My 347ci build
Chuck, yes I am running Manton straight walled 11/32".
The msrd preload column was done on the pushrod side with an indicator. But I was in the car and since that means half of the motor is under the cowl in an f body it was not easy. I was also not able to get the angles just right as my crappy indicator rods got a case of the comeaparts. I decided that the rotation to torque measurement was enough of a sanity check and carried on.
I was going to ask on the diameter of your washer holes. The way I see it is that it is a potentially huge source of error. I would consider either making your own washers (and verifying the comp tool optically) or going with overall length. Fwiw, when I checkefd with Tony on vader he said he was running 7.6x. That was 1 year ago though..I was surprised the Johnsons needed such long rods and double checked with Randy too.
Ill throw my two comp tools on our quadracheck at work and see what I see. May take a couple of days.
The msrd preload column was done on the pushrod side with an indicator. But I was in the car and since that means half of the motor is under the cowl in an f body it was not easy. I was also not able to get the angles just right as my crappy indicator rods got a case of the comeaparts. I decided that the rotation to torque measurement was enough of a sanity check and carried on.
I was going to ask on the diameter of your washer holes. The way I see it is that it is a potentially huge source of error. I would consider either making your own washers (and verifying the comp tool optically) or going with overall length. Fwiw, when I checkefd with Tony on vader he said he was running 7.6x. That was 1 year ago though..I was surprised the Johnsons needed such long rods and double checked with Randy too.
Ill throw my two comp tools on our quadracheck at work and see what I see. May take a couple of days.
Nice job on the oil pan it looks very slick. I can't give you an educated answer to your question on setting up the fluid dynamics equation at this point. It's been a minute since college when I last used them. Let me dig out some old books and I'll get back to you this week. I'm also interested in this subject of calculating optimum preload so its no big deal.
Two things assured - You are trying to figure out the theoretical optimum preload to which at max rpm you are:
1) At the closest to bottoming out the lifter at max lift without actually hitting the "zero" point. Some important factors are bleed down rate, "buoyancy" of the lifter filled with oil, spring strength in lifter, tangential force to find inertia as you come around the corner of lobe to max lifter, etc.
2) Closest to full extension of the lifter after just arriving on the base circle of the cam lobe without actually having your normal force override the downward force of lifter wheel on cam lobe. Important factors are the same as above except take into account "bleed in" rate. This goes for the same on forces on the topside of lifter.
Yea way nerdy like I said its possible but not easy lol.
Two things assured - You are trying to figure out the theoretical optimum preload to which at max rpm you are:
1) At the closest to bottoming out the lifter at max lift without actually hitting the "zero" point. Some important factors are bleed down rate, "buoyancy" of the lifter filled with oil, spring strength in lifter, tangential force to find inertia as you come around the corner of lobe to max lifter, etc.
2) Closest to full extension of the lifter after just arriving on the base circle of the cam lobe without actually having your normal force override the downward force of lifter wheel on cam lobe. Important factors are the same as above except take into account "bleed in" rate. This goes for the same on forces on the topside of lifter.
Yea way nerdy like I said its possible but not easy lol.
In regards to mics and calipers you can make even the best read whatever you want to see if you put enough pressure on it. If the dial caliper is reading a true 0.002" off, just zero it out and rock on. That's why you always check to a known "good" standard.
Nice job on the oil pan it looks very slick. I can't give you an educated answer to your question on setting up the fluid dynamics equation at this point. It's been a minute since college when I last used them. Let me dig out some old books and I'll get back to you this week. I'm also interested in this subject of calculating optimum preload so its no big deal.
Two things assured - You are trying to figure out the theoretical optimum preload to which at max rpm you are:
1) At the closest to bottoming out the lifter at max lift without actually hitting the "zero" point. Some important factors are bleed down rate, "buoyancy" of the lifter filled with oil, spring strength in lifter, tangential force to find inertia as you come around the corner of lobe to max lifter, etc.
2) Closest to full extension of the lifter after just arriving on the base circle of the cam lobe without actually having your normal force override the downward force of lifter wheel on cam lobe. Important factors are the same as above except take into account "bleed in" rate. This goes for the same on forces on the topside of lifter.
Yea way nerdy like I said its possible but not easy lol.
Two things assured - You are trying to figure out the theoretical optimum preload to which at max rpm you are:
1) At the closest to bottoming out the lifter at max lift without actually hitting the "zero" point. Some important factors are bleed down rate, "buoyancy" of the lifter filled with oil, spring strength in lifter, tangential force to find inertia as you come around the corner of lobe to max lifter, etc.
2) Closest to full extension of the lifter after just arriving on the base circle of the cam lobe without actually having your normal force override the downward force of lifter wheel on cam lobe. Important factors are the same as above except take into account "bleed in" rate. This goes for the same on forces on the topside of lifter.
Yea way nerdy like I said its possible but not easy lol.
Originally Posted by ironmanLS1
In regards to mics and calipers you can make even the best read whatever you want to see if you put enough pressure on it. If the dial caliper is reading a true 0.002" off, just zero it out and rock on. That's why you always check to a known "good" standard.
Last edited by ckpitt55; Aug 12, 2013 at 08:36 PM.
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Verdad Gallardo Thanks for the kind words guys
I made new "washers" for the pushrod measuring fixture - ended up using a #28 drill bit going through some bits of steel that I cut from a big washer I had lying around. the bit measured out as close to .140" as I was able to measure with calipers (measuring the drill bit, not the hole) - chucked it up in a drill press, set up the steel on some parallels in a vice and went to town.
doing this brought me to within 0.004" of where I'm supposed to be at with the checker tool fully closed - I got 6.796" and it's repeatable. Somewhere in there is still tolerance of the pushrod checker itself and a little bit in the hole size - I'm sure the machining isn't perfect with a relatively flimsy drill bit walking around, table not being exactly perpendicular to the spindle, vice deforming the material a bit to clamp it, spindle having a little bit of runout - but it's as close as I'm probably going to get it I think without spending a lot more time on setup and using a LOT more expensive machining equipment....i have access to all that stuff but its not worth the effort to get those last few tenths.
might just add 0.004" to whatever my pushrod measurement is and call it a day. thinking about it now, the accuracy check I did on the calipers isn't really relevant to what I'm doing here because my measurements aren't referenced against 0 - they're relative to some other non-zero point that also has error. the net difference between the two points is going to be the same regardless of what the accuracy of the tool is - that is assuming that there is no appreciable difference in error at those points (which is what I showed with that calibration exercise).
Looks like I'll be remeasuring the set of 8 I already finished for the sake of consistency. I still have to do a bit of hand finishing to deburr the other bank of lifters and then I'll be on my way. Sharp edges around the roller axles seem to be getting bound up in the lifter bores.
For those watching this measurement thing, does that seem to make sense? Still interested to see what Steve comes back with on the checker tool length.
I made new "washers" for the pushrod measuring fixture - ended up using a #28 drill bit going through some bits of steel that I cut from a big washer I had lying around. the bit measured out as close to .140" as I was able to measure with calipers (measuring the drill bit, not the hole) - chucked it up in a drill press, set up the steel on some parallels in a vice and went to town.
doing this brought me to within 0.004" of where I'm supposed to be at with the checker tool fully closed - I got 6.796" and it's repeatable. Somewhere in there is still tolerance of the pushrod checker itself and a little bit in the hole size - I'm sure the machining isn't perfect with a relatively flimsy drill bit walking around, table not being exactly perpendicular to the spindle, vice deforming the material a bit to clamp it, spindle having a little bit of runout - but it's as close as I'm probably going to get it I think without spending a lot more time on setup and using a LOT more expensive machining equipment....i have access to all that stuff but its not worth the effort to get those last few tenths.
might just add 0.004" to whatever my pushrod measurement is and call it a day. thinking about it now, the accuracy check I did on the calipers isn't really relevant to what I'm doing here because my measurements aren't referenced against 0 - they're relative to some other non-zero point that also has error. the net difference between the two points is going to be the same regardless of what the accuracy of the tool is - that is assuming that there is no appreciable difference in error at those points (which is what I showed with that calibration exercise).
Looks like I'll be remeasuring the set of 8 I already finished for the sake of consistency. I still have to do a bit of hand finishing to deburr the other bank of lifters and then I'll be on my way. Sharp edges around the roller axles seem to be getting bound up in the lifter bores.
For those watching this measurement thing, does that seem to make sense? Still interested to see what Steve comes back with on the checker tool length.
Last edited by ckpitt55; Aug 13, 2013 at 10:01 PM.
Chuck, yes I am running Manton straight walled 11/32".
The msrd preload column was done on the pushrod side with an indicator. But I was in the car and since that means half of the motor is under the cowl in an f body it was not easy. I was also not able to get the angles just right as my crappy indicator rods got a case of the comeaparts. I decided that the rotation to torque measurement was enough of a sanity check and carried on.
The msrd preload column was done on the pushrod side with an indicator. But I was in the car and since that means half of the motor is under the cowl in an f body it was not easy. I was also not able to get the angles just right as my crappy indicator rods got a case of the comeaparts. I decided that the rotation to torque measurement was enough of a sanity check and carried on.
Hi guys, got on the quadracheck at work and measured my two Comp 7702-1 checkers. Its basically a camera on encoded stages with a little computer that can calculate diameters and distancesdumfrom points measured on surfaces.
Flat to flat mine measured 6.8185 and 6.8194 overall length. Double checking with calibrated digital mitutoyo calipers I got 6.8195 and 6.8210 respectively.
I used the tool to measure the gauge length with the optical equivalent of Chuck's 0.140" washers. For gauge length of the checkers I got 6.8079" and 6.8046" respectively.
Two interesting observations. On both checkers the "oil hole" on the shorter section that spins was 0.100" diameter. But the hole on the longer side was larger on both. One was 0.1145" and the second was 0.1200. The diameter of the ball ends also ranged from 0.3087" to 0.3160" between all four ends.
While I am using 5 significant digits here please take these numbers with a grain of salt. I didnt get a chance to measure any gauge blocks or standards today...but my company makes very small parts and we do depend on this technique to be good to 0.001". Second, the ball diameters do appear to be different based on visual comparison, but im not going to bet the farm on these particular numbers. In each case I marked 5 or 6 points on the ball surface and let the computer fit that data.
I hope this is useful info. If I missed something or youd like some other measurement let me know. Ive measured a stock rocker this way. Its handy because you can measure to the extents of the scrub marks and other visible markers.
Flat to flat mine measured 6.8185 and 6.8194 overall length. Double checking with calibrated digital mitutoyo calipers I got 6.8195 and 6.8210 respectively.
I used the tool to measure the gauge length with the optical equivalent of Chuck's 0.140" washers. For gauge length of the checkers I got 6.8079" and 6.8046" respectively.
Two interesting observations. On both checkers the "oil hole" on the shorter section that spins was 0.100" diameter. But the hole on the longer side was larger on both. One was 0.1145" and the second was 0.1200. The diameter of the ball ends also ranged from 0.3087" to 0.3160" between all four ends.
While I am using 5 significant digits here please take these numbers with a grain of salt. I didnt get a chance to measure any gauge blocks or standards today...but my company makes very small parts and we do depend on this technique to be good to 0.001". Second, the ball diameters do appear to be different based on visual comparison, but im not going to bet the farm on these particular numbers. In each case I marked 5 or 6 points on the ball surface and let the computer fit that data.
I hope this is useful info. If I missed something or youd like some other measurement let me know. Ive measured a stock rocker this way. Its handy because you can measure to the extents of the scrub marks and other visible markers.
Jake...good point. My build started out as headers and an underdrive pulley. Seriously. The 9" the trans, all of it was rationalized afterward. I was headed to rent a cherry picker for the day when I realized if I took the motor out id be doing what ckpitt and rezintexas have in these threads...and I couldnt put my wife through that. Shes put up with enough for a couple of years...haha.
Hi guys, got on the quadracheck at work and measured my two Comp 7702-1 checkers. Its basically a camera on encoded stages with a little computer that can calculate diameters and distancesdumfrom points measured on surfaces.
Flat to flat mine measured 6.8185 and 6.8194 overall length. Double checking with calibrated digital mitutoyo calipers I got 6.8195 and 6.8210 respectively.
I used the tool to measure the gauge length with the optical equivalent of Chuck's 0.140" washers. For gauge length of the checkers I got 6.8079" and 6.8046" respectively.
Two interesting observations. On both checkers the "oil hole" on the shorter section that spins was 0.100" diameter. But the hole on the longer side was larger on both. One was 0.1145" and the second was 0.1200. The diameter of the ball ends also ranged from 0.3087" to 0.3160" between all four ends.
While I am using 5 significant digits here please take these numbers with a grain of salt. I didnt get a chance to measure any gauge blocks or standards today...but my company makes very small parts and we do depend on this technique to be good to 0.001". Second, the ball diameters do appear to be different based on visual comparison, but im not going to bet the farm on these particular numbers. In each case I marked 5 or 6 points on the ball surface and let the computer fit that data.
I hope this is useful info. If I missed something or youd like some other measurement let me know. Ive measured a stock rocker this way. Its handy because you can measure to the extents of the scrub marks and other visible markers.
Flat to flat mine measured 6.8185 and 6.8194 overall length. Double checking with calibrated digital mitutoyo calipers I got 6.8195 and 6.8210 respectively.
I used the tool to measure the gauge length with the optical equivalent of Chuck's 0.140" washers. For gauge length of the checkers I got 6.8079" and 6.8046" respectively.
Two interesting observations. On both checkers the "oil hole" on the shorter section that spins was 0.100" diameter. But the hole on the longer side was larger on both. One was 0.1145" and the second was 0.1200. The diameter of the ball ends also ranged from 0.3087" to 0.3160" between all four ends.
While I am using 5 significant digits here please take these numbers with a grain of salt. I didnt get a chance to measure any gauge blocks or standards today...but my company makes very small parts and we do depend on this technique to be good to 0.001". Second, the ball diameters do appear to be different based on visual comparison, but im not going to bet the farm on these particular numbers. In each case I marked 5 or 6 points on the ball surface and let the computer fit that data.
I hope this is useful info. If I missed something or youd like some other measurement let me know. Ive measured a stock rocker this way. Its handy because you can measure to the extents of the scrub marks and other visible markers.
Can't really come to any sort of sweeping conclusion with such a small sample size but I think it's safe to say that the checker tools aren't really all that accurate. At the very least, great info for discussion purposes.
That being said, I squeezed out another 0.002" of "error" from my measurement setup by stoning the washer pieces flat on my hunk of granite. I say "error" in quotes because I'm comparing to what the checker is supposed to measure.
.222" washer thickness
7.020" overall measurement (closed checker + washers)
= 6.798" measured gauge length in the closed position
That would be star-spangled awesome if I knew for sure this thing was 6.800" long, but given Steve's findings I'm not sure really what to think. I removed all the error I could from the setup itself to the best of my ability so maybe that 0.002" really is in the checker. I don't know.
It's a dark day when you no longer trust your measuring tools. Gonna chew on this one for a little while.
I placed the focal plane so I was measuring the widest part of each ball. So nominally the center of the shaft. Then I started working my way along the ball surface such that I could measure a line that was .140" Nominally centered on the shaft. I set the location of this line to zero, moved to the other end of the shaft and established another 0.140" line as the msmt endpoint.
I can draw a little diagram if that would help, but just think that I basically have a microscope with an encoded xyz. I set the focal plane halfway through the thickness of the shaft and manually generate the point cloud from the encoder readout. Ill try and sna a few picd of the tool in use...wasnt thinking.
Your conclusions are the same as mine. If you had some close known length pushrods it would be helpful. ..you could measure your realized preload in the motor. Maybe make all your measurements and order a median length test pushrod, measure in the motor with it, then order the set?
I can draw a little diagram if that would help, but just think that I basically have a microscope with an encoded xyz. I set the focal plane halfway through the thickness of the shaft and manually generate the point cloud from the encoder readout. Ill try and sna a few picd of the tool in use...wasnt thinking.
Your conclusions are the same as mine. If you had some close known length pushrods it would be helpful. ..you could measure your realized preload in the motor. Maybe make all your measurements and order a median length test pushrod, measure in the motor with it, then order the set?
Gotcha on the .140" line, makes sense. That machine sounds pretty badass - it'd be interesting seeing some pics of the setup if you have a minute to snap one or two.
I tried measuring a stock 7.400 as a second reference and ended up not even being close. Got 7.373 or something like that. I have a hard time believing my measurement is that far off - but then again I have no idea what tolerances they hold the stockers to at GM. Or perhaps that 7.400 is an overall length. Anyone know?
For now I think I'm going to take my measurements and add 0.002" making the assumption that the checker is "perfect", even though I know it's not. Without sending it to you to measure it I don't have enough information to make a judgement otherwise. Then I'll order a sample rod like you suggest and see what my preload is. If it gives me the preload I'm expecting then I'm good and will order the rest. If it's not, then I need to make some adjustments.
I tried measuring a stock 7.400 as a second reference and ended up not even being close. Got 7.373 or something like that. I have a hard time believing my measurement is that far off - but then again I have no idea what tolerances they hold the stockers to at GM. Or perhaps that 7.400 is an overall length. Anyone know?
For now I think I'm going to take my measurements and add 0.002" making the assumption that the checker is "perfect", even though I know it's not. Without sending it to you to measure it I don't have enough information to make a judgement otherwise. Then I'll order a sample rod like you suggest and see what my preload is. If it gives me the preload I'm expecting then I'm good and will order the rest. If it's not, then I need to make some adjustments.
Last edited by ckpitt55; Aug 15, 2013 at 08:37 AM.
Sounds like a plan. Get this, gas main blew up by my work yesterday, knocked out the electricity and killed the tool...must have happened right after I got done. It will be a couple (of crappy) weeks until we get the tool back. Damn it.
finally finished measuring pushrod lengths for all 16 valves. ended up going through them all twice over a few day span to try an obtain some feel of repeatability of measurements. pretty satisfied with it. using an average of 4 measurements for each pushrod.
Those length values are assuming a 0.030" preload on the lifter. Ordering them "long" because it's easier to remove preload if necessary by adding a little more shim to the rocker.
I'm going to order a pushrod from trend to get a feel for how far off my checker tool is / how much preload I'm actually getting compared to what I'm expecting before I order the whole set. For the custom length stuff, they hold tolerances to +/-0.001" but use the thick wall rods. Still need to finalize my decision but right now I'm leaning towards 3/8" - 5/16" double taper rods in what I understand to be a .135" wall. Hope to get that ordered tomorrow.
In the mean time I'm set up and ready to measure PTV - hope to get to that tomorrow. Checker springs, solid lifter, checker set to 0 lash. Pics of the setup later. A prelim sanity check shows that I have a hell of a lot of room - only looked at the intake valve on #1 so far but I have in the neighborhood of .175" minimum clearance.
Those length values are assuming a 0.030" preload on the lifter. Ordering them "long" because it's easier to remove preload if necessary by adding a little more shim to the rocker.
I'm going to order a pushrod from trend to get a feel for how far off my checker tool is / how much preload I'm actually getting compared to what I'm expecting before I order the whole set. For the custom length stuff, they hold tolerances to +/-0.001" but use the thick wall rods. Still need to finalize my decision but right now I'm leaning towards 3/8" - 5/16" double taper rods in what I understand to be a .135" wall. Hope to get that ordered tomorrow.
In the mean time I'm set up and ready to measure PTV - hope to get to that tomorrow. Checker springs, solid lifter, checker set to 0 lash. Pics of the setup later. A prelim sanity check shows that I have a hell of a lot of room - only looked at the intake valve on #1 so far but I have in the neighborhood of .175" minimum clearance.
Ordered 7.730 and 7.700 sample pushrods from trend today. 3/8"-5/16" double taper with .135" wall. Hopefully I'll get them early next week.
Also checked PTV, looks like we're good to go.
Min intake: .173"
Min exhaust: .192"
The list of things left to do is getting short. Aside from ordering the rest of my pushrods and measuring lifter preload, the hard **** is done and the rest of the engine is ready to bolt together aside from a few odds and ends. Along those lines, did a little bit of a mock up tonight to see how things come together. I think it'll look decent when finished.
Also checked PTV, looks like we're good to go.
Min intake: .173"
Min exhaust: .192"
The list of things left to do is getting short. Aside from ordering the rest of my pushrods and measuring lifter preload, the hard **** is done and the rest of the engine is ready to bolt together aside from a few odds and ends. Along those lines, did a little bit of a mock up tonight to see how things come together. I think it'll look decent when finished.
Last edited by ckpitt55; Aug 23, 2013 at 12:46 AM.
