[Hot Rod]

I agree with David Reher!!!!!! But I will also say that it did cost me some $ to change it over.... I run a baby roller compaired to what is out there, I wanted to accomplish a engine combo with the e-heads that would run the same et as the old combo.. But what happened is the car runs better in the heat than expected....

I love mine!!!!!!

Rodney

[suzyq]

Hello, I did buy the 068 style cam from the Dude. I really love the cam, but havent had a chance to drive it much due to a top end oil issue. I am also installing a TKO-500 in the firebird, so its going to be about 2 weeks befor I hit the street with the car.
I will say the cam sounds very mild and revs very fast to 4500. I did change more then the cam with the car so I cant do a cam only test.
I went to 1.6 roller rockers and a 65 tripower intake
Scott

[Flamin65]

Ok I scanned the National Dragster article and saved it as a bmp file. Now if someone can tell me how to post it I'll be ok. Or if someone would like it in an e-mail give me your address. Mine is [email protected] Thanks Greg

[Larry Navarro]

QUOTE:"For my money, flat tappets belong in the museum, not the racetrack."

....keyword.... RACETRACK.
Now for those who don't tear down motors on a weekly basis for the next event.....

[PONTIAC DUDE]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Larry Navarro:
QUOTE:_"For my money, flat tappets belong in the museum, not the racetrack."_

....keyword.... RACETRACK.
Now for those who don't tear down motors on a weekly basis for the next event..... <HR></BLOCKQUOTE>

Then ya use a Hydraulic Roller for the street. best of both worlds.

[Bruce Meyer]

Larry this is the racing section isnt it? Read the article.

[partimer]

Hope y'all don't mind me chiming in been lurking. After reading this I'm with the Pontiac dude guy- gosh hydraulic fl;at tappet cams they went out with the flathead Ford didn't they ? I'd be afraid to run one at the track for fear of getting laughed at. Even the ricers have solids and rollers. All the new GM stuff is hydraulic roller- they make more power- even a heavy car goes faster with a hyd roller or solid roller. well back to lurking for me..

[77TA]

Hotrod do you run a hyd roller or a solid roller ? how big ?
What did you change from also?

thanks

[Brian '74]

Here is the article from National Dragster.

[Larry Navarro]

I'm sorry but David Reher's name isn't on my check book.
Most everything in his article has been discussed here over and over, in one form or another.
One thing he forgot to mention is that when roller tappets fail....and they DO fail, the engine will ingest the same particulates of metal as found when a flat tappet cam failure occurs. HA...where's the cost savings in that! Been there, done that!
Expensive or inexpensive....parts fail.
Suggesting that flat tappets don't belong on the racetrack?.....well, that all depends on who's footin' the bill.

[PONTIAC DUDE]

Larry, why don't you like the concept and theory of the solid or hydraulic roller cam and lifter?

You run roller rockers and a roller timing chain right?

[buwalda]

I think Reher must been absent from 'logic' class at school. He says a low tension spring, 130lb, & a heavy valve

[buwalda]

Sorry,
Don't know what went wrong.........
As I was saying, Reher quotes a 130 lb seat tension & heavy valve as the "worst combination for high rpm reliability" with a flat tappet cam. Well, why not increase seat tension to 150lb?? Silly argument. "Heavy valve?" It's the same weight valve with a roller cam also! Silly argument. He then talks about the 300lb seat tension required for roller cams!!!!
No prizes for guessing which spring is more likely to break something! He talks about the failures of flat tappet cams in race engines as though it is a foregone conclusion. Considering the simplicity of the flat tappet system, it has alot going for it when you consider all the components of a roller lifter that can, & do, fail. More components = more chance of failure, especially considering the much greater spring tensions required with roller cams. No doubt the roller cam does make more power, but to imply that it is also more reliable defies logic.

[77TA]

I can't beleave that some of the builders here have never dyno tested a hyd cam of some duration and a hyd roller of very similar durations measured at the common accept .050 measuring point. This is the type comparison I am looking for. THis is the way most of us buy cams we look at the basic measurements lift,duration,lobe sep. There are cams of the two types that are either very close or the same in the duration and lobe sep figures. the lift is one area the roller would seem to beat the flat lifter cam, on paper anyway, but does it make much difference on the dyno or track in a pontiac engine. Anyone got any numbers to post instead of beliefs and opinion ?????
Am I asking for private information or something ???

Thanks

[slowbird]

Here is a better view of that article
http://www.rehermorrison.com/techTalk/index.htm

[slowbird]

Well that didnt take you staight to the article so just scoll down to the bottom of the page click on the last one #43

[Brian '74]

Here is the link, sorry my server was acting up w/ that scanned image.

http://www.rehermorrison.com/techTalk/43.htm

[PONTIAC DUDE]

R & M are right. The weight of the valve contributes to valve bounce which can destroy lifters and cams. Hard to make or pick a spring that will control it without overloaded the cam and lifter plus maintain durability and longevtivity for hi-perfromance use. That's the purpose the the spring rate charts in the catologs. The biggest issues with valve train is the mass. It's been proven way back that the lighter the valve train components the less spring pressure is needed to attain a higher rpm and make more hp with less mass to move.
Titanium valves, titanium retainers, etc.

As far as testing hyd rollers against a hyd grind with similiar profiles. The Pontiac engine building community is a lot smaller then the Chevy and Ford contingincy.
Most of the time, people already have a basic idea as to what they want. From my business and reading what most people are running about 20% of the market would benifit from the current selection of hyd roller profiles available.
The hydraulic roller for Pontiacs is fairly new. Hence very little comparisons out there. Taking an engine and trying different cams for a even more limited market is expensive and time taker. Your investment is sitting there waiting for someone interested in it. Then you have the trouble of trying to keep up with current demands most Pontiac builders have anyway.
Remember that this technology has been in use since 1985 with the SBC & Ford manufactures from the factory. Almost 25 years ago. They haven't looked back.

[Larry Navarro]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> Larry, why don't you like the concept and theory of the solid or hydraulic roller cam and lifter?
You run roller rockers and a roller timing chain right? <HR></BLOCKQUOTE>
Ken, I NEVER said I didn't like the concept and theory! Comparing roller rockers and roller chain to that of a roller cam assembly, is not the argument here.
I merely challenged the misconceptions and opinions of David Reher. He is downright wrong in his analogy that flat tappet cam failures attribute to more money being spent to repair damage from the use of such components. Thats just plain stupid!
In my previous post, I refered to a roller tappet that "went south".....upon investigation, that tappet had NO needle bearings left and the body chewed up the lobe on the cam on which it was riding on.
Now since all this "high-tech" material was circulated throughout the engines oiling system, take an educated guess on the COST associated with getting that particular engine back in service.
Any rocket scientists out there?
If a roller setup is in your budget, then by all means, go with it man!

[PONTIAC DUDE]

How many people have wiped out hyd or solid cams and the damage sustained. I have read more about people wiping hyd cams on the PY forums in the last 2 years then I have seen in 35 years dealing with Chevy and Fords.

Most solid roller lifter deals with wiped rollers is due to the excessive pressures needed for high rpm and making hp. Or people not keeping a check on the increased lifter adjustemnt needed and then realizing that something must be happening.
This isn't the issue with a hyd roller to which this topic is about.

No high rpm break-in required.
I can change cams and use the <span class="ev_code_RED">Same</span> lifters over and over.