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I am in the process of replacing a head and valves after one valve broke and dropped into the cylinder (it was not pretty!). I have studied the service manual but am confused in several areas where I ask for your advice:
1. With brand new valves and head - do the valve/seats need to be ground in?
2. I am not able to see any marker to indicate TDC - how do I know that I am precisely in the right place?
3. I am confused about setting the vale cams in their correct timing position when re-fitting the timing chain. With the crank locked in TDC where should the markers on the cam sprockets face? I can only see one marker and presume that there is a mark underneath the inlet sprocket cover plate.
Sorry I am a novice to all this but learning fast!
Not sure about grinding in new valves to a new head, but I'm sure someone else will let you know.
There is a TDC hole which you can screw a bolt through to lock the engine at TDC. The hole is filled with a shorter bolt normally, and it's located above the crank near the starter motor. You need a longer (about 5 + cm) version of the bolt you remove, with the threaded end ground to a point. Screw it in with your fingers until it stops, then slowly rotate the crank until the bolt screws in a bit further, that's TDC. You will also see the piston is at the top of its travel.
From memory: On the cams there's a scored line on the exhaust one, which needs to line up with a white painted tooth on the inlet cam, which I find is difficult to see. Get the exhaust cam in roughly the right place( scored line pointing towards inlet cam) then match the angle of the inlet lobes to the exhaust lobes and closely inspect the inlet teeth nearest the scored line of the exhaust cam. Maybe squirt a bit of degreaser on them to wash off any deposits covering up the white paint.
You can see the marked tooth easier with the inlet cover plate removed BUT avoid this if you can because the cam bolts have a habit of coming loose once they've been disturbed, and that can be catastrophic.
hi jaye, to add to andrew's comments:
with cams out, you will notice that the key pin corresponds with the tooth marker. the inlet marker can be verified in this way (faint white or pink paint blob)
if you bought an assembled head the valves would have been lapped in, otherwise check with engineers blue and lap with fine grit paste
you will also have to check valve clearances (inlets 0.05 to 0.14mm, exh. 0.20 to 0.29mm). the head is a real swine to assemble and you will need a special valve spring compression tool. you can also easily lose a collet in the process as forum members will attest
i would also recommend that you install a new cam chain and if it is a high mileage bike, also a chain tensioner
there is plenty of good info on the forum which i recommend you read
this work is quite risky for a novice (as you say you are) to tackle and i would strongly recommend that you download the excellent (free) bmw c1 repair manual.
it may help your mood if i say that i consider the c1 a giant meccano set!
One other tool which is a bit specialist is the torque wrench required to reach the 2 external nuts which hold the head on I.e. those on the opposite side from the timing chain. They're only really accessible by a spanner, so a normal torque wrench and socket won't fit, even with a UJ joint.
I admit I judge the tightness of those two by hand/ guesswork, but it's not ideal. I think some people have bent a spanner into a C shape and used a torque wrench on that. Just had a look in Screwfix, there's a double ended flex head spanner set which might work, no guarantees but the principle of putting one end over the nut and then finding an adapter to fit the torque wrench to the other end, when it's around the head projection and above the nut sounds good to me.
Or if you're good at engineering a torque wrench attached to a straight spanner and adjusted to a lower torque to allow for the length of the spanner is another possibility, but way beyond my feeble mathematical ability.
i quote from a previous posting of mine:
"as my friend jak says, if you have a grinder you can also weld"
my effort at the torque wrench is attached
Looks good. The ring spanner is slimmer than the ratchet mechanism of the one I was looking at, which means it'll fit, not 100% sure a ratchet one would fit over the nuts.
I can't justify welding gear while I only work on C1s, there's not enough rust I'm delighted to say
One of the many benefits of C1 ownership.
i've got this joy to come at the weekend
I'll be using an open ended 13mm ring spanner to torque up the outside nuts, with a bolt fitted through the other end of the spanner and tightened to hold it in place, leaving the top part of the bolt exposed.
I may use a stack of 13mm nuts on a 13mm bolt, so it will pass through the other spanner end and leave a 13mm bolt head available to use my torque wrench on.
Then I will attach a torque wrench to the bolt, and using the CNCEXPO.com site, work out the new torque setting-the calculations are pretty easy as it will be a straight spanner I use, or even easier if I set the spanner up so I'm using it at 90 Degrees (so the distance the newtons are applied over remain the same) .
At least that's the plan. I could weld something up but hopefully won't be doing this much, and if my plan works then job done!
I bought a flex head spanner in the end, 13 mm I think. It just fits over the head nuts, then with it swivelled almost 90 degrees and the other flex head also swivelled 90 degrees, you almost achieve a C shape which you can attach the torque wrench to using a hexagonal drive.
I’ll try to shrink a photo to attach here, but no promises!
that's much more elegant, and future-useful too.
I'll see what screwfix/halfords/ebay sell...then I hope I have a large enough Hex key attachment!
Actually, those are £30 where i've found them-is that what you Paid? Or do you recall where you found them cheaper?
Price looks about right unfortunately. I got it from Cartoolsdirectuk on eBay: £28.95
Needs to be decent quality because that hinge part has to take a lot of torque, in a direction that isn’t ideal for it.
Trident T212612 XL Double Flex Head Ratchet Spanner 12mm x 13mm Length 320mm
That's a bit dear when my bodge should work for £0. I also considered bending a long double ended spanned for £10, but I think I'll stick with my original plan.
There is a brilliant tip on the Italian forum where you use a double ended 13/15mm spanner tool and fit the 1/2" torquemeter tool in a 90 degrees angle and it translates to the same torque applied on the nut.
I have tried it with success!http://www.bmwc1club.com/forum/topic.asp?TOPIC_ID=6284
That's how I'm going to do it (see above)
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