Engine Timing - 32vr & Dial Gauge Disagreement (Issue Found I Think)
12-31-2010, 03:51 PM
#31
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1. Good job. Cam PNs OK?
2. Your chains are fine. If you don't have the lines inscribed in the gear face, just count the holes between the gear teeth.
3. Do the adjustment for #6, and get it dead on 2.0 at the 20 mark of the crank. go around a few times by hand and then check it with the 32Vr. Then do #1 and get it to the book value. That's the only thing that matters is the mfg reference.
4. Recheck your tension, then check the 32Vr tool, and report what you have.
2. Your chains are fine. If you don't have the lines inscribed in the gear face, just count the holes between the gear teeth.
3. Do the adjustment for #6, and get it dead on 2.0 at the 20 mark of the crank. go around a few times by hand and then check it with the 32Vr. Then do #1 and get it to the book value. That's the only thing that matters is the mfg reference.
4. Recheck your tension, then check the 32Vr tool, and report what you have.
Based on what I've read, it seems like it would have been unusual to see a chain issue on a car with only 70K miles on it. One question about indexing...if the chain had stretched, I guess the lobes would have been further apart than 113mm...is that the point of the indexing measurement...or is more to see that the cams were installed at the proper teeth relative to each other? Also, I will check part numbers of the cams.
Going forward, I think I am going to give Kens suggestion a go first because it is listed at part of the Porkensioner procedure. I would hate to mess with the timing only to have to put it back if its just a matter of settling the belt.
If I spin the belt on the stater, I presume the cam covers need to be on to prevent a mess of oil. Do I also need to ground the spark since there are no plug wires installed currently? Or...does pulling the EZK solve this?
Thanks,
Dave
12-31-2010, 03:53 PM
#32
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Check TDC on Cyl #1 with the dial indicator. #6 and #1 should be ever so slightly different.
As to the comment about the cams not needing the adjustment. The earlier ones didnt have adjustment. Showing that precision was there. However the factory felt the need for individual adjustment to ensure that one could dial in the cams to proper settings and compensate for belt stretch etc.
As to the comment about the cams not needing the adjustment. The earlier ones didnt have adjustment. Showing that precision was there. However the factory felt the need for individual adjustment to ensure that one could dial in the cams to proper settings and compensate for belt stretch etc.
Thanks,
Dave
12-31-2010, 04:52 PM
#33
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12-31-2010, 05:55 PM
#34
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Assuming the intake cam sprocket has only 19 cogs, then it being installed off by only one cog would result in about 19 cam degrees, or 38 crank degrees of error. So I don't see how, with the dial and dampener readings you've presented, that they could be installed wrong.
Further, how much belt stretch or belt seasoning would you expect to see? Any belt stretch would give results that would be more pronounced on the right bank (cylinder #1) than the left (cylinder #6), because there is be more belt length between the cam gear/sprocket and the crank gear/sprocket. The more the belt stretches the more the intake cam will lag. Your results don't show this, in fact, just the opposite. Both type tensioners provide similar belt tension; any difference in tension will result in minimal belt stretch differences. So, I wouldn't be concerned about the type of tensioner or belt seasoning.
Further, how much belt stretch or belt seasoning would you expect to see? Any belt stretch would give results that would be more pronounced on the right bank (cylinder #1) than the left (cylinder #6), because there is be more belt length between the cam gear/sprocket and the crank gear/sprocket. The more the belt stretches the more the intake cam will lag. Your results don't show this, in fact, just the opposite. Both type tensioners provide similar belt tension; any difference in tension will result in minimal belt stretch differences. So, I wouldn't be concerned about the type of tensioner or belt seasoning.
01-01-2011, 01:12 AM
#35
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Had to drag my feet on 928 chores due to b-days and other holiday stuff, but I would like to wrap this up since I am close on finishing almost everything else. The timing set me back a bit plan wise, but better to (i) learn and (ii) get it right.
Based on what I've read, it seems like it would have been unusual to see a chain issue on a car with only 70K miles on it. One question about indexing...if the chain had stretched, I guess the lobes would have been further apart than 113mm...is that the point of the indexing measurement...or is more to see that the cams were installed at the proper teeth relative to each other? Also, I will check part numbers of the cams.
Going forward, I think I am going to give Kens suggestion a go first because it is listed at part of the Porkensioner procedure. I would hate to mess with the timing only to have to put it back if its just a matter of settling the belt.
If I spin the belt on the stater, I presume the cam covers need to be on to prevent a mess of oil. Do I also need to ground the spark since there are no plug wires installed currently? Or...does pulling the EZK solve this?
Thanks,
Dave
Based on what I've read, it seems like it would have been unusual to see a chain issue on a car with only 70K miles on it. One question about indexing...if the chain had stretched, I guess the lobes would have been further apart than 113mm...is that the point of the indexing measurement...or is more to see that the cams were installed at the proper teeth relative to each other? Also, I will check part numbers of the cams.
Going forward, I think I am going to give Kens suggestion a go first because it is listed at part of the Porkensioner procedure. I would hate to mess with the timing only to have to put it back if its just a matter of settling the belt.
If I spin the belt on the stater, I presume the cam covers need to be on to prevent a mess of oil. Do I also need to ground the spark since there are no plug wires installed currently? Or...does pulling the EZK solve this?
Thanks,
Dave
No prob on the testing method. Whatever floats your boat. Understand, that the guys that designed the engine want the #1 intake at 1.8 or 1.6 plunge and the #6 intake at 2.0 plunge @ 20deg. If your damper is right, and you have the chains right, then it's isn't really complicated to me.
01-03-2011, 12:58 PM
#36
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Let's start from the top. Cam PNs: Left bank 928.105.292.04, 928.105.294.02, right bank 928.105.291.04, 928.105.293.04. This is for 87 model year, US build. Or, it could be 928.105.272.00, 274.00, and 271.00, 273.00. The later numbers are for the 88, but I'm betting that's what you have.
Now, if you'll set it up by the book, at TDC, check the marks on the cam gear, and see that they point straight up. 113mm between the marks in the cam, or 12 link holes from gear nub to gear nub. I'm guessing you've got this already. Make sure the belt tension is per the book. At TDC, set for zero on the gauge, then roll the crank around to 20 and leave it there. At this point, get the wrench on the camshaft for adjustment, then loosen the cam bolt while keeping the cam still. Turn the cam around to 2.0 on #6 intake lifter. Hold it there, and lock the cam bolt down. Go around two revs, and see what you've got. Then repeat for #1 intake lifter, and set for the 1.6. Don't let any slack get in the chain by moving the crank backwards.
Once these are set, check it with the 32vR, and go around twice on the crank again. I'm betting they'll line up pretty well. If not, the other thing I would be concerned about is that the harmonic balancer has shifted a bit on the crank inner hub. The difference in the reading could be due to the slope of the cam lobe not starting in the right spot on TDC. If you have a long extension for your gauge, you can check the TDC by performing a plunge test into the spark plug hole, and rock the engine for maximum rise of the piston on either #1 or #6 (they are 90deg crank throw offset, so both are at TDC at the same time).
Now, if you'll set it up by the book, at TDC, check the marks on the cam gear, and see that they point straight up. 113mm between the marks in the cam, or 12 link holes from gear nub to gear nub. I'm guessing you've got this already. Make sure the belt tension is per the book. At TDC, set for zero on the gauge, then roll the crank around to 20 and leave it there. At this point, get the wrench on the camshaft for adjustment, then loosen the cam bolt while keeping the cam still. Turn the cam around to 2.0 on #6 intake lifter. Hold it there, and lock the cam bolt down. Go around two revs, and see what you've got. Then repeat for #1 intake lifter, and set for the 1.6. Don't let any slack get in the chain by moving the crank backwards.
Once these are set, check it with the 32vR, and go around twice on the crank again. I'm betting they'll line up pretty well. If not, the other thing I would be concerned about is that the harmonic balancer has shifted a bit on the crank inner hub. The difference in the reading could be due to the slope of the cam lobe not starting in the right spot on TDC. If you have a long extension for your gauge, you can check the TDC by performing a plunge test into the spark plug hole, and rock the engine for maximum rise of the piston on either #1 or #6 (they are 90deg crank throw offset, so both are at TDC at the same time).
In the mean time, I quickly wanted to post the part numbers for the cam shafts that docmirror asked me to confirm. They seem just a bit different from those posted but - matching except for the last number. Not sure if this tells anything new, but figured it was best to be compete.
Dave
Passenger - Upper Cam (Part # - 928 105 2916 R E1-4) (Not sure if last is positively a six)
http://www.flickr.com/photos/51967142@N00/5320464316/
Passenger - Lower Cam (Part # - 928 105 2935 R A1-4)
http://www.flickr.com/photos/51967142@N00/5320464022/
Driver - Upper Cam (Part # - 928 105 2926 R E5-8)
http://www.flickr.com/photos/51967142@N00/5319862513/
Driver - Lower Cam (Part # - 928 105 2944 R A5-8)
http://www.flickr.com/photos/51967142@N00/5320464656/
Last edited by aaddpp; 01-03-2011 at 06:02 PM.
01-03-2011, 05:16 PM
#37
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All of those cam numbers aren't in my reference. Maybe they have a slightly different lobe profile? That would account for the discrepancy with the 32Vr setting.
If anyone has the PN for reference and can identify these cams, that would be helpful.
If anyone has the PN for reference and can identify these cams, that would be helpful.
01-03-2011, 05:27 PM
#38
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Those are raw casting numbers (not enough digits and an "R" suffix). "E" (as in "E1-4") is intake and "A" is exhaust ("Einlass" and "Auspuff" or something like that).
The part numbers for the finished cams will be stamped on the end of the cam, back end of the engine.
The part numbers for the finished cams will be stamped on the end of the cam, back end of the engine.
01-03-2011, 05:48 PM
#39
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From the WSM, the id code on the end of the cam is just the last 4 digits. So, his ID codes would be 2916, 2935, 2926, etc. And picture #3 is the same as picture #1 and it should be A5-8 (ausfahrt cyl 5-8), so we don't know what that cam is at all, and we need to know.
They are different castings and different codings. I don't think we can proceed until we find out what those cam profiles are.
They are different castings and different codings. I don't think we can proceed until we find out what those cam profiles are.
01-03-2011, 05:56 PM
#40
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May not be till the end of the week, but I'll see if I can use a mirror and my camera get the reflection of the numbers. Might be possible with a macro lens....at least the shortened cams work in my favor...
01-08-2011, 01:42 AM
#42
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Passenger Top (Intake) - 291
Passenger Bottom (Exhaust) - 293
Driver Top (Intake) - 292
Driver Bottom (Exhaust) - 294
Each cam shaft also had a "60" or "90" stamped on its end along with the other number. Based on what docmirror suggested, it looks like the cams are a match for the earlier number set. Any thoughts on where to go from here?
Thanks,
Dave
01-08-2011, 02:14 AM
#43
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Spec book needs to be cross referenced before you go further --- see charts below.
Seems to suggest you have the correct set of camshafts (assuming they are on in the correct places on the car)
Am assuming what you read as "90" was "09". And hypothesizing that what you read as "60" was really "08".
A mirror thang?
I can't add more, am learning with you on this, just trying to follow along.
(WSM has odd way of listing camshaft numbers, this spec book reference is more clear)
Seems to suggest you have the correct set of camshafts (assuming they are on in the correct places on the car)
Am assuming what you read as "90" was "09". And hypothesizing that what you read as "60" was really "08".
A mirror thang?
I can't add more, am learning with you on this, just trying to follow along.
(WSM has odd way of listing camshaft numbers, this spec book reference is more clear)
Last edited by Landseer; 06-22-2011 at 03:22 PM.
01-08-2011, 02:33 AM
#44
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HOWEVER,
If you really do have a camshaft that you read to be "60".... that was really "06"....
then we have a bogey, see below, and refer to the previous post for the difference in lift:
(but it doesn't help much, because wouldn't that mean expecting 3.0 instead of 2.0 ? For something where you measured 1.4.)?
If you really do have a camshaft that you read to be "60".... that was really "06"....
then we have a bogey, see below, and refer to the previous post for the difference in lift:
(but it doesn't help much, because wouldn't that mean expecting 3.0 instead of 2.0 ? For something where you measured 1.4.)?
Last edited by Landseer; 06-22-2011 at 03:22 PM.
01-10-2011, 02:20 AM
#45
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Spec book needs to be cross referenced before you go further --- see charts below.
Seems to suggest you have the correct set of camshafts (assuming they are on in the correct places on the car)
Am assuming what you read as "90" was "09". And hypothesizing that what you read as "60" was really "08".
A mirror thang?
I can't add more, am learning with you on this, just trying to follow along.
(WSM has odd way of listing camshaft numbers, this spec book reference is more clear)
Seems to suggest you have the correct set of camshafts (assuming they are on in the correct places on the car)
Am assuming what you read as "90" was "09". And hypothesizing that what you read as "60" was really "08".
A mirror thang?
I can't add more, am learning with you on this, just trying to follow along.
(WSM has odd way of listing camshaft numbers, this spec book reference is more clear)
I see where you are coming from on this since it looks like the numbers for the 87 & 88 can be confused pretty easily. Looks like I will need to have another look, though I would be REALLY surprised to find something non-stock on the car. Once I'm sure, then I'll retake the measurements after I spin the motor on the starter per Kens instructions for the Pkensioner install. Will list what I find... though it might not be for a week thanks to work
Thanks for the help,
Dave
P.S. Were did you pull the spec sheet from?