Cams: solid flat tappet vs. hydro roller?

[AmericanPie]

I've been wondering why so many guys are using hydraulic roller cams these days, instead of the traditional solid flat tappet cams that were installed in muscle cars including Cobras. It's always been my understanding that, even given the extra lift available with a roller, the solid cam would give all-around better performance. (A solid roller would be another story, however.)

Im suppose the hydro roller makes more sense in a relatively low-speed stroker motor that won't see more than about 6000 rpm; but if I were sinking big bucks into an aluminum Shelby FE motor capable of revving to 7500 and wanted "the best of everything", it seems like a hydraulic cam would be compromising its performance potential. Am I missing something here?

This, of course, assumes one doesn't mind the minor inconvenience of adjusting valves every few thousand miles.

[Burnd]

Originally posted by AmericanPie


This, of course, assumes one doesn't mind the minor inconvenience of adjusting valves every few thousand miles.

BINGO!!!

[Roxie_427]

Yes, but to those that LOVE the clatter . . .



. . . priceless.

[Michael C Henry]

I was led to believe that roller lifters in a FE were a short life item and trying to stretch the life of the lifters was a gamble on them not comming appart before you change them. I was told that the FE doesn't have enough oil at street revs to lube the rollers. Maybe they have made some changes since I last asked Comp Cams. I wasn't happy when two shell lifters and lobes went flat.

[mikiec]

Michael,

I believe the problem is with solid roller lifters, not the hydraulic ones.

Mike

[Don]

Same topic , but in reference to a small block Chevy


http://www.idavette.net/hib/camcon.htm



BEFORE AFTER
TORQUE HORSEPOWER TORQUE HORSEPOWER
2500 345.6 164.5 352.1 167.6
3000 342.0 195.4 380.7 217.5
3500 334.8 223.1 391.9 261.2
4000 330.8 252.0 397.6 302.8
4500 337.3 289.0 388.0 332.4
5000 303.3 293.5 356.7 339.6
PEAK 346.2@2600 296.7@51000 397.9@3700 340.0@48000

[Michael C Henry]

Two years ago when looking at cams and lifters I asked Comp cams and was told they didn't recamend rollers in street driven FEs. They said that the little needle bearing in the rollers would not get enough oil to survive.They had a limitted life expendency.You had to replace or have the rollers rebuilt. Like a spare set of roller lifters was the normal thing to have .Shame on you if you let them go too long .The rollers would come appart and metal went everywhere in your motor. As I understood it, the rollers got their oil thrown up from the crank. If someone could get pressureized oil from the lifter gallery to the roller needle bearings they might last longer.
Remember I'm talking about a street driven car not an all out racer with a quick change engine.Changing the cam shaft is an ordeal, let alone a bunch of metal through out my engine. Releiabillity is a major concern for me.

[DuckRyder]

Originally posted by Michael C Henry


If someone could get pressureized oil from the lifter gallery to the roller needle bearings they might last longer.

Crower (HiPPO option [for High Pressure Pin Oiling])
Crane (Pro Series)
(And possibly others)

Do exactly that.

It also has a lot to do with spring pressures. Generally, solid rollers are very "BIG" cams, and require high spring pressures not suited to longevity. This is beginning to change, as Crower makes "Street Rollers" and I am very happy with mine so far.

There have been quite a few folks displeased with the hydraulic rollers in FE's floating very early, seems that the weight of the valve train makes it difficult to select springs heavy enough to prevent float, but light enough to allow the hydraulic roller to work properly.

YMMV

[Cobrabill]

Having one rollor lifter come apart and take out my engine far out-weighs the perceived P.I.T.A of setting valve lash on a solid once maybe twice a year.

[Tout]

Eric or Kieth,

We need an expert on this topic, both are building monster FE engines and would the person's to explain what and why they uses either type of lifters and cam.

Tout

[cobra]

I would also like to listen George Anderson view, after my great experiences with him, I think he prefere quality and duration instead high hp figures ( on street cars ).
Greetings from Switzerland
Walter

[Michael C Henry]

With the advent of new products like the bee-hive valve springs with smaller keepers- retainers maybe lighter springs can be used.Im sure it is all enginered as a system.Cam shaft, lifters, pushrods, valves springs ,and retainers, etc. but get the geometry off and it will crapout on you, not something a mailorder parts hange should try.

[Snakebit]

Solid lifter cam. I may be old fashioned but it has less moving parts to break and tear up the motor. I don't mind adjusting valves, all part of being a motorhead.

[clayfoushee]

Walter, agree I'd like to hear George's views too, and don't want to put words in his mouth. But, after several conversations with him, I know at least one thing he'll say. "Learn how to adjust your valves."

[FUNFER2]

I agree with the solids. I've had no problems with mine. 600 lift-252 duration. Roller Earson rockers. Adjusting the valves take's less than a hour, from removing the valve covers, adjusting the valves & buttoning it all up again. Things like, using all studs, rubber gaskets & the valve lash tools, help in a faster job. After the engine build, I lashed them twice. Since then, only twice per year. With a flat tappet, you can hear & feel when they get loose. I'm happy with my set-up anyway.

[Naumoff]

I agree that flat tappets are the way to go. It's not that hard to adjust the valves and is part of the fun of having a Cobra. You can hear and feel when you need to adjust them. Besides if you don't have a old set of adjustable rocker arms you will find that they don't need to be adjusted that much anyway.

Just my two cents
Tony

[ffindling]

I agree!! Solid lifter setups aren't that
hard to deal with as long as it easy to
get to get valve covers off in your installation and your rocker arm setup is
fairly good in maintaining a reasonable
valve lash adjustment. Having an easy
means to bump the starter when you're
underhood makes lash adjustment that
much easier. Improvements in hydraulic
lifter valve trains in recent years have
diminished much of the advantage of solid lifter trains, but I love the noise of
solid lifter trains, the clicking sound they
make adds so much to the "classic" hot
rod experience and it sounds rather
intimidating to the opposition!

.......Fred

[Ant]

I saw somewhere that Ceramic lifters are being manufactured for flat tappets camshafts, and very hard wearing?

[RICK LAKE]

AmericanPie I am going to take a shot at this. First off you are going to get different HP and TORK readings using basicly the same cam numbers on 2 different types of lifters. Ramps are different design. The question is how high an RPM range are you going?? Under 6500 rpm I go with rollers, hydro. Over 6500 rpm spend the money and go with the larger Dodge solid rollers, larger wheel,bearing and oiling system. However downside, adjusting of valve train on a regular couple hundred miles check depending on HOW HARD you beat on the car. George runs solid in alot of his motors, he is building endurance motors with good hp and tork. I have not seen a Gussford motor break at any of the R&G in the 12 years I have been going. I like exhaust noises not engine ones. A .020" gap between to moving parts(cold) is going to wear and need adjustment. Comp sells a groove tool to help put oil on the roller wheel. It's a bleed down. I am going with Beehive springs, lite valves, and roller in motor 2. A dry sump setup with filters going into the pump will save the engine if a roller breaks. I am surprised that no one has come out with a aux oiling system for the lifters and cam. Splash is not the answer. Alot of people are running windage tray, so there is no splash, I have a canton with the screen but have hydro lifters in this motor. How big a motor where you looking at is also going to deceide rpm range and cam. I love tork motors. It's easier to change trans, 5 or 6 speed, or even gears, than to change motors, cheaper also. Just my 2 cents. Rick Lake

[DuckRyder]

I saw somewhere that Ceramic lifters are being manufactured for flat tappets camshafts, and very hard wearing?

Do not know of anyone doing it for the FE, but Jake Raby at Raby's Aircooled Technology RAT uses ceramic lifters in some of his engines. They are said to be reusable on a new cam. Expensive at about 500 for a set (8).

Seems that several companies are now laser drilling an oiling hole in the lifters face on flat tappets. Crower and I believe Isky offer this option.

IMHO, the chance of a flat tappet cam break-in failure is at least as great as the possibility of a roller lifter failure, with similar implications.

As long as the Valve Covers come off easily, the solid lifter adjustment is less than an hour, so it is not a great big deal.