[Murf'sDad]

Originally Posted by DiamondJim

I am bringing this back up because I am a little confused. I have a Comp XR288HR and Endur-x solid lifters. .006 lash, is that at the lobe? With 1.65 rockers would I set lash at .0.010 (1.65 x .006) ? Thanks -Jim

Jim, lash is measured at the rocker arm/valve stem. Lash it at .006" cold, at that point. You can vary from .006" - .010" depending on what your engine likes.

Stewart

[DiamondJim]

Well...., I know that most cam cards list lash at the valve with 1.5 rockers, you would need to add 10% with 1.65's. For example, Harold Brookshire suggested I use .018 with 1.5's and the UD solid, I run .020 with 1.65's. Also there is such a thing as "lobe lash" which confuses the matter even more(to my small brain-LOL). So... do you think .006 at the top of the valve stem would be correct with 1.65 rockers? I am thinking maybe ..007? Does it matter? Is there a range for tight lashing solids on a HR? Cliff, you out there? Thanks -Jim

[ponjohn]

Is there any way to view the actual profile of the lobe?

Meaning, the 050 is being shown with a hyd roller lifter. What are the real specs with the solid?

[Murf'sDad]

Jim:

If you want to take it to .007" or .008" go ahead, no harm, no foul. I've never heard of varying the lash because of the rocker ratio though.

Stewart

[Murf'sDad]

Originally Posted by ponjohn

Is there any way to view the actual profile of the lobe?

Meaning, the 050 is being shown with a hyd roller lifter. What are the real specs with the solid?

Yes there is a way. You just attach a degree wheel to the crank and plot the lobe's profile, just like degreeing a cam. Other than that it would be purely spec. Using the solid rollers on a hydraulic profile will loose you some duration but the HR doesn't have the milder ramps of the solid profile so it lifts quicker. That's why it is lashed tight.

Stewart

[DiamondJim]

Originally Posted by Murf'sDad

Jim:

If you want to take it to .007" or .008" go ahead, no harm, no foul. I've never heard of varying the lash because of the rocker ratio though.

Stewart

My thoughts are the space is most important between the cam lobe and the lifter (lobe lash). To make this space the same when measured between 1.5 and 1.65 rockers, 10 percent should be added when measured at the top of valve stem? -Jim

[440GP69]

I degree My cams with sollid lifters regardless, I also use light checking springs instead, don't forget to check piston to valve clearance. .006 lash is ok with 1.65 rockers, .010 is as loose as you want to run it, The more i look at running a sollid roller on a hyd roller I don't like it, No lash ramp and a Very small lash window to stay in, I know Myself and I'd be checking all the time to make sure its not loosening up I guess the proof will be a real street/strip car and lots of Miles, I know there are cars running them But i think for the majority Hyd roller is plenty fine for anything 10's and slower JMO, The Comp Xtreme Street Sollid Rollers are good cams, The XR292R in Cutrones 69 GP is awesome gring for 455's

[ponjohn]

Originally Posted by Murf'sDad

Yes there is a way. You just attach a degree wheel to the crank and plot the lobe's profile, just like degreeing a cam. Other than that it would be purely spec. Using the solid rollers on a hydraulic profile will loose you some duration but the HR doesn't have the milder ramps of the solid profile so it lifts quicker. That's why it is lashed tight.

Stewart

I guess that is my point, you have no real idea of the cam you are getting by not using it with the proper lifter. Of course until after you buy it.

[Murf'sDad]

Originally Posted by ponjohn

I guess that is my point, you have no real idea of the cam you are getting by not using it with the proper lifter. Of course until after you buy it.

John: Remember that my cam is a custom UD grind and because I it is all of the various parameters of the engine and usage were discussed with Tim Goolsby prior to finalizing which lobes ground where would be the best. This included the fact that the cam would be run with tight-lashed solid rollers. I know what I'm getting.

Stewart

[Murf'sDad]

Originally Posted by 440GP69

I degree My cams with sollid lifters regardless, I also use light checking springs instead, don't forget to check piston to valve clearance. .006 lash is ok with 1.65 rockers, .010 is as loose as you want to run it, The more i look at running a sollid roller on a hyd roller I don't like it, No lash ramp and a Very small lash window to stay in, I know Myself and I'd be checking all the time to make sure its not loosening up I guess the proof will be a real street/strip car and lots of Miles, I know there are cars running them But i think for the majority Hyd roller is plenty fine for anything 10's and slower JMO, The Comp Xtreme Street Sollid Rollers are good cams, The XR292R in Cutrones 69 GP is awesome gring for 455's

The lack of lash ramps is one of the reasons to do this. The valves open more quickly. As to why you would need to recheck the lash all the time I don't understand. If you are using good polylocks there shouldn't be any need to do more than a cursory check to make sure all is well after you had run the motor for a while. After that I'll only be checking the lash seasonally.

Stewart

[Murf'sDad]

Originally Posted by DiamondJim

My thoughts are the space is most important between the cam lobe and the lifter (lobe lash). To make this space the same when measured between 1.5 and 1.65 rockers, 10 percent should be added when measured at the top of valve stem? -Jim

Lash is an absolute. You set it to where you want it. Varying it because of rocker ratio isn't necessary. The recommended lash is the space necessary for hot/cold clearance. That will not change because of the rocker ratio.

Stewart

[ponjohn]

Originally Posted by Murf'sDad

John: Remember that my cam is a custom UD grind and because I it is all of the various parameters of the engine and usage were discussed with Tim Goolsby prior to finalizing which lobes ground where would be the best. This included the fact that the cam would be run with tight-lashed solid rollers. I know what I'm getting.

Stewart

I am not throwing darts here, just trying to undertand how the (not specifically yours) is being spec'd with different components.

Why go through all this when you can specify fast ramp action (different lobe profiles MSP-UD, RT, etc -comp) in a solid profile?

[Murf'sDad]

Originally Posted by ponjohn

I am not throwing darts here, just trying to undertand how the (not specifically yours) is being spec'd with different components.

Why go through all this when you can specify fast ramp action (different lobe profiles MSP-UD, RT, etc -comp) in a solid profile?

I wanted a UD cam because of the asymmetrical lobes which are quieter and easier on the valve train. Some of the comp hydraulic roller grinds are noisier than solid FT grinds, so I've been told and read here.

As to how it is spec'ed, I guess you'd have to talk to Tim Goolsby at Bullet Cams.

Stewart

[ponjohn]

Stewart-

I agree on the asymmetric lobes being easier on components.

[Steve C.]

Stewarts Ultradyne hydraulic roller could be lobes HR14 and HR15 but that's a guess based on their website information or it's close to these. The specs on these lobes are:
284/292 rated at .006" tappet lift, 230/238 at .050, 152/158 at .200 and both have .3533" lobe lift or 0.529" lift with 1.5 rockers before his proposed 0.006" lash. When your dealing with such a small amount of duration it's hard to find the same or something similar in a SOLID roller profile, example the Comp RT series mentioned, which are also asymmetrical lobes, doesn't even start untill 244 degrees at .050 lift. The Comp Xtreme Energy Street solid roller, again with assymmetrical lobes, is available with the same 230 degrees of duration. It has 153 degrees duration at .200" lift and a larger .3680" lobe lift, or .552" lift with 1.5 rockers before lash. But remember when evaluationg the differance the XE solid roller will have 0.014" (or 0.016") lash compared to his proposed .006" lash. And since the lash shortens the actual duration I suspect he is counting on it being slightly more aggressive off the seat and up toward .200" lift, but this is just a guess. And then there is the fact that the XE lobe would net about 0.538" lift verses his 0.523" lift. I wonder which one would have more area under the curve ?

[DiamondJim]

Originally Posted by Murf'sDad

Lash is an absolute. You set it to where you want it. Varying it because of rocker ratio isn't necessary. The recommended lash is the space necessary for hot/cold clearance. That will not change because of the rocker ratio.

Stewart

Stewart, I understand what you are saying but the amount of space(at the lobe) does change between 1.5 and 1.65 rockers. If you set lash at .006 on to top of the valve stem using a 1.5 rocker, to get the same space between the cam lobe and lifter you would have to add 10 percent if using a 1.65 rocker. Basically with a 1.5 rocker you would have .004 space between the cam lobe and lifter if you set lash at .006, if using a 1.65 rocker to get the .004 space you would set the lash at .0072. Hope this makes sense. -Jim

[Murf'sDad]

Originally Posted by DiamondJim

Stewart, I understand what you are saying but the amount of space(at the lobe) does change between 1.5 and 1.65 rockers. If you set lash at .006 on to top of the valve stem using a 1.5 rocker, to get the same space between the cam lobe and lifter you would have to add 10 percent if using a 1.65 rocker. Basically with a 1.5 rocker you would have .004 space between the cam lobe and lifter if you set lash at .006, if using a 1.65 rocker to get the .004 space you would set the lash at .0072. Hope this makes sense. -Jim

It makes sense when you think of the cam lobe/lifter interface but I've never thought of lash in these terms. Plus this is the first time I've even heard it spoken of as a consideration, so you can see my point.

Stewart

[Murf'sDad]

Originally Posted by Steve C.

Stewarts Ultradyne hydraulic roller could be lobes HR14 and HR15 but that's a guess based on their website information or it's close to these. The specs on these lobes are:
284/292 rated at .006" tappet lift, 230/238 at .050, 152/158 at .200 and both have .3533" lobe lift or 0.529" lift with 1.5 rockers before his proposed 0.006" lash. When your dealing with such a small amount of duration it's hard to find the same or something similar in a SOLID roller profile, example the Comp RT series mentioned, which are also asymmetrical lobes, doesn't even start untill 244 degrees at .050 lift. The Comp Xtreme Energy Street solid roller, again with assymmetrical lobes, is available with the same 230 degrees of duration. It has 153 degrees duration at .200" lift and a larger .3680" lobe lift, or .552" lift with 1.5 rockers before lash. But remember when evaluationg the differance the XE solid roller will have 0.014" (or 0.016") lash compared to his proposed .006" lash. And since the lash shortens the actual duration I suspect he is counting on it being slightly more aggressive off the seat and up toward .200" lift, but this is just a guess. And then there is the fact that the XE lobe would net about 0.538" lift verses his 0.523" lift. I wonder which one would have more area under the curve ?

Hi Steve:

I didn't want to go to a solid roller profile. For my purposes SR profiles start at "too big" for my engine, given the stated purpose of the build is a broad, flat torque curve with power to pull well to a 6K shift point. Plus I didn't want to have to use 650#+ springs. I could have gone with hydraulic rollers but I was intrigues by the thread on solid rollered HR grinds. I figured I would try it, save some $$ and weight (I know, probably not relevant) on the lifters and see if it would give me what I wanted better than other options. After talking all this over with Tim he said this cam, using the HR14 and HR15 lobes and the 106 ICL and 110 LSA, would fit my wants/needs very well. Our discussions were fairly lengthy and detailed.

There may be better cams out there but this one fits what I need as well as what I want and I've always wanted to build a Pontiac engine with a custom UltraDyne roller cam. Go figure! Plus it's different to do it this way.

Stewart

[Steve C.]

Stewart, it all sounds fine I'm sure you will be pleased. But for conversation there is little differance between the UD 230 hyd roller lobe and a Comp XE 230 solid roller lobe, as noted they are about the same. Again we are talking about a small roller cam. And with some thought the XE lobe could probably be run with similar spring pressure. I suggest the differance in your 175 lb seat pressure and 180-190 or so lbs. seat pressure is mute. And any differance in "noise" between the two cams, again probably a mute point to most.

[tom s]

when going to solid roller lifters it is much better to err on the high side of spring pressure.It seems that roller lifter failure can be pointed to lifter bounce or float.That might be the reason Comp had me run 200 on the seat with my 400 lobe lift HR cam and solid roller lifters.Tom