Could someone give me a quick tutorial on cams? What are the specs? I'm looking into buying a new cam and need to know what it is I want(fairly mild I quess). What kind of hp increase would I see with stock(97)heads.

 

Here's a good forum that discusses cams in more detail.

 

We just published a Cams 101 paper on our site. Check under the "Tech" Section and let me know what you think. I would really like to know if it was helpful or not.

 

Know what? I appreciate you putting all that good info on cams on that site, however, I read it and came away like a calf looking at a new gate. :crazy: :crazy: I am sure for real smart guys it is excellent, but I just need to know how each grind of cam would differ basicly from another. I know that is an over simplefication for so many other varibles present, yet I am a bottom line guy and would like the know....lets say...this one give high end power while another spec give low end torque and idles lumpy. Is this possible? :conehead

 

This is really generalized, and not true in many cases, but here goes nothing

1) Intake duration - increases the rpm at which the HP and Torque value peak - Hp will increase, torque may stay the same or drop. A bigger intake duration can give a worse idle

2) Exhaust duration - may increase torque or keep it the same, will extend the HP range without changing the peak hp much. A bigger exhaust duration can give a worse idle

3) Lift - more lift is always good - it's free hp and torque. The only negative is wear on valvesprings. On the LS1 just get some good double springs (heads need to be machined) and you are golden. Get as much lift as possible, but don't sacrafice other specs for lift.

4) LSA - the narrower (lower number) the lower the rpm peak and higher the torque value. Hp peak will generally stay the same, but the rpm at which it occurs will be lower. Overlap will increase and the cam will be "lumpier" As it (LSA) increases your torque value may stay the same or lower. The rpm of your hp peak will increase, and your hp value may also increase - though at a higher rpm. Your average torque will be lower. The cam will idle better as the LSA get's wider (bigger).

5) Advance (LSA - Intake Centerline = advance) Advancing the cam will shift your torque curve to the left so yoru peaks are at a lower rpm, and your hp values are lower (because of lower rpm). Retarding it will do the opposite. Advancing helps idle, retarding hurts it.


Okay, now also realize that when we look at duration numbers they are duration @ a single point (normally how long the valve is open @ 0.05" or more). There are ton's of other point on the cam. YOu can have 2 cams with the same 0.05" duration that act totally different because of their other values (how quick the lobes are, etc.). When you get into agressive hydraulic rollers they will be similar, though some will be more predisposed to valve bounce/float because of their profiles (like the xtreme energy cams).


Now again, this is VERY general and is only applicable to a narrow range of camshafts, but hopefully should give you a general idea.

 

Chris,

Thanks....even I half way understand that. Used to live in CC...don't mess wit Texas because the eyes of Texas are upon you. :p:

 

Thanks chris that definitly helped. Is machining the stock heads cheaper? I notice new heads are alot more that a cam, would it make sense to do a cam and not heads? What can I get for my used heads from my 97?

 

You can certainly do a camshaft without porting your heads. I would suggest you consider pulling them and having them machined for double valvesprings. the single springs work well for some people, but for every person who has no problem there are 2 who have broken them. A broken valvespring can cause anything from minor downtime to a trashed motor, but is something you should avoid at all costs!

A fully worked and assembeled set of stage II heads (valves, springs, etc.) is about 2000 dollars. On the flip side camshafts are around the 400 dollar area (Depending on who you go with for your grinder, etc.). Now you can't just swap in a camshaft - at a minimum you need to change the valvesprings also. You can do this while the heads are on the motor, but this not only a PITA, but isn't the best way to do it - and wont allow you to run better springs.

A few f-bodies are hitting close to 400rwhp with cam and bolt ons only, though the average is around 370 rwhp - this is definitly a worthwile mod!

Re: used heads - you can pick up cores from many places. I think LS1 cores are going for around 350 if I am not mistaken. You can also use 5.3l truck heads on your engine for a bit more compression with the same flow (if ported), and 6.0l truck heads (which are virtually identical to the Z06 heads, but for ~450 bucks).

 

ok now I'm sounding stupid but whats the core. Will a used ls1 core alow me to run double springs. Would that be the best route for saving money

 

"core" is a term that basically means a used motor part. If you go to someplace like auto-zone and bought, say, a new master cylinder you can either return your old (broken) one as a core, or pay a "core charge".

When talking about heads, blocks, it just means a used set of heads/castings generally. When porting heads it's actually better to start with heads that have been run before (heat cycled). Brand new heads will exhibit a little core shift for the first few heat cycling events, and so ifyou port a set of virgin heads after you runt hem they *may* move around a bit.

The cheapest way would either be

1) Pull your heads and send them off to be worked - there will be no out of pocket expenses for heads, but you have down time.

2) You can either pay a core charge, which gets refunded when you send in your stock heads, or buy a new set of castings yourself. This requires a little more money up front - but money you should get back when you turn in your heads (for the core charge) or sell your stockers (if you bought new castings outright). So the net outlay will be similar, but without the down-time.

 

so the used heads(or cores) you are referring to(for $350) is minus the core charge? So I buy a set of used heads(for around3-400) pay the core charge wich should be what? Have them machined for double valvesprings which should cost about what? Then send back my old heads and recive my core charge back? Whats a ballpark out of pocket price after all is said and done on getting the heads that I need(after core is refunded or old heads are sold)?You've been very helpful thanks!!
Could you suggest some cams, just wand some more power and some better sound something thats not going to have me in the engine all the time cause of broken springs etc,...(I already have most of the bolt ons)

 

Let me correct that for ChrisB.
If you pay a Core charge up front, you will not have to buy a set of heads(StageII + core charge is $2500). We have extra heads in the shop. We will port those and send them to you. When you receive them, you would take your old ones off and send them to us and bolt the ported set on to your car. We would then promplty refund the $500 care chage when we got them in the mail from you.
The other option would be to pay $2500 outright for a set of Stage II heads and keep yours. This would allow you to return to stock at a later date. Some people prefer this.
As for cams, one of my favorite cams is our #2 custom grind. This is a little milder of a cam that has made in the high 420's RWHP on a C5 with LT6 intake and TPIS headers. It idles VERY near stock. The Specs are:
222/222 .540/.540. Depending on what you are looking for, I would recommend this ground with a 114* or 116* Lobe Seperation angle. This will give you better idle quality.

We have some much more radical cams if you are interested in those also. They will make more power, but the idle smoothness will decrease somewhat.

I am sure ChrisB will reccommend a cam or two also.
Good Luck,

 

Or you could pay 2200.00 outright for our stage 2 heads and add a cam for 375.00! Regular price is 399.00 but we give a discount with a head purchase.
400.00 core refund if you send yours back!Of Course all of our heads are machined and ported in house and come wih flow sheets so you know what you got for your hard earned money.
Also all heads come with dual valve springs and titanium retainers.