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Old 02-16-2013, 01:37 AM   #61
disston
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Once the 5 flywheel bolts are off the flywheel pulls off but it is tight fit, not a pressed fit, just tight. I use an old Plomb 4021 puller. The problem is you can't really get your arms in there for a good yank. Sometimes a little wiggling helps.

Best crank block of all time. It's not easy really to move the crank and cause the bearing shim to move but since the consequences of having done that are so bad the restraint is highly recommended.
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Old 02-16-2013, 06:00 AM   #62
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Neat job-- that's what I was thinking about! Since the front ball bearing is off you probably could have mounted the timing case dry, put the front cover on and used a longer bolt on the crank stub.

The 10mm flywheel bolts on the /5 are stretch bolts and need to be replaced each time. Torque is 45 ft-lbs, dry.

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Old 02-17-2013, 12:17 PM   #63
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may have to rename this thread

Nearing completion? Ha!



At least I've almost rounded up most of the parts I'll need to fire the engine up. Picked up a pair of used valve lifters yesterday (the two at the top of the photo). They actually appear to be new -



Also bought new chain, tensioner, front end seals and crank sprocket. Check out the difference between old and new -




Did get around to removing the flywheel by reinserting a couple of bolts on each side of the unit and GENTLY levering against the engine case - be careful not to damage the case.



Previous mechanic had used a million foot pounds to torque the phillips screws on the oil pump cover and didn't use antiseize. Absolute joy to remove. Question: how does one remove the rear main seal without using the crank itself as a fulcrum? Even though I've blocked the crank, I wouldn't want to push my luck.



Spent rest of this morning checking tolerances. So far, the right exhaust valve stem is the only thing out of spec and even that is only by .0003".



I was wrong when I said I suspected a 'recent' valve job by the PO - will probably have the heads done professionally next year.



But the weather's improving here so off to do other chores . . .

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Old 02-17-2013, 01:33 PM   #64
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I reuse 11mm flywheel bolts all the time but not 10mm bolts.

What makes you think the top end isn't low time? I don't see anything in the photos?

Do not use a drill and insert sheet metal screws to take that RMS out. I have seen a lot of cases F'ed up for people doing that! Plus there is absolutely no need for it! Go down to Kragens and get a seal puller. $10. Shorten the handle if you need to. Use the seal iteslf as a fulcrum point. Or just the right board. It will come right out. I worked with a numnut that put superglue on them. If they are super stuck, a little heat will help. Now you can use the same puller to better pull out tons of seals! I have three or four of them modified in different ways to pull different seals. They are worth their weight in gold!

How does the cam sprocket look? Although I have never seen a simplex cam sprocket wear, I have seen a number of duplex cam sprockets worn out.

supershaft screwed with this post 02-17-2013 at 01:54 PM
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Old 02-17-2013, 02:09 PM   #65
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I had to Heli Coil one of the oil pump cover threads. I also had a later style cover that uses small bolts for attachment. I really don't like those Phillips screws in that application. And they aren't available if you need new ones. So if you get the bolts you have to also get the newer cover or counter sink the holes for the bolt heads. I don't know if it's an absolute touch if you don't counter sink the holes but it's really close, too close.

I believe the White seal is the original seal. About time that got changed.
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Old 02-17-2013, 05:04 PM   #66
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Supershaft, when I originally pulled the heads, I was surprised the chambers were so clean. I thought that perhaps the PO actually had done some maintenance. The first valve I pulled, however, looked like this so I assumed they were all the same - actually the rest of the valves look pretty good. You're right, evidence now points to a 'recent' valve job.



I've read the cam sprocket doesn't wear as quickly as the crank sprocket so based on your comment, I compared the old cam sprocket to the new crank sprocket. Looks acceptable - would you agree?



Good tip concerning removal of the seal - I think I'll take your advice - thank you.

Disston, as I mentioned in my preamble, this bike is like a time capsule. You're probably seeing parts you haven't seen in years.
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Old 02-17-2013, 05:45 PM   #67
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Yes, that cam sprocket looks low miles. They don't wear near as quick but the duplex cam sprockets do wear on a regular basis from what I have seen.
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Old 02-18-2013, 07:34 PM   #68
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Tonight's discoveries were straightforward. Rear seal actually pulled out easily. I wonder what left the bright mark on the flywheel mating surface? Is this normal? Not a ridge, just a highly polished line.



Teeth on the flywheel looked fine until I took this close up photo. Looks like the Bendix has chewed up the teeth a little - is this flywheel toast?



Cylinders are perfect with exception of course of the pitting on the left one. Pistons seem to be in spec - can still see the original machining on the piston walls. These are the original pistons (or rather, they have the markings of the original ones of 73.47 B), I'm a little mystified - the hone marks look fresh in the cylinder barrels. The ring end gaps are way out of specification - almost like the last mechanic mixed up metric and standard measurements.Or do the rings just wear like this? This would possibly explain oily buildup on exhaust.



Observations?
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Old 02-18-2013, 11:17 PM   #69
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Yes, the seal making that mark is very normal. Lucky there isn't a ridge there. There often is. The replacement will be a different type seal. Much better design in form and function. Their sealing surface is mm's long. They don't wear grooves into the flywheel for it.

The flywheel teeth came machined like that.

The piston ring gaps often came way out of spec too large from the factory. Some guru's have you check piston ring gap for cylinder wear. That will get you a lot of work since they very often came brand new with ring gaps that were way out of spec. I have measured at least a dozen sets of brand new matched at the factory nikisil cylinder/piston sets. ALL of them had way over spec too large ring gaps brand new. They sure would run a lot better gaped properly!
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Old 02-18-2013, 11:46 PM   #70
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So do you recommend new rings? Or simply reinstall the old ones?
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Old 02-19-2013, 12:13 AM   #71
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New BMW rings will most likely have the same huge gap. Despite there monster gaps, I have had better luck with stock rings versus aftermarket. The aftermarket rings I have used and seen used are too thin allowing too much ring groove clearance resulting in too much ring flutter and poor oil control. Some people forget that the rings seal on BOTH sides. On the cylinder wall? Most people get that but they also need to seal on the piston! On that note, check your pistons' top ring groove. The top side of that top groove wears on BMW pistons. If they are worn, you can see it with a magnifying glass. The wear doesn't go all the way back to the back of the groove. You can see the ridge if there is one right where the ring always rides in the groove. A lot of people measure the ring groove clearance by putting their feeler gauges all the way to the back of the groove. The groove is always like brand new back there and will measure like brand new even though the groove is badly worn further out where it actually matters. Good luck!
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Old 02-26-2013, 08:29 PM   #72
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Thanks for that, SS. Grooves seem fine. One question, though - the manual advises leaving the carbon intact above the top ring. Other forums advise hot tanking the pistons to remove all carbon. What side of the fence are you on?

And on a totally different subject which I have already flogged to death, tonight while installing new seals on the chain cover, curiosity overcame me and I tried pulling the quill out of the old cam. With minimal effort, here's the result -



The project continues to lurch forward at a glacial pace. . .
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Old 02-26-2013, 09:01 PM   #73
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Quote:
Originally Posted by Tin Woodman View Post
And on a totally different subject which I have already flogged to death, tonight while installing new seals on the chain cover, curiosity overcame me and I tried pulling the quill out of the old cam. With minimal effort, here's the result -



The project continues to lurch forward at a glacial pace. . .
Congratulations on being the first ever to publish a picture of the quill in the tip of a BMW cam shaft. Nice pic too.
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Old 02-27-2013, 08:20 AM   #74
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Thanks Disston - it's a dubious distinction. I'm smiling. Who knew this little part would lead to such a fiasco. But then again, the engine had to be torn down sooner or later.

Question - had the tach gear apart last night. Cleaned it out and re-lubed and it is all good but I'm wondering if that little seal should be changed 'while I'm at it'. It seems OK but is this typically a problem area?
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Old 02-27-2013, 09:16 PM   #75
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I know there is a seal there but don't recall anybody ever saying they changed it. I didn't when I did my chain some years ago. I also don't recall anybody ever saying this seal leaked. Just because of a lack of any further info I think you can forgo changing it if you wish. It may actually be a place that never leaks?
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