Proper pushrod length checking
#1
Proper pushrod length checking
I read an incredible amount about this last night! Maybe we can get all of this answered in one place.
1) When using the pushrod checker should a solid lifter (or one made to be solid) be used? If so should it be the exact same brand so the geometry remains the same? The lifter plunger does compress when opening the valve if the regular springs are used.
2) Can a checker spring be used instead of using a solid lifter? It may be hard to get a pattern mark though?
3) If using a checker spring, should the lifter be preloaded?
4) Car Craft had an article on checking pushrod length where you get the lifter on the cam base circle, put the rocker arm on, and just move the roller enough to mark where it's hitting. They recommended it be on the inboard 1/3 of the valve stem. This won't show the full marking pattern but it should show the start of the pattern. Thoughts on this?
1) When using the pushrod checker should a solid lifter (or one made to be solid) be used? If so should it be the exact same brand so the geometry remains the same? The lifter plunger does compress when opening the valve if the regular springs are used.
2) Can a checker spring be used instead of using a solid lifter? It may be hard to get a pattern mark though?
3) If using a checker spring, should the lifter be preloaded?
4) Car Craft had an article on checking pushrod length where you get the lifter on the cam base circle, put the rocker arm on, and just move the roller enough to mark where it's hitting. They recommended it be on the inboard 1/3 of the valve stem. This won't show the full marking pattern but it should show the start of the pattern. Thoughts on this?
#2
Re: Proper pushrod length checking
Originally Posted by Jeff95TA
I read an incredible amount about this last night! Maybe we can get all of this answered in one place.
1) When using the pushrod checker should a solid lifter (or one made to be solid) be used? If so should it be the exact same brand so the geometry remains the same? The lifter plunger does compress when opening the valve if the regular springs are used.
2) Can a checker spring be used instead of using a solid lifter? It may be hard to get a pattern mark though?
3) If using a checker spring, should the lifter be preloaded?
4) Car Craft had an article on checking pushrod length where you get the lifter on the cam base circle, put the rocker arm on, and just move the roller enough to mark where it's hitting. They recommended it be on the inboard 1/3 of the valve stem. This won't show the full marking pattern but it should show the start of the pattern. Thoughts on this?
1) When using the pushrod checker should a solid lifter (or one made to be solid) be used? If so should it be the exact same brand so the geometry remains the same? The lifter plunger does compress when opening the valve if the regular springs are used.
2) Can a checker spring be used instead of using a solid lifter? It may be hard to get a pattern mark though?
3) If using a checker spring, should the lifter be preloaded?
4) Car Craft had an article on checking pushrod length where you get the lifter on the cam base circle, put the rocker arm on, and just move the roller enough to mark where it's hitting. They recommended it be on the inboard 1/3 of the valve stem. This won't show the full marking pattern but it should show the start of the pattern. Thoughts on this?
2) yes you can do it that way as well, you don't get as much of the deflection in the system when you are checking it though.
3) yes you want to setup the system exactly how you are going to run it.
4) I shoot for the narrowest pattern that is in the middle of the valve, there are a lot of ways to do this but once I saw that Warren Johnson argeed with my way I'm sticking to it.
Bret
#3
Re: Proper pushrod length checking
Bret, what is your opinion of these:
http://store.summitracing.com/egnsea...115+4294859056
I have an adjustable pushrod from comp cams that I usually use, but I saw this and was curious so I bought one (seeing how it was pretty cheap) I figured I'd give it a try in conjuction with my adjustable pushrod and see how I liked it. Have you ever used one?
http://store.summitracing.com/egnsea...115+4294859056
I have an adjustable pushrod from comp cams that I usually use, but I saw this and was curious so I bought one (seeing how it was pretty cheap) I figured I'd give it a try in conjuction with my adjustable pushrod and see how I liked it. Have you ever used one?
#5
Re: Proper pushrod length checking
Originally Posted by SStrokerAce
yeah I don't get the point of those.....
FWIW, here is my thoughts on it: It says to slide it over the stud while the pushrod is in place, (and while the lifter is on the base circle of the cam of course) and if the checker contacts the pushrod first to measure the gap between valve stem tip and the checker and then order a pushrod that is that paticular length shorter. Of course its vice-versa if it contacts the valve stem tip first.
So I figure I'll try it and use my adjustable pushrod to figure what length pushrod it says I need, and then install one of my rocker arms and see if its right....I guess I'll let ya know how close it is
Last edited by Colin91Z; 05-13-2006 at 02:08 PM.
#6
Re: Proper pushrod length checking
Messed around for a few hours this morning.
Tried a checking spring but still got a good bit of movement in the lifter, and it didn't want to make a mark on the valve real well.
I already had a solid lifter that I had made with epoxy, but it was an OEM lifter, not a Comp like I'll be running. Don't have a good way to measure the wheel-to-cup distance, but I compared the base circle valve tip mark between the two and they were close but not exact. Two extra discs under the cup of the OEM got it darn close to the Comp one.
Checked the marks starting at 7.200 and went down in 0.050 increments to 7.050, which looks the best. 7.050 got it closest to where it belongs (pretty much centered over the valve, maybe a little biased to the intake side). But the mark got wider. I was confused by some earlier stuff I read - is it possible to change the mark width without moving it's location? Changing length always moves the location, correct?
Tried a checking spring but still got a good bit of movement in the lifter, and it didn't want to make a mark on the valve real well.
I already had a solid lifter that I had made with epoxy, but it was an OEM lifter, not a Comp like I'll be running. Don't have a good way to measure the wheel-to-cup distance, but I compared the base circle valve tip mark between the two and they were close but not exact. Two extra discs under the cup of the OEM got it darn close to the Comp one.
Checked the marks starting at 7.200 and went down in 0.050 increments to 7.050, which looks the best. 7.050 got it closest to where it belongs (pretty much centered over the valve, maybe a little biased to the intake side). But the mark got wider. I was confused by some earlier stuff I read - is it possible to change the mark width without moving it's location? Changing length always moves the location, correct?
#8
Re: Proper pushrod length checking
Lateral placement won't be a problem since I have adjustable guide plates.
This is what I ended up with.
7.100"
http://home.comcast.net/~jsaccani/DSC02675.JPG
7.050"
http://home.comcast.net/~jsaccani/DSC02676.JPG
http://home.comcast.net/~jsaccani/DSC02679.JPG
http://home.comcast.net/~jsaccani/DSC02681.JPG
7.050"(base circle mark)
http://home.comcast.net/~jsaccani/DSC02677.JPG
7.000"
http://home.comcast.net/~jsaccani/DSC02682.JPG
http://home.comcast.net/~jsaccani/DSC02683.JPG
Debating between 7.050 and 7.000.
One other thing. I noticed that sometimes the roller tip didn't leave a mark across the whole valve tip. Maybe the marker just didn't want to come off or could it be a problem with flatness of the valve stem or roller? Or am I worried about nothing?
This is what I ended up with.
7.100"
http://home.comcast.net/~jsaccani/DSC02675.JPG
7.050"
http://home.comcast.net/~jsaccani/DSC02676.JPG
http://home.comcast.net/~jsaccani/DSC02679.JPG
http://home.comcast.net/~jsaccani/DSC02681.JPG
7.050"(base circle mark)
http://home.comcast.net/~jsaccani/DSC02677.JPG
7.000"
http://home.comcast.net/~jsaccani/DSC02682.JPG
http://home.comcast.net/~jsaccani/DSC02683.JPG
Debating between 7.050 and 7.000.
One other thing. I noticed that sometimes the roller tip didn't leave a mark across the whole valve tip. Maybe the marker just didn't want to come off or could it be a problem with flatness of the valve stem or roller? Or am I worried about nothing?
Last edited by Jeff95TA; 05-14-2006 at 01:05 PM.
#10
Re: Proper pushrod length checking
Originally Posted by A/G
Actually, based on the pics, I prefer the 7.100.
What do you make of the marks that aren't across the whole stem?
#12
Re: Proper pushrod length checking
Checked several more with the 7.100" length:
http://home.comcast.net/~jsaccani/DSC02684.JPG
http://home.comcast.net/~jsaccani/DSC02685.JPG
http://home.comcast.net/~jsaccani/DSC02686.JPG
There's still that one pesky valve with only a partial mark. I tried rotating the valve 180 degrees, same thing. Also tried changing the rocker arm stud and a different lifter, no change. Could the hole for the stud not be lined up with the valve? The edge of the roller is just BARELY not touching. Almost can't even get an 0.001 feeler in there. And this is with the regular spring not a checker spring.
http://home.comcast.net/~jsaccani/DSC02684.JPG
http://home.comcast.net/~jsaccani/DSC02685.JPG
http://home.comcast.net/~jsaccani/DSC02686.JPG
There's still that one pesky valve with only a partial mark. I tried rotating the valve 180 degrees, same thing. Also tried changing the rocker arm stud and a different lifter, no change. Could the hole for the stud not be lined up with the valve? The edge of the roller is just BARELY not touching. Almost can't even get an 0.001 feeler in there. And this is with the regular spring not a checker spring.
#14
Re: Proper pushrod length checking
Hrmm.. I ordered and have some checker springs with an adjustable trickflow pushrod and I was going to do this tomorrow so I could order new pushrods since I don't think my 7.2's are gonna work with the zero decked block.
Hopefully these will work in my case...
Hopefully these will work in my case...
Last edited by Javier97Z28; 05-14-2006 at 10:28 PM.
#15
Re: Proper pushrod length checking
Originally Posted by Jeff95TA
Checked several more with the 7.100" length:
http://home.comcast.net/~jsaccani/DSC02684.JPG
http://home.comcast.net/~jsaccani/DSC02685.JPG
http://home.comcast.net/~jsaccani/DSC02686.JPG
There's still that one pesky valve with only a partial mark. I tried rotating the valve 180 degrees, same thing. Also tried changing the rocker arm stud and a different lifter, no change. Could the hole for the stud not be lined up with the valve? The edge of the roller is just BARELY not touching. Almost can't even get an 0.001 feeler in there. And this is with the regular spring not a checker spring.
http://home.comcast.net/~jsaccani/DSC02684.JPG
http://home.comcast.net/~jsaccani/DSC02685.JPG
http://home.comcast.net/~jsaccani/DSC02686.JPG
There's still that one pesky valve with only a partial mark. I tried rotating the valve 180 degrees, same thing. Also tried changing the rocker arm stud and a different lifter, no change. Could the hole for the stud not be lined up with the valve? The edge of the roller is just BARELY not touching. Almost can't even get an 0.001 feeler in there. And this is with the regular spring not a checker spring.
Yea your stud is out of line causing the rocker to coc* a little in relation to the valve. It's not a big issue as a lot of heads do this. What ya have to watch for is the rocker pushing hard on the guide plate on the opposite side of the way the rocker wants to twist. Have seen the roller tip eat up into the rocker body from this also but that was after 25/30,000 miles. I wouldn't worry about it,just something to keep a check on in the future.