Yella Terra Ultralites vs. Comp Dual 921 springs.
03-16-2008, 05:20 PM
#23
So, if I don't use the .048" shims at all, the 7.400 magnum pushrods (currently installed) would push the wipe pattern more towards the exhaust side (generally speaking because no two setups can be guaranteed to be the same, though all parts supposedly are assumed equal)?
03-16-2008, 05:31 PM
#24
The shims will move the wipe pattern towards the exhaust side of the valve stem. The pushrods have absolutely no affect on the wipe pattern, they will only change the preload on the lifter with the two extremes being a loose pushrod or a valve held open. The shims are the only thing that will alter the wipe pattern.
03-18-2008, 05:16 AM
#25
... posed this question to a local shop:
So these YT Ultralite’s need to be shimmed with the thicker .078 - .080 shims to get the wipe pattern dead center (instead of the .048 shims which come with the Ultralites). I currently have stock 1.8 rockers with 7.4 comp magnum pushrods. If the YT Ultralites are 1.7’s, the pushrods need to be longer to keep the lifter preload in check, right?
If I need a longer pushrod, what would be the best lighter / stronger pushrod for me to buy, without getting rediculously expensive? I know this really can't be determined until the actual install is done ... just looking for a ballpark estimate.
So these YT Ultralite’s need to be shimmed with the thicker .078 - .080 shims to get the wipe pattern dead center (instead of the .048 shims which come with the Ultralites). I currently have stock 1.8 rockers with 7.4 comp magnum pushrods. If the YT Ultralites are 1.7’s, the pushrods need to be longer to keep the lifter preload in check, right?
If I need a longer pushrod, what would be the best lighter / stronger pushrod for me to buy, without getting rediculously expensive? I know this really can't be determined until the actual install is done ... just looking for a ballpark estimate.
03-18-2008, 05:56 AM
#26
JEB99TA
Where did you come up with .078-.080? The ratio of the YT's being 1.7 vs. your (what you call stock) 1.8's won't matter with regards to pushrod length; it's the shim that is making it longer to get the right preload back. As far as pushrods, ballpark $125-$200.
Where did you come up with .078-.080? The ratio of the YT's being 1.7 vs. your (what you call stock) 1.8's won't matter with regards to pushrod length; it's the shim that is making it longer to get the right preload back. As far as pushrods, ballpark $125-$200.
03-18-2008, 11:03 AM
#27
I installed a set of these last summer on a friends car with a FTI cam and stock 241 heads. To get the wipe correct, we used the supplied shims. Final pushrod length came to 7.500".
I am not sure I understand the question that you posed to the local shop. I also wouldn't be as concerned about pushrod weight, stiffness yes, weight no. Stiffness is a function of OD and ID.
I am not sure I understand the question that you posed to the local shop. I also wouldn't be as concerned about pushrod weight, stiffness yes, weight no. Stiffness is a function of OD and ID.
03-18-2008, 05:32 PM
#28
Head's spinning ... lol! Actually, I was misreading this post:
Obviously, somewhere along the way, I got confused. So, I am interpreting the thickness (or thinness) of the shims only changes the wipe pattern ... shimming it with thicker shims creates the need for a longer pushrod, if I am understanding this right.
Of course, I won't really know for sure until I make the swap and know how thick of a shim gets the wipe pattern dead center. Let me go back and read this whole thread again. I really appreciate you guys trying to help me ... sorry I'm a little dense these days.
Quote:
Originally Posted by 98camaroLS1M6
they will work with dual springs, the YT work best shimmed to .050 which will require a .050 longer pushrod.
Actually, they will change the pushrod by 0.075" (actual number is 0.080" longer).
Originally Posted by 98camaroLS1M6
they will work with dual springs, the YT work best shimmed to .050 which will require a .050 longer pushrod.
Actually, they will change the pushrod by 0.075" (actual number is 0.080" longer).
Of course, I won't really know for sure until I make the swap and know how thick of a shim gets the wipe pattern dead center. Let me go back and read this whole thread again. I really appreciate you guys trying to help me ... sorry I'm a little dense these days.
03-18-2008, 07:02 PM
#29
Let me explain. The shim is under the pivot point of the rocker. If you add 0.050" to the pivot point, the pushrod end of the rocker will go up more than 0.050". Assuming the YT's rocker ratio is 1.7 when closed (the rocker ratio varies during rocker motion), then to figure out how much the pushrod length changes you have to use parallel triangles, or
pushrod length increase = shim thickness X 2.7/1.7 = shim thickness X 1.59
So, if you use a 0.050 shim the pushrod will increase as follows:
pushrod length increase = 0.050 X 1.59 = 0.0795" longer
That is why in the above post I stated that using the 0.050" shim will require 0.075" longer pushrods.
Hope this makes sense.
pushrod length increase = shim thickness X 2.7/1.7 = shim thickness X 1.59
So, if you use a 0.050 shim the pushrod will increase as follows:
pushrod length increase = 0.050 X 1.59 = 0.0795" longer
That is why in the above post I stated that using the 0.050" shim will require 0.075" longer pushrods.
Hope this makes sense.
03-18-2008, 07:38 PM
#31
Man-oooohhhh-man ... I went back and re-read everything and re-read the link to your write-up and I gained a much clearer understanding of everything you and the other good folks here were saying.
Thanks for further clarifying and expounding on things. This has helped me learn about things I always wanted to learn about ... didn't know there was so much to installing rocker arms ... wow!
I am going to have my engine builder to do the rocker install, but, he has agree'd to allow me to be part of the installation. I think I could prob do it myself, but, I really don't have the tools to do it with.
Again, thanks to all in a very big way. I really appreciate you spending your valuable time helping somebody like me.
Thanks for further clarifying and expounding on things. This has helped me learn about things I always wanted to learn about ... didn't know there was so much to installing rocker arms ... wow!
I am going to have my engine builder to do the rocker install, but, he has agree'd to allow me to be part of the installation. I think I could prob do it myself, but, I really don't have the tools to do it with.
Again, thanks to all in a very big way. I really appreciate you spending your valuable time helping somebody like me.
03-18-2008, 10:17 PM
#33
Hey Vettenuts...you seem really knowledgable on this subject and i've read/researched most of your stuff on it. I'm nearing closer to doing this myself on my brand new 402 and I want to get it right, but I had a few questions.
What do you mean when you say intake or exhaust side of the valve stem exacty? If I understand it right, it basically means the intake side is the wipe pattern is towards the left of the valve stem and right for the exhaust side. Looking at your pics in your link look like the lines are going the wrong way and it freaks me out!??
Also, your saying the pushrods have no affect on the wipe pattern...so does that mean its okay if I set the wipe pattern with a wrong lengh pushrod? I'm saying because I already bought the 7.4" and they might not be right.
Oh yea, and with everything being new, the lifters aren't really pumped up...I will put them in oil before hand, but isn't that going to throw off the right lengh pushrod thats needed?
What do you mean when you say intake or exhaust side of the valve stem exacty? If I understand it right, it basically means the intake side is the wipe pattern is towards the left of the valve stem and right for the exhaust side. Looking at your pics in your link look like the lines are going the wrong way and it freaks me out!??
Also, your saying the pushrods have no affect on the wipe pattern...so does that mean its okay if I set the wipe pattern with a wrong lengh pushrod? I'm saying because I already bought the 7.4" and they might not be right.
Oh yea, and with everything being new, the lifters aren't really pumped up...I will put them in oil before hand, but isn't that going to throw off the right lengh pushrod thats needed?
Last edited by HotWhipT/A; 03-18-2008 at 10:22 PM.
03-19-2008, 05:58 PM
#34
Hey Vettenuts...you seem really knowledgable on this subject and i've read/researched most of your stuff on it. I'm nearing closer to doing this myself on my brand new 402 and I want to get it right, but I had a few questions.
What do you mean when you say intake or exhaust side of the valve stem exacty? If I understand it right, it basically means the intake side is the wipe pattern is towards the left of the valve stem and right for the exhaust side. Looking at your pics in your link look like the lines are going the wrong way and it freaks me out!??
The intake side would be when the wipe pattern is parallel to the head and is closer to the intake side of the head. The exhaust side would be parallel to the head and on the exhaust side (too much shim).
Also, your saying the pushrods have no affect on the wipe pattern...so does that mean its okay if I set the wipe pattern with a wrong lengh pushrod? I'm saying because I already bought the 7.4" and they might not be right.
No, it will affect the wipe because the rocker motion won't be correct. When you check wipe, you need to move the rocker through the correct lift (say 0.600"). If your pushrod is long you may hang the valve open so your start point is in the wrong position on the valve stem. Also, with hydraulic lifters, if the bleed down you may start too low (not at zero lash). I like to rotate them by hand with checking springs then I know I have the correct valve lift. This can be done on the car as well if you replace the valve springs with check springs, leave out the pushrods and move the piston down the cylinder so you don't contact it with the valve. However, an adjustable pushrod can be used with checking springs if you want to roll the motor over by hand.
Oh yea, and with everything being new, the lifters aren't really pumped up...I will put them in oil before hand, but isn't that going to throw off the right lengh pushrod thats needed?
No, once you set the wipe pattern and establish if you need a shim and if so how thick, then you use the adjustable pushrod to measure to zero lash with the lifter on the base circle of the cam. If they are new lifters you just have to be very sensitive with your fingers as the plunger will be easy to depress and throw off the measurement. Once you measure to zero lash, add in the lifter preload and that is your final pushrod length.
What do you mean when you say intake or exhaust side of the valve stem exacty? If I understand it right, it basically means the intake side is the wipe pattern is towards the left of the valve stem and right for the exhaust side. Looking at your pics in your link look like the lines are going the wrong way and it freaks me out!??
The intake side would be when the wipe pattern is parallel to the head and is closer to the intake side of the head. The exhaust side would be parallel to the head and on the exhaust side (too much shim).
Also, your saying the pushrods have no affect on the wipe pattern...so does that mean its okay if I set the wipe pattern with a wrong lengh pushrod? I'm saying because I already bought the 7.4" and they might not be right.
No, it will affect the wipe because the rocker motion won't be correct. When you check wipe, you need to move the rocker through the correct lift (say 0.600"). If your pushrod is long you may hang the valve open so your start point is in the wrong position on the valve stem. Also, with hydraulic lifters, if the bleed down you may start too low (not at zero lash). I like to rotate them by hand with checking springs then I know I have the correct valve lift. This can be done on the car as well if you replace the valve springs with check springs, leave out the pushrods and move the piston down the cylinder so you don't contact it with the valve. However, an adjustable pushrod can be used with checking springs if you want to roll the motor over by hand.
Oh yea, and with everything being new, the lifters aren't really pumped up...I will put them in oil before hand, but isn't that going to throw off the right lengh pushrod thats needed?
No, once you set the wipe pattern and establish if you need a shim and if so how thick, then you use the adjustable pushrod to measure to zero lash with the lifter on the base circle of the cam. If they are new lifters you just have to be very sensitive with your fingers as the plunger will be easy to depress and throw off the measurement. Once you measure to zero lash, add in the lifter preload and that is your final pushrod length.
I copied my CF post over here.
I have had several people e-mail and ask how to do this so I thought I would post this for discussion and information. I just finished setting up the wipe pattern of my Yella Terra roller rockers on my new AFR heads. The Yella Terra rockers are fixed fulcrum rockers (as opposed to a fully adjustable rocker like the Crane I set up on my current configuration) and are furnished with a rocker pedestal and a single shim that is 0.048” thick, which when placed under the pedestal, will raise the fulcrum of the rocker and move the roller location towards the exhaust side of the valve stem. The goal is to center the wipe pattern on the valve stem and minimize the width of the pattern. When the width is reduced over the course of rocker motion, then the side loading into the valve guides is also reduced. This not only provides faster valve motions but also minimizes valve guide wear. Below is a photo of how the Yella Terra setup is installed with the pedestal and shim (if used) under the rocker shaft and the bolt passing through the assembly and into the threaded hole in the head.
I am doing this on the workbench but this can also be done on the car. The workbench has the advantage that there is more time to set things up and if parts are needed the car won’t be down as it would if you were in the middle of the head installation. Plus, it’s easier on the back.
The first step is to remove two valve springs and replace them with checking springs. I have two sets of checking springs and I used the stiffer set since they provide more force against the rocker to help in wiping off the ink that is applied to obtain the final wipe pattern.
Once the check springs are installed, set the cylinder head in the air such that the valves can be manually operated without contacting the workbench surface. Using a dial indicator allows you to manually operate the rocker arm to the required valve lift. Since the final wipe pattern is lift sensitive, you have to ensure that the motion you are moving the rocker through imitates that which will be driven by the cam.
The next step in the operation is to setup your rockers and snug the bolts. There is no need to fully torque the bolts and load the threads in the aluminum head. Hand snug is fine and will eliminate thread wear as the bolts are taken in and out several times during the process. Once the rockers are in place with the shims that are being checked, and your measurement method is setup to determine how much the valve is being moved, use a Sharpie to spread black ink on the upper surface of the valve stem. I have found it best to not allow the ink to dry too long as with checking springs it doesn’t wipe off as well. Instead, I use a cotton swap and pull off most of the cotton then soak it with ink from the Sharpie. Then I simply rotate the rocker back off of the valve stem and apply the ink. After it is just dry, then the wipe test is conducted by rotating the rocker arm by hand in the same manner as the pushrod and cam would if the head were on the motor. This process is repeated until a satisfactory wipe pattern is found by adjusting the height of the shim. A thicker shim should push the wipe pattern towards the exhaust side of the valve stem. This will be critical later as the pushrod length changes approximately 0.016” in length for every 0.010” of shim you add to the rocker pedestal so that the wipe pattern needs to be established first followed by the pushrod length.
I started the process with no shim in place under the pedestal and then added shims until I got the desired wipe pattern. Washers can be used and stacked for this process but once a thickness is found you need to find a single piece shim of the correct thickness. In the photo below (sorry for the crappy photography), three of the patterns are shown. On the left is the wipe pattern without a shim. Notice that the wipe pattern is towards the intake side (that is the intake manifold side, the bottom of the photo would be towards the exhaust headers) of the valve stem and barely gets to the valve stem center over the course of travel of the roller on the rocker. In the middle photo, shimming has now moved the wipe pattern towards the center of the valve stem. It is still biased to the intake side and a little wide. The final wipe pattern on the right is the shim setup I will use for final installation, as I am very pleased with the final wipe pattern obtained. Note that the shim value can be different for any given setup, the point being that simply bolting on the rockers from the box would have yielded the pattern on the left and likely resulted in not only disappointing results but higher than necessary valve guide wear for my installation. I bought my final shims (11/32" ID, 13/16" OD from McMaster-Carr, which are available in a lot of thicknesses. These were pretty much a perfect fit under the pedestal if you need a thickness that differs than the one provided by Yella Terra for any reason.
03-19-2008, 08:09 PM
#36
Yes, I just carefully move them through the correct lift with my hand. Dial indicator gives me the required amount of movement. I found if I left the Sharpie on for too long to dry, the checking springs didn't have enough force to provide a good wipe pattern.
03-19-2008, 09:57 PM
#37
I read that already...its good. Well i'm going to buy me a cheap dial indicator. It shouldn't be that hard to figure out as I don't know how to use one yet. Is there a certain way it has to be set up? I'll be getting a pushrod checker too for when I put the heads on. Also, I'm just suppose to do this on just one intake and exhaust valve right? The others will be the same as the first? I mean I can't have shims on some cylinders and not others...the geometry would be different.
Only other question is these check springs. Its just a regular spring from home depot right? I mean it should be a lil taller to hold but also fat enough so retainer isn't lop sided and stuff. Oh and a regular spring compressor will work since my heads aren't on right?
Thanks again!
Only other question is these check springs. Its just a regular spring from home depot right? I mean it should be a lil taller to hold but also fat enough so retainer isn't lop sided and stuff. Oh and a regular spring compressor will work since my heads aren't on right?
Thanks again!
03-20-2008, 05:15 AM
#38
I read that already...its good. Well i'm going to buy me a cheap dial indicator.
Comp cams has one that comes with the degree kit they sell. You will need a stand as well to hold it in place. The stand I use (I think made by MBC) has an 8 mm thread on the end which is perfect since it screws right into an adjacent rocker hole in the head. You can see it in the photo above.
You might be able to just use a very good metal rule to take the measurement, but its not as accurate and if you are off the shim requirement could change somewhat.
It shouldn't be that hard to figure out as I don't know how to use one yet. Is there a certain way it has to be set up?
You use the stand and then pre-compress the dial indicator so the dial spins about 8 times (0.800") since the valve movement will decompress the dial indicator. Then rotate the dial so the needle will be at zero. Install your rockers without a shim and rotate the one you are checking back so the roller is in the air, mark the valve stem with a Sharpie, wait about 15 seconds, then gently put the rocker down in contact with the valve stem and rotate the rocker with your hand through your cam lift several times. Remove the rockers and check the wipe. Its actually very easy but very few people seem to check this.
I'll be getting a pushrod checker too for when I put the heads on. Also, I'm just suppose to do this on just one intake and exhaust valve right?
Yes, unless someone has messed up the heads they will be consistent. I have another simple test I do on new heads but you don't have to worry about that.
The others will be the same as the first?
Yes, just work on cylinder #1 so access is easy.
I mean I can't have shims on some cylinders and not others...the geometry would be different.
Only other question is these check springs. Its just a regular spring from home depot right?
That will work, but they need to have a diameter large enough to fit around the valve seal.
I mean it should be a lil taller to hold but also fat enough so retainer isn't lop sided and stuff. Oh and a regular spring compressor will work since my heads aren't on right?
You mean one that looks like a "C" clamp, should work fine. Don't use the one that grabs the springs like a puller with the **** on the top. Those can cause issues with aftermarket springs if they scratch the surface.
Thanks again!
Comp cams has one that comes with the degree kit they sell. You will need a stand as well to hold it in place. The stand I use (I think made by MBC) has an 8 mm thread on the end which is perfect since it screws right into an adjacent rocker hole in the head. You can see it in the photo above.
You might be able to just use a very good metal rule to take the measurement, but its not as accurate and if you are off the shim requirement could change somewhat.
It shouldn't be that hard to figure out as I don't know how to use one yet. Is there a certain way it has to be set up?
You use the stand and then pre-compress the dial indicator so the dial spins about 8 times (0.800") since the valve movement will decompress the dial indicator. Then rotate the dial so the needle will be at zero. Install your rockers without a shim and rotate the one you are checking back so the roller is in the air, mark the valve stem with a Sharpie, wait about 15 seconds, then gently put the rocker down in contact with the valve stem and rotate the rocker with your hand through your cam lift several times. Remove the rockers and check the wipe. Its actually very easy but very few people seem to check this.
I'll be getting a pushrod checker too for when I put the heads on. Also, I'm just suppose to do this on just one intake and exhaust valve right?
Yes, unless someone has messed up the heads they will be consistent. I have another simple test I do on new heads but you don't have to worry about that.
The others will be the same as the first?
Yes, just work on cylinder #1 so access is easy.
I mean I can't have shims on some cylinders and not others...the geometry would be different.
Only other question is these check springs. Its just a regular spring from home depot right?
That will work, but they need to have a diameter large enough to fit around the valve seal.
I mean it should be a lil taller to hold but also fat enough so retainer isn't lop sided and stuff. Oh and a regular spring compressor will work since my heads aren't on right?
You mean one that looks like a "C" clamp, should work fine. Don't use the one that grabs the springs like a puller with the **** on the top. Those can cause issues with aftermarket springs if they scratch the surface.
Thanks again!
03-20-2008, 11:44 PM
#39
I spent some time today before dinner working on this stuff. I bought a cheap dial indicator which looks exactly like the comp one minus the logo! I got it mounted on another thing I designed/welded so its pretty easy to use now. Secondly, I bought a large C-clamp and made my own valve spring compressor. It involved some cutting and welding, but its really trick. Oh, and I found some perfect springs at Home Depot with about 24lbs of force.
BUT, I do have a lil problem! I understand how the dial gauge works now. I set it to .612 and I put it right on the tip of the valve stem and compressed the valve/spring with my hand, but it stopped at .165 because thats as far as the valve will go down. I was just messing around because I was done for the evening, but i'm pretty sure that thats not the right spot to measure from. I realize the rocker arm is going to be there so it wasn't the right spot anyways. From the looks of your picture, it is setup on the retainer? That would be no different of a reading that what I was getting though...I tried that too. Where is is suppose to go? Or what am I doing wrong? Is it suppose to be lobe lift? Thats .360/.362 for me which work.
I just thought of this too. Odds are the shims I got with the YT rockers are not going to be ideal. Basically the only way to tell is to get an assortment of shims right? In that case, i'll have to order the kit from that McMaster-Carr to find the right one, then order again the right ones.
BUT, I do have a lil problem! I understand how the dial gauge works now. I set it to .612 and I put it right on the tip of the valve stem and compressed the valve/spring with my hand, but it stopped at .165 because thats as far as the valve will go down. I was just messing around because I was done for the evening, but i'm pretty sure that thats not the right spot to measure from. I realize the rocker arm is going to be there so it wasn't the right spot anyways. From the looks of your picture, it is setup on the retainer? That would be no different of a reading that what I was getting though...I tried that too. Where is is suppose to go? Or what am I doing wrong? Is it suppose to be lobe lift? Thats .360/.362 for me which work.
I just thought of this too. Odds are the shims I got with the YT rockers are not going to be ideal. Basically the only way to tell is to get an assortment of shims right? In that case, i'll have to order the kit from that McMaster-Carr to find the right one, then order again the right ones.
Last edited by HotWhipT/A; 03-21-2008 at 12:08 AM. Reason: One more thing!
03-21-2008, 05:42 AM
#40
You will need to put the dial indicator on the retainer, out of the way of the rocker. If you have the head sitting on the workbench, you need to set it up on some 2X4's or something. Note in my photo above I have the head on a set of 2X4's that I covered with a soft sheet so the gasket surface wouldn't get scratched. You're getting there, can't wait to see what you get for a wipe pattern. 