Solid Roller vs. Hyd. Roller - Pros/Cons?

[Excaliber]

Modern 'rollers', be they hydraulic or solid can be made to rev high and live! Hydraulic rollers can push the 7000 rpm range these days. Solid roller lifters, in certain blocks not all, can be force fed oil pressure to make them 'live long'. Lack of oiling on a street driven (lower rpm for much of the time) has been the killer of solid roller bearings. With the new pressure oil feed, thats no longer an issue. High tech hydraulic rollers can see some lofty rpms these days.

BUTT, there is a significant cost to either approach, this is NOT a cheap solution. Even standard roller hydraulic lifters cost considerably more than a flat tappet combination. Valve springs, rockers and push rods will still need to be matched for the cam/lift/geometry no matter which one you choose.

When I was rebuilding my motor I considered all the various factors and went with flat tappet at a max rpm of around 6400. Number one, I didn't want to rev the engine much higher than that for longevity reasons. The higher you rev, the shorter the life of the motor, period! Number two I wanted to control costs, which can VERY quickly spiral out of control when your building a motor. You find yourself in a trap like. Well, it's 'only' a few bucks more to do this or that. Those 'few bucks more' add up to a substantial number when the smoke has cleared! Spend your money wisely. I chose to spend big bucks on the pistons, for instance. Cost/benefit analysis, in my case, showed that was where the money needed to go.

A flat tappet cam would do a fine job for my projected horse power and combination street driving and some track use. The price difference sealed the deal. I get all the performance I want at a nice price. Flat tappets can cost more if your having the motor built for you because of the extra work involved initially 'breaking in the cam'. That extra cost MAY make it advisable to go with a roller because the cost of the parts may be offset by the cost of the labor to properly setup a flat tappet. I built my motor myself, labor was not an issue. I work for 37 cents an hour...

Labor costs and risk management are the PRIMARY reason professional engine builders recommend a hydraulic cam. Thats the PRIMARY reason. It is then justified by pointing out the 'performance' enhancements, high rev potential, blah blah blah. But don't forget the PRIMARY reason, it's easier for them to build, warranty and the parts profit level is better!

Proper breakin and careful oil selection will gaurentee a long life for a flat tappet cam, as long as the engine itself holds together.

[patrickt]

Originally Posted by Excaliber

Labor costs and risk management are the PRIMARY reason professional engine builders recommend a hydraulic cam. Thats the PRIMARY reason. It is then justified by pointing out the 'performance' enhancements, high rev potential, blah blah blah. But don't forget the PRIMARY reason, it's easier for them to build, warranty and the parts profit level is better!.

Excalibur is right on the money -- breaking in a solid lifter cam takes extra work and is a little risky. Breaking in a roller is easy. On the street though you're not going to notice any performance difference between a solid roller and a solid flat. So, if you elect to go with the solid roller be careful about restricting the lifter galleys as you do with a solid flat tappet. Low FE oil pressures and street idling can limit the life of the solid roller. I believe the problem of a few years ago with the cheap foreign lifters has now passed us by, but perhaps Barry R. could chime in on that. Other than the break-in issue, there is no real benefit on a street machine to going with a solid roller over a solid flat and, with the solid roller, you still have the specter of limited life. Makes it all simple, huh?

[Chaplin]

Originally Posted by patrickt

Excalibur is right on the money -- breaking in a solid lifter cam takes extra work and is a little risky. Breaking in a roller is easy. On the street though you're not going to notice any performance difference between a solid roller and a solid flat. So, if you elect to go with the solid roller be careful about restricting the lifter galleys as you do with a solid flat tappet. Low FE oil pressures and street idling can limit the life of the solid roller. I believe the problem of a few years ago with the cheap foreign lifters has now passed us by, but perhaps Barry R. could chime in on that. Other than the break-in issue, there is no real benefit on a street machine to going with a solid roller over a solid flat and, with the solid roller, you still have the specter of limited life. Makes it all simple, huh?

I don't know if I agree with that. Because of the cam lobe profiles of a roller cam are much more aggressive and open and close the valves faster (whether solid or hyd roller) than a flat tappet cam, you will get better performance from a roller than you will from a flat tappet cam with similar or even slightly greater duration. The aggressive lobe shape of the roller cam effectively opens and closes the valves faster (as compared to a flat tappet cam) which allows the valves to stay open longer, thereby creating more "area under the curve" which provides the cylinders more time to fill at any given duration as compared to a flat tappet cam with the same duration. Or put another way, you can run a smaller duration roller cam (which means better throttle response and better idle quality, i.e., more streetable) but still have as much if not more power than you could get out of a flat tappet cam of the same duration or even slightly larger duration.

IMO, hyd roller is the way to go for a street cruiser. You eliminate the break-in problems associated with flat tappets, don't have to worry about roller bearings in solid rollers, and because of the cam lobe profiles, can run a smaller cam with better street manners without sacrificing performance of a larger flat tappet. Needless to say, I am having one installed in my motor as we speak.

[patrickt]

Originally Posted by Chaplin

I don't know if I agree with that. . .IMO, hyd roller is the way to go for a street cruiser. You eliminate the break-in problems associated with flat tappets, don't have to worry about roller bearings in solid rollers, and because of the cam lobe profiles, can run a smaller cam with better street manners without sacrificing performance of a larger flat tappet. Needless to say, I am having one installed in my motor as we speak.

All very valid points, and difficult to argue against. BUT, there is something to be said for the sound of a solid, flat tappet cam in an FE. I've never heard a hydraulic that came close to it. On the other hand, that sound doesn't mean much to a lot of people (and I've even on occasion had someone ask "Is your engine supposed to sound like that?")

[Chaplin]

Originally Posted by patrickt

All very valid points, and difficult to argue against. BUT, there is something to be said for the sound of a solid, flat tappet cam in an FE. I've never heard a hydraulic that came close to it. On the other hand, that sound doesn't mean much to a lot of people (and I've even on occasion had someone ask "Is your engine supposed to sound like that?")

True, there is no disputing that solid flat tappets sound great!

And I think you need a bigger wrench!

[hi-tech cobra]

Great info guys! Thank you.

Here is the cam (solid roller cam) I'm looking at. How does it look?
Duration Is 259* intake and 269* exhaust at .050. The total lift is .640

undy, Crane said their solid rollers don't have a problem like you mentioned. Do you have any experience with the Crane solid rollers?

Excaliber, do you know if the Pond block allow for the increased oil pressure needed for the solid rollers?

Will the stock Edelbrock FE alum heads work with the solid rollers or will I need to upgrade springs?

bobcowan, I know what you mean about getting accurate info for dist. gears. I got 20 different opinions from MSD and Comp Cams for my sbf roller cam...depending on the day.

Are there other distributors other than MSD that offer plug and play with the MSD 6AL? I ask because my wiring is already installed.

[undy]

Originally Posted by hi-tech cobra

Great info guys! Thank you.

Here is the cam (solid roller cam) I'm looking at. How does it look?
Duration Is 259* intake and 269* exhaust at .050. The total lift is .640

undy, Crane said their solid rollers don't have a problem like you mentioned. Do you have any experience with the Crane solid rollers?

Excaliber, do you know if the Pond block allow for the increased oil pressure needed for the solid rollers?

Will the stock Edelbrock FE alum heads work with the solid rollers or will I need to upgrade springs?

bobcowan, I know what you mean about getting accurate info for dist. gears. I got 20 different opinions from MSD and Comp Cams for my sbf roller cam...depending on the day.

Are there other distributors other than MSD that offer plug and play with the MSD 6AL? I ask because my wiring is already installed.

The cam is not very radical, for a solid roller. Peak power probably will be around 7K, +/-.

You need to talk to Barry R (survival motorsport) or Keith Craft on what's required, if anything, to modify the Pond block to work with a solid roller. I am still not understanding why you're hung on a solid roller.

Buy the Ebok heads bare and build them to your cam/engine's specs. The assembled ones come with 2.09 intakes (too small for a 427 up) and springs suited for a flat tappet up to .600 lift.

Check what your cam mfr recommends for the distributor gear. MSD makes a ditributer "roller" gear for my hydraulic roller application. Some roller cam mfrs are making their distributor drive gears (on the cam) a little more distributor gear friendly.

[patrickt]

Originally Posted by undy

I am still not understanding why you're hung on a solid roller.

I'm wondering the same thing. Are you going to track/race this car? Or will it be overwhelmingly a street car? Almost any cam that you put in a freshly built FE is going to get you well over 400HP. But if your car is going to be predominantly a street car you might want to pick a cam that has some manners around town (forgetting altogether whether it be solid/hydraulic/roller/flat). Regardless of what anyone says on this board, pretty much anything over around 450HP is wasted on the street and can actually detract from the overall enjoyment of a street Cobra.

[Tom Wells]

hitech,

I bought my hydraulic roller setup, springs, distributor gear and all from Crane. More than 20K street + race track miles later, no regrets! I use the MSD 6AL & distributor. MSD installed the Crane gear for me. Buying the distributor gear from the cam mfr at the same time as the cam eliminates any guesswork...

Dunno whether there's any significant reliability difference between the 385 & the FE, sorta doubt it. The FE should do fine with either lifter - note comment below.

Springs need to match the cam, rockers and lifters too. Don't guess, ask Crane!

If you can replace solid roller lifters every 3-5K miles as a regular maintenance item, go for it. Otherwise I'd suggest the hydraulics.

Tom