I am in the market to purchase a set of cams and was wondering what the pros and cons are for the Tomei Poncams (260,270, and 280) against Cosworth's M1, M2, and M3 grinds?

Which would you purchase, and why? I wouldn't mind upgrading the entire valvetrain completely (valves, springs, cams, ect.), but I know saying that, if I purchase Cosworth (or Tomei) cams, I am going to be sticking with that brand. I perfer reliability of outright power, but I think my brand choices ensure I get good quality. BTW: for the time being, I'd like not to touch the head until I have another car to daily drive; so maintain a civilized car is perfered, though sometimes I do take the least civilized product because of some aspect that just out shines, and out weighs the cons of a more aggressive operating vehicle.

Thanks

 

Lots of info in the forum-- here's the deal--a civilized car--remains to be deifined--to me it means one thats drivable and its going to depend on your personal tolerance. A mild cam will improve drivability across the power band and longer durnation cam will drive top end power at the expense of lowend power--you decide. Pick a good cam company and you have listed 2 and make a choice. you want big power go for big cam numbers--you want to stay civilized as you have outlined--stay at 270* or below.

 

BTW: for the time being, I'd like not to touch the head until I have another car to daily drive; so maintain a civilized car is perfered, though sometimes I do take the least civilized product because of some aspect that just out shines, and out weighs the cons of a more aggressive operating vehicle.

Thanks[/QUOTE]


I think you may be a little confused about headwork and reliability. Replacing the head improves flow, although the stock head is good for a decent amount of power. Aftermarket heads are going to be reliable as well.

As for a "civilized" vehicle I'm not entirely sure what you mean there either but I will take a swing in that you mean something that isn't breaking down (or sounds like it). Cams alter your car's sound. The exhaust changes from a steady idle to a lopey idle. The following is an example: http://www.youtube.com/watch?v=f0x2s841J3s . I personally have Cosworth M2s on my car and they run and sound great. Cosworth is also of a good quality and you can rely on the name. It also depends on what you want to do with the car to determine which cams to get. If you are going with a big turbo then you probably want to get more aggressive cams. If you are sticking with the stock turbo then M2s are about as aggressive as you want to get (as far as Cosworth is concerned).

 

[/QUOTE]

As for a "civilized" vehicle I'm not entirely sure what you mean there either but I will take a swing in that you mean something that isn't breaking down (or sounds like it). Cams alter your car's sound. The exhaust changes from a steady idle to a lopey idle. The following is an example: http://www.youtube.com/watch?v=f0x2s841J3s . I personally have Cosworth M2s on my car and they run and sound great. Cosworth is also of a good quality and you can rely on the name. It also depends on what you want to do with the car to determine which cams to get. If you are going with a big turbo then you probably want to get more aggressive cams. If you are sticking with the stock turbo then M2s are about as aggressive as you want to get (as far as Cosworth is concerned).[/QUOTE]

What I mean by civilized is an idle that's not much higher than stock.

Now did you replace springs and valves when you did the M2s? I am thinking about going with Cosworth just because I can continue the Cosworth treatments for most of the engine. I want to try to keep the performance mods from the same company.

 

I read that unless you plan on reving past 7600 you don't need upgraded springs and valves. I did it anyway just to be on the safe side. It was only like $250 so I figured it was good peace of mind. My tuner up'd my idle to about 1k rpm because they are aggressive cams and when it was set at the stock idle it was kinda rough to sit in the car because it shook. Since then I've forgotten what the stock idle sounded like so I can't really tell you how much louder the car is, but I don't think the sound at my idle is obnoxious or overly loud. Sounds normal to me.

 

GSC S2 cams

 

I take it that I don't need upgrade valve springs and retainers with these cams so long as I don't rev past 8K, correct?

 

It really makes little difference, as Cosworth's parts are heavily outsourced anyway.


It's never a smart idea to combine factory valve springs with cams that specify a valve spring upgrade, for several good reasons.

FYI

 

Can you enlighten me further? Also, I will be needing to replace my timing belt, should I stay stock or are the other companies, such as Cosworth, Greddy, PE, ect. worth strapping on? What are the pros and cons of upgrading the timing belt to a non OE belt?

 

It's very simple. A cam with a more aggressive ramp profile requires higher spring pressures for the follower (lifter) to track the lobe accurately. If the spring is inadequate, we get valvetrain deflection, and that costs power. Think of it like you would a car with worn struts bouncing up and down as it goes down the road. You wouldn't exactly take it to an autocross.

When we get deflection in the valvetrain, we lose power, and may not even realize it. That would be a best case scenario. If the effect is allowed to go on, we'll begin to experience unusual wear to the cams and valvetrain. If something breaks in the valvetrain as a result, damage to the valves, pistons, etc., is a risk. In a nutshell, it's like buying a set of 3-piece wheels, and fitting them with non-speed rated tires.

As for timing belts, there are several aftermarket belts that should provide increased strength with upgraded valvetrains. I don't know of any cons to using them.

 

Tomei 260 poncams sounds like what your looking for you don't have to change the springs, and you get a lot of performance. But I suggest you put in arp studs when your installing your cams if you haven't already done so.