Called Comp cam tech line to discuss higher lift 224 236 hyd variables they told me I can run hydralic lifters with my street solid roller.

Is anyone out there doing this and how did it work out.

John

 

From my experience, i wouldnt listen to comp. I asked them about a custom cam at the power tour and the guy just looked in a book and picked one, then he told me he put a hotcam in an LT1 and they had to change the pistons cause there wasnt enough piston to valve clearance.
hyd and solid cams are different, not an expert but i dont see how that would work.
-Mark

 

Theoretically, a roller cam is a roller cam... I know the solid grinds have a more aggressive ramp than the hyd grinds... But as for listening to comp, I agree. I called up and asked for them to suggest a turbo grind... he spouted off an off the shelf N/A cam but swapped the intake & exhaust durations.

 

I've heard of the opposite being done (solid lifters on a hydraulic cam) but not hydraulic lifters on a solid cam. Solid cams have "lash ramps" built into the grind and that would probably make for some very lazy valve action and increased duration way down in the very low lift range.

 

Good story about this....

Back when we were working on the Engine Masters motor we were lucky enough to talk to one of the head engineers at Comp about the valvetrain setup. One of the lobes he suggested for a HR setup was a small duration TK lobe profile. Which is a very aggressive solid roller profile, and they are very similar to the 319X series lobes.

It can be done. The issue is you need to talk to the right guys at any company to get the info you are looking for.

Bret

 

Thanks for the response, I'll call them again tomorrow.

John

 

Then it works both ways right (as long as you get the right parts to do the job) you can put solid lifters on a hyd. cam?
or am I mixed up

 

Solids on a hyd is always OK, just the other way I thought would be a prob.

John

 

Why would you? solid roller cams and hyd roller cams are a lot different.

The solid roller cam has a gentle slow ramp up lobe at the very beginning and then WAM! and opens, the slow portion is to take out the clearance so the rockers doesn't hammer the valve, so if you put a hydrolic lifter it would be a waste, why have the slow ramp in the very beginning when you are running preload? There is no point, solid rollers run with clearance between the rocker tip and valve hence needing this slow ramp and then wam! and open, with hydraulic thats a waste of durration and then when the cam opens ultra fast it might hurt the lifter with time and most likely will just cause the plunger to collapse momentarily loosing all benifit of the solid roller cam, its better to start relatively fast right away like all HYD roller cams do since there is preload.

If you use a solid lifter then you will kill the valve train because you will need to run clearance between the rocker tip and valve, with HYD cam you will slam the rocker onto the valve without the gentel ramp like the solid roller has, and then the steepness of the hyd cam after that is just slow and useless.

You can not run 0 lash well because what is zero lash on a solid lifter when cold will be clearance as the engine heats up and the heads expand away creating clearance, and if you set to 0 lash when hot, then in the morning you will be floating valves.

Hope this helps, HYD belongs with HYD and solid with solid IMO, if you need steeper go with a steep lobe on the HYD roller cam.

 

Good points, bunker, and in MOST cases that's the plan.

However, in some cases, like when one is limited to hydraulic roller (HR) lifters per class rules, and you need solid lifter profiles, which can be more aggressive than HR profiles, you might resort to running the HR on the SR profiles. Look at Comp's TK short duration profiles as Bret mentioned.

Obviously there are things you can do to a HR to make it act more like a SR. That's the rub when sanctioning bodies try to enforce HR rules.

So it CAN be done, but unless you really need it you are probably better off using HR lifters on HR profiles and SR on SR.

 

i wouldt trust comps "cam help", i told them what i want out of my car and all that good stuff, i told him i didnt want an xe cam that will drop off hard higher in the rpm's. he told me to get a 224/230, exactly what i didnt want. still dont know what cam i want to get.

 

Part of Comps Cam help is getting the right guys. The average guy off the street doesn't get the right guy or use the same guy time and time again there so it's hard to get what you want out of them.

That's why working with a dealer the specailizes in what you own is the best way to go.

Bret

 

Mechanical roller cams are built on a billet core,hyd cams are not. If you put solid on a hyd you are looking for a wore out cam,and a torn up valve train.
Unless you get a billet core ground to hyd spects to take the wear and extra spring load you are asking for trouble. Best to leave the cam and valve train choices to them that know, what is what, and all cam salesman DON'T know. Some do and when you find one you need to keep him/her.

 

What's wrong with those numbers.A224/228 on a 112* + 4* is a HELL of a cam for a 356CID LT-1 with head work and good compression.

 

Somewhere along the line you are going to have to trust someone with more knowledge than yours about a cam recommendation. If you don't like Comp's recommendations, try an engine designer. If he recommends a similar grind, as 1racerdude pointed out, and you still don't like it, you need to specify your own grind. It's a lot like having a doctor or doctors diagnose your illness, and you then telling them they are wrong. That is your choice, of course, but it may not be the best thing for you.

Some folks think they can just change the cam without changing the other valvetrain parts and achieve their goals. Often that's not the case if aggresive profiles are used. The other valvetrain parts can triple the price of a billet cam alone in some cases, but it can pay off.

Some folks who sell "custom" cams almost always use billet cores for HR. The cost is higher than a cast core, but not a lot.