Cam question???
Thread Starter
Racer
Joined: Feb 2003
Posts: 475
Likes: 0
From: cincinnati oh
Cam question???
I am thinking about buying a cam from a speed shop and they told me that the perfect cam for my 9-1 comp. 86 engine in my 84 vette is a crane 480 lift and 280-282 duration, with lifters for 120.00. now is that a good size of cam, and will i need a stall conv. for it?? Will i be able to hear the cam in it and is this a lot bigger and better than factory? :steering:
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: Cam question??? (vettespd20)
What series Crane camshaft is it? Cranes makes tons of cams in different series. Some are specifically designed to work with computer controlled TPI engines, some aren't.
Get the full specs on the cam: The .050 duration figures, lobe seperation Angle (which is important for a TPI engine) and what ratio rocker is used to derive the valve lift (I suspect 1.5 but always good to check to be sure).
We also need to know what you plan to do with the engine, modifications made or planned, expected idle characteristics' daily driver, racing, fuel economy, emissions testing, etc.
It's hard to be specific with only the information you posted.
Jake
Get the full specs on the cam: The .050 duration figures, lobe seperation Angle (which is important for a TPI engine) and what ratio rocker is used to derive the valve lift (I suspect 1.5 but always good to check to be sure).
We also need to know what you plan to do with the engine, modifications made or planned, expected idle characteristics' daily driver, racing, fuel economy, emissions testing, etc.
It's hard to be specific with only the information you posted.
Jake
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Cam question??? (vettespd20)
What is the LSA on that cam?
As a general rule the effectivenes of the cam depends on your target and on duration overlap, i.e. more overlap is good for high rpm but gives up low end torque whereas less overlap is better for low end but top end rolls off earlier.
So, try to chose a cam with overlap at advertised lift of around 30-55deg for good drivability. To calculate overlap in deg. add the two lobe durations, divide by 4 and subtract the LSA (LSA is measured in crank shaft rotation deg.).
As a general rule the effectivenes of the cam depends on your target and on duration overlap, i.e. more overlap is good for high rpm but gives up low end torque whereas less overlap is better for low end but top end rolls off earlier.
So, try to chose a cam with overlap at advertised lift of around 30-55deg for good drivability. To calculate overlap in deg. add the two lobe durations, divide by 4 and subtract the LSA (LSA is measured in crank shaft rotation deg.).
