Dueclaws

You can make 800hp using hydraulic rollers.
My engines are relatively mild 572's:
8.5-1, Iron Merlin heads, 8-71 TBS, no intercooler, custom grind Crane hydraulic roller cam

Running rich on the dyno (9.3 AFR)-
5,200, 6# boost (1-1 ratio): 754.9 hp
5,578, 7.07#=801.5 hp

5,400, 7.7# (5% over)= 798.5 hp.....
it'll spin to 6000

Due

cstraub69@comcast

Wette,
Yes it is doable with a hyd roller. Now that I know what your goal is power and MPH then yes. You may also what to consider running a hyd lobe profile and mechanical lifters. This gives excellent power production and since the opening and closing ramps and flank area is not as aggressive as a solid roller lobe you can run a lighter seat pressure, ie around 170# @ seat.

The 572 package I worked on a few years back made 725 HP @5200 with a hyd roller that was in the 250 range and it was onlya 9 to 1 engine.

There are no solid answers in this business, just goals to be reached. Each engine needs to be designed to reach that goal. You take a customer of mine that has to use flat tappet solid stuff with OEM 990 heads with a CID limit of 470. He gets 730HP to 750HP out those engines. Good numbers, but then you take a Cup engine that is 12 to 1 and 358CID limit and a flat tappet cam and they make 835 to 850HP. It is what you have to work with to accomplish the goal.

chris

rmbuilder

Craig,
I have the dyno sheet on RLW's N/A 540, 305 CNC chamber AFR, 1050 Nickerson, Hyd-roller 236*/240* @ .050" .625"/. 630" on 112*
700.9 Peak TQ @ 4900......1.3 lb/ft per CID
718.4 Peak HP @ 5900.......1.33 hp per CID
Translate that to 598 CID
777.4 peak lb/ft
795.3 peak hp
It would appear possible that with the proper component changes 800 HP is possible
The acceleration would be close up to peak TQ for the Hyd-roller (5000 RPM)
The .050” numbers are not as spread as would first appear due to the fact that you need to pull approx 8* duration at the valve from the solid to account for lash.
The significant advantage of the solid is its ability to maintain Dynamic Valve train Stability under conditions the hydraulic is limited due to:
Plunger deflection
Insufficient spring force
component weight
lofting
RPM limitations/lifter collapse
Roller lifter rate of rise per * only limited by side loading of lifter in its bore.
Bob

Boatlesss

Here is what my friends 588’s made with 9:1 compression and dart iron heads and hydraulic cam. I do not understand any of the #’s other than the hp, rpm and torque.


RPM CBTRQ CBPWR FHP ME% FA+FB BSFC
4600 725.3 635.3 133.7 81.9 256.6 .44
4700 728 651.5 139.3 81.6 271.2 .44
4800 724.7 662.3 145.9 81.2 274.9 .44
4900 730 681.1 152.6 80.9 285.4 .44
5000 724.4 689.6 159.6 80.1 281.3 .44
5100 724.3 703.3 166.5 79.8 285.7 .44
5200 722.4 715.2 173.8 79.3 291.9 .44
5300 722.6 729.2 181.1 79 293.6 .43
5400 721.9 742.2 189.5 78.5 304.1 .44
5500 723.8 758 198.6 78.1 304.7 .43
5600 720.5 768.2 207.8 77.5 321.6 .45
5700 715.1 776.1 217.3 76.9 328.2 .45
5800 709.1 783.1 226.9 76.3 334.9 .46
5900 703.8 790.6 236.8 75.6 342.7 .47
6000 690.8 789.2 246.9 74.9 350.7 .48
6100 683.7 794.1 257.6 74.1 351.8 .48
6200 680.4 803.3 269.6 73.8 361.1 .48

WETTE VETTE

Thanks for the info gents!! Boatless can you find out the particulars of the cam used to make those numbers? Thanks!

Boatlesss

He purchased the engines second hand in a boat and they had the dyno sheets. He like me, doesn't know squat about them other than what the dyno sheet says.

IRONMAN

When you say "Translate that to 598 cid" do you mean using all of the same components OR adjust the components accordingly to fit the larger displacement? Thanks, Chris

WildWarrior

Before I met Rudy Dryden our present motor builder in Wilmington DE, I would never have considered hydraulic rollers.
Our previous high hp applications for or over 25 years including my Pro mod race car engines always ran big solid cams.

At this point I see no reason on a blown boat application to run a solid lifter cam with higher spring pressure and lash beating the valve train to pieces.

By using higher than recommended spring pressure ,the proper lifter as well as the correct pre load we get more than 3 times the longevity than previously attained with solids and still spin our 565CIs with high Helix 1471s past 6500 rpm's at will ,and make over 1250hp on pump gas along with Methanol injection which comes in at 8lbs of boost.
I know another well known boat engine guy that is now running hydraulics on his big stuff as well.The down side for the builder is just like running big fat jets in your 2 circuit Dominator is that they don't get to tare them down every season with washed down cylinders and beat up valve trains.

jeff1000man

WOOOOAAAAHHHHHHH.

Every one of you guys is working to the extreme on every application that you are posting.

There is not one apples to apples application.

Solid lifters whether roller or flat tappet will yield better horespower or torque, and you know it, based on equal comparison of lift vs. duration on the same cam. on the same CI.

Problem is, no engine builder will waranty solid anything because of need for maintenance.

Work on that argument for a little while.

IRONMAN

I am not looking for the extreme, I just want to build somthing similar to a Hawk 750 that will run for 500 - 600 troublefree hours with normal maintenance. Personally I don't really care about making 750 hp I just want a high torque curve from a 588 or 598"motor that will be happy propped to turn 5400 - 5600