Hey - my 455 (1970 SX) was just finished and the builder put in an Engine Pro MC2010, Stage 3 Cam:

Duration at .05: 214/224
Duration: 280/290
Lift: .472/.496
Lobe Sep: 107/117

Anyway, I had wanted a fairly stock cam with a bit of a performance upgrade, but appropriate for street use. This cam seems a bit radical for me, but was hoping to get your comments on the specs and also if anyone has had any experience with Engine Pro products.
I have a TH400 with 3.08 rear end, 215-75 R14 tires, dual stock exhaust system, stock intake, stock 4B quadrajet, stock ignition, power brakes. The rest of the engine rebuild was fairly stock with new Keith Black pistons KB277 30 over.
Here is a link to the Engine Pro site:
http://www.enginepro.com/oldsmobile.html


Thanks, Peter

 

Those are all generic grinds, you should be fine but they are a bit lazy.

I hope he didn't charge you more than about $80.00 for that cam, they're available everywhere.

 

Not sure I understand what you meant by "but they are lazy?". Could you elaborate?

Thanks.

He charged me a bit more than $80, but he has to make money too.

 

It's more of a dated,obsolete grind.With today's knowledge & technology,there are a lot better grinds out there.

 

Thanks Brian. Could any one offer a specific suggestion, considering I did not want to be too radical, with some good low end torque.
The engine is still out of the car, and if there is an opportunity to change the cam it is now.

 

Joe - thanks for the info.
After reading a bunch of stuff I now know what a "lazy" cam means.
All in all I decided I am going to keep the cam that is in there. Since it will be street and highway ride I do not not need anything too big, and am looking for quiet effeciency.

Thanks to everyone for their time and thoughts.
Peter

 

Just an FYI, that's incorrect. You're describing duration, there is no decimel point in that. The editors on HP TV make the same mistake all the time. And LCA is centerline, that's adjustable, normally it's stated as LSA, that's ground into the cam.
Size has nothing to do with whether or not it's lazy. You can have a small cam that's lazy and big one that's not.

 

I once got a cam that was 2.26 / 23.00 @5.00 4.96 / 5.12 lift on a .110 LCA, it was a great mix of street and strip and wasn't too loud. But it was a bit lazy as well...it wouldn't get in the engine when I told it to. I had to pick it up and put it in myself.

 

Then y0u have to spank it.

 

What I want to know is where I can get one of these cams for $80.00 retail. The cheapest I've found any of the "generics" is about $100.

 

If it is lazy then send it to the Army (or Air Force ).
But seriously:
- so does "lazy" mean that it is a bit slow of the mark?
- does "big" mean long duration and high lift?

I paid $116 for my cam, but that was through the installer, who ordered it and had it shipped. I would imagine his cost would be about $85.

 

When Mark says it's "lazy", he means the ramps are less steep/aggressive. It takes more degrees of rotation to get to max lift. Consequently, the valve doesn't spend as much time at higher lift where there is more flow.

Yes, big generally means more duration and lift.

By way of comparison, the Lunati 00083 (which is supposedly a "generic" grind you can get from Edelbrock and others) has these specs:

Advertised duration: 290 int/300 exh
Duration @ .050": 224/234
Valve Lift with 1.6:1 rocker: .496"/.520"
Lobe separation: 112 deg

The Engle/Mondello JM20-22 has these specs:

Advertised duration: 266 int/274 exh
Duration @ .050": 226/230
Valve lift with 1.6:1 rocker: .496"/.512"
Lobe separation: 110 deg

The .050" duration and total lift of both cams is pretty close, but there's a pretty big difference in advertised duration. So the Engle is going from zero to full lift more quickly than the Lunati. So even though both have similar .050" duration, the Engle will keep the valve open farther for a longer portion of that duration than the Lunati. (More "area under the curve".)

The Engle also has less overlap (although the Lunati has 2 deg more lobe separation to offset that somewhat). With less overlap, the Engle will hold more cylinder pressure, which may be desirable if your compression is on the low side.

 

Thanks for the short lesson. This is very interesting; I am going to find a good primer on cam design.

 

One footnote to that J is that the Engle's advertised specs are taken at .008 tappet lift, the Lunati's at .004. That will make the Engles' seem even faster than it really is when compared to the generic ones.
It is a fast ramp cam and they tend to be noisy but ramp profiles different in the way they accelerate the lifter throughout the lifting phase.
More area "under the curve" is better in most cases but not always.
Take a syringe and hold your finger over the end covering the hole only partially, then retract the plunger quickly. It's hard to pull open isn't it. That may happen if you have ports that don't flow that well. Now do it more slowly. That's why on stock iron headed applications I don't normally recommend fast ramp profiles. You may not have enough off the seat time on a fast ramp cam to better utilize your port characteristics.

If the fast ramp stuff was really for everything, don't you think the cam companies could save money by reducing thier inventory to only those grinds, I do. But on the flipside there are better grinds than the generic stuff too.

Hope this helps.

 

How can you tell by him posting the lift and duration. If cam A is the same numbers as cam B how do you know cam a is a fast ramp and cam B is a lazy ramp ? I understand the
speed or off seat time part but how do you know this cam is said lazy or outdated ?

 

Let's take 2 hypothetical cams with the same at .050 and both have their advertised duration taken at .006 of tappet lift.

1) has 285/300 advertised, with 228/235 at .050
2) has 274/286 advertised with the same 228/235 .050.

Cam #1 is slower because it has a total of 285/300 off the seat time in order to achieve the same at .050 numbers as Cam #2.

By the same token take the W-31 cam, 308/308, 232/232 at .050. This would seem way slower than Cam #1 but advertised figures back then were taken at .000 tappet lift. So even though it is slower than both #1 and #2 it's maybe not as much as it seems.

But something else to consider, how long does the fast ramp cam stay at max lift? Does it just kiss it then head back down or does it stay there as long as the slower ramped cam might? That will depend on lobe profile and the printed specs very seldom ever do a good job of describing that aspect.

Another potential issue with the fast ramp stuff can be described this way, would it be easier to climb a mountain 400' high if the base was 150' wide or if it was 200' wide? Obviously the latter is true, the faster the ramp the harder it is on parts, period.

Hope this helps.

 

I thought slower ramp speeds helped air flow in stock heads. That's what I have been told.

 

They can by helping port velocity.

 

Cutlassefi Im not busting your chops here. But why would someone want to stay away from a "lazy" cam . i mean we are dealing with 40 plus year old machines here. Assuming there is good compression and the converter is right. What would make these old generic cams less desireable. I have the lunati 00083 on a shelf and im currently running the comp cams 280h . Would the 00083 be better or im better off with what i have. Im currently working on a new shortblock and id like to pick a a cam that would improve my performance but if the one i have now will work i have it already.

 

As an aside here, if you or anyone is wanting to "go ancient" and are wanting a W-31 camshaft (402194), let me know. I've got about 15 left that I got from the OE supplier to Olds back in the day that he was about to scrap!

 

I don't think there is anything wrong with a so-called lazy cam. It just depends on your application. And I seem to recall that Bill Trovato says a somewhat "lazy" exhaust lobe can help exhaust flow by keeping the velocity up.

Part of the deal with most of the the so-called generic grinds is that they are meant to work with a stock valvetrain without causing accelerated wear.