[Bud Lyons]

77TA, You asked a question and I gave you an answer. If you want to run a big hyd. go for it. If you want to try a hyd. roller call Pdude. He will have a custom ground for you.

[PONTIAC DUDE]

Hard to compare. Think about it. That's an impossible question if you deal with engines everyday for a living.

That question can't be answered. You can't even compare grinds between companies as if you change one thing it makes the cam totally different. Increase the ramp speed and things happen.
Look at the XE series from Comp. makes the heads think their doing something they aren't. LOL. Same goes with your combo.
I always look at the packages and go from there. And not always hit it too. but 75% of the time I do. But not to say that another cam change might not make more.

Look at it this way. Why do you think Dynos are used and cam changes with timing are made?

<span class="ev_code_RED">501 RWHP</span> with pump gas (500 + cu.in.)
10.5-1 compression, hydraulic roller. This is one of my 511 cu.in. 600hp plus street packages.

And run mid to low 10's too.

B.B. Chevys have been doing it for 20 plus years.

Hey, meanken..........isn't that a streetable BBC?

[Steve C.]

I may have lost the bet on idle quality...
If you compare a hyd-roller cam to a flat-tappet hyd cam with similar duration at .050 numbers, the hyd-roller cam will always have a longer seat-duration. While the roller configueration allows faster ramp acceleration, it also suffers from slow acceleration off the seat compared to a flat-tappet cam. Therefore, the advertised-duration numbers are slightly longer. This means that a hyd-roller cam with the same duration at .050 lift as a flat-tappet hyd will not idle exactly the same.

(this from a article about fact vs. fiction on hyd-roller cams/ May'02 Chevy High Performance magazine)

[Steve C.]

In contrast to the roller boogie...

This from Ken Crocie in a engine article/March-April '02 Pontiac Enthusiast magazine:
"We are firm believers in hydraulic cams for street/bracket engines and roller cams for race cars".
The article continues...
"If you examine the actual lift curve at the valves, a modern quick-lift hydraulic cam, in conjunction with high-ratio rockers and Rhoads Vari-Duration lifters, will approximate the valve-lift curve of a traditional solid roller up to about .600 lift. Over about .650 valve lift, the big-nose solid roller is king."

Note, for this piticular engine build-up they were using a cam with 268 degrees of duration at 0.050-inch tappet lift and 0.594-inch gross valve lift.

[Jim Hand]

Dude,
I will make it easier for you to give us an estimate of the actual power difference between a standard hydraulic and a hydraulic roller cam. I have picked a standard catalog mid-range hydraulic roller from the Comp Cams catalog – the XR288H It has 236 degrees intake duration with .520 lift (.347 lobe lift), and the lobe is at 106. The exhaust is 242 degrees with .540 (.360 lobe lift) and is at 114 degrees.

I have selected comparable duration lobes from the Bullet Racing catalog and can have a cam made for $150. This standard hydraulic cam will have the lobes in the same exact positions – 106-114. The intake is 235 with .507 lift (.338 lobe lift), and the exhaust is 242 with .510 lift (.340 lobe lift). They do not have a 236 lobe with decent lift, so I chose the 235 lobe. If you prefer different lobe positions, change them but make both cams the same.

Assume a 462 engine with stock 87 cc E-heads with either an RPM or T-II and appropriate carb (but same on both setups). How much power difference in torque and HP will there be at 3000 RPM, 4000 RPM, 5000 RPM, and 6000 RPM (assuming the h rollers can make it to 6000 RPM)? And assume the Rhoads lifters are used on the standard cam to assure it will easily run to 6000!

And after making that estimate, assume the rocker ratio was changed from 1.5 to 1.65 on the standard cam, making the lift .558 and .561. How do the two cams compare then? Note the same valve springs and related parts could be used with no other changes in cost or effort.

As an engine builder, I suspect you would know this in order to be able to recommend the best power increase for the dollar spent. Thanks.

Jim Hand

[Steve C.]

Junk Yard Dog- just wait around a bit, it will be coming to that here pretty soon

[PONTIAC DUDE]

If I understand your question right. Here ya go.
From what I have seen so far with my installs,research,etc. The hydraulic roller will have a flater power and torque curve with longer stroke engines. Especially in the mid range where most of the power ends up after your shift. Engine Dyno #'s for a motor might not show the E.T. difference........ for the gain.
Rhoades lifter is another ballgame. I call them the Pre-hyd roller set up. LOL.
Sorta a controlled variable cam deal to increase bottom end with a cam that is to big for certain combinations and the other parts used. Trying to give a cam street drivability, low end torque. Which is the purpose of the aftermarket competition hyd roller grinds.
Money spend is the issue currently being debated for the power gain.
I just had an e-mail conversation with a dude that had a milder combo worked out and wanted my opinion on the upgrade but keep the same cararcteristics. I told him he had his combo right on the money and for the money spent for the gain...stay with what he had. I guess he didn't like my answer. Wanted to go to a hyd roller and felt i would offer a cam that might or might fit his bill. Didn't want to say that changing cams along the same lines would be the best bang for the buck. Same deal here. Yes you will see a gain over a regular hyd cam if it get more agressive. Changing a regular hyd cam to 1.65 might give you the advantage, but would have to check the figures at .100 and thru the lift range.
If your starting from scratch and want a Street deal with more power and better pulling capability, then I like the hyd roller. If money is not the issue. And they have their limits as to ramp speed, etc. same as the hyd lifter. And the solid has it's limits.
It all depends on the application.

The engine your using. Compared to Rhoads and the solid lifter noise the customer has to live with and don't want when I talk to them. I'd recommend the hyd roller. Remember they are a compromise deal. No break-in deal. Work the same rpm range as a hyd cam. more power under the curve with a greater ramp speed.
Compared to a Rhoads lifter bigger cam and a higher ratio then the hyd roller? Then I would say the hyd cam would make more useable power throughout the entire range. And give almost the same idle and power deal
Did I miss anything or your point?

[Jim Hand]

Dude,
My first question was with the same engine, and same cam specs on an approximate 500 peak HP 462, what would be the power gain of the H roller over an identical duration and lobe position standard hydraulic cam with slightly less lift. And the second question was:

If 1.65 rockers were used on that standard hydraulic cam, then what would be the power difference? Incidentally, the Bullet lobes are the latest high toot, fast rise, unsymmetrical lobe design, if that makes any difference.

Rhoads lifters were specified in order to remove any question about RPM with the standard hydraulic. They are a true anti-pumpup lifter and will ran as high or higher in RPM as any currently available true hydraulic lifter.

I do have a third question: At what RPM do the H roller lifters begin to pump-up or not follow the cam lobe! I had read that due to the excessive weight of these retro-fit lifters, RPM is clearly limited with them.

I understand that all folks should use what they want for whatever reason. But I am trying to get a clearer idea of the real differences in power between the two types. There sure hasn't been any reliable test reports with true Pontiac engines in the media since these were introduced.

Thanks. Jim Hand

[fdowdy]

"Bullet lobes are the latest high toot"

What are those?

[PONTIAC DUDE]

Ok, I'll try. And this isn't gospel according to Luke. LOL.
Just observations and the results I have found in my personal Test car, customers comparing, etc. Still have more testing to do.

Will be tearing my IA engine apart this weekend to address some sealing issues. Ok Marty your turn. LOL.
However, have 40 passes since last done.

Peak would probably show the same #'s. lift is lift. Total duration is total duration. That's a given. However, given the newer unsymmetrical profile might not show a difference over a Hyd roller. A sorta loaded question that most people won't have those profile cams available too. Haven't looked at or tried their cams to make a comparison. The unsymmetrical cam is a totally different deal and depending on the aggressive ramps is hard on valve train components compared to a Hyd roller. That's the purpose of a hydraulic roller. To save cam wear/break-in and still make big power for the street. Not race. And I know you know that a basic Hyd cam compared to a Hyd roller won't make the same power.
But if you can bring on the early lift figures on quicker with a better flowing head, you have to see a hp increase in the upper low to mid rpm range. The Rhoades lifters work the opposite scenario. They take a bigger cam and tame it to run at lower rpms. So the same Hyd cam with stock lifters will not show as high an average figure.
Same deal as the flow figures for heads. I'm more concerned about mid then total figures. Companies are always bringing out new profiles and designs. Look at UltrDyna and the person that develop the unsymmetrical cam.

Third Question:
I don't see an issue with stock lifters and 6200/6600 rpm. It's the springs. The Rhoades are an advantage with that duration cam.
Like I said in the above post, I have had my current Comp Cam Hyd roller to 6800 at the track and even 7000 on the chassis dyno, the power just fell off with my heads and combo that's all. I run a 140 seat with 380 open. Sorta like a competition solid lifter/hydraulic cam spring. Anything over that that the plunger will fail.

[Jim Hand]

Dude,
Thanks for the info.

What I believe you have said is there is very little real average power difference between an H roller and a standard hydraulic of the same grind, providing the standard has decent lift. And further, it appears you said that with higher ratio rockers to raise the standard hydraulic cam lift higher then the H roller, (and also increase the open/close rate), the standard cam with higher ratio rockers will likely produce more average power then the same grind H roller with 1.5 rockers.

You also said the H roller will be easier on the valve train, both during break-in and normal operation. And that the H roller will be quieter.

In no way am I suggesting H rollers should not be used for any reason. However, I believe it is appropriate that we know that it is not going to magically add a bunch of power over a similar grind hydraulic. And obviously, the hydraulic roller can be customized to obtain a lot of lift, and quicker open/close rates. But my interest, and I believe also the interest of the originator of this Topic, is what is the real difference in normal street/strip versions of the H roller and standard cam.

Based on the rigged tests that have been published, and the research I have done, and results from guys running similar grind cams, I believe we would be lucky to see even five peak HP and five # torque added on a 500 HP engine with a 236 range H roller cam.

Thanks for taking the time to respond.

Jim Hand

[Steve C.]

6800 RPM with hyd roller lifters is impressive! Two years ago the magazines were touting that they were somewhat of a work in progress with premature valve float still an ongoing problem. The roller foot combined with the hyd mechanism makes for a hefty overall assy.
It's been a few years but when I spoke with Crane tech on the subject they left me with the impression they wern't too keen on applications way above 6000 RPM. They didn't say they wouldn't go there, just really implied a big concern.
I still think this is a good potential application for the Comp "Beehive" valve springs. Higher RPM with less spring, means more power and reliability. David Vizzards experiance to date indicates that they will run a typical street roller valve train to 2-300 rpm more while the seat load drops from 145 to 130 lbs. and over the nose from 345 to 310 lbs.

[Junkyard Dog]

Dude, 140 seat and 380 open seems kinda light. Are hydraulic roller ramps a lot different than solid roller ramps? Comp recommends a much heavier spring for my very mild 288r (244 at .050, .550 lift with a 1.5)

Jim, what if you put 1.65 rockers on the roller, too?

Maybe I should put 1.65 rockers on mine. What's that, .605?

[Steve C.]

Comps valvespring recommendations typicaly run high, more like BBC stuff.
Cranes published info for hyd rollers say Small Block applications: 120-145 lbs seat pressure and Big Block applications: 130-165 lbs seat pressure.
Subject to some debate but I think the typical valve weight used in the Pontiac heads are not like a BBC application.

[Jim Hand]

Fred,
"High toot" is the same as "high zoot" only spelled wrong!

JYD,
I mentioned the option of adding lift to the H roller in my last post:

"And obviously, the hydraulic roller can be customized to obtain a lot of lift, and quicker open/close rates. But my interest, and I believe also the interest of the originator of this Topic, is what is the real difference in normal street/strip versions of the H roller and standard cam."

Jim Hand

[tom s]

when I first built my 446in RA V motor I bought the Comp 245-252 400 lobe lift hyd roller and kit.After thinking about the RPM range of a V I called comp.They did not feel that the hyd. rollers would be good for over 6000 RPMs so they took back my hyd roller lifter and spring kit and sent solid rollers and spring kit and had me set them at 6 thou.I have the same cam in a couple motors and REALLY like the performance and street manners.Makes in the 500 plus HP range.Has enough vac. to run the power brakes in the T/A.Tom(SD Man) has driven the car and will attest to its driveablity with a wide muncie and 3.55 gears.FYI,Tom

[PONTIAC DUDE]

Jim this could turn into a heavy discussion without actually going anywhere, LOL. Yes, peak can remain the same with either cam. However, from the chassis dyno pulls I have run, I see more mid to lower rpm hp #'s. And as we know peak isn't always where it's at. Same applies to heads and everyone wanted to know the peak flow #'s.
I would like to have the additional hp right where my rpm falls when I shift to pick it up.

Give me a set of heads with 10/15 cfm less peak and 15/20 more bottom and mid and I'll beat ya. LOL.

Question about those unsymmetrical Hyd cams? Wouldn't they be harder on the plunger/lifter? more so then a Hyd roller ramp with the roller absorbing the load on the quick dropping ramp with the right spring.
I would think you have more of a chance of spring bounce with a Hyd unsymmetrical cam over a Hyd roller with the same design.

Personally, I had a same design 068 cam made in a Hyd roller, but sold it as I went on to another project, so I can't tell ya. However, the dude in Hawaii might be able to give some info. Comparing specs, the quicker acceleration rate should have been worth a tenth or two. But then again speculation.

[69Goat1]

I am not sure but I think I read that the "guy in Hawaii" had either switched cams already or is getting ready too...

Think He go's by 468Bird...

[Steve C.]

Can you hear it ? Listen close. The Classical Pontiac ghosts are stiring and starting to moan and grown.... can you hear them over there ?
Ohhhhh, ohhhhh... "Don't waste your money"..... Ooooh... doooon't waste your money.

[tom s]

EXACTLY my thoughts Steve!LOL,Tom