Did anyone read the piece in the new Hot Rod issue about using solid roller lifters on a hydraulic roller cam? A while back I considered this and called Comp. The *tech* on the phone advised against it, stating dissimiliar metals and/or hardness would wear out the cam or roller. I didnt really buy it, as the roller is supposed to roll, right?

Now here in the new Hot Rod, theyre saying you can use a solid roller lifter on a hydraulic roller cam. Theyre even saying solid flat tappet on a hydraulic flat tappet cam is OK too.

Obviously the use of a solid type lifter would have to be lashed appropriately, and some lift and duration would be lost, but who is right?? Has anyone here tried this?

 

Can't say I have done it. Heard of it, not sure I would recommend it.

When you think about it, there is really nothing "special" about solid cams vs hydraulic and flat tappet. This is a statement I use loosely. But in the sense that using a solid roller vs a flat tappet, the roller should be much less "wear" and tear on the cam than the flat tappet with no roller at all.

Now, I have to say this and this is what I think it boils down to. Why would you want to use a roller on a hydraulic cam. Sure you eliminate any bleeding of the lifter that may be a cause of concern at high RPMs. But the real crux of it is you usually move a solid type cam to take advantages of the characteristics that come with a solid cam. These include more aggressive ramp rates, slow rates and lift. These are all things that say a hydraulic or flat tappet cam would have trouble handling.

My final point is, is you want to run a solid cam, then why not just go the couple extra bucks and get a solid cam also and get all the advantages.

I would not build another performance motor and NOT use a solid roller. When proper geometry is used and components they are virtually maintance free. I have not adjusted mine in the last 4 months and I race nearly every weekend and drive the car on the street during the week when the weather is nice.

 

I haven't read THIS article, yet. Lifter format swapping has been around for decades, yet the cam grinders continue to grind both solid and hydraulic cams. If mixing components were such a great idea don't you think the manufacturers would jump on the band wagon and reduce the quantity of part numbers they produce and have to inventory?

RACE ON!!!

 

I have to say this also. Its always best to stay with tried and true combinations. To me mixing and matching is going out on a limb. Should there be a failure, you are going to loose much in the mistake. Its tough enough building a GOOD solid combo, and I advise you have your ducks in a row if you opt to go this route.....

 

I was interested in this for reasons that the article talked about; They said that the RPM range is extended by using the solid roller lifter on a hydraulic roller cam. The cam will act smaller, but the range is extended. I wouldnt purposely build a motor with a hyd. roller rcam and solid roller lifters, but I would consider swapping in the lifters if I thought it would help the combo. Hot Rod also said the hydraulic ramps are more aggressive on cams under 240 @.050, and some hyd. grinds can be more forgiving on valvetrain parts, so there may be some benefits to using alternate grinds. Like I said, I wouldnt purposely build an engine this way, but I am interested in the compatability just in case the situation ever arises that I want or need to try it.

I just found it odd that I proposed this same thing and Comp said "no", now Hot Rod says its OK, and has a reference to Comp Cams at the end of the article. I just wonder if the metals are compatable like Hot Rod says (and I thought) or if they are not compatable like Comp originally told me.

 

What month/year Hot Rod was this in?

 

THey may physically work as in the motor runs, but I wouldn't do it. Why not use the proper parts as they were intended to ? I like Hot Rod magazine too, but somewhere out there some 18 yr. old kid is throwing some stock GM HR lifters in a motor with his buddie's inverted ramp SR cam ....But it said in Hot Rod".....

 

I believe they use differnt cores for the Solid roller cams. I think that they use a differnt hardening process but that is just a guess on the solid roller sticks then the Hyd. Roller version. I know if I called the cam manufaturer and they advised me against it I would probably stay far away from it unless I had proof positive that 40,000 miles from now it would not have caused a problem. There is a big difference between running a combo for a drag motor that will be torn down after 2-3 years max and a daily driver street rod you will hopefully see 100K + out of. JMHO, if you want a solid roller and then be safe and get a SR cam.

 

Just remember that when you use the solids you have to set the lash, no big deal, but the lash will leave slack in the valve train and that will probably beat the hyd cam to death if they are not made out of the same billet steel.

 

For the most part this is true about different cores. If you have a off the shelf Comp Cams hydraulic roller the core is what they refer to as an AUSTEMPERED core. This core is a cast iron core undergoes a specifice heat and hardening treatment for roller lifter compatibility. If you have one of these cores I would NOT recommend trying to use a solid lifter on it. However if you have a Crane cam, then their 8620 billet cam cores are the same cores they use for their solid roller cams. Erson also uses the same Crane cores as does Lunati. I would feel safe using a solid on these cores. Comp also has a steel billet core as well but I am not aware of the alloy that they use. GM's stock roller cams are what is referred as a induction hardened core, these are different than the 8620 cores and I would not attempt to use a solid on these either, but then why would one even bother on a stock cam

 

Curveit- Its in the newest issue, with power tour coverage. I have a subscription and I just got it a few days ago. It may not be on the stands yet I dont know.

TJWong- Thanks for the answer, that was just what I was looking for.

To all who have replied, Im not going to do this, but it was something I considered a while back. I was just wondering who was actually right- the "tech" or Hot Rod. I really dont have much faith in either thats why I posted the question here, hoping to get a truly intelligent answer as to why you can or cant. Its just one of those questions thats been sitting in the back of my mind unanswered. I wasnt really sure if a solid roller cam and a hydraulic roller cam were actually made from different metals. Sure I have seen some advertised as billet and such, but TJWong seems to have summed it up. Thanks to all!