The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: montmil on February 27, 2014, 08:57:16 AM
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My 1981 R65 has had weepy pushrod tube seals since the day I bought it some several years ago. Even though all the needed parts have been on hand, I've tolerated the occasional drip and the grungy collection of dirt n' road grit for as long as possible. Recent threads and comments from our forum members have finally moved me "off the dime".
I've been photo documenting the process. The left side is now ready to snug up. Then I'll get the right side on TDC and repeat the process. No leaks on the starboard side so it should go faster.
Couple photo teasers:
1) The nastiness.
2) Some fool used 3M Gorilla Snot to bond the rubber seals to the pusrod tubes!
No wonder it was leaking. Suggest using only a little oil on the tubes and a touch of dielectric
grease on the outside of the new seal where it mates to the engine case.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi196.photobucket.com%2Falbums%2Faa1%2Fmontmil%2FBMW%2520Pushrod%2520Tube%2520Seals%2FPushrodSeal05_zps330f3478.jpg&hash=43d35666e0831e9d82ca600e953a54b3c4ce45c1) (http://s196.photobucket.com/user/montmil/media/BMW%20Pushrod%20Tube%20Seals/PushrodSeal05_zps330f3478.jpg.html)
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi196.photobucket.com%2Falbums%2Faa1%2Fmontmil%2FBMW%2520Pushrod%2520Tube%2520Seals%2FPushrodSeal12_zpsf2155d46.jpg&hash=8f715ba9eb0ffbc8812ba9c98cdf208608295810) (http://s196.photobucket.com/user/montmil/media/BMW%20Pushrod%20Tube%20Seals/PushrodSeal12_zpsf2155d46.jpg.html)
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I had that same looking crap on the inside of my seals that came out. Wonder if it was some previous recommended sealant. I went with the dielectric grease on the inside and oil on the outside.
What color big O-ring did you have on the 81? Black or White? Mine was white, which would suggest it had last been opened up a while ago.
Looking forward to more pics... to see what else I might have screwed up.
Still no leak for me after 4 days. I'm almost ready to crack open the celebratory beer ;D
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What color big O-ring did you have on the 81? Black or White? Mine was white, which would suggest it had last been opened up a while ago.
Out of curiosity, how do you figure that?
To my way of thinking - White "O" ring means made of viton or similar heat resistant material. Black means a "standard "O" ring with indifferent heat tolerance.
Without knowing for certain (my R100 is too old to have "O" rings it has base gaskets - I would suspect that white is OEM and black is non OEM.
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I had the cylinders off of my '81 R65 back in '98 I am the original owner and no one has worked on the bike since I took it home from the dealer in January, '81, I had large white o-rings on the cylinder base .
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My suspicion that the higher quality white rings are the OEM fitment is starting to look good.
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Not at all !
I've changed them recently and bought from BMW. As the previous I changed a little more than 10 years back they are black.
I can't remember what color where the previous previous ones but ....
As I own the bike from new, and I'm the only mechanic touching it, I'm pretty sure of the parts fitted ;-)
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Snowbum has a bit on his webpage on this particular o-ring. Can't remember exactly where it is at the moment. Apparently the white ring is NLA. BMW apparently decided to make the o-ring slightly larger. According to snowbum, this isn't a problem and is a fine seal. I think it's more of an interesting tidbit to see when you pull off the jugs for the first time on a new to you bike. If the o-ring is white, it's probably never been done. If it's black, who knows? I do not recall what year they switched to a black o-ring, but I'll try to search through his site and see what I come up with.
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Hello !
When reassembling, put a very thin smear of Permabond on the base of the barrel to ease the job for the O-ring.
I had to remove the barrels one more time to stop a leak on the base... Frustrating ...
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The big ol' o-ring at the base of the cylinder was "two-toned." Looked rather light colored (vintage white) in the groove but was a dark brown on the outside (old white). New large and small OEM o-rings from Bob's BMW. Large 0-ring is black, smaller are a translucent brown-ish color.
All four tube seals had been glued onto the tubes with that nasty 3M stuff. I recall using this yellow adhesive to seal cases and such on my old MX bikes in the 60s. That was about the only option back in the days.
Removing both pistons revealed other surprises. All three piston rings had their end gaps lined up in a neat row. That's incorrect and could be partly responsible for some of the coke on the piston crowns and cylinder heads. Spent some time removing that. The most excellent news is that the exhaust valves are in fine fettle. Absolutely no evidence of the dreaded recession experienced on some bikes.
I used a heat gun to warm the pistons and the gudgeon pins came out smoothly. After removing the rings, all these bits were tidied up and the pistons got a wash n' dry in SWWBO's kitchen sink. I got a pass on that job.
Will wrap up the job today. The mechanics of the seal replacement was straight forward. It was the cleaning that was a time consuming PITA. You've got to know when to stop rubbin' and buffin' or else you'll never finish the seal job. Too clean and shiny is just wrong. :D
I'll let the bike sit with the rocker boxes off until this afternoon; then re-check torque on the six nuts. Valve lash is set and will re-confirm that, too. Today, we're off on the Trophy for an AYCE catfish lunch at the Lonesome Spur Cafe in scenic downtown Justin, Texas... home of the world's largest discount cowboy outfitters.
When refitting the piston to the connecting rod for reassembly, there's minimal space available to fit the gudgeon pin while keeping the rings within the bore. Go slowly and try not to pop out the ring/s. When slipping the piston and rings back into the cylinder, I used wooden craft sticks to aiid in compressing the sharp-edged rings.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi196.photobucket.com%2Falbums%2Faa1%2Fmontmil%2FBMW%2520Pushrod%2520Tube%2520Seals%2FPushrodSeal13_zpsc5681b28.jpg&hash=c168241435b9021412e58935c6c90bb5863c6979) (http://s196.photobucket.com/user/montmil/media/BMW%20Pushrod%20Tube%20Seals/PushrodSeal13_zpsc5681b28.jpg.html)
Pad the contact point where the connecting rod meets the engine case opening. Avoid nicking the aluminum case. If that does occur, you must carefully dress out any irregularity or oil leaks are guaranteed to happen. I also stuffed paper toweling into the tube seal openings to prevent exterior gunk from entering during the lengthy cleaning chore.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi196.photobucket.com%2Falbums%2Faa1%2Fmontmil%2FBMW%2520Pushrod%2520Tube%2520Seals%2FPushrodSeal15_zps9a566797.jpg&hash=549b7f4611ee8698659d4aae87db6b3e298a8914) (http://s196.photobucket.com/user/montmil/media/BMW%20Pushrod%20Tube%20Seals/PushrodSeal15_zps9a566797.jpg.html)
Be gentle with the Bings. Avoid hanging the carbs by their cables. So rather than go through the lengthy process of detaching and reattaching the cables, I used light line to hold them clear of the work site and plugged both openings to avoid catching any debris.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi196.photobucket.com%2Falbums%2Faa1%2Fmontmil%2FBMW%2520Pushrod%2520Tube%2520Seals%2FPushrodSeal07_zpsc94bb09f.jpg&hash=29ddcecfe0ea323e949dba56d90a0b49cd366faf) (http://s196.photobucket.com/user/montmil/media/BMW%20Pushrod%20Tube%20Seals/PushrodSeal07_zpsc94bb09f.jpg.html)
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Mongo,
Keep the photos and updates coming. I was curious about the color of your connecting rods having a cepia type shade, or is that reflection of some kind?
Did your pushrods show any radial scars or marks about where they exit the upper opening of the pushrod tubes?
Just curious.
Good stuff, keep it coming.
-Mike V.
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... I was curious about the color of your connecting rods having a cepia type shade, or is that reflection of some kind?
Did your pushrods show any radial scars or marks about where they exit the upper opening of the pushrod tubes?
Sepia, dark copper, bronze -all would be a good color description of the connecting rods.
The pushrods showed radial contact marks but not at the upper or exit end of the tubes. I looked into the tubes in the area of the engine case and noted a small contact point perhaps 0.5-0.75-inch in from the crankcase end of the tubes. Nothing to indicate hard contact; just the pushrods normal rotation and a slight kiss contact. I have seen issues with the pushrods making contact on the upper end. Either an incorrectly installed head gasket or metal-to-metal.
The witness marks can't be felt with a fingernail test so if they're still pushin' after 33 years, I'm going to give 'em another thirty-three before replacement.
The photo shows a similar coloring within the rocker box area of the heads. I don't know if a particular oil would possible stain the metal at operating temps or what. Also note, in an earlier photo, the bronzed coloration on the gudgeon pin recess and the interior dome of the piston.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi196.photobucket.com%2Falbums%2Faa1%2Fmontmil%2FBMW%2520Pushrod%2520Tube%2520Seals%2FPushrodSeal01_zpsd36e9aa4.jpg&hash=c17d72401f51ebe159c28d926f14a202793ffb2d) (http://s196.photobucket.com/user/montmil/media/BMW%20Pushrod%20Tube%20Seals/PushrodSeal01_zpsd36e9aa4.jpg.html)
After returning from our fried catfish lunch run -and resisting the urge to add to my cowpoke boot collection- I took off on the New Seal R65 and put enough miles on to bring the engine and fresh seals up to operating temps. Didn't take long as the temp was up to 82 degrees. No weeps, seeps nor leaks. Fingers crossed.
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Curious - did they look anything like this? Top of the photo (pushrod) would be the cam or lifter side. The allen wrenches point to the score markings.
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Ah ha! Now I recall where I saw those marks.
Yep. Just like yours except only one mark per pushrod. Mine would be about the 8 inch mark on your ruler. Left side only.
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The marks on the push rods are from the head gasket being installed backwards. There is a small difference of the holes for the push rods. One way the holes are line up and flip they are off center a small amount and the push rod rub on them. Cannot remember who's site I found out about it. Had my heads off shortly after to fix some leaks and found out there is a difference.
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Don,
Not caused by the head gasket being installed backwards in this particular case. Long story, maybe an opportunity for another thread at another time not to hijack Monte's PTS topic.
But here's a before and after...
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The brownish color on the conrods and rocker arms is oil staining, or a mild "oil blackening," caused by soaking or quenching hot metal in oil. The more heat/the dirtier the oil the darker it will stain until you have yourself a cast iron frying pan. Metal porosity will affect the finish too.
Some people, such as metal sculptors, experiment with heating and oil quenching temps/concoctions to produce different finishes. I've put such a finish on an engine cover bracket that bolts to the carb throat on my 1964 Ariens snow thrower this way.
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And in my R65's particular case, some "mechanic" or PO may have flipped the pushrobs end-to-end. Quien sabe?
The last old head gaskets I removed were properly installed as were the new ones going back together. It only takes a quick look to confirm proper orientation. Noting the other posted errors and poor decision making from my bike's POs, I wouldn't be surprised that somewhere in the past thirty-three years a head gasket on one side may have been incorrectly installed. Quien sabe?
There were no metal-to-metal contact marks on my R65 pushrod tube exits as those shown in Mike V's photos -which could possibly explain my witness marks.
Besides the '81 R65's re-seal job, I'm still having fun straightening out multiple minor issues on my kinda recently acquired '78 R100S. The next 'S' job is... pushrod tube seals! Got one weepy and three tight. Going for all four, "Since I'm gonna be in there."
Our Classic Airheads don't always come from Airhead people. Some previous owners never even learned to RTFM. [smiley=thumbdown.gif]
Let the games continue [smiley=thumbup.gif]