Lets talk about roller cams for stroked big blocks!

INTMD8 · Jun 11, 2022

Kern Dog said:
I do wonder though.....why wouldn't the cam grinder just make a milder version of the solid cam?

That's basically what I have. Cam Motion low lash solid roller.

68 HEMI GTS · Jun 11, 2022

Any good cam company can grind you a tight lash solid roller for street use. Running the solids on a HR cam is more of a I have the parts and I’m hell bent On running them thing. At least the times I’ve seen it done. I’ve ran a ton of the comp tight lash street rollers in big blocks, they’ve worked well. I put the biggest xtream energy in a buddies 440 street car. It’s been 11.40’s, runs on pump gas, and he drives it everywhere. I have a bullet that I had ground about 10 years ago that we ran in a different motor. I may try that in my roadrunner when I freshen up the 511. 270/270 .650 on 110. It’s a tighter lash “street” cam. The PRH solid flat tappet has treated me well though on the current combo.

I did run a hydraulic roller in a 440 for a bit with the old crane HR lifters. I was having an issue with the six pack (that I didn’t realize, (pin hole in the vacuum tee)) at the time. There were times it flat screamed, other days it just felt slow (guess it would be when the out boards don’t open). I thought it was cam related so I swapped in an old MP .557. When it did the same thing and we figured out the outboards were acting up I realized the HR may have been a solid performer had I left it in. The mopar cam ended up loosing 2 lobes after about 2 years. I did run mid 11’s though with that old .557.

Dodge Bros · Jun 12, 2022

Just for a little comparison and discussion about lash and SR cam design. Rev kits use to be used to help make roller lifters last longer. Some said it would double the life of the lifters. It helped because it kept the lifter against the profile all the time and didn’t skip around. The tight lash profiles try to do the same thing, maybe not as effective, but don’t have any parasitic losses rev kits can have. It can limit the bouncing of the lifter.

BUT, the tight lash solids are nearly always designed that way to accelerate the lifter longer for more curtain area, they gain endurance from the tight lash, then loose some endurance since they are ground more aggressive. Compcams entreme energy SR’s fit in that category. Tight lash range .014”-.018”. But it is more of a pro street profile and still takes some diligence being on top of regular maintenance, especially on the bigger durations that are up toward .6” lift. They aren’t a bad choice though on the street, but are more what I would call pro street. I think cam motion offers some SR profiles somewhat similar.

Some SR designs, such as for example a Bullet/Ultradyne .4176” lobe, are large design lash profiles, (1.5 rocker .026” is the design lash), but have a pretty large lash window. They can be set as tight as .018” instead of base advertised lash of .026”, and are easier on the valve terrain than the comp extreme energy HR grind. With bushed lifters on the street that can take a lot of abuse I think your better of with the longer lash ramp design that is a little easier on valve terrain parts. With bushed lifters I would want to pick between that those two examples, but I think I would rather use the Ultradyne for more street driving. It is a little easier on parts, then for the street run on the tight side of the lash to limit the lifter bounce. The old comp High energy SR profiles are similar, and are easy on parts. If your not going to drive the car much, and are more pro street, go with the tight lash more aggressive grind like the comp extreme solid.

For the street with needle bearing lifters the gentle tight lash profile are not all that easy to find. Sure they could grind a cam that is both tight lash and gentle, but they are generally all fairly aggressive. You can pretty much use any solid roller lifter on a hydrualic roller profile and make it work. But that doesn’t necessarily make it a good combination of parts. An example would be a XFI extreme energy HR comp profile will work with solids, but about have to be zero lashed or they will make a racket. The HR profile we used Tim at Bullet didn’t really even call it a HR profile, even though that is what it actually is. It has a design lash of .010”, but can go as HIGH as .014” (for a while any way, for say tuning) and as tight as zero. It has as large of lash range as a lot of solid profile designs. It is a .3823” lift profile, it would take 1.6 rockers to get it up past .6” lift if your after lift, but for the street it can be ground in increments of 2* from a little over 230* to over 260* @.050”. We run Cam Motion, Compcams, Isky and Bullet solid roller cams. All are solid roller profiles except that particular cam, which is absolutely the QUIETEST solid roller cam of those. I just did a Compcams cam hyd roller upgrade in a 5.7 Hemi, which I have been happy with so far. But it is actually a little louder that the Bullet HR with the solid rollers on it. The Hemi has .5” lift, the Bullet has .630”.

Valve lash work in ranges, depending on expansion rates, and the length of the lash ramp design. If you have ever noticed when a top fuel dragster start up it is coughly and spitting when it is cold, the smooths out after it is warmed up some. That is because the expansion is so high they set the valves so they are still open slightly when cold. When the engine warms up it smooths out becuase the expansion rate gets the lash back were it needs to be. Some guys on hybrids cams will tighten the lash until the pushrod won’t turn. But fully warm it might still have .008” lash on an aluminum head. If the expansion rate is to great the SR lifter on a HR cam will start to get up into where the cams has to much acceleration. The cam hybrid cam I have had a big operating range on the lash. It isn’t something I thru together, Tim a Bullet was the one that suggested it as the best fit for what I needed.

Geoff 2 · Jun 12, 2022

Couple of comments:
- hyd cams have lash ramps, but are shorter duration that sol lifter cams.
- Comp is one company that has hybrid lobes that can be used with hyd or sol lifters.
- I have used sol lifters on hyd lobes, no problems. Lots of people have. Trick is keep lash tight, about 0.006" hot. This is tricky with alum heads but can be done by checking lash with the engine still hot & then leaving o'night to cool down & re-checking. You now have the hot/cold difference & can set lash cold.

biomedtechguy · Jun 12, 2022

With the Bill Mitchell aluminum block and aluminum TrickFlow heads and heat expansion, well, again my builder has been there and done that, so I'm hoping that will make it easier for me to do my part.

Curiousyellow71 · Jun 12, 2022

66 Sat · Jun 13, 2022