Theoretical question. Hydralic roller vs solid roller

Theoretically you loose zero.

The problem with hydraulics is that you never get 100% of the lift because it is the oil pressure that provides the resistance to the lifter.
The more pressure you have the more efficient the lifter is. It is never 100%.

Solid lifters in a Boss head aren't hard to maintaine at all. It is the Chevy solid lifters that have given solids a bad name.

Roller lifters theoretically give you more area under the curve because the lobe can be cut closer to the optimum ramp angle for faster valve opening.

That inturn maximizes the port velocity and effects mostly more torque, but a couple of hp too.

Roller lifters are in current production engines for fuel efficentcy and emmissions (remember the zinc you need for lifters that the cats don't like).

There is no performance reason to add roller lifters to an engine that will only see 6000rpms on an non-emmsissions engine. It's a waiste of money.

The answer to the question is how efficient your hydraulic lifters are. Are they 98% efficieint? What's 98% of 600hp? 588hp.

You lost 12hp because of hydraulics.

Keep in mind that the roller lifter assembly is heavier then a normal lifter. To compensate for that you need to add spring pressure.

The spring pressure pushes back on the hydraulic lifter and you get less lift then normal. How much? Who cares?

Thank you Doug. But isn't the valve spring rate determined by the valve weight? It is the valve that has to be pushed back by the valve spring, so if you use lighter valves, you should be able to use lighter springs. That would make a more durable engine.

Sure, titanium valves and retainers would be the way to go.
Light valves aren't going to make the hydraulic lifter 100% efficient though. There will still be a loss.

If you go to roller lifters you are adding far more weight to the valvetrain then you would be eliminating in the titanium valves. Those assemblies are heavy and not known to be reliable for high reving engines for long durabilaty cycles. They break a lot. They are certainly not low maintanence items.

With roller lifters the valve springs need to replaced more often and the higher spring rate beats up on the valve train more.

There is more potential for catastrofic valve train failure with roller lifters.

You need rocker arm stud girdles and even then you can snap rocker arm studs. I can testify first hand on all of these points.

Last but not least titanium components also tend to be a little pricey.

On the plus side I suppose it sounds cool to say you have a roller lifter cam?

Wait a minute Doug. You have shown me the light and now I know what to do. I will just go ahead and buy the titanium valves, because Dan Jones is giving me a sweet deal I can't pass up, and leave the regular cam in there and just go light valve springs. SUre i won't make much HP, but I will make up for it in higher revs. I figure a 7500 Redline. That way I can make almost all the power back.
Thanks Doug!! I love ya man!!

Kiss, kiss, hug, hug...who luvs ya' baby?

I am only partly kidding Doug. You are the only one I can count on to answer my questions. I know to other people my questions may seem dumb, but I can always count on you to at least try to answer.
I have put a new engine in a few years back and I saved the CC heads off theold engine hopeing to get some of my lost horsepower back by putting them on the new engine, someday. Well they have those hand grenade valves in them so I have to get new valves anyway. So since I am getting new valves I may as well get really good and light ones so I can rev the engine a little higher since just putting the heads on is only a eight horsepower increase. I know I lost way more than eight, I can tell by the feal, So if I can get a few more ponies via high revs, well maybe it will be good enough.

You can probably gain 200 to 250 hp with a simple,cheap engine.
If the cam is a hydraulic lifter CJ type it isn't going to rev over 6,500 no matter how light the valve train is.

All you need to make 450-500hp is a stock short block with flat top pistons, a set of ported 2v closed chamber Australian iron heads (cheap), and an aggressive, rumpity, rumpity hydraulic lifter cam with the right springs.

You can probably use your stock short block, even if it has dished pistons, spend $2,500 and be over 450hp.

You will be happier and live longer if you do it. Why wait?

quote:

Originally posted by PanteraDoug:
You can probably gain 200 to 250 hp with a simple,cheap engine.
If the cam is a hydraulic lifter CJ type it isn't going to rev over 6,500 no matter how light the valve train is.

All you need to make 450-500hp is a stock short block with flat top pistons, a set of ported 2v closed chamber Australian iron heads (cheap), and an aggressive, rumpity, rumpity hydraulic lifter cam with the right springs.

You can probably use your stock short block, even if it has dished pistons, spend $2,500 and be over 450hp.

You will be happier and live longer if you do it. Why wait?

Actualy, my goal is to be just under 400 horsepower and use premium pump gas. I already have the 4v closed chamber heads and I was wanting to put them on my new engine. So if I get a hotter flat tappet hydralic cam, my Closed chamber heads with light valves, correct spring for the applicatio, keep the dished pitons, would I get close???

Easaly 400hp. You might want to consider a small port inkake manifold with that setup. Something like the Edelbrock 2v ports with 4v carb.
You can get them cheap used on ebay.
You can use just about any carb you want with that set up and get 450hp. Even a 600 Holley.
Expect it to run out of oats by 6500 though.

Thanks again Doug. My car came with a 650 Holley double with mechanical secondaries and I have an edlebrock performer, which I believe is a duel plane. That should let me get away with quite a bit of overlap on the cam. But I will have no vacuum, which is why I have been asking around about hydraulic assit power brakes.
I love the lumpa-lumpa sound of a big cam. I just want the brakes to work too.