just got this in the mail

Twin_Turbo said:
how much lift?
Click to expand...

.583" intake, .591 exhaust.

I think plenty,since the dart pro1's I have don't flow much more over .600. I could have gone all the way to .650 if I wanted since my springs allow the travel, but I trusted Mike on it. He bases his cams on the type of flow generated with your heads and intake. This one is specifically for the ITB crossram setup. I should get me close to my projected redline of 7500.

A bit worried about the large overlap it has and possible reversion. Then again I will build an airbox over the intake to feed it with cool air and to keep reversion contained.
 
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Who/what made that cam, I wish you better luck than with my higher lift cam and I didn't even have inverted ramps/etc....

:surrender:
 
mrvette said:
Who/what made that cam, I wish you better luck than with my higher lift cam and I didn't even have inverted ramps/etc....

:surrender:
Click to expand...

You mean the cam that went through the hardening ?

This is a whole different animal. Steel billet + iron gear for compatibity. Springs have the required travel + pro series lifers with pressurized oiling. I will also go shaft rockers this time because i've seen the roller rockers with studs riding the side of the valve stem with only 20 minutes on them.

The Jones cam has a surface hardening that's a whole lot deeper than normal (I think .100)

Manufacturer is Jones Cams : www.jonescams.com
 
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I understand what a cam is supposed to do, but reading this thread I realize I'd like to get more in depth knowledge on this.
Could anyone point me a good information source?
I'd like at least to be able to tell from the numbers if a cam's timing is rather conservative or totally outlandish. You know, this kind of stuff...
 
Denpo,

A good book is the book from D. Vizard on Camshafts and Valvetrains (chevy). I have it here. It tells you almost anything you need to know, from crunching the mayor numbers to the relationship between CR and cam timing, plus some things like spring pressures etc.

This will only leave the most in depth analysis on the table, being things like jerk, mayor intensity etc.

As for this cam : yes it has a lot of overlap. To note here is I run an ITB on FI. so the overlap will not be as much of a problem like in a 4 barrel app. Seen the fact I don't have a plenum I cannot run on engine vacuum for brakes and such and will have to employ a vacuum pump.

Furthermore, both engine, trans and rear end prefer high rpm's. Cam is geared towards higher rpm (3000-7000).

Mike asked me the specifics of heads, valvetrain, CR, induction and such and based on that provided the cam. Although a very good piece, price was the same as a custom cam from the mayor manufacturers which whom I had less succes.

As for the inverted flanks : the cam is lazy off and on the seat. I assume this was done to minimize valvetrain/seat problems (47° mayor intensity). then it picks up speed due to the inverted flanks, to keep the valve longer open at maximum lift.

Overlap is 120° (seat timings) which is huge in my opinion as well, but could work in this app.

This is a tight lash cam also.

Seat timings at .012 are 292/296, @0.050 245/249.
Rpm max should be close to 8000.

I know it's maybe a bit to much racy, but then again I do not run her as a DD.
 
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Yeah, but am I seeing that correctly? Looks like the exhaust lobes are typically eccentric in design, but that intake looks almost squared off. That is just about the craziest cam I've ever seen. If I am seeing things right, it looks like there would actually be two lift peaks on intake with a very slight dip in between. Or at the very least, it would hold the lift peak for at least 20* of cam rotation.
 
clutchdust said:
Yeah, but am I seeing that correctly? Looks like the exhaust lobes are typically eccentric in design, but that intake looks almost squared off. That is just about the craziest cam I've ever seen. If I am seeing things right, it looks like there would actually be two lift peaks on intake with a very slight dip in between. Or at the very least, it would hold the lift peak for at least 20* of cam rotation.
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Sure you not lookin at a fuel pump eccentric??

:surrender:
 
If you look closely at the second picture, you're looking at the forward end of the cam. Beyond the partially obscured fuel pump eccentric, the first lobe is the #1 exhaust; the second lobe is the #2 exhaust, but it looks very unusual since its shape actually includes the shape of the 3rd lobe, which is really the #1 cylinder's intake lobe. Unfortunately, it makes it look like the second lobe has a double hump peak lift. I'm sure this is not the case; perhaps another picture is warranted. BTW, Crower has been making inverted flank roller cams for many years - by the "Inrad" name.

Belgian1979vette said:
...
1194f5f73bc44a0f.jpg

These lobes are nothing like I've seen until now. Inverted flanks...
245-249°@@ 0.05
Click to expand...
 
larrywalk said:
If you look closely at the second picture, you're looking at the forward end of the cam. Beyond the partially obscured fuel pump eccentric, the first lobe is the #1 exhaust; the second lobe is the #2 exhaust, but it looks very unusual since its shape actually includes the shape of the 3rd lobe, which is really the #1 cylinder's intake lobe. Unfortunately, it makes it look like the second lobe has a double hump peak lift. I'm sure this is not the case; perhaps another picture is warranted. BTW, Crower has been making inverted flank roller cams for many years - by the "Inrad" name.

Belgian1979vette said:
...
1194f5f73bc44a0f.jpg

These lobes are nothing like I've seen until now. Inverted flanks...
245-249°@@ 0.05
Click to expand...
Click to expand...

Ah, that's what you mean. Yes, those are 2 lobes behind eachother.
 
Yes, I see that now. It is very hard to discern but I can now just barely see the line between the two lobes. Thought that was a seriously crazy design.
 
Okay, obviously I don't know as much as alot of guys about cams, so I'll ask...what's an inverted flank design, and why is it benefical? Is this particular to roller cams?

Thanks!
 
damoroso said:
Okay, obviously I don't know as much as alot of guys about cams, so I'll ask...what's an inverted flank design, and why is it benefical? Is this particular to roller cams?

Thanks!
Click to expand...

A lobe with an inverted flank has more the shape of an 8. It allows slower initial acceleration to not put to much stress on the valvetrain when the valve is coming of and on the seat, and then in the next fase it accelerates the valve faster towards maximum lift. So the area under the curve stays the same.
 
I see, kind of gives the lifter a "primer" start to the lift allowing a smoother transition and an overall more stable high lift situation right? Thanks for the info!
 
damoroso said:
I see, kind of gives the lifter a "primer" start to the lift allowing a smoother transition and an overall more stable high lift situation right? Thanks for the info!
Click to expand...

I don't think so. The idea is to simply keep the valve fully seated until the last possible cam angle.
Maybe Belgian could post more pictures. I'm curious if the trailing profile is the same. I would think so allowing the valve to completely seat as early as possible.

The most ideal profile would be closest to a square. The only way to create that would be electrically operated valves.
 
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