I know this must have been covered in the past, but my searches came up empty... Is there a likely local source for shims, a car or motorcycle dealer that uses the same diameter shim? I haven't removed my .021" clearance intake yet, so I'm not sure what they look like. Also, is there a thread on cam removal for valve adjustment? Thanks!
Valve Shim Source?
1 - 13 of 13 Posts
Joined
·
11,890 Posts
What type of motorcycle or boat are you working on?
All kidding aside, if you need Alfa shims, try the normal sources - IAP or Centerline.
All kidding aside, if you need Alfa shims, try the normal sources - IAP or Centerline.
I was hoping to avoid the wait... I assume these are under-bucket shims, are they 7 or 8 mm valves?
Joined
·
11,890 Posts
You still haven't told us what you're working on. Alfa has used 7, 8, 9, and 10mm shims, plus I think a 9.5 on a few early models. The 9mm is the common size for the 60's through 90's 4 cylinders. I don't know about the various 6 cylinder models, or Alfasud.
What engine are you working on?
What engine are you working on?
Sorry, it's my '87 Quad. Sounds like I need 9 mm shims. Still haven't pulled the cams: my factory shop manual (worst I've seen), says after removing cam caps and loosening chain tensioner "remove the complete camshaft and the chain, then rest them on the central part of the head." Does this mean there will be enough slack in the chain to keep it on the cam so I can roll the cam and move it over to rest between the head bolts? When I retension the chain, do I just loosen, then retighten the tensioner bolt? If so, it all sounds fairly straight forward. Might as well pull both cams, one at a time, to measure all the shims. Thanks for any other tips.
Joined
·
18,843 Posts
The actual shims are cup shaped - not simply flat discs.
To 'adjust' valve clearances, I loosen the chain tension (just loosen the lock bolt 1/2-3/4 turn - do not unscrew it too far or the small nib on the end will disengage from the locking wedge), push the tensioner back and lock it there temporarily. With the chain thus loosened, you can remove the cam caps and lift/roll the camshaft up & out leaving the cam gear & chain meshed. This will maintain cam timing when the camshaft is re-installed & the chain re-tensioned. You can only do one cam at a time this way - there isn't enough slack to lift both cams out with the chain & gears meshed.
If/when you remove a camshaft, measure & record all the shim sizes. Then, if you ever need to adjust a valve in the future you will know what size shim is in there (assuming you remember where you recorded the shim sizes...) and thus can calculate & obtain the size shim you need before removing the camshaft.
Chain tensioner, lock bolt & locking wedge:
To 'adjust' valve clearances, I loosen the chain tension (just loosen the lock bolt 1/2-3/4 turn - do not unscrew it too far or the small nib on the end will disengage from the locking wedge), push the tensioner back and lock it there temporarily. With the chain thus loosened, you can remove the cam caps and lift/roll the camshaft up & out leaving the cam gear & chain meshed. This will maintain cam timing when the camshaft is re-installed & the chain re-tensioned. You can only do one cam at a time this way - there isn't enough slack to lift both cams out with the chain & gears meshed.
If/when you remove a camshaft, measure & record all the shim sizes. Then, if you ever need to adjust a valve in the future you will know what size shim is in there (assuming you remember where you recorded the shim sizes...) and thus can calculate & obtain the size shim you need before removing the camshaft.
Chain tensioner, lock bolt & locking wedge:
Attachments
Thanks Eric. That's what I thought they'd look like. I have some Ducati valve-top shims laying around, but those are 8 mm valves. Good tip on not loosening the tensioner bolt too much, might have fallen into that one 
. Do you just push the tensioner back with a big screw driver? Manual said to push down on the chain?
. Do you just push the tensioner back with a big screw driver? Manual said to push down on the chain?
Joined
·
11,890 Posts
Fritz...
1. BEFORE taking anything apart, remove the plugs and roll the engine over taking base-line measurements of each cup-to-cam lobe. Mark these down. Measure carefully, as mistakes will force you to start over.
2. Set engine to TDC #1 during compression stroke. #1 cam lobes will be pointing outward, and you can observe matching marks in the front cam bearing cap and cam that should be lined up. Confirm you are on the TDC mark on the front pulley. I think it says "PMS", but it's been a while since I played with a 115. I generally prefer to un-latch the chain and pull both cams simultaneously, but this requires that you roll the engine around until the master link is where you can get to it, and take extraordinary precautions to avoid dropping any parts of it into the sump via the front gallery in the timing cover/head. Rolling the cam out as described is possible as well. Whatever floats your boat.
3. I use a 1/2" breaker bar to press back the tensioner. It's not all that stiff. Just re-tighten the bolt a little to hold it in place. Over-tightening this bolt is as bad as loosening it too much. You can swage the taper-piece into the tensioner shaft and it makes future adjustments very difficult.
4. If you have unlatched the chain and secured the loose ends with safety wire so it doesn't drop down into the sump, you can now remove both cams and set them wherever you want. Middle of the head is as good as any. I prefer a less cluttered work area.
5. Remove the buckets, and set them somewhere in a manner where they can be replaced into the holes they came from. The shim is usually stuck to the top of the bucket, but sometimes is stuck to the valve head. Be careful that you don't carry the bucket across the open front of the engine, as this might be the moment that the shim decides to come unstuck and drop down into the depths of despair (to mix metaphors).
6. Using a dial caliper, measure the thickness of the shim. Calculate the difference in what your previous clearance was and what it needs to be. Add/subtract the difference from your existing shim to define the necessary thickness of the new shim. Select the new shim from your $600 collection of shims, and reinstall it all in reverse order.
7. Reinstall cams, but not chain, and measure new clearances. If they are all close, button it all up.
Good luck.
1. BEFORE taking anything apart, remove the plugs and roll the engine over taking base-line measurements of each cup-to-cam lobe. Mark these down. Measure carefully, as mistakes will force you to start over.
2. Set engine to TDC #1 during compression stroke. #1 cam lobes will be pointing outward, and you can observe matching marks in the front cam bearing cap and cam that should be lined up. Confirm you are on the TDC mark on the front pulley. I think it says "PMS", but it's been a while since I played with a 115. I generally prefer to un-latch the chain and pull both cams simultaneously, but this requires that you roll the engine around until the master link is where you can get to it, and take extraordinary precautions to avoid dropping any parts of it into the sump via the front gallery in the timing cover/head. Rolling the cam out as described is possible as well. Whatever floats your boat.
3. I use a 1/2" breaker bar to press back the tensioner. It's not all that stiff. Just re-tighten the bolt a little to hold it in place. Over-tightening this bolt is as bad as loosening it too much. You can swage the taper-piece into the tensioner shaft and it makes future adjustments very difficult.
4. If you have unlatched the chain and secured the loose ends with safety wire so it doesn't drop down into the sump, you can now remove both cams and set them wherever you want. Middle of the head is as good as any. I prefer a less cluttered work area.
5. Remove the buckets, and set them somewhere in a manner where they can be replaced into the holes they came from. The shim is usually stuck to the top of the bucket, but sometimes is stuck to the valve head. Be careful that you don't carry the bucket across the open front of the engine, as this might be the moment that the shim decides to come unstuck and drop down into the depths of despair (to mix metaphors).
6. Using a dial caliper, measure the thickness of the shim. Calculate the difference in what your previous clearance was and what it needs to be. Add/subtract the difference from your existing shim to define the necessary thickness of the new shim. Select the new shim from your $600 collection of shims, and reinstall it all in reverse order.
7. Reinstall cams, but not chain, and measure new clearances. If they are all close, button it all up.
Good luck.
Thanks for the tips, guys. I haven't been back to the car yet, got distracted by a rotted porch column, but hopefully earned some Alfa (brownie) points. I've done a few valve adjustments in my time, even conquered the Ducati Desmodromic! But advice from the experienced Alfisti is always a good idea. I'll be especially wary of dropping a shim down the timing chain galley; I can see myself doing just that.
1 - 13 of 13 Posts
Join the discussion
