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Howards Cams

27K views 21 replies 6 participants last post by  ap72 
#1 ·
Does anyone know where I can find cam cards or cam timing specs on Howards Cams? All I can find is lift, dur, and LSA. I have no idea when the valves open and close etc. The problem is that I work hours that do not allow me to call their tech support. They're closed by the time i get home. Anyone have any info?
 
#3 ·
F-BIRD'88 said:
You can easily calculate the valve events using a calculator.
with .050" duration and LSA. If it really matters to you, you are going to degree a cam in on install and adjust the cam phasing accordingly anyway.

I know, but I want to find the actual intake valve closing at .050 before I buy the cam. I need an early closing intake, say about 34* to 35*, with a 108* LSA. I found a couple of cams that have the specs I'm looking for but don't know the valve timing events.

I hear ya, techinspector1, I'm about to go with the Crower or Isky that I found.
 
#5 ·
Greg T said:
I know, but I want to find the actual intake valve closing at .050 before I buy the cam. I need an early closing intake, say about 34* to 35*, with a 108* LSA. I found a couple of cams that have the specs I'm looking for but don't know the valve timing events.

I hear ya, techinspector1, I'm about to go with the Crower or Isky that I found.
Contact Crower,they can grind most cams with the LSA you want if you don't find an off the shelf offering.Also Engle Cams will do that for you too.
 
#8 ·
F-BIRD'88 said:
You can easily calculate the valve events using a calculator.
with .050" duration and LSA. If it really matters to you, you are going to degree a cam in on install and adjust the cam phasing accordingly anyway.
This is not possible. You must have at least one additional value to figure the timing events, either Intake Centerline or Exhaust Centerline.

Examples:
Cam A has a 0.050" duration of 240 degrees, lobe separation angle of 112 degrees, intake centerline of 112 degrees and the exhaust centerline is not published. Since we know that the LSA is a result of adding the intake and exhaust centerlines and dividing by 2, we can deduce that the exhaust centerline is 112. Timing events would be 8/52/52/8.

Cam B has a duration of 240 degrees, lobe separation angle of 112 degrees, intake centerline of 110 degrees and the exhaust centerline is not published. By deducting 110 from 112, we find the value 2. By adding 2 to the lobe separation angle of 112, we can deduce that the exhaust centerline is 114. Timing events would be 10/50/54/6.

Cam C has a duration of 240 degrees, lobe separation angle of 112 degrees, intake centerline of 108 degrees and the exhaust centerline if not published. By deducting 108 from 112, we find the value 4. By adding 4 to the lobe separation angle of 112, we can deduce that the exhaust centerline is 116. Timing events would be 12/48/56/4.

Cam D has a duration of 240 degrees, lobe separation angle of 112 degrees, intake centerline of 106 degrees and the exhaust centerline is not published. By deducting 106 from 112, we find the value 6. By adding 6 to the lobe separation angle of 112, we can deduce that the exhaust centerline is 118. Timing events would be 14/46/58/2.

So you can see that even though all 4 of these cams use the same duration and the same lobe separation angle, the timing events vary widely depending on the intake and exhaust centerlines. Therefore, it is not possible to figure timing events with duration and lobe separation angle only.
 
#9 · (Edited)
ap72 said:
calculating the valve events isn't taht hard, use your LSA to find your ECL off your ICL and you're almost done- assuming symmetrical lobes.
Please explain in detail how this is possible. I am always interested in learning new methods. :rolleyes:

I have a camshaft that has 240 degrees duration @0.050" with a lobe separation angle of 112 degrees and the lobes are symetrical from opening to closing flanks. What are the timing events, based on your statement here??? :spank:

Oh, and just so you and the rest of the lads here know, there is no difference afforded by whether the opening and closing flanks of a lobe are symetrical or asymetrical. That part of the lobe profile has nothing to do with the opening and closing points ground into the lobe at the time of manufacture. An asymetrical lobe is used to jerk the valve open quickly and return it to its seat more gently to help prevent valve bounce on the seat. A lobe can be ground symetrically or asymetrically and still have the same opening and closing points.
 
#10 · (Edited)
airboat said:
While we have the Howards cams heading, Good quality stuff? How is their Roller lifters and cams. Price? I was thinking of checking them out
I have never heard anything bad about Howards Cams. My problem with them is that they don't publish enough information. If they would simply add either intake centerline or exhaust centerline to their specs, all aspects of timing events could be figured.
 
#12 ·
F-BIRD'88 said:
You do not know the actual "running duration" of a cam anyways from the published specs therefore you cannot determine the the actual intake valve closing point in the actual running engine. The "advertized duration" is not the same a the actual running valve open, valve close duration in a running engine. Without knowing the actual running timing points any/all such dynamic compression calculations will be false.
A running engine is not just a simple compression pump. The in cylinder pressure is a lot different at the running rpm in a running engine than it is while just cranking the motor over with the starter.

If the Howards cam is manufactured so that when you install it, it is "straight up", then there is nothing stopping you fome moveing it a bit to achieve X intake closing point.
If the howards cam is manufatured so that it goes in 4deg advanced (typical of most street cams) and that does not result in your predetermined optimin intake closing point, then nothing is stopping you frome moveing the cam a bit.
if all this really matters to you you will be doing the math and degreeing in the cam anyways to verify correct valve timing regulardless of what brand you buy.
You're not making any sense here.

In the third paragraph, you say "if all this really matters to you you will be doing the math and degreeing in the cam anyways to verify correct valve timing".

But in the first paragraph, you are saying
"You do not know the actual "running duration" of a cam anyways from the published specs therefore you cannot determine the the actual intake valve closing point in the actual running engine. The "advertized duration" is not the same a the actual running valve open, valve close duration in a running engine. Without knowing the actual running timing points any/all such dynamic compression calculations will be false."

So again, I ask, why rely on numbers at all. You're saying in the first paragraph that we can't possibly know the actual timing events and in the third paragraph you're saying that a builder should verify correct valve timing. You can't have it both ways.

I'm aware that pumping cylinder pressure is higher at the torque peak than it is cranking the motor with the starter, but WE HAVE TO START SOMEWHERE. Otherwise, like I said in a previous post, we should just belly up to the counter and buy any cam and install it on the marks and forget it.
 
#13 ·
Techinspector1 has the right idea. The problem here is that everyone is assuming way too much and being much more critical than is necessary.

First, if I could determine the valve timing events from the info provided by Howards I would have done so. All they give me is lift, dur, and LSA. Now, I don't claim to know a hell of a lot about cam timing, but I do know that the intake valve can close just about anywhere and still maintain these given fugures.

The cam I choose is not critical to a build because it is going into a fairly stock 350 with ehaders, 416 heads and 175 psi cranking pressure. Yes, that is all I know about the engine. The only reason I am changing the cam is because I have a bad lifter that intermittently collapses. So, as long as I am changing the cam and lifters I may as well put something in there that will give me some grunt. The reason I want an early closing intake is preserve the cylinder pressure. I know enough to know that a 34* or 35* intake closing will give me more torque and streetability than a 46* closing and the tighter LSA will give me some good low end torque. I have found THIS ISKY , and THIS CROWER . The Crower would be installed at 4* advanced to get near my desired closing point. I have a found a couple from Howards but they don't include this info. Thats why I asked.

Thanx very much, Techispector1, for the wealth of info.
 
#14 ·
Greg T said:
Techinspector1 has the right idea. The problem here is that everyone is assuming way too much and being much more critical than is necessary.

First, if I could determine the valve timing events from the info provided by Howards I would have done so. All they give me is lift, dur, and LSA. Now, I don't claim to know a hell of a lot about cam timing, but I do know that the intake valve can close just about anywhere and still maintain these given fugures.

The cam I choose is not critical to a build because it is going into a fairly stock 350 with ehaders, 416 heads and 175 psi cranking pressure. Yes, that is all I know about the engine. The only reason I am changing the cam is because I have a bad lifter that intermittently collapses. So, as long as I am changing the cam and lifters I may as well put something in there that will give me some grunt. The reason I want an early closing intake is preserve the cylinder pressure. I know enough to know that a 34* or 35* intake closing will give me more torque and streetability than a 46* closing and the tighter LSA will give me some good low end torque. I have found THIS ISKY , and THIS CROWER . The Crower would be installed at 4* advanced to get near my desired closing point. I have a found a couple from Howards but they don't include this info. Thats why I asked.

Thanx very much, Techispector1, for the wealth of info.
Greg, if you don't know where you're starting from, it's difficult to know where you're going. If I were in your position, I would mount a degree wheel and dial indicator and find out exactly where the intake closes on your present cam. I have a solid bar of steel cut to Chevy lifter bore size on one end and Ford lifter bore size on the other end. The bar is 8" long and squared off smoothly on the faces. I use it in place of a tappet when checking timing events instead of a solid lifter. If you turn the block so that the tappet bore is vertical, there is enough weight from the bar that it will ride the lobe well and give you credible readings on your dial indicator. The other reason to use it is so that the length will get you up past the deck so you can easily mount your indicator.

Once you know the timing on the cam that is in the motor now, you will be able to make an intelligent decision on which way you want to go. Doesn't make any difference whether the present cam is installed straight up, advanced or retarded. Just read the numbers off the degree wheel and write them down. That's what the motor is seeing. It doesn't care where the centerline is, it just know that is opens and closes the valves subject to the present centerline, whatever it is.

So, when choosing the replacement camshaft, you can replicate the timing events you now have going on or change them according to what you think the motor will tolerate. You can order a cam with custom events or an off the shelf unit and install it wherever you want to alter the events you currently have in the motor.

But, like I said, I would find out where I am first.
 
#15 ·
Thats an idea. It is just a stock-type parts store rebuilt motor with very smooth idle. But i will slap a degree wheel on just to make sure. I'm not wanting to go radical because the 416 heads don't flow anyway. And, it's just a daily driver S10.
Thanx!!
 
#16 ·
techinspector1 said:
Please explain in detail how this is possible. I am always interested in learning new methods. :rolleyes:

I have a camshaft that has 240 degrees duration @0.050" with a lobe separation angle of 112 degrees and the lobes are symetrical from opening to closing flanks. What are the timing events, based on your statement here??? :spank:

Oh, and just so you and the rest of the lads here know, there is no difference afforded by whether the opening and closing flanks of a lobe are symetrical or asymetrical. That part of the lobe profile has nothing to do with the opening and closing points ground into the lobe at the time of manufacture. An asymetrical lobe is used to jerk the valve open quickly and return it to its seat more gently to help prevent valve bounce on the seat. A lobe can be ground symetrically or asymetrically and still have the same opening and closing points.

symmetrical lobes can affect it because it changes where the CL's are at, do you mark the centers at the lobe peak or split the difference on the .004" numbers, the .001" numbers, the .050" numbers or the .200" numbers- all of them will give you a different centerline on the same lobe profile if it is assymetrical, and even cam manufacturers disagree on the best method.
 
#17 ·
Am looking at the following:

Chev SB (Hydraulic)
Lift: .449/.449
Adv. Duration: 290/290
Duration @ .050": 224/224
Lobe Center: 108
Hot Street, 4bbl. & Headers Recommended


And:

Chev SB 262-400
Application: Max Torque
RPM Range: 1700-5700
Lift w/1.5 Rockers: .470/.470
Adv. Duration: 284/284
Duration @ .050": 220/220
Lobe Sep. Angle: 108
Recommended Valve Springs: 98214



But I wanted to kow how the intake closing coinsides with the Isky and the Crower.
 
#18 ·
Okay, one more question. Let's say the cam card shows an intake closing of 35* at .050. But the cam card also says 4* advanced. Does this 35* fugure mean the 4* advance is already accounted for, or if i install the cam normally without an offset key will it close at 31*? In other words, are the valve events posted on the card using straight up or 4* advanced timing?
 
#19 · (Edited)
I havent had the time to calculate anything since I spent most of the day yesterday in the ER. But, you're saying that the isky's timing card already reflects the 0* advance. So, in other words, just installing the can as directed by isky using the existing marks should be correct. Or. close to it depending on tolerances. I will check it, I'm just trying to clarify. Some cam cards make note that the cam is 4* advanced and I didn't know if the card timing frelected that or, if I installed using their timing marks the valve events would not coincide with the cards events. Does that make sense?

On a second note, the Crower I'm looking at says intake close at 37* but says nothing about advance. Should I advance that one 4* to get my targeted 35* . See, this is not a build. It's just a simple cam swap cuz I have a lifert collapsing in a stock rebuilt 350.
 
#20 ·
Because I skipped over all the back and forth about cam degreeing, I am not sure if anyone has answered your question about Howards quality....I have used their stuff and it is on par with any of the Big Name valvetrain components out there. Usually the price is better but the quality is very very good. (if not excellant)
 
#21 ·
Well, that's really why I was looking at them to begin with. I know, roughly, what I want to throw in there for the time being and found it hard to swallow Isky's pricing. This cam will probably only be in service for a year or so as I am planning on making a drag truck of this S10. I just need it to be dependable until I get everything I need to do the project. Right now it is my daily driver and since I need to replace a lifter I thought I would just give it a little more snot and a tougher sounding exhaust note while I had it apart. I may just grab the Howards based purely on price alone. As long as I can get thru the break in process I should be fine. I don't even plan on changing springs for this motor.
 
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