For what it's worth, I mentioned upgrading the cam in my 3.2 to an RV style cam when I thought I needed a rebuild. Both rebuild companies I spoke to said they could do it, but would not offer any type of warranty on the engine. I decided it would have been a bad idea anyways, since most of the driving I do is at the lower end of the power band.

Based on that argument, I guess I should change back to the original exhaust system so my engine will last longer. <img src="/forums/images/graemlins/smile.gif" alt="" />
Don't you think they keep OEM cams "tame" for a reason other than for the sake of the engine's overall durability? Like the same reason they use lousy, restrictive exhaust systems, pull hot air into the air box, and all the other power-robbing things they do?
<img src="/forums/images/graemlins/cheers.gif" alt="" />
Phil

Cahse si Rgiht gyus.

There isn't enough difference between the stock cam and the Delta regrind to make any difference in longevity. It's not like you are putting a high lift high duration cam in the little 2.6 and getting 300 horsepower out of it.

Manufacturers are trying to please everyone. They have to please the ones that want gas milage, emmissions, smooth power all along the rpm range, good idle. All of which most of us would give up if it meant we could upgrade our chipmunks to squirrels. I know I will find a Delta cam and put it in next valve adjustment and not think twice about it.

As for the Honda/Toyota comment about them making cams, well yeah why does Crane cams exist, for people that want to put in a cam that's beyond what normal america wants in their "stock" mustang or S2000.

Let's all agree this is speculation--despite deeply stuck ideas, none of us have talked to designers, planners and costs analysis folks at Toyota, Honda, or Isuzu.

I can understand why vehicle manufacturers would use smaller tailpipe, if it has only a small effect on HP. 2 lbs less metal per vehicle, times millions of vehicles...times the current price of steel. 5 cents per narrow tailpipe, vs a 1 hp or 1/10th MPG loss (Reported vehicle MPH is rounded to the nearest integer anyway), pretty soon you've saved a lot of money. Ford celebrated saving 5 cents on their ashtray design about 4 years ago.

ò Belief 1. I believe that cam timing wasn't chosen at random on vehicles, but for an overall balance of many factors, including power and reliability.
ò Belief 2. When you're machining millions of cams, a slight change in the lobe shape is inconsequentional in cost (from what I know about metalworking 100k+ runs of housings and frames at my job).

Who do I put blind trust in: a team of Toyota/Honda (and Isuzu) engineers with decades of experience who mass-produce millions of the USA's most reliable vehicles and proudly display their HP/Torque numbers, or some guys (including me) with no engine design or engine reliablity experience guessing on a web board.

I'm not saying professional engineers can't screw up and someone else can come along later and re-design better. I'm just having a hard time believing some small shop can out-design Honda-Toyota-GM-Ford-Chevy-Isuzu, and in 10 years time, the auto manufacturers can't copy the idea. Getting a small HP increase must come at the cost of something else--even if it's just a slight drop in *projected* engine life, fuel efficiency, rougher running, etc.

As for the "There's a cam company out there, so it must be true" arguement...that's the classic example of circular, self-reinforcing logic. there's MAF resistors out there (that work--with a cost). There's turbos and superchargers that work--with a cost. There's intake "tornados" and magic magnets that have all been out there longer than Crane and people buy them--so they must be true, too. There's even pills out there that will make me lose weight and make my...uh...well, that's just spam. Nowhere on Cranes website does it say "More power with absolutly zero negatives or drawbacks-guaranteed." Unfortunatly, their help line isn't 1-800 or I'd call.

You may *want* a free lunch, but it's very rare to find a working perpetual motion machine. If anyone wants to call a major automotive systems engineer or even a cam design shop and get facts, I'd be willing to listen.

What exactly does Crane Cams or Comp cams do as a company? I thought they designed and dyno tested cams for engines. If they were not successful in what they did they wouldn't still be around. Evidently they do something the car manufacturers don't do. Although Ford has stepped up in the past and has thrown some pretty radical (used to be aftermarket only) cams in new mustangs and warrantied them.

I relize what you are saying. I already said it. Yes, there are trade offs. These trade offs don't necessarily include decreased engine life. They may if you are radically modifing the stroke and bore and drastically changing cam profiles. I don't think that's what's going on here.

Most of us would agree that if we could gain 15 hp and loose a mile per gallon we'd do it in a heartbeat. Or even get a lopey idle, who cares.

A simple regrind isn't going to change your longevity. It it very well could change your gas milage, your quality idle (not in a 2.6 to begin with), and possibly your vaccum. But you have to remember everything works together as a system. The fact that I have already changed a bunch of stuff on my engine to begin with says that I'm already outside of the scope of Isuzu manufacturing. And yes I like it better. Is it better? In my opinion it is.

I agree that manufacturers don't pick cam timing out of the air, but I believe it's based more on emmissions, gas milage, and a flat torque curve than reliablity.

I will be contacting Delta and Calmini and see what they have to say about engine life and the use of their cams.

I doubt any of us know personally a cam profile designer that would be candid. Although I doubt Calmini or Delta will tell me that using their cam will shorten my engine life (even if it would) They wanna sell cams.

\

True, but di you know that you can slightlyincrease hig end power(at a loss to low end), by advancing you cam timing a a couple degrees, adn slightly increase low end, at a loss to high end by retarding....


Okay, how about someone who has worked ina speed shop, that has worked with Callaway, adn Lunati... regardless.

Anyone I have built enough motors, adn still do regularly, to know what I am saying.. you may not want to believe, or agree with me, "because I seem to young to know anything"..

But Wayne, we are all familiar with your skeptism, adn thats cool. I can totally go with that. I am the same way with "cheap speed"..and agree there is no such thing..but this isnt what we are discussing here.

GM offered performance cam shafts as RPO options during the 60-70s.. one of 2 ot them were
Off road Specail" cams(one for SBC 327/350), the other for BBC..

Both were solid lifter(adjusting valve lash very frequently), adn both were covered under the factory warranty, as long as they were installed by a GM certified tech...

That is just one example....
ANd honda has come up with a cam set-up..its called VTEC, it has 3 cam profiles.. very effecient, --all the way to very powerfull...(same motor that got 120 hp per liter in the orignal S2000)

Regardless, designers/engineers, have to meet a certain VE(volumetric effeciency), and them make the engine runn smooth at idle, under the load of accersories, maintian a certain vacuum at various points int he rpm band, AND meet EPA/emission standards... and the fact the these motors will be used behind auto adn manaul trans..(which can make a world of difference)

When cams are replaced with aftermarket, there are some comprimises(sp?).. like vacuum, ilde, and emissions..
Second to a super/turbo charger, adn Nitrous, cams produce the most bang per buck of mods, adn if selected properly.. without much, if any difference in reliablilty.
Allt he cam does, is open and close valves.. allowing air in and out. The only time there is a bad side to this, is when you force it in(super/turbo). The motor can only take in so much air/fuel per stroke, and then you get to a point, when the cam isnt worth the money, because you aer losing vacuum at no gain...

Valve lift is the point where you could break stuff, if the cam mfg'r doesnt do their homework, as you can bend.break stems, seals, followers, keepers..etc....

Duration, is what determines the actual power band..lower duration number, the lower the power band, adn usually broader.. just the opposie fro a higher duration number, though there are variations there as well... lobe seperation, and centerline have an effect as well...

There is a lot of science that goes into this, even in a regrind.. then motors are tested, thuroughly, and when a profile works, the keep those numbers, adn run the cam...

Again, I understand your standing... adnI will not say there is no trade-off..there is, your vacuum is lower(though you shouldnt notice that ), you are burning more fuel, adn you are smiling...
As far as longevity,in such a smal cam, no...if you beat the snot out of it..to show the difference in your cam..then yes.
If you do other things to enhance the cam profile, like zero decking the block, machining the head, etc.. then all bets are off.

Teh most common problem with cam profiles, in fuel injection, is with speed density..but thats a whole other ball game....

Chase

I just have to ask...are you serious? I mean, seriously...are you seriously serious when you question the merits of a performance cam? Do you not understand the concept of emissions and efficiency requirements and such, as they pertain to automobile manufacturing?
I mean this with all due respect, but are you really serious?
<img src="/forums/images/graemlins/cheers.gif" alt="" />
Phil

I'm quite serious.
But I am not questioning the *merits* I keep saying I have one and like it. People like GreenAmigo say it goes beyond dyno and they can feel the difference.

I am questioning when people say there are zero tradeoffs. ChaseSpeed is agreeing/disagreeing with me at the same time--I don't see how you can change cams and get more power without affecting longevity, fuel efficiency, emissions, etc. He agrees with that. So...end of story. The only thing I'd disagree with him on is the "Cam Testing." They might test for power/torque over RPM, but they don't put them in 20 engines and run them for 150k miles to test them for longevity. (Side note: It's not personal and I don't know your age.)

If you're going to say there are only gains and no drawbacks/negative effects, then I'm asking for actual proof. That seems to wind people up. "They make things and people buy them" is not proof that something has zero drawbacks. See the MAF resistor (and how someone asks about it every few months). People will buy anything--even pet rocks. Millions get spent on "magic pills" you get in your e-mail, despite news article after news article they don't work.

ChaseSpeed said it best, if not the most clearly. There are tradeoffs, usually in the power/torque curve, but I'll also bet in emissions. This might be important if you're close to the line and living in California.

A great example is Honda's VFR750 engine. It was a classic in it's day, and still a great engine. They tweaked it for more low-end torqe, at a cost of high-end torque/hp. Now it's a great cruiser engine. Speaking of proof, here's dyno run results:

Okay...I see your concern. Certainly, there are cams available (for more popular engines) which are designed for high-RPM horsepower on overreved and/or overboosted engines which can hardly idle straight and probably don't last as long as a Yugo. But in the case of these comparatively mild cams for the 4ZE1, I just don't see any longevity issues other than the point Chase made earlier, about how you treat your engine. If you throw in a new cam and drive it like you stole it, you're bound to run into longevity issues (well, even without the new cam the same thing would apply). "Valve float" would be much easier to achieve if you're pushing the rpms and you've got a performance cam. And that would be less than ideal.
So, let's assume that you drive normally (if we can agree on what "normal" is). For example, my 2.6 rarely exceeds 3500 rpm, and *almost* never exceeds 4000. If I had a "performance" cam, all it would be doing is opening the valves a little longer and/or a little further to allow more air/fuel mixture in. Not so much more that the computer and injectors can't keep up with the increase. And the mixture is not being "crammed" into the combustion chambers by forced induction. It's just allowing a little more to come in.
As far as emissions go, it's increasing the total amount of exhaust gases (because it's allowing more air/fuel into the combustion chambers), but it's not doing anything to increase the concentration of harmful pollutants found in those exhaust gases. Same thing with headers, really...you still have "x" ppm of any given pollutant, but more exhaust in total. Which is why people in CA have passed smog inspection with headers and/or a Delta/Calmini cam...the bad stuff is measured in ppm without regard for any grand total. Along the same lines, but at the opposite end of the spectrum...some redneck tweaker once told me to cut a hole in the exhaust pipe of a car I had that wouldn't pass smog. That wouldn't have done anything to affect the sniffer test because it's measuring parts per million, regardless of how many parts there are in total.
Well, that's all just my opinion anyways...that if you drive "normally" with a Delta/Calmini cam, you won't run into any longevity issues. I understand and respect your concerns, but I don't happen to share them on this issue.

oh...one more thing. Your example of the Honda motorbike engine...look at the significant difference in those numbers, is one engine "less durable" than the other?
I'd venture to say no, unless it's abused regularly.

It's never personal, bro. And I'm 32 next month.
As always: <img src="/forums/images/graemlins/cheers.gif" alt="" />
Phil

one thing i can garantee after market cams effect are the valve springs. You open up the valves more, you also compress the springs more, which for sure decreases the life of them. I am no spring expert, but in the injection mold i run, springs break a lot faster if i compress them more.

kevan