Post by: Steveo909 on May 18, 2017, 10:03:14 PM
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Post by: mash on it on May 18, 2017, 10:43:21 PM
Having trouble degreeing my cam on 460. Gears are installed straight up. From TDC I'm rotating clockwise to max lift. Zero dial. Turn to .050. Record number (45). Back up past max lift to .050. Record number (141). Divide by 2. This gives me 93. Numbers are way off. Should be 108. What am I doing wrong ?
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What you are doing is starting at the top of the mountain, and going down .050". thats bass ackwards.
zero the heel of the cam. Then fwd to .050". log degrees (A).
then Fwd rotation, over the top (.320" Cam Lobe lift), all the way to .050". log that degree (B).
Then (B)-(A)= intake lobe centerline in relation to the crank. Adjust ISL from there.
If the valve is adjusted already, It needs to be done with rocker removed. Ideally off the rim of the lifter.
Dan'l
Post by: GT Jets on May 18, 2017, 10:51:16 PM
What you are doing is starting at the top of the mountain, and going down .050". thats bass ackwards.Exactamundo..... The .050" is at the base, or "minimum lift".
zero the heel of the cam. Then fwd to .050". log degrees (A).
then Fwd rotation, over the top (.320" Cam Lobe lift), all the way to .050". log that degree (B).
Then (B)-(A)= intake lobe centerline in relation to the crank. Adjust ISL from there.
If the valve is adjusted already, It needs to be done with rocker removed. Ideally off the rim of the lifter.
Dan'l
GT
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Post by: Steveo909 on May 18, 2017, 10:52:53 PM
What you are doing is starting at the top of the mountain, and going down .050". thats bass ackwards.I have the heads off. I found TDC with a piston stop and recorded numbers going both ways. Found the middle and zeroed the degree wheel. This was done with the gears installed straight up initially. When trying to find intake centerline, it's starting at the bottom of the lobe with the dial indicator on the edge of the lifter. Very frustrating.
zero the heel of the cam. Then fwd to .050". log degrees (A).
then Fwd rotation, over the top (.320" Cam Lobe lift), all the way to .050". log that degree (B).
Then (B)-(A)= intake lobe centerline in relation to the crank. Adjust ISL from there.
If the valve is adjusted already, It needs to be done with rocker removed. Ideally off the rim of the lifter.
Dan'l
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Post by: Steveo909 on May 18, 2017, 11:29:12 PM
Exactamundo..... The .050" is at the base, or "minimum lift".Ok I see what your saying. I need to be measuring from both sides of the bottom. Not the top of the lobe. That makes sense. I'll try that. Thanks for the info!
GT
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Post by: Six-Oh-Nine on May 19, 2017, 07:22:40 AM
The biggest reason I have seen people be off, is not finding true TDC. I had a customer pissed that the cam I had ground for him was junk and ground wrong... turns out... his trusty stock tin timing tag and stock 30+ year old balancer (complete with blown out rubber)... was 12 degrees off from true TDC when checked with a degree wheel and indicator.
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Post by: Steveo909 on May 19, 2017, 09:44:48 AM
If you're doing it the centerline method... then as long as the lobe is symmetrical, then the way you were doing it will work... if it is not, then peak lift may not be the centerline of the lobe... though I'd zero off the base circle of the cam, then just measure .050" down either side of peak lift... gives you smaller numbers to deal with. No matter whether you go .050 from zero, or .050 from peak... or hell .127 from either direction... as long as you zero off the base circle, and go the same measurement on both sides of the lobe, you'll get there. You can always verify if you are way out in left field, or somewhat close, by checking the intake opening @.050" (zeroed off base circle) to see if the the numbers jive.... if you're doing it right, and your cam grinder is worth a damn... both sets of numbers should jive together.Thanks James. Yes i am trying the intake centerline method. I will give it another try after work today and start from scratch.
The biggest reason I have seen people be off, is not finding true TDC. I had a customer pissed that the cam I had ground for him was junk and ground wrong... turns out... his trusty stock tin timing tag and stock 30+ year old balancer (complete with blown out rubber)... was 12 degrees off from true TDC when checked with a degree wheel and indicator.
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It's my first attempt degreeing a camshaft so I'm pretty sure it's me and not the cam. It's a clay smith so I'm assuming it's been made correctly.
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Post by: mash on it on May 19, 2017, 10:25:28 AM
Thanks James. Yes i am trying the intake centerline method. I will give it another try after work today and start from scratch.
It's my first attempt degreeing a camshaft so I'm pretty sure it's me and not the cam. It's a clay smith so I'm assuming it's been made correctly.
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Yep, the cam from Clay Smith should be right.
However, when you degree in a cam, you are also checking several other things:
...Crank key way position.
...Crank gear key way position.
...Cam gear dowel position.
...Cam face dowel position.
If each of these were off by 1*, there is a 4* 'outa-whack', or 'stacking tolerances'.
Dan'l
Post by: GT Jets on May 19, 2017, 11:16:23 AM
GT
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Post by: Steveo909 on May 19, 2017, 11:21:49 AM
What timing set are you using?It's a clay smith true roller with the 9 way crank gear. I have it set at zero with the woodruff key pointed up. the dowel and timing mark on the cam gear pointed down towards the crank.
GT
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Post by: Six-Oh-Nine on May 19, 2017, 11:41:25 AM
It's a clay smith true roller with the 9 way crank gear. I have it set at zero with the woodruff key pointed up. the dowel and timing mark on the cam gear pointed down towards the crank.
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You should be in the ballpark then... BUT... it never hurts to check, since sometimes, people can make mistakes. Seen a really nice timing set by a well known mfg be off half a tooth... and had a cam by a very large popular cam company actually not only degree in off to the dowl pin, but come up 6 degrees short @.050... but correct duration @ .006. No matter how good a quality of a part and company that produces said part... ultimately they are made by people... and occasionally, rven the best can make a mistake... so best rule is to check everything twice... then check again.
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Post by: Steveo909 on May 19, 2017, 11:45:57 AM
Couldn't agree more. Not to mention the time and money invested only to slap it all together in good faith.
You should be in the ballpark then... BUT... it never hurts to check, since sometimes, people can make mistakes. Seen a really nice timing set by a well known mfg be off half a tooth... and had a cam by a very large popular cam company actually not only degree in off to the dowl pin, but come up 6 degrees short @.050... but correct duration @ .006. No matter how good a quality of a part and company that produces said part... ultimately they are made by people... and occasionally, rven the best can make a mistake... so best rule is to check everything twice... then check again.
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Post by: Steveo909 on May 19, 2017, 08:57:10 PM
Couldn't agree more. Not to mention the time and money invested only to slap it all together in good faith.Well I checked. Double checked. And checked again. And I'm still getting the same number. 93. I measured from the top of lift an from the bottom of the circle. Same result.
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Does this mean the cam is jacked up? Or do I need to retard or advance the crank gear to a different key slot??? Seems really far off.
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Post by: GT Jets on May 19, 2017, 11:57:40 PM
Well I checked. Double checked. And checked again. And I'm still getting the same number. 93. I measured from the top of lift an from the bottom of the circle. Same result.Not to sound stupid, but what lifter are you reading?
Does this mean the cam is jacked up? Or do I need to retard or advance the crank gear to a different key slot??? Seems really far off.
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GT
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Post by: Steveo909 on May 19, 2017, 11:59:52 PM
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Post by: Steveo909 on May 20, 2017, 12:01:30 AM
Not to sound stupid, but what lifter are you reading?
GT
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Post by: GT Jets on May 20, 2017, 12:26:48 AM
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Post by: Steveo909 on May 20, 2017, 12:34:43 AM
Have a better picture of the timing set?
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Post by: Six-Oh-Nine on May 20, 2017, 12:54:10 AM
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Post by: Steveo909 on May 20, 2017, 01:10:08 AM
Just for shits n giggles... what do you get at .050" lift intake opening?On the degree wheel I'm getting 46 before max lift and 142 after at .050
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Post by: Steveo909 on May 20, 2017, 01:18:41 AM
On the degree wheel I'm getting 46 before max lift and 142 after at .050
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Post by: Steveo909 on May 20, 2017, 01:43:33 AM
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Post by: Flusher on May 20, 2017, 08:12:06 PM
I also 2nd the taking measurements at .050 tappet lift. Modern cam lobe profiles are asymmetric, having different rates for opening and closing profiles.
Post by: GT Jets on May 20, 2017, 09:10:46 PM
GT
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Post by: GT Jets on May 20, 2017, 09:15:43 PM
I think there is 24 teeth on the gear. One tooth equals 15 degrees.
Food for thought.
GT
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Post by: GT Jets on May 21, 2017, 08:53:30 AM
Is it possible the cam is pinned wrong or am I retarded?Actually, you're advanced.
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Post by: Steveo909 on May 21, 2017, 09:13:35 AM
Actually, you're advanced.Lol glad someone picked up on it.
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Post by: Steveo909 on May 21, 2017, 10:44:25 AM
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Post by: GT Jets on May 21, 2017, 10:45:54 AM
Adjusted the chain one tooth forward and one tooth back. This resulted in the timing marks very obviously not lining up. So it seems the place a had it originally is the correct position. I'll see what clay smith has to say about it tomorrow but I know they will just ask me to bring the engine to them so they can degree it. I really don't want to put my half assembled engine in the back of my truck.Do you have a picture of the back side of the gear?
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Post by: Steveo909 on May 21, 2017, 10:52:07 AM
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Post by: GT Jets on May 21, 2017, 11:07:38 AM
Do you have the original set that came if the engine?
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Post by: Steveo909 on May 21, 2017, 11:15:11 AM
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Post by: GT Jets on May 21, 2017, 11:17:10 AM
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Post by: Six-Oh-Nine on May 21, 2017, 11:21:59 AM
On the degree wheel I'm getting 46 before max lift and 142 after at .050
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No... i mean zero out your indicator on the base circle... then at .050" lift from the base circle... what is the degree number you are seeing?
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Post by: Steveo909 on May 21, 2017, 01:13:40 PM
From TDC as installed, it traveled 336 clockwise to .050.
No... i mean zero out your indicator on the base circle... then at .050" lift from the base circle... what is the degree number you are seeing?
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I also measured from the centerline of the base circle and it travels 250 degrees to .050.
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Post by: GT Jets on May 21, 2017, 01:24:42 PM
From TDC as installed, it traveled 336 clockwise to .050.Base circle is base circle.
I also measured from the centerline of the base circle and it travels 250 degrees to .050.
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As long as your wheel is centered at true top dead center, the lifter will reach .050" at the same exact spot in degrees. No matter the starting point.
I feel you are reading the wheel incorrectly. But again, not there starting at it.
Did you use a piston stop to determine tdc?
I thought you did.
GT
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Post by: Steveo909 on May 21, 2017, 01:53:57 PM
Base circle is base circle.Yes. As installed the lifter sits on the far end of the base circle. It traveled 336 degrees to get to .050.
As long as your wheel is centered at true top dead center, the lifter will reach .050" at the same exact spot in degrees. No matter the starting point.
I feel you are reading the wheel incorrectly. But again, not there starting at it.
Did you use a piston stop to determine tdc?
I thought you did.
GT
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The other measurement was just made from where the lifter sits centered on the base circle or 180 from top of lift.
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Post by: jim brock on May 21, 2017, 02:00:24 PM
are all like that. not like a chevy
Post by: Steveo909 on May 21, 2017, 02:21:09 PM
At 93 the smaller the number the more advanced it is, so 93 subtracted from 108 is 15 degrees advanced, try setting it at 4 retard and running thru it again you should be closer, the number should get bigger, that should tell you if you are going in the right direction, maybe to much or not enough, 460 fordsThanks Jim. Yeah I'm currently playing with some of the key ways to see what it does.
are all like that. not like a chevy
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Post by: Flusher on May 21, 2017, 09:32:08 PM
Yes. As installed the lifter sits on the far end of the base circle. It traveled 336 degrees to get to .050.
The other measurement was just made from where the lifter sits centered on the base circle or 180 from top of lift.
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Based on your statement, "It traveled 336 degrees to get to .050". I see the following:
When you zeroed your degree wheel at TDC, both lifters are on the base circle of the cam lobe, i.e. TDC #1 Firing Position. You rotated the crankshaft 180-degrees to BDC (end of power stroke/beginning of exhaust stroke), then another 156 to where the tappet is at .050 lift. 180 + 156 = 336 crankshaft-degrees out of 720-degrees of crankshaft rotation to complete all four strokes of a four stroke internal combustion engine.
What you actually want to look at is cam timing events relative to the appropriate stroke (out of the four strokes). So far, in 336-degrees of crankshaft rotation, the firing stroke is complete (180-degrees) and 156-degrees (out of 180-degrees) of the exhaust stroke have been completed. Now the intake valve is starting to open during the overlap period, 24-degrees BTDC (Before Top Dead Centre).
If you add up the events and compare them to your cam card Intake Duration @ .050 of 231-degrees - add (24-degrees BTDC) + (180-degrees for the intake stroke) = 204-degrees. Subtract 204 from 231 = 27-degrees or the @ .050 intake tappet closing point should be 27-degrees ABDC (After Bottom Dead Centre). This is where you appear to be now, advanced 14.5-degrees. According to your cam card (and my math), the @ .050 opening point should be 9.5-degrees BTDC and close 41.5-degrees ABDC.
I think you have some errors in your measurements somewhere. I'm curious if, with your current setup, will your @ .050 intake valve closure point be 27-degrees ABDC? I would recheck zero on your degree wheel to make sure it didn't get accidentally bumped (I do this all the time).
Next, get the peak lift point out of your head! That point is totally irrelevant to finding centerline of your cam. In fact, peak lift doesn't always correspond to lobe centerline. Only concern yourself with the @ .050 opening and closing points.
Lastly, you may be fighting accumulated error. From what I understand, the cam bearing bores are machined in a different operation than the main bores and the lifter bores in yet again another operation. 14.5-degrees sounds a bit excessive for the marks to be off, but if you get your numbers to come into spec and repeat, the engine won't care what number is stamped on the crank sprocket.
You need to get your technique down first. A little extra practice won't hurt.
The following is FYI:
What does it mean for the end user who is degreeing his/her camshaft? If the lifter bores are not exactly centered on the camshaft, cam timing will be either advanced or retarded. Advanced if the bearing journals are shifted to the right or lifter bores are shifted to the left. You may also find that the camshaft is not parallel to the crankshaft and the degree of advance/retard will vary from the front cylinders to the rear. Then you have crank index, cam index, and manufacturing tolerance on everything compounding the problem.
What can be done about this? Short of correcting the cam bearing and lifter bores, if you are OCD about your cam timing, centerline the intake lobes for the four corner cylinders and split the difference to achieve the best compromise between all cylinders. Otherwise, only the #1 cylinder will be optimized and all others are an unknown compromise.
There are plenty of engines out there, that have had only the #1 centerlined, that haul the mail. I'm only trying to say, you may be fighting accumulated error.
Good luck,
Joe
Post by: Steveo909 on May 21, 2017, 10:18:49 PM
Based on your statement, "It traveled 336 degrees to get to .050". I see the following:Thanks for the reply. There's a lot of good info there. I think I understand a little better what's going on now. The consensus is that it seems to be advanced 15 degrees.
When you zeroed your degree wheel at TDC, both lifters are on the base circle of the cam lobe, i.e. TDC #1 Firing Position. You rotated the crankshaft 180-degrees to BDC (end of power stroke/beginning of exhaust stroke), then another 156 to where the tappet is at .050 lift. 180 + 156 = 336 crankshaft-degrees out of 720-degrees of crankshaft rotation to complete all four strokes of a four stroke internal combustion engine.
What you actually want to look at is cam timing events relative to the appropriate stroke (out of the four strokes). So far, in 336-degrees of crankshaft rotation, the firing stroke is complete (180-degrees) and 156-degrees (out of 180-degrees) of the exhaust stroke have been completed. Now the intake valve is starting to open during the overlap period, 24-degrees BTDC (Before Top Dead Centre).
If you add up the events and compare them to your cam card Intake Duration @ .050 of 231-degrees - add (24-degrees BTDC) + (180-degrees for the intake stroke) = 204-degrees. Subtract 204 from 231 = 27-degrees or the @ .050 intake tappet closing point should be 27-degrees ABDC (After Bottom Dead Centre). This is where you appear to be now, advanced 14.5-degrees. According to your cam card (and my math), the @ .050 opening point should be 9.5-degrees BTDC and close 41.5-degrees ABDC.
I think you have some errors in your measurements somewhere. I'm curious if, with your current setup, will your @ .050 intake valve closure point be 27-degrees ABDC? I would recheck zero on your degree wheel to make sure it didn't get accidentally bumped (I do this all the time).
Next, get the peak lift point out of your head! That point is totally irrelevant to finding centerline of your cam. In fact, peak lift doesn't always correspond to lobe centerline. Only concern yourself with the @ .050 opening and closing points.
Lastly, you may be fighting accumulated error. From what I understand, the cam bearing bores are machined in a different operation than the main bores and the lifter bores in yet again another operation. 14.5-degrees sounds a bit excessive for the marks to be off, but if you get your numbers to come into spec and repeat, the engine won't care what number is stamped on the crank sprocket.
You need to get your technique down first. A little extra practice won't hurt.
The following is FYI:
What does it mean for the end user who is degreeing his/her camshaft? If the lifter bores are not exactly centered on the camshaft, cam timing will be either advanced or retarded. Advanced if the bearing journals are shifted to the right or lifter bores are shifted to the left. You may also find that the camshaft is not parallel to the crankshaft and the degree of advance/retard will vary from the front cylinders to the rear. Then you have crank index, cam index, and manufacturing tolerance on everything compounding the problem.
What can be done about this? Short of correcting the cam bearing and lifter bores, if you are OCD about your cam timing, centerline the intake lobes for the four corner cylinders and split the difference to achieve the best compromise between all cylinders. Otherwise, only the #1 cylinder will be optimized and all others are an unknown compromise.
There are plenty of engines out there, that have had only the #1 centerlined, that haul the mail. I'm only trying to say, you may be fighting accumulated error.
Good luck,
Joe
I new about accumulated machining errors but that seems excessive.
I am pretty OCD about putting this back together. Especially since I haven't been this deep in a 460 ever. I work for yamaha and rebuild small engines quite frequently so I'm no stranger to motors. Just different.
I have never dealt with a timing set with multiple key ways so that's why I'm through a loop. Usually I just line up the marks and the computer does the rest.
I'm glad I decided to buy a degree wheel. I was really close to just throwing the timing cover on and calling it a day. But then there was that whole OCD thing again.
Thanks again.
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Post by: Six-Oh-Nine on May 21, 2017, 10:26:25 PM
From TDC as installed, it traveled 336 clockwise to .050.
I also measured from the centerline of the base circle and it travels 250 degrees to .050.
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Man... I'm just going to be quite honest here... no offense intended, but you are making this way more complicated than it needs to be and way over thinking this. If you've gotten this far... you can figure this out.
The following is AFTER you are sure you have the degree wheel set for proper tdc... as in the degree wheel reads "0" or TDC... and the #1 piston is in fact, at Top Dead Center.
Rotate the crank until the lifter is resting on the base circle... heel of the cam... whatever... just so that it is roughly opposite of the lobe side on the intake lobe.
At that point... set your dial indicator to "0"... not the degree wheel... at this point... we don't even care what the degree wheel says.
Once your dial indicator is "zeroed" on the base circle of the cam... rotate the crank clockwise until that dial indicator on the intake lifter starts to move... when it does... keep rotating slowly, until you have reached .050" of lift... at that point, NOW you look at your degree wheel and whatever number it is pointing at, is your intake opening timing event for .050" lift... otherwords... intake opening @.050. What is THAT number?
If it still doesn't quite make sense... Feel free to give me a call and perhaps ypu can facetime what you got going on... it is either something super simple that your just overlooking...or some super screwed up part.
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Post by: Steveo909 on May 21, 2017, 10:40:03 PM
Man... I'm just going to be quite honest here... no offense intended, but you are making this way more complicated than it needs to be and way over thinking this. If you've gotten this far... you can figure this out.No offense taken. That's funny I told myself the same thing. Probably making this way harder than it is. I really appreciate your advice.
The following is AFTER you are sure you have the degree wheel set for proper tdc... as in the degree wheel reads "0" or TDC... and the #1 piston is in fact, at Top Dead Center.
Rotate the crank until the lifter is resting on the base circle... heel of the cam... whatever... just so that it is roughly opposite of the lobe side on the intake lobe.
At that point... set your dial indicator to "0"... not the degree wheel... at this point... we don't even care what the degree wheel says.
Once your dial indicator is "zeroed" on the base circle of the cam... rotate the crank clockwise until that dial indicator on the intake lifter starts to move... when it does... keep rotating slowly, until you have reached .050" of lift... at that point, NOW you look at your degree wheel and whatever number it is pointing at, is your intake opening timing event for .050" lift... otherwords... intake opening @.050. What is THAT number?
If it still doesn't quite make sense... Feel free to give me a call and perhaps ypu can facetime what you got going on... it is either something super simple that your just overlooking...or some super screwed up part.
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I'll check it again the way you explained when I have some time to work on it. I'll let you know what I get. If I have troubles I will definitely give you a call.
Thanks man!
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Post by: Flusher on May 21, 2017, 11:34:49 PM
I'm glad I decided to buy a degree wheel. I was really close to just throwing the timing cover on and calling it a day. But then there was that whole OCD thing again.
Thanks again.
You have just taken your first steps from being an engine assembler to being an engine builder.
Cheers,
Joe
Post by: LakesOnly on May 24, 2017, 11:40:15 AM
Having trouble degreeing my cam on 460. Gears are installed straight up. From TDC I'm rotating clockwise to max lift. Zero dial. Turn to .050. Record number (45). Back up past max lift to .050. Record number (141). Divide by 2. This gives me 93. Numbers are way off. Should be 108. What am I doing wrong ?You said, "should be 108*" but your cam card calls for a 106* intake centerline. (If your engine builder specified 108* then go with that.)
Well I checked. Double checked. And checked again. And I'm still getting the same number. 93.If you're certain that you are evaluating your intake center line correctly then, of course yes, you use the keyways on the timing chain set to make the adjustment--that's what they're there for. The chain set need not be set in the 0* or "straight up" position. Whether it's the cam, the chain set, the crankshaft keyway, or whatever combination thereof, etc, that is putting the camshaft out of phase is irrelevant--just get the intake centerline correct. And be sure to verify both intake and exhaust lobe profiles per the cam card once the centerline is set.
Does this mean the cam is jacked up? Or do I need to retard or advance the crank gear to a different key slot??? Seems really far off.
Post by: Steveo909 on May 24, 2017, 11:50:30 AM
. It checks out perfectly now. A good learning experience.
Going to continue to put it together and will post pictures when it's done.
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Post by: Steveo909 on May 24, 2017, 11:56:53 AM
You said, "should be 108*" but your cam card calls for a 106* intake centerline. (If your engine builder specified 108* then go with that.)You're right. 106. My mistake. Thanks Paul.
If you're certain that you are evaluating your intake center line correctly then, of course yes, you use the keyways on the timing chain set to make the adjustment--that's what they're there for. The chain set need not be set in the 0* or "straight up" position. Whether it's the cam, the chain set, the crankshaft keyway, or whatever combination thereof, etc, that is putting the camshaft out of phase is irrelevant--just get the intake centerline correct. And be sure to verify both intake and exhaust lobe profiles per the cam card once the centerline is set.
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Post by: GT Jets on May 24, 2017, 12:28:09 PM
Thanks for the help everyone. After playing with it some more it turns out it was one tooth offThat's what I said...............
A good learning experience.
Going to continue to put it together and will post pictures when it's done.
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Lol
Glad you found it brother.
GT
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