How much HP is a roller cam really worth?

[Jerryl]

Similar grind to similar grind id bet ts not more than 10hp. Like a 212-212 FT vs. a 212-212 roller with 853 lifters. It takes a lot more spring to run a hydraulic roller than a FT on the similar grind. The roller lifters are heavy. If you were talking about the potential in an engine that could take advantage of a solid roller vs. a hydraulic cammed roller or FT in the same engine it could be a huge difference. Like 200 hp or more. ........

Thanks Bison.
I am drawing that conclusion myself.
There is a LOT of HP in a roller, IF, the supporting mods are there.

I think it should be a wash.
Where does the energy go?

Energy conversion is never 100%, so it can not be a "wash".

........ There's alot of other ways to add 60hp. Cam's not the cheapest way to add 60hp. .........

Scott,
I agree based on the postings of Nick and Bison.
If you start from scratch and have the $$$, get a roller.
If your motor already runs without mechanical problems, the $$$ is better spend elsewhere. Unless of course your goal is to be "top dog", or you get one HECK of a deal on a set-up.

 

[Blown&Injected]

Of course there is no one size fits all for every situation and I do agree that energy is never perfectly converted, but the same things interfering with conversion works both ways.

CraneCams
Common Misconception:
Many people mistakenly think that using higher seat pressures causes a reduction in the horsepower delivered to the flywheel because higher seat pressures (and also higher spring rates required for high performance) require horsepower to compress the springs. This thinking is simply incomplete! For every valve that is opening and its valve spring being compressed, another valve is closing and its valve spring is expanding. This expansion returns the energy to the valve train and the engine. This results in a net power loss of "0" hp. Many engineering texts refer to this as the "regenerative characteristic" of the valve train. Recent tests at Crane have shown no horsepower loss on a hydraulic roller equipped engine when changing the seat pressure from 135# to 165#. Power actually improved significantly at top end, probably due to better control of the relatively heavy valves in the engine.

...the next article in the google search said heavy springs rob HP

 

[Blown&Injected]

A 212 Flat Tappet Hydraulic is not a similar to a 212 Hydraulic Roller because of the difference in ramp speed.

The over-all duration at .050 can be the same but what is it at .1, .15, .2, .25... The roller will attain higher lift much sooner then the FTH thus making much better use of the increased flow for a longer period of time.

 

[GSTOY]

Since I'm still very new to the v6, but I try to read up as much as possible, if you were to take a stock engine and convert it over to a roller, you would ned to replace the cam..dahhh, lifters and valve springs...correct? What about the rockers? Do the 6's suffer the same problem that the 8's do with the rocker shaft now being the weak point because of the increased valve spring pressure?

Steve

 

[Jerryl]

Of course there is no one size fits all for every situation and I do agree that energy is never perfectly converted, but the same things interfering with conversion works both ways.

CraneCams
Common Misconception:
Many people mistakenly think that using higher seat pressures causes a reduction in the horsepower delivered to the flywheel because higher seat pressures (and also higher spring rates required for high performance) require horsepower to compress the springs. This thinking is simply incomplete! For every valve that is opening and its valve spring being compressed, another valve is closing and its valve spring is expanding. This expansion returns the energy to the valve train and the engine. This results in a net power loss of "0" hp. Many engineering texts refer to this as the "regenerative characteristic" of the valve train. Recent tests at Crane have shown no horsepower loss on a hydraulic roller equipped engine when changing the seat pressure from 135# to 165#. Power actually improved significantly at top end, probably due to better control of the relatively heavy valves in the engine.

...the next article in the google search said heavy springs rob HP

Cool!
So, heavier springs do NOT rob HP, according to this article.
Guess I learn something new everyday, although I do not agree 100% with the statement ........... unmeasureable/negiable, Plausible ......... "0", Disagree ......... But I'll be the first to admit that I am far from an expert.

Anyway ...... So the "-10" for springs (I pulled out of the dark )needs to be divided up elsewhere. , so we can get back to the 60 mark .

 

[Jerryl]

A 212 Flat Tappet Hydraulic is not a similar to a 212 Hydraulic Roller because of the difference in ramp speed.

The over-all duration at .050 can be the same but what is it at .1, .15, .2, .25... The roller will attain higher lift much sooner then the FTH thus making much better use of the increased flow for a longer period of time.

Understand "Ramp" and "Area under the curve".
How much HP is the increased ramp and area worth provided the shift RPM and boost/set-up is unchanged?

Edit:
Really just wanted to find out if making a switch based on PERFORMANCE, is all worth the effort.
In other words: If you have a total budget of $850, just enough to get the complete kit, will you see a significant HP increase to make it worth the effort.

Edit #2
The answer to that is "It based on the mods you currently have".

 

[Alky V6]

Don't forget to add 10 hp for the Cal Custom air cleaner.

 

[Alky V6]

What? Nobody remembers Cal Custom parts?

Sorry. Just having a little fun.

 

[jhanson1750]

From first hand experience (chassis dyno and lots of idle time/money about 8 years ago) we swapped a ft cam from a 69 302 ford (has chevy type adj rockers) to the exact (can't rember the specs) roller. With NO other changes we saw 10-13 hp. No change in Tq. We had @ 12 pulls with the ft setup and did 8 or 9 with the roller. We chalked up 4-7hp to the fact that all the roller pulls were done at night with cooler air. We made a couple of "passes" on the street and would have sworn that there was a bigger diffrence by the seat-of-the-pants. Wish we would have waited and made some more pulls during the day to get a better average. We ended up putting in an "x" grind and picked up 34hp (off of memory?) then heads and oter mods. Jon Hanson

Edit: If the question is to switch or not the I say YES!!! The question is not IF but WHEN will the stocker eat the lower end. I like to schedule my down time and not to have it thrust apon me. I just completed the Full Throttle (Thanks Mike!) roller swap and it was a breese......with the engine on the stand!!!

 

[rw87tt]

I remember Cal Custom

Also Stone, Woods and Cook and some old dude named Don Garlits

 

[Alky V6]

Also Stone, Woods and Cook and some old dude named Don Garlits

Yo! Dude! Represent!

 

[bison]

A 212 Flat Tappet Hydraulic is not a similar to a 212 Hydraulic Roller because of the difference in ramp speed.

The over-all duration at .050 can be the same but what is it at .1, .15, .2, .25... The roller will attain higher lift much sooner then the FTH thus making much better use of the increased flow for a longer period of time.

The FT has a slightly lower ramp speed but it doesnt equate to a noticeable difference in performance. The hydraulic roller is still limited by the springs that can be used. Most guys here run production style heads anyway and the highest flow concerns are at low lift anyway since thats where the valve will be spending most of its time. With the cams ground on the same center and all else the same you are not gaining much at all from the roller other than durability. The springs need more frequent changing also. Ive run both 212-212 cams roller and ft and they both produced the same results. Fwiw i shift mine at 5800 and it goes through the end of the quarter at around 6000.

If we were talking about an engine that had the ability to rev to 7000+ then a solid roller would be the way to go. Solid rollers are light and allow the engine to rev. You wouldnt even come close with a hydraulic cam.

 

[bison]

Since I'm still very new to the v6, but I try to read up as much as possible, if you were to take a stock engine and convert it over to a roller, you would ned to replace the cam..dahhh, lifters and valve springs...correct? What about the rockers? Do the 6's suffer the same problem that the 8's do with the rocker shaft now being the weak point because of the increased valve spring pressure?

Steve

The shafts can be a problem but most guys run adjustable roller rockers. There are replacement shafts available. Roller rockers increase valve guide longevity in higher lift applications vs stock style rockers that rub on the end of the valve. They also have several ratios available for added lift needed.

 

[Blown&Injected]

It is that ramp speed that lets the valve spend just that little amount of time at higher lift at the edges of the duration event.
The heads, even production heads, flow better with higher lift; up to about .550" with my heads.

The roller just holds the valve, at higher lifts, for a longer time - even if the over-all duration and lift are the same.

 

[Alky V6]

It is that ramp speed that lets the valve spend just that little amount of time at higher lift at the edges of the duration event.
The heads, even production heads, flow better with higher lift; up to about .550" with my heads.

The roller just holds the valve, at higher lifts, for a longer time - even if the over-all duration and lift are the same.

A roller cam allows that steeper ramp rate your talking about. More overall area under the curve.

 

[bison]

A roller cam allows that steeper ramp rate your talking about. More overall area under the curve.

This is true but a hydraulic roller profile is no where near as aggressive as a solid roller profile. It would be hard to maintain control of the valves with the small springs that are used on most of these engines with a very aggressive open/close speed.

 

[Alky V6]

This is true but a hydraulic roller profile is no where near as aggressive as a solid roller profile. It would be hard to maintain control of the valves with the small springs that are used on most of these engines with a very aggressive open/close speed.

You're right. I keep over looking hydraulic rollers. My mindset is, if a racing engine is going to have a roller cam, it's going to be a mechanical roller.