Go Back   V6 F-Body.com > Technical Discussion > Valvetrain
Valvetrain Heads | Cam | Rockers | Pushrods | Valves

Closed Thread
 
Thread Tools Display Modes
  #1  
Old 09-03-2008, 02:59 PM
tkoforpresident's Avatar
tkoforpresident tkoforpresident is offline
Conservo-Ninja
LS Supporting Member


 
Join Date: Aug 2008
Location: Buffalo, N.Y.
Rank: First Lieutenant
Posts: 2,401
Default Camshaft FAQ

Compliments of FTV6

Camshafts and Your Car


-What does a cam do?
-How much power will I gain?
-How hard is a cam to install?
-What do I need to install a cam?
-Are there downsides to having a cammed car?


Well to start out, a cam is not a simple bolt-on modification, it is an integral part of the proper operation of your vehicle. THIS IS NOT A BEGINNER MOD. If you are not sure what it does, what it is, or how it works, I recommend a bit of research before you spend your money and make the wrong decisions.

For beginners, a cam is the brain behind the valvetrain, it is a shaft that has lobes (non-circular shaped arms that control the opening and closing of the valves) and these lobes are ground to a certain specification catered to the conditions your engine will see.


You have certain classifications of cam grinds:

Naturally Aspirated (N/A, all motor): specific for engines that have no power adders (Nitrous, Turbo, or Supercharger) Nitrous can be used, but gains will not be as high as a Nitours specific cam

Turbo: specific for engines running a turbo charger, pretty self explainatory

Supercharger:
specific for engines running superchargers, these are not the same as a turbo cam, since the process of building boost is different between the two

Nitrous:
these are modified N/A cams, they have certain specs built in to benifit from the nitrous, They are designed to be benifitial in a N/A application, but will optimize ppwer when nitrous is used.


What do the cam specs mean?


Duration:
This is the basis for how your motor will perform in the RPM range. A higher duration cam will make power higher in the powerband, and lower duration will make power lower in the RPM range. Duration refers to how long the valve is opened in relation to Crankshaft position. If a cam is listed as a 220 Duration, that means the valve is opened for 220 degrees of crankshaft rotation.

Lift: This spec is stating how far the valve is opened. measured in thousandths of inches (.xxx). More isnt always better, but you want to make sure that you have enough lift to compliment the duration, or you will have an airflow restriction.

Lobe Separation:
This refers to the spacing between the Intake Lobe, and the Exhaust lobe on the camshaft. This value is expressed in the in degrees on the camshaft, NOT the crankshaft.

Every company that sells camshafts will include what each cam is designed for. Naturally Aspirated cams will normally have a lobe separation between 110 and 113, Nitrous Cams are between 112 and 115, and Forced induction cams are from 114 and higher.


When looking at Lift and duration:

Naturally aspirated cams will tend to have an identical or closely split lift and duration.

Nitrous cams can tend to favor the exhaust side of the lift and duration to aid in relieving the cylinders of built pressures that the nitrous produces.

Turbo cams will tend to have a larger intake duration and lift compared to the exhaust side.

Supercharger cams will normally have a larger exhaust lift and duration for the same reason as the Nitrous, to help relieve cylinder pressures.


What do I need to buy along with a cam?


Valvesprings and Retainers
These are a must with any cam purchase. The extra load put on the valve trian due to larger lifts and faster ramps will be too much for our stock springs, so we must upgrade these.

The minimum for any swap is the 90 pound LS6 springs, these are good for most cams up to around .512" lift. You cannot use our stock retainers with these springs, you need to use a LS6 retainer or a comp cams brand retainer.

The next step up would be the Comp 915 springs, rated at 105 pounds. These are good springs which offer more tension, but less seat pressure than the LS6 springs. These can be used with any cam up to around .530" lift. Also you must use a comp cams retainer.

The largest valvspring we would need to use is a Comp Cams 918 rated at 130 pounds. these are heavy duty, use these with anything over .530 lift. these springs put a load on the timing chain and tensioner, so its reccommended to upgrade to a double-chain timing setup.

Install Kit
ZZperformance and Abbot Racing Heads offer a "cam install package" which basically consists of necessary gaskets, bolts, and other small odds and ends that you will need to complete the cam install. A few noted items that must be included are Rocker arm bolts and new Crank pulley bolt. These bolts are a one time use item, so after removal, you must use a NEW bolt for the crank and each rocker arm.

Rods and Lifters

New pushrods and lifters are not a necessary item to replace if you have a low mileage car, but if you have the motor apart and are replacing the rest of the valvetrain, why not go the extra step and finish it off with a fresh set of lifters and rods. The extra wear and tear that a camshaft puts on the valvetrain can prematurely wear out stock lifters, and the higher rev limiters and shift points can cause rods to bend slightly if a missed shift occurs or you bounce off the rev limiter a few times.


How Hard is it to install?

This is not a beginnners modification, you are working with key parts of the engine that have exact tolerances, one degree off in any direction can cause chaos in the motor, and frustration for the owner. Install time is around 8-12 hours, and can be done in a garage. You MUST have these tools before you think about diving into the motor.

Accurate Torque wrench, both ft/lbs AND in/lbs
Fuel line removal tool
Quality set of wrenches, sockets, and small hex bits
Sockets ranging in size from 7mm to 1 5/16"


Patience is the name of the game, there are alot of bolts that are a PITA, if you dont have the patience to allow yourself to be smarter than the car, you may need to talk with your councelor before attempting this. I HIGHLY reccomend going to the library and checking out the Chiltons Manual of your year car. DO NOT use a Haynes manual, that junk is not detailed enough for someone to effectively tear apart an engine.


How much power will I gain?

Each car is individual as the owner. Some cars are a bit quicker than others in stock form, some have issues that are unknown that will effect the performance. Some people have gained 10 HP from the cam swap, others have gained almost 100 with a good set of heads and a decent tune. At the track some have seen a gain of a few tenths, others a full second. The key to the camshaft is to have complimenting modifications. You cant just slap a cam in and be a new beast, the cam will make more power with the more you add to the car to help it do its job.


Any downsides to having an aftermarket cam?


As with any modification you do to your car, there are adverse effects. There really arent any serious effects to having a cam, depending on how radical you go, or the manintence you provide to your car the more issues you may encounter. You may lose some gas mileage, you may have issues with passing emmissions in some areas. The big thing you have to know is that your car will last as long as you let it. If you dont take care of it, or dont keep up with routine maintence then you will prematurely wear it out. As long as you supported the camshaft swap with quality parts and components rated for the specs of your cam, it should last as long as any other car out there.

I hope this helps some of you guys out there with some of the basics and i guess a bit of the advanced stuff that deals with this subject. There is a list of cams in this forum, use that and see whos running what. If there is a cam on that list that you are interested in, get in contact with the manufacturer, or if there is a members name beside it, contact them, ask them how they like their choice.

Go Back   V6 F-Body.com > Technical Discussion > Valvetrain
Closed Thread

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -4. The time now is 09:24 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
2008 - 2017 V6F-Body.com