Roller CAM -FE

[Chaplin]

Originally Posted by patrickt

Remind me again why a roller is better than a solid, flat tappet cam?

Ok, see my first post on this link.

http://clubcobra.com/forums/search.php?searchid=952333

[patrickt]

Originally Posted by Chaplin

Ok, see my first post on this link.

http://clubcobra.com/forums/search.php?searchid=952333

OK, I read it, and after I read it, remembered it from the first time I read it (it's copied below for everyone's convenience). I think I would tend to agree that rollers are better than non-rollers if, and only if, they have conquered the limited lifespan and distributor gear issue. You know as well as I that you can get a ridiculous amount of power out of a solid flat tappet cam in an FE. If we just skip over the "I'm afraid to break the cam in" issue then the increased potential power from a roller would have to be such that it offsets the limited lifespan/distributor gear issue (if those issues still exist). Would you agree with that?

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.

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[767Jockey]

OK, so I'm a thick headed Italian and it takes me a while to get things through my skull. I'm still confused a bit. If I understand correctly, the cam mounted gear that drives the distributor gear on a hydraulic roller is harder than that same gear on a solid roller????? Why?

As an aside, I distinctly remember some small cam company somewhere that had a setup that mounted their flat tappet cams in an electric motor driven device of some sort, and mounted the lifters in their proper position, and loaded the lifters down with springs. They then spun this contraption and broke in the cam on it before they sent it to you. Obviously, you would have to keep track of which lifter went onto which lobe, but that shouldn't be too difficult. Does anyone remember who this company is and if the technique works? I don't see whay it wouldn't be successful, and if it is why isn't everyone with a flat tappet cam doing it? It rather the lobes, if bad, went flat on the break-in machine than inside my engine.....

[Chaplin]

Jockey-
I think you are thinking of Cam Research. And just as an FYI, I know if at least one person who had them break-in their cam as you describe prior to delivery and they still wound up wiping a cam lobe. There are no guarantees.

Patrick- Fair 'nuf ;-)

[patrickt]

Originally Posted by Chaplin

Patrick- Fair 'nuf ;-)

So then you would agree that if one felt he could get sufficient horsepower for himself from a solid, flat tappet cam then a solid, flat tappet would be superior to a roller, for that person, if there was any additional maintenance required for the roller's distributor gear or if there was any shortened life of the roller's lifters, no matter how small that might be, correct?

[Chaplin]

Originally Posted by patrickt

So then you would agree that if one felt he could get sufficient horsepower for himself from a solid, flat tappet cam then a solid, flat tappet would be superior to a roller, for that person, if there was any additional maintenance required for the roller's distributor gear or if there was any shortened life of the roller's lifters, no matter how small that might be, correct?

As Jamo says, sounds like you've asplained it to your satisfaction.

Kidding aside, I don't necessarily agree. I will agree that if someone is willing to deal with the potential break-in issues because they prefer a solid flat-tappet, there is nothing wrong with running a solid flat tappet cam, as there can be no argument that they can make more than sufficient power.

However, remember, we're talking hyd roller, not solid roller. Production cars have been using hyd rollers with no issues for years in cars that see more mileage in their lifetime than your average 10 Cobras will see combined. Crane is making (or at least was making before they closed down and were bought out) a steel distributor gear to use with FE hyd roller cams that is advertised to wear like a factory steel- i.e, last 100k plus miles. I have one of their new steel gears on my dist now and will let you know how it works out (so far about 1500 miles and no issues at all (knock on wood)). But, even if Crane were not making the new steel gear and you had to replace the distributor gear periodically, that is a much easier (and faster) task than adjusting the valves. With the right tools and an asspert techinician you can change a dist gear on the side of road! Just ask Jamo. Try adjusting your valves on the side of the road. So for that reason, and the others mentioned, I still say a hyd roller is superior to a solid flat tappet for general street duty.

But if you like solid flat tappets, there aint nothing wrong with them at all.

[patrickt]

Originally Posted by Chaplin

... I still say a hyd roller is superior to a solid flat tappet for general street duty.

But if you like solid flat tappets, there aint nothing wrong with them at all.

Would you go so far as to say "If it were not for the break-in and lash adjustment issues, a solid flat tappet would be superior to both a hydraulic flat and hydraulic roller cam?"