waited too long
12-30-2010, 07:18 PM
#31
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Hey nath,
I just saw this thread, and although I haven't read every previous post, I have a comment.
Having adjusted valves on hundreds of engines, and checked/assisted with valve adjustment on easily over a thousand on students' cars in the past, I'm suspecting a common problem.
If you're checking valve lash at TDC on the exhaust stroke, you will have zero lash (intake and exhaust) due to valve overlap...every time. A 4 stroke engine has 2 TDC positions...TDC compression and TDC exhaust. Valve lash (clearance) should be checked at TDC compression.
I don't know about the cam sprocket marks on our bikes, but if it's running well there's no way you have zero lash on all the valves. My bike has 45,000 miles on it, and I've never checked valve lash. I know I should check it before too long, but shims maintain correct lash much longer than set screw type adjustment. As an example, I would check and adjust the valves at least every 2000 miles on my old BMW R100RS and my old VWs and my old '59 356A Porsche. My 4Runner (shims over buckets) has 266,000 miles and has never required adjustment.
Try turning the crank one full revolution from the marks you are using (that will be only 1/2 turn of the camshaft). Then check lash again. I think you will find you have lash.
Valve adjustment used to be one of my favorite things to teach.
I just saw this thread, and although I haven't read every previous post, I have a comment.
Having adjusted valves on hundreds of engines, and checked/assisted with valve adjustment on easily over a thousand on students' cars in the past, I'm suspecting a common problem.
If you're checking valve lash at TDC on the exhaust stroke, you will have zero lash (intake and exhaust) due to valve overlap...every time. A 4 stroke engine has 2 TDC positions...TDC compression and TDC exhaust. Valve lash (clearance) should be checked at TDC compression.
I don't know about the cam sprocket marks on our bikes, but if it's running well there's no way you have zero lash on all the valves. My bike has 45,000 miles on it, and I've never checked valve lash. I know I should check it before too long, but shims maintain correct lash much longer than set screw type adjustment. As an example, I would check and adjust the valves at least every 2000 miles on my old BMW R100RS and my old VWs and my old '59 356A Porsche. My 4Runner (shims over buckets) has 266,000 miles and has never required adjustment.
Try turning the crank one full revolution from the marks you are using (that will be only 1/2 turn of the camshaft). Then check lash again. I think you will find you have lash.
Valve adjustment used to be one of my favorite things to teach.
12-30-2010, 07:41 PM
#32
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lousy pics in the honda manual, my pre-conceived notion that the lobes should be oriented toward the shims, and a couple of other dumb-assed assumptions caused me to be one revolution from the proper TDC where the lobes are pointed up and in rather than down and out.
when I finally got to the right place, the valves were at .005 Intake and .010 Exhaust instead of the recommended .006 and .012. I was worried that at 28,000 miles I waited too long to check them when I couldn't get any free play between the cam and the shim and that there was no full closing of the valves at what I had determined to be TDC.
It's great to have knowledgeable people who want to help when you get yourself up against the wall like I tend to do periodically. I apersheate it! thanx.
when I finally got to the right place, the valves were at .005 Intake and .010 Exhaust instead of the recommended .006 and .012. I was worried that at 28,000 miles I waited too long to check them when I couldn't get any free play between the cam and the shim and that there was no full closing of the valves at what I had determined to be TDC.
It's great to have knowledgeable people who want to help when you get yourself up against the wall like I tend to do periodically. I apersheate it! thanx.
12-30-2010, 07:42 PM
#33
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ok, i think i got how those things work, and now understand. i need to get a set of old ones to play with to make manuals out of.
so i can grind the bolt end to a blade and thread it in until it stops and lock the lock nut, so when adjusting these they adjust the same way as the apes, if needed at all
so i can grind the bolt end to a blade and thread it in until it stops and lock the lock nut, so when adjusting these they adjust the same way as the apes, if needed at all
12-30-2010, 08:48 PM
#34
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haha ........... keep those questions coming r80gsman. You only got a few more to get up to that umptenth mark. You're making me look me look like a freakin genius. Now we're rockin and rollin huh! yeehah!
12-30-2010, 08:54 PM
#35
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Several years ago I went to the Honda dealer to swap some shims while installing my Yoshi cams. The guy in service whipped out a HotCams shim kit that skipped every other increment which was otherwise covered by the OEM listing. At that point I decided to just order my own kit and skip all the driving around.
Do not assume that the dealer will have better shim choices for swaps, and do not try to get the clearances exactly at spec. The engine will run perfectly well within +/- values. If you really think that hitting the mark perfectly will make your bike run better, you might be good at convincing anyone that your choice of engine oil is better than the other guy's
With the kit you will be able to get the valves within tolerance but certainly not all exactly at the specified clearance values. After changing a few shims and then measuring again I ended up with all the original shims, except maybe one.
Do not assume that the dealer will have better shim choices for swaps, and do not try to get the clearances exactly at spec. The engine will run perfectly well within +/- values. If you really think that hitting the mark perfectly will make your bike run better, you might be good at convincing anyone that your choice of engine oil is better than the other guy's
With the kit you will be able to get the valves within tolerance but certainly not all exactly at the specified clearance values. After changing a few shims and then measuring again I ended up with all the original shims, except maybe one.
12-30-2010, 09:02 PM
#36
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...and I also installed manual tensioners in place of the factory cam chain trashers, since it was a good time to knock that out with the cams already off. I now ride worry free (fingers crossed about the 3rd voltage regulator).
12-30-2010, 09:11 PM
#37
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How to prevent a poke in the eye
I usually use a length of wire or a long screw driver but you do less damage with a skewer if you happen to screw it up.
12-30-2010, 09:27 PM
#38
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Hell, you'd think the shim kit would be the way to go, but not necessarily so, huh> Sounds like trying to find exactly what you need could be lots of fun, and lots of trips to the dealership. It will probably take me days just running back and forth. I think this is gonna suck.
Maybe i'll try to land on .007 I and .013 EX so that by the time they tighten up over time, we'll be right there at .006 and .012. It is +or - .001 I believe.
Maybe i'll try to land on .007 I and .013 EX so that by the time they tighten up over time, we'll be right there at .006 and .012. It is +or - .001 I believe.
And it sounds like from what others are saying, shim kit may be the way to go... then you have it all there with you, less chance of goofing it up and then you have that shim kit for the future! The way that I did it I took all of the shims out, recorded their position and thickness, then added the thickness that I needed from my tolerance check, then made a list of the thicknesses that I needed. I went to the dealer with this list, so it was only one trip, but there are definitely a lot of steps where error could occur with this method.
Either way, you have some options to play with...
And p.s. don't accidentally try to take the cam lobe covers off without setting it to TDC. That one didn't fair so well, heh heh
12-30-2010, 09:36 PM
#39
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lol I laugh at myself regularly and it seems necessary more often and time passes. haha
I would rather do them separately so I can use the other for reference, and I'm not goin to take it apart til I get a shim kit. That way the taking apart and putting together will be in close proximity.
i wanna take the ccts out in the meantime cause I just have the bolt in only method, and accord to tweety and others, it won't stop it from failing. I'm going to see if I can modify it somehow esp since it's gonna cost 90 bucks for the shims/
I would rather do them separately so I can use the other for reference, and I'm not goin to take it apart til I get a shim kit. That way the taking apart and putting together will be in close proximity.
i wanna take the ccts out in the meantime cause I just have the bolt in only method, and accord to tweety and others, it won't stop it from failing. I'm going to see if I can modify it somehow esp since it's gonna cost 90 bucks for the shims/
Put a cable (zip) tie around the cam chain and sprocket to keep the timing.
There is a tool you can make that looks like a key. There is a drawing in the manual. I made mine out of an old sawsall blade using a grinder. The tool releases the tension in the CCT and keeps it slack while you work.
Carefully measure and record all your clearances.
Then pull the cams and record the shim thicknesses. I only had to do the intakes at 24K.
Keep all parts arranged so they can return to their original positions.
Follow the directions in the manual for determining the correct shim to install. Chances are that some of your shims can swap places. Order new ones and wait for them or go to a shop and buy or swap with them. Doesn't have to be a honda show, just same diameter shims.
Read the manual carefully and look closely at the pics.
Good Luck
12-30-2010, 10:37 PM
#40
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You know, I just reread my post and realized I screwed it up, but it sounds like you have it figured out. I meant to say that I assume the FE and FI marks on the sprockets for the front cylinder are facing outward when the crank is at the FT mark and likewise (RE and RI marks facing outward when the crank is at the RT mark) for the rear valvetrain.
The deal is that you want to take all the tension out of the system when you make your measurements (and when you change shims) and the best way to do that is to have the cam lobes pointing up and away from the shims (buckets) where there is no possibility of them putting pressure on the shims (buckets). You can make adjustments this way with no likelihood of slipping timing when you remove the cams to change shims, but be sure to zip tie the sprockets and make marks anyway and work on one cylinder at a time. It's really not difficult when you think it through and watch the valvetrain as you rotate the crank a few times to see how it works. It just seems that way when you try to understand it from just reading the manual.
By the way, my local mechanic, who I have known for 30 years, will swap shims for free and he is not unusual. I just take him my old shims and he gives me the ones I need.
Last edited by killer5280; 12-30-2010 at 10:50 PM.
12-31-2010, 06:43 AM
#41
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Not to be rude, but you are repeating a couple of the top ten questions for the umptenth time... Go read the links, use search and if and when you come up with some new, interesting questions I'll gladly answer... Not too interested in handfeeding already available info though...
no worries, i have read most of the treads, some time it is hard to get the meaning of folks through there writings. i must have missed a response on one of the those threads, i went back and read them again after i posted and answered my question. i understand about questions and repetition. i get a lot of QTs about bmw's and ktms as this is my forte. not sure why honda designed the CCT this way with no fail safe. i had a cbr600 with apparently the same CCT and it never broke, even at the track, however i did not know that they were a trouble spot. i will pick up a set of used oems and modify them cause i am cheap right now. i'll post in the classifieds.
12-31-2010, 08:12 AM
#42
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Ah- so yeah, tie the cam chain to the sprockets while you're working on the CCT's, and do them one at a time.
And from advice that others- I think 8541Hawk actually- a shim kit isn't always the best route because the shims don't go in as small of steps as if you were to go order/trade individual ones from the dealer. In other words, you won't be able to fine tune as much with a shim kit. Just a thought.
And from advice that others- I think 8541Hawk actually- a shim kit isn't always the best route because the shims don't go in as small of steps as if you were to go order/trade individual ones from the dealer. In other words, you won't be able to fine tune as much with a shim kit. Just a thought.
Remove the cam chain tensioner from that cylinder only. Remove the cams and lifter buckets. If you are just replacing the tensioner, you don't need to worry about the timing. Just install the new tensioner.
Replace the shims, where you are adjusting valve clearance.
Reassemble that head.
Repeat for the other head, starting at top-center-compression for that cylinder.
The shim kit will have all of the shims, in every increment - several of them. The main reason for not buying the kit, is so you are not buying a big box of shims, when you only need a couple.
If anyone is buying a shim kit. I'll buy the leftovers. I'm getting close to buying a set myself.
Last edited by RCVTR; 12-31-2010 at 08:20 AM.
12-31-2010, 08:18 AM
#43
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My old CBR600 Hurricane had the same (or similar) tensioner. It started sounding like a bag of rocks, so I replaced the CCT with an Ape. I was probably lucky that it didn't fail. I ran the stock tensioners on my Super Hawk and never had a problem. But since that time, there have been a lot of failures reported.
12-31-2010, 10:06 AM
#44
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Several years ago I went to the Honda dealer to swap some shims while installing my Yoshi cams. The guy in service whipped out a HotCams shim kit that skipped every other increment which was otherwise covered by the OEM listing. At that point I decided to just order my own kit and skip all the driving around.
Do not assume that the dealer will have better shim choices for swaps, and do not try to get the clearances exactly at spec. The engine will run perfectly well within +/- values. If you really think that hitting the mark perfectly will make your bike run better, you might be good at convincing anyone that your choice of engine oil is better than the other guy's
With the kit you will be able to get the valves within tolerance but certainly not all exactly at the specified clearance values. After changing a few shims and then measuring again I ended up with all the original shims, except maybe one.
Do not assume that the dealer will have better shim choices for swaps, and do not try to get the clearances exactly at spec. The engine will run perfectly well within +/- values. If you really think that hitting the mark perfectly will make your bike run better, you might be good at convincing anyone that your choice of engine oil is better than the other guy's
With the kit you will be able to get the valves within tolerance but certainly not all exactly at the specified clearance values. After changing a few shims and then measuring again I ended up with all the original shims, except maybe one.
12-31-2010, 10:09 AM
#45
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OK, now you're off the hook in terms of bearing any responsibility for my blinding myself. thanks Kai
12-31-2010, 10:15 AM
#46
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I had gotten that advice from others as well- put shims in on the + side of the tolerance so that over time you get the most use from them
And it sounds like from what others are saying, shim kit may be the way to go... then you have it all there with you, less chance of goofing it up and then you have that shim kit for the future! The way that I did it I took all of the shims out, recorded their position and thickness, then added the thickness that I needed from my tolerance check, then made a list of the thicknesses that I needed. I went to the dealer with this list, so it was only one trip, but there are definitely a lot of steps where error could occur with this method.
Either way, you have some options to play with...
And p.s. don't accidentally try to take the cam lobe covers off without setting it to TDC. That one didn't fair so well, heh heh
And it sounds like from what others are saying, shim kit may be the way to go... then you have it all there with you, less chance of goofing it up and then you have that shim kit for the future! The way that I did it I took all of the shims out, recorded their position and thickness, then added the thickness that I needed from my tolerance check, then made a list of the thicknesses that I needed. I went to the dealer with this list, so it was only one trip, but there are definitely a lot of steps where error could occur with this method.
Either way, you have some options to play with...
And p.s. don't accidentally try to take the cam lobe covers off without setting it to TDC. That one didn't fair so well, heh heh
12-31-2010, 10:24 AM
#47
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You can get shims from bike bandit for about $7 each.
Put a cable (zip) tie around the cam chain and sprocket to keep the timing.
There is a tool you can make that looks like a key. There is a drawing in the manual. I made mine out of an old sawsall blade using a grinder. The tool releases the tension in the CCT and keeps it slack while you work.
Carefully measure and record all your clearances.
Then pull the cams and record the shim thicknesses. I only had to do the intakes at 24K.
Keep all parts arranged so they can return to their original positions.
Follow the directions in the manual for determining the correct shim to install. Chances are that some of your shims can swap places. Order new ones and wait for them or go to a shop and buy or swap with them. Doesn't have to be a honda show, just same diameter shims.
Read the manual carefully and look closely at the pics.
Good Luck
Put a cable (zip) tie around the cam chain and sprocket to keep the timing.
There is a tool you can make that looks like a key. There is a drawing in the manual. I made mine out of an old sawsall blade using a grinder. The tool releases the tension in the CCT and keeps it slack while you work.
Carefully measure and record all your clearances.
Then pull the cams and record the shim thicknesses. I only had to do the intakes at 24K.
Keep all parts arranged so they can return to their original positions.
Follow the directions in the manual for determining the correct shim to install. Chances are that some of your shims can swap places. Order new ones and wait for them or go to a shop and buy or swap with them. Doesn't have to be a honda show, just same diameter shims.
Read the manual carefully and look closely at the pics.
Good Luck
12-31-2010, 10:30 AM
#48
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You know, I just reread my post and realized I screwed it up, but it sounds like you have it figured out. I meant to say that I assume the FE and FI marks on the sprockets for the front cylinder are facing outward when the crank is at the FT mark and likewise (RE and RI marks facing outward when the crank is at the RT mark) for the rear valvetrain.
The deal is that you want to take all the tension out of the system when you make your measurements (and when you change shims) and the best way to do that is to have the cam lobes pointing up and away from the shims (buckets) where there is no possibility of them putting pressure on the shims (buckets). You can make adjustments this way with no likelihood of slipping timing when you remove the cams to change shims, but be sure to zip tie the sprockets and make marks anyway and work on one cylinder at a time. It's really not difficult when you think it through and watch the valvetrain as you rotate the crank a few times to see how it works. It just seems that way when you try to understand it from just reading the manual.
By the way, my local mechanic, who I have known for 30 years, will swap shims for free and he is not unusual. I just take him my old shims and he gives me the ones I need.
The deal is that you want to take all the tension out of the system when you make your measurements (and when you change shims) and the best way to do that is to have the cam lobes pointing up and away from the shims (buckets) where there is no possibility of them putting pressure on the shims (buckets). You can make adjustments this way with no likelihood of slipping timing when you remove the cams to change shims, but be sure to zip tie the sprockets and make marks anyway and work on one cylinder at a time. It's really not difficult when you think it through and watch the valvetrain as you rotate the crank a few times to see how it works. It just seems that way when you try to understand it from just reading the manual.
By the way, my local mechanic, who I have known for 30 years, will swap shims for free and he is not unusual. I just take him my old shims and he gives me the ones I need.
sounds like a good plan, but i wasn't sure that i could get the cams out and still have the chain ziptied to the sprockets. Evidently this is possible.
12-31-2010, 10:43 AM
#50
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Several years ago I went to the Honda dealer to swap some shims while installing my Yoshi cams. The guy in service whipped out a HotCams shim kit that skipped every other increment which was otherwise covered by the OEM listing. At that point I decided to just order my own kit and skip all the driving around.
Do not assume that the dealer will have better shim choices for swaps, and do not try to get the clearances exactly at spec. The engine will run perfectly well within +/- values.
Do not assume that the dealer will have better shim choices for swaps, and do not try to get the clearances exactly at spec. The engine will run perfectly well within +/- values.
Sure the difference is small but with the kit you can only go in .002 increments instead of the .001 increments you get with the stock parts.
So yeah you can get close but I would rather do it right and get them exactly where I want them after doing all the work to get to them.
Then again I might just be a bit more picky than some.
Also the best place to get replacement shims is right here:
http://www.hondapartsline.com/fiche_...1998&fveh=4077
12-31-2010, 10:54 AM
#51
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cool. thanks RC. What i was thinking relative to the shims deal is that if i bought a box from Hot Cams, it could be shared by others because the actual shim number would never be reduced since each would be replaced by used ones and it would be unlikely that any one size would be depleted because of the variance of sizing needed for any one adjustment.
To pay 90 bucks for a box of shims that you'll likely not use for 6-10 years or maybe never is something that may not be significant for some, but others may not be so casual about it.
To pay 90 bucks for a box of shims that you'll likely not use for 6-10 years or maybe never is something that may not be significant for some, but others may not be so casual about it.
12-31-2010, 11:03 AM
#52
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12-31-2010, 12:35 PM
#53
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well lets work something out here. like i'll send you some rent money, pay for the shipping to and fro, and you can recoup some of your money and i can save some.
01-01-2011, 05:44 AM
#54
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Well you can go that way but you still might not get the clearance in spec.
Sure the difference is small but with the kit you can only go in .002 increments instead of the .001 increments you get with the stock parts.
http://www.hondapartsline.com/fiche_...1998&fveh=4077
Sure the difference is small but with the kit you can only go in .002 increments instead of the .001 increments you get with the stock parts.
http://www.hondapartsline.com/fiche_...1998&fveh=4077
I thought the same way as you do up to the point where I actually tackled the problem hands on. Having the shim selection on-hand before starting the job will let you get it done quickly and get the bike back together, allowing more time for riding, beer drinking and other fun with the woman.
01-01-2011, 05:54 AM
#55
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+1 to that!
I tried removing the cams on the rear cylinder of my spare parts engine first, just for practice before digging into the good engine. While attempting to maneuver the cam/sprocket assembly out from under the chain I accidentally scored one of the cam bearing surfaces,on the cylinder head, with a nice thick and noticeably deep groove. I did not even realize what had happened right away since the edges of the cam lobes are quite sharp and apparently very little effort is needed to cause damage. Steel beats aluminum in any fight.
Removing the sprockets is easy and adds a few extra minutes to the job, while making other things easier and SAFER.
I tried removing the cams on the rear cylinder of my spare parts engine first, just for practice before digging into the good engine. While attempting to maneuver the cam/sprocket assembly out from under the chain I accidentally scored one of the cam bearing surfaces,on the cylinder head, with a nice thick and noticeably deep groove. I did not even realize what had happened right away since the edges of the cam lobes are quite sharp and apparently very little effort is needed to cause damage. Steel beats aluminum in any fight.
Removing the sprockets is easy and adds a few extra minutes to the job, while making other things easier and SAFER.
01-01-2011, 06:00 AM
#56
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Actually, you will not be lucky to get it 'in the ball park' but instead should be assured of it. It is a simple matter of mathematics.
01-01-2011, 06:48 AM
#57
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Do not over think the problem, else you may end up with a soar head. Do not try to anticipate wear, just deal with the here and now... get it within tolerance if it is out. If it is within specs then leave it be.
Actually, you will not be lucky to get it 'in the ball park' but instead should be assured of it. It is a simple matter of mathematics.
Actually, you will not be lucky to get it 'in the ball park' but instead should be assured of it. It is a simple matter of mathematics.
Sounds reasonable. My plan is to measure the present clearance with the cams in place still tightened, record that per position, remove the sprockets and cams. Then remove each shim and replace with a shim that is the amount of the clearance minus what is needed to bring it into spec.
In other words, if the exhaust is .010 gap now, and it needs to be .012-.013, i need to subtract .002-.003 from the size of the removed shim to be in spec. Will that work?
01-01-2011, 07:01 AM
#58
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+1 to that!
I tried removing the cams on the rear cylinder of my spare parts engine first, just for practice before digging into the good engine. While attempting to maneuver the cam/sprocket assembly out from under the chain I accidentally scored one of the cam bearing surfaces,on the cylinder head, with a nice thick and noticeably deep groove. I did not even realize what had happened right away since the edges of the cam lobes are quite sharp and apparently very little effort is needed to cause damage. Steel beats aluminum in any fight.
Removing the sprockets is easy and adds a few extra minutes to the job, while making other things easier and SAFER.
I tried removing the cams on the rear cylinder of my spare parts engine first, just for practice before digging into the good engine. While attempting to maneuver the cam/sprocket assembly out from under the chain I accidentally scored one of the cam bearing surfaces,on the cylinder head, with a nice thick and noticeably deep groove. I did not even realize what had happened right away since the edges of the cam lobes are quite sharp and apparently very little effort is needed to cause damage. Steel beats aluminum in any fight.
Removing the sprockets is easy and adds a few extra minutes to the job, while making other things easier and SAFER.
That said, it's obvious that no one wants to put a divit, scar or any type of scratch on the cam lobe, but it really doesn't seem like it would be of any consequence as long as the surface was still the correct size. The surface of the cam would only be riding on the shim, and wouldn't change anything in terms of the distance it moved the valve regardless of a scratch. Is that a valid assumption?
01-01-2011, 07:13 AM
#59
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Posts: 489
Happy happy 2011.
Sounds reasonable. My plan is to measure the present clearance with the cams in place still tightened, record that per position, remove the sprockets and cams. Then remove each shim and replace with a shim that is the amount of the clearance minus what is needed to bring it into spec.
In other words, if the exhaust is .010 gap now, and it needs to be .012-.013, i need to subtract .002-.003 from the size of the removed shim to be in spec. Will that work?
Sounds reasonable. My plan is to measure the present clearance with the cams in place still tightened, record that per position, remove the sprockets and cams. Then remove each shim and replace with a shim that is the amount of the clearance minus what is needed to bring it into spec.
In other words, if the exhaust is .010 gap now, and it needs to be .012-.013, i need to subtract .002-.003 from the size of the removed shim to be in spec. Will that work?
It seems like you have it about right to me. I also suggest stuffing clean shop rags into the area where accidentally dropping something would require extraordinary recovery methods. Removal of small shims from the oil pan could be a difficult problem to solve. Also, using a good strong telescopic magnet will let you pull the buckets easily and help keep from dropping the shims.
It is good to also measure the old shims with a micrometer and compare the actual thickness with the replacements to ensure you really get the right amount of change. It may also help to think in terms of mm vs inches since the shims are labeled with metric numbers, so using the corresponding specs and metric feeler gauges will help things along a bit more easily... that is, if you have all the right tools.
01-01-2011, 07:24 AM
#60
Slacker
Superstock
Superstock
Join Date: Jun 2005
Location: San Antonio, TX
Posts: 489
thanks for the info. Makes sense. Sprockets are coming out first.
That said, it's obvious that no one wants to put a divit, scar or any type of scratch on the cam lobe, but it really doesn't seem like it would be of any consequence as long as the surface was still the correct size. The surface of the cam would only be riding on the shim, and wouldn't change anything in terms of the distance it moved the valve regardless of a scratch. Is that a valid assumption?
That said, it's obvious that no one wants to put a divit, scar or any type of scratch on the cam lobe, but it really doesn't seem like it would be of any consequence as long as the surface was still the correct size. The surface of the cam would only be riding on the shim, and wouldn't change anything in terms of the distance it moved the valve regardless of a scratch. Is that a valid assumption?
The cam lobe does not make direct contact with the shim.
