what cam do you recommend?
08-23-2007, 02:31 PM
#1
Thread Starter
Join Date: Jun 2007
Posts: 26
what cam do you recommend?
alright guys-i'm ready to buy a cam but im unsure which cam would be best for the setup i have. i was looking at the comp xtreme but didnt know which one or do you recommed a diff cam. any helpwould be great...ive got a '91 mustang 5.0l w/gt40 (not the p's) heads/w.1.7 rockers //65mm tbody/gt 40 intake//22 lbs injectors maf to match--aod -- going with a 3.73 ratio rear end but right now i will be using the stock 7.5" rear end...thanks
08-23-2007, 02:38 PM
#2
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
RE: what cam do you recommend?
If your block is stock and you are going with 1.7 rockers unless you plann to notch the pistons I would keep the base lift of a cam you choose at or around .480 to .498 lift as a general rule of thumb the 1.7 rockers from 1.6 give you a base increase in lift of about .030 so add that to the lift of the cam and you get the final overall lift
08-23-2007, 03:17 PM
#4
5th Gear Member
Join Date: Jan 2006
Location: Puerto Rico
Posts: 3,926
RE: what cam do you recommend?
ORIGINAL: mjr46
If your block is stock and you are going with 1.7 rockers unless you plann to notch the pistons I would keep the base lift of a cam you choose at or around .480 to .498 lift as a general rule of thumb the 1.7 rockers from 1.6 give you a base increase in lift of about .030 so add that to the lift of the cam and you get the final overall lift
If your block is stock and you are going with 1.7 rockers unless you plann to notch the pistons I would keep the base lift of a cam you choose at or around .480 to .498 lift as a general rule of thumb the 1.7 rockers from 1.6 give you a base increase in lift of about .030 so add that to the lift of the cam and you get the final overall lift
08-23-2007, 08:47 PM
#6
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
RE: what cam do you recommend?
What Is Piston-to-Valve Clearance And How Does It Affect Me?
This is best said simply ... "If You Do Not Want Your Engine To Explode And You Have Installed A Performance Cam, You'd Better Check The Piston-To-Valve Clearance!"
Piston-To-Valve clearance is just what it says ... the minimum distance between the engine exhaust and intake valves and the top of the piston at the closest given position of the reciprocating cycle. Piston to valve contact is probably one of the most common causes of damage to a racing engine. Piston to valve interference can be caused by many items, including: Cam Lift, Cam Timing, Piston Design, Timing Chain/Drive Failures, Deck Height, Cylinder Head Modifications, Valve Diameter, Broken Valvetrain Parts (valve locks, springs, retainers, lifters, pushrods and cam lobe failures), Valve Diameter, Connecting Rod Stretch, etc. In this article I will simply be addressing cam timing, cam lift, and basically anything that has to do specifically with the valvetrain.
Anytime you make a change to your engine in relation to the cam lift, cam timing, pistons, cylinder heads, rockers arms, or anything else that can change, even so slightly, the position of the valve in relation to the piston, you MUST verify that you have the minimum clearances safely met. This procedure consists of setting up your engine and measuring the clearance at the valves closest point to the piston and validating a "safety margin" clearance. This is typically .080" on Intake valves and .100" on Exhaust valves when using steel connecting rods. With aluminum connecting rods this dimension changes to .100" on Intake and .120" on Exhaust. The exhaust always needs more clearance because of the added COE (Coefficient of Expansion) of the hotter exhaust valve. These are standard numbers, in some cases you have to look at your entire combo and make your own decision as to the minimum clearance values.
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I agree that ptv issues are not always a result and or deciding factor in ptv problems....and I know duration plays a major factor in ptv issues......but come on....were dealing with a bone stock block and stock pistons ...you won't get 600 lift with 1.72 rockers to not have ptv issues even if your duration was on the light side.....I seriously doubt the guy is going to degree in the cam and or advance it or retard it to achieve maximum valve timing and efficiency.....most people install their cams straight up to be safe so this is why I reccommended what I did.......I agree with you Joel 5.0 that irregardless of cam choice ptv should always be checked....
This is best said simply ... "If You Do Not Want Your Engine To Explode And You Have Installed A Performance Cam, You'd Better Check The Piston-To-Valve Clearance!"
Piston-To-Valve clearance is just what it says ... the minimum distance between the engine exhaust and intake valves and the top of the piston at the closest given position of the reciprocating cycle. Piston to valve contact is probably one of the most common causes of damage to a racing engine. Piston to valve interference can be caused by many items, including: Cam Lift, Cam Timing, Piston Design, Timing Chain/Drive Failures, Deck Height, Cylinder Head Modifications, Valve Diameter, Broken Valvetrain Parts (valve locks, springs, retainers, lifters, pushrods and cam lobe failures), Valve Diameter, Connecting Rod Stretch, etc. In this article I will simply be addressing cam timing, cam lift, and basically anything that has to do specifically with the valvetrain.
Anytime you make a change to your engine in relation to the cam lift, cam timing, pistons, cylinder heads, rockers arms, or anything else that can change, even so slightly, the position of the valve in relation to the piston, you MUST verify that you have the minimum clearances safely met. This procedure consists of setting up your engine and measuring the clearance at the valves closest point to the piston and validating a "safety margin" clearance. This is typically .080" on Intake valves and .100" on Exhaust valves when using steel connecting rods. With aluminum connecting rods this dimension changes to .100" on Intake and .120" on Exhaust. The exhaust always needs more clearance because of the added COE (Coefficient of Expansion) of the hotter exhaust valve. These are standard numbers, in some cases you have to look at your entire combo and make your own decision as to the minimum clearance values.
back to top
I agree that ptv issues are not always a result and or deciding factor in ptv problems....and I know duration plays a major factor in ptv issues......but come on....were dealing with a bone stock block and stock pistons ...you won't get 600 lift with 1.72 rockers to not have ptv issues even if your duration was on the light side.....I seriously doubt the guy is going to degree in the cam and or advance it or retard it to achieve maximum valve timing and efficiency.....most people install their cams straight up to be safe so this is why I reccommended what I did.......I agree with you Joel 5.0 that irregardless of cam choice ptv should always be checked....
08-24-2007, 01:59 PM
#8
I ♥ Acer
Join Date: Apr 2006
Location:
Posts: 5,116
RE: what cam do you recommend?
what maf is in car? hell a cam isn't going to help much without a convertor your wasting $$$$$ also I never get a cam based on a 1.7 rocker....stay where you at,your at about .468 lift off top my head.
with your chosen cam would be a disater with bend valves and push rod......what size valve are in those heads stock? there are many 12 sec stock cam cars out there
with your chosen cam would be a disater with bend valves and push rod......what size valve are in those heads stock? there are many 12 sec stock cam cars out there
08-24-2007, 03:46 PM
#10
4th Gear Member
Join Date: Aug 2007
Location: Texas
Posts: 1,788
RE: what cam do you recommend?
since your using an aftermarket stall converter, pick a cam that compliments the converter. Trickflow Stg-1 cam makes a good choice for your mild h/c/i combo. FRRP E-cam is respectable, but a little outdated. Your best bet is to call the maker of the stall converter and ask what they would reccomend. I used my stock cam with 2600 stall and my car was a dog. Choose wisely
