Ford Muscle Cars Tech Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
116 Posts
Discussion Starter #1
What are the benefits / drawbacks of both the solid and hydraulic camshafts? In reading past posts it seems the hydraulic was better for low end power as the lifters could not keep up with the high engine RPM. It also seemed that solid cams would make more power. Is this correct? What's the benefit of the hydraulic cams?
 

·
Registered
Joined
·
1,105 Posts
All of your assumptions are correct. The nice thing with hydraulic lifters is that you adjust them, and forget about them. With solid lifters, you need to adjust them, usually every time you change your oil. They ususally require adjustment every 7k, but since you're messing around under the hood, might as well check right? Solid lifters will give you more of a mechanical sounding engine. Hydraulic's takes away the maintence that some find to be unbearable (pussies) to have to take off the valve covers (good god) and adjust them. You are able to go higher into the rpm band with solid lifters, but unless your engine is designed to operate in the higher rpms, then why do it?
 

·
Registered
Joined
·
116 Posts
Discussion Starter #3
Just to make sure I'm square on things, the difference between hydraulic and solid cam/lifter setup is entirely in the lifters? So you could run either solid or hydraulic lifters with any cam?

I never knew the maintenance with solid lifters was so intense. In my truck I haven't adjusted them for over 40,000 miles and I haven't had any trouble. Maybe I should re-torque them soon...

So lower maintenence is the only advantage of a hydraulic set up?
 

·
Premium Member
Joined
·
14,758 Posts
There's more to it than just lifters. The solid version also has different lobe ramps, require different springs, & sometimes a different installed height on the spring. As for constant adjusting, I only run the ones on my race car about 2-3 times a year, it's amazing what a stud girdle does. My 429SCJ hasn't had an adjustment in years, all you need is a good poly lock & they usually stay in place.
 

·
Premium Member
Joined
·
14,758 Posts
I've run nothing but fairly big solid lifter cams in all my race cars, now and before.
Being as I"m a 'tinkerer' at heart, I'd adjust before every race, just to cover my ass.
If there was something that was going to be off, it sure as hell wasn't going to be valve lash!
It's fun. (well, I guess ya gotta be a true gearhead to enjoy it that much)


Besides, then you've got an excuse in the middle of the week, (usually at nite), to fire up the race motor, make lots of noise, annoy the neighbors, and have an excuse. (motor's gotta be up to operating temp to adjust 'em).......
 

·
Registered
Joined
·
231 Posts
The only advantage that hyd lifter cams have over solids is quiet operation and almost zero maintanance. Often they can be used with a non adjustable valvetrain in mild applications as well. But from a power and torque producing standpoint, if you don't mind the light chatter and a bit of maintanance occasionally, solids are the way to go. A comparable solid will make more torque and power everywhere in the power band when compared to a hydraulic cam. Because the solid cam has clearance and doesn't have to start opening the valve while coming right off the base circle, the valve opening rates can be a lot faster at lower lifts. That adds lots to low and midrange torque. At high RPM lifter pump up is not a problem so they make more power there too. One of the biggest problems is finding solid profiles small enough to use in high torque, low rpm conditions. Most solid cams are basically street/strip cams with lots of duration and lift.
 

·
Registered
Joined
·
3,700 Posts
I second all of what Morgan said. I have run both in my Mach 1. Currently running "mechanical roller" in 351C 4V.

More power at any point in the power band you want to talk about (compared to hydraulic)
 

·
Registered
Joined
·
116 Posts
Discussion Starter #8
Thanks. That clears things up for me. So the hydraulic cam is a little like a sponge that compresses before actually transfering lift along the pushrod?

Do either of the cams (hyraulic or solid) have a benefit from a vaccum standpoint? Or is that more due to the duration of the cam? My car is a 68 Cougar and it has the vacuum powered headlamp covers, if possible I wanted to keep those working.

Also, is there a way to help compensate for the lack of a hydraulic cams intitial lift by changing the rocker arm ratio? It doesn't seem like it would but do you have any experience with it?

<font size=-1>[ This Message was edited by: Wildcat on 2/7/02 8:53pm ]</font>
 

·
Premium Member
Joined
·
280 Posts
I run a soild lifter cam in the comet race.we adjust before we start a weekend race. In our falcon is a hydraulic twise a year. the soild cam reacts much faster then the hydrulic.both work in there applicartion. both cars are race only but the falcon is streetable
Alan
 

·
Registered
Joined
·
749 Posts
While all the advantages of a solid flat tappet cam/lifters over the hyd flat tappet/cam mentioned above are true, in a street engine built for every day use with a mild increase and hp and torque desired, hyd flat tappet will achieve the goal easily. No reason to run a solid lifter if a hyd lifter will achieve the goal. Then there is the roller lifter which is best of all...and the hyd roller lifter being best for street engines. 300 to 500 hp street engines can easily be built around hyd flat tappet valvetrains and it make sense to do so because of simplicity and cost.
 
1 - 10 of 10 Posts
Top