a small adjustment to the blocks. Again, just my opinion.
Good luck!
--Steve
Steve -
I should also qualify my input...I've never worked on the early /5 rockers so I don't know how useful the proposed tool is. I just know that Oak spends time discussing it and providing the template in his top end manual. That told me that it was of some importance.
But thanks for laying out details of what to watch for. Armed with this knowledge, Brian can be aware of what's happening and look for things that don't make sense. Afterwards, he can decide if he needs "the tool" based upon how the bike runs and sounds.
I should also qualify my input...I've never worked on the early /5 rockers so I don't know how useful the proposed tool is. I just know that Oak spends time discussing it and providing the template in his top end manual. That told me that it was of some importance.
But thanks for laying out details of what to watch for. Armed with this knowledge, Brian can be aware of what's happening and look for things that don't make sense. Afterwards, he can decide if he needs "the tool" based upon how the bike runs and sounds.
stevesgarage
New member
Kurt- Oak has a stellar reputation, so I'm curious what he has to say. Maybe I should finally get around to buying his "book"...
Brian - As you can see, some of this stuff is still up for discussion - 30 years later! The Clymer book is the best starting point. It'll help you get the head on and off without ruining anything. The rest is a continuous learning process!
--Steve
Brian - As you can see, some of this stuff is still up for discussion - 30 years later! The Clymer book is the best starting point. It'll help you get the head on and off without ruining anything. The rest is a continuous learning process!
--Steve
Steve -
In looking at his manual, I don't actually see the "H" tool. I was remembering the diagram he has which sticks in my memory as an "H". But he does spend 3 full pages on this subject, with the stated diagram with dimensions X, Y, and V to be determined and measured. He states that the alignment is critical to ensure that the pushrods don't rub, the rocker arm stub pushes on the proper place on the valve tip, and that the valve rotates when operated. All this prevents cracking, spalling, or breakage of the rocker and/or the tip of the valve.
So, there's a lot going on with this measurement. As you indicated, it's important to get it right.
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