After speaking with the guys at CraneCams I found that the Ramp on the Hydralic roller cams can only be at specific rate of attack, or other wise the pressure from the cam & the springs will squeeze the lifter dry. Hence to get a great/ quicker opening/closeing event on the cam lobe, you switch to a Soild roller Cam & solid roller lifters.

Questions:

1) What adverse effects do Soild roller lifters have on the Knock sensor?

2) How much of a gain can be expected from a quicker ramp event with the same lift as a Hydralic Roller Cam? (if you where to have two cams that are the same, with the same lift but one is Hydr and the other is solid roller)

3) Where can you get a truely custom cam ground for good money?

After speaking to Crane Cams about a custom cam they said that they can make a cam with a preset ramp/ duration that I can pick from. But as far as the cam being custom to my numbers, it would cost 700 a lobe!

Thanks in advance.

 

are you sure you need a solid roller?...........these is alot of maintenance involved, definetly not for a daily driver

 

There are very few people here who know how to properly spec a "custom" cam even by just picking lobes from a "lobe library". There are just one or two people who have the expertise to spec a true "custom" and that's their job, so they aren't going to give you specs for free!

I don't want to be condescending, but if you need to ask that kind of question you do not need a SR cam. They are not really street friendly, though knowledgable people who like to fiddle with their cars are running them. They are the way to make big NA hp, for sure. But the whole combo has to be able to take advantage of the benefits, and it's not cheap. But the advantages are pretty simple to generalize. An SR v. an HR cam allows steeper lobes. This increases the "area under the lift curve" and hence hp. They can also rev higher, another way to make hp if the supporting components are up to it. If you have good heads, intake, exhaust, and the shortblock up to high rpm, you may be ready for a SR cam.

Rich Krause

 

Listen to the wise ol' Doc. (rskrause). He's right on.

 

Good advice from Rich and reconfirmed in OS, but I'll add this....

"Pressure from the cam and springs" is a good deal of the limitation in an HR setup. You can however alleviate some of this with a lightweight valve, spring, rocker, and retainer. Lessen the equivalent valve mass and you alleviate alot of the problems with making a hydraulic cam system rev higher and make more power.
I have a good feeling that that's the route Bret took in his "LS1 inspired" valvetrain combination.... a good play.

Solids are the way to go for big power though... no doubt.

-Mindgame

 

Game,

Just so you know I saw this and still no comment.

Getting a HR cam to rev high is quite a big deal.

Bret

 

Well I appreciate all of the great advice, a couple of things that I should probably clarify though in my questioning. Increasing the "area under the lobe" is exactly what I am looking to do. My goal here is to have more air flow from the same duration. When guys talk of lift they really don’t get it (IMOP). They are all shooting for these really high lift numbers (i.e. over .600). But what I am try to ascertain is the ability to have say .540 lift or even .550 lift, but to have the valve stay open longer, even though the duration is the same or even less in some cases, instead of increasing the gross increase the average lift.

As I understand it. it would make more sense to have the valve get open quicker (i.e. steeper ramp) and have the valve reach its highest lift point sooner and stay there longer than a valve the goes out to .610 and then rush back because it ate up all of its duration getting to the lift number. I might be wrong; I am not the utmost authority on this by a long shot.

But wouldn’t this allow you the ability to run a nice wide lobe sep like 114 or even 116 SR, and have greater average lift & a great idle, and not have to deal with a tight lobe sep like 108 or 110 HR, because it take longer for the valve to travel the greater distance due to the slower ramp?

And even if so, would the power even be greater or would we be talking about micro HP? I am not a guy who is greatly bothered by pulling my valve covers every couple of weeks to do a valve job. If the power I would be making SR over HR would be worth it. Thanks for all the help. I really appreciate all of the input.

 

Ok, I think I know what your trying to get at, you mean that you want the same seat-to-seat duration but increase the duration at .050" lift hence a steeper ramp resulting in more lift during the duration so you wouldn't have to have the .610 max lift you were talking about.

It's great for HP, but harsh on the valve-train, So a good SR setup would be a good way to go...

As long as you work out the ICL (intake centerline) so that it matches up the IVO/EVC degrees fairly evenly with that high of a LSA, you should be able to get away with it... But I think you would be sacrificing some top-end though...

I may be wrong on a couple details but I'm not good at explaining things.

 

Going with a good Solid setup... what kinda gains would you see typically/Roughly? How much does it cost to convert to solid?

 

1000 dollars plus to change.
If ya get the right cam ya could see 50/75 more FWHP and EVERYTHING else being spot on.
If your present cam was spot on and ya got the heads for it I would say 40/50. If your HR is off and the SR is spot on then the 50/75FWHP.

350 for the cam
500-600 for the lifters
500 for the springs and jewelery
not including any machine work that may have to be done to make the springs fit. ya need about 200 seat and about 600+ on the nose depending on the ramp rate of the cam. It is better to over spring than under.

 

Make that around $400 for a cam core that has a hardened gear on it so you can run the stock oil pump drive.

Don't forget the new 3/8 pushrods and adjustable guideplates, that's about $175 or so.

$1700-$1800 easy.

Bret

 

You'd be spending a decent chunk of that for a roller setup anyhow.
Now assuming you built a bottom end to handle the RPM... ($$$)

Having a car that revs high and runs solids gives you nice bragging rights.
If you feel up to it, I say go for it
At the very least you will learn about some hardcore stuff that most of us don't get to play with.

 

it can be pretty expensive but i put mine together alot cheaper than the prices above. the most expensive part(s) are going to be the lifters. one thing we shouldnt look over is the life of these parts. a SR will not last nearly as long as a HR but i'm not trying to persuade you one way or the other.

good luck

 

I just went back and saw this and I have some concerns for you here....

There are a few problems with this logicso let's hightligh a few and discuss them.

"Increasing the "area under the lobe" is exactly what I am looking to do. My goal here is to have more air flow from the same duration. When guys talk of lift they really don’t get it (IMOP). They are all shooting for these really high lift numbers (i.e. over .600). But what I am try to ascertain is the ability to have say .540 lift or even .550 lift, but to have the valve stay open longer, even though the duration is the same or even less in some cases, instead of increasing the gross increase the average lift."

There are some problems with this, it applies more to hyd roller valvetrain stability than it does to solid roller but both have to deal with the same motions here. I know this is not intuitive but when you have the consition you are talking about here of having more area in the lobe and less lift you are missing the boat in terms of valve control AND what is happening in terms of velocity and it's derivitives. Those being acceleration (v^2, rate of change of velocity) and jerk (v^3, rate of change of accleration). I think you are a little over your heads, but at the notion of a solid lifter for this situation is a very good idea since it plays havoc on the hyd lifter. You are going to need more spring pressur eand much better pushords and rockers if you want to induce these accerations and jerks into the system. When it really comes down to it you might see a slight gain in average TQ but you will have a very hard time with the valve control and it just ges worse with RPM.

"As I understand it. it would make more sense to have the valve get open quicker (i.e. steeper ramp) and have the valve reach its highest lift point sooner and stay there longer than a valve the goes out to .610 and then rush back because it ate up all of its duration getting to the lift number. I might be wrong; I am not the utmost authority on this by a long shot."

Opening the valve faster is not a problem but you have to realize the inertia of the valve and the rest of the parts in there along with what I said above. Holding that valve open at it's max lift is a god idea but mother nature combines these two ideas I gave ya here called jerk and inertia and they really don't like each other.

"But wouldn’t this allow you the ability to run a nice wide lobe sep like 114 or even 116 SR, and have greater average lift & a great idle, and not have to deal with a tight lobe sep like 108 or 110 HR, because it take longer for the valve to travel the greater distance due to the slower ramp?

I don't you are getting whatis going on with the lobe seperation angle here, when you have the more aggressive ramps the motor will idle better, the LSA is just a byproduct of the placement of the lobes. Your square lobes like you mentioned will make the cam less sensitve to LSA changes since it will have the valve open at its max lift when the inertai of the air/fuel mixture needs it to be, but there are the associated problems with the valve contorl mentioned above.

Basically you don't get something for free and the whole system and it's parts are more interconnected than you can imagine.

Bret