Camshaft question?

[Rich65]

Normally you replace the cam, springs and lifters at the same time. I mean they all got to come out anyways, plus the cams usually have matching springs and lifters.

[john253a]

the correct answer in yes and no,

when you get a cam, that cam will have a recommended seat pressure and valve lift

if and i mean if you new cam falls into the parameters of old springs and valves then yes

but you will always need to resurface lifters of get new ones

normally you cam will say something like 244/244@ 50 540/540"lift 106lc (this is what i run on my 4.2ltr)

and to achieve the lift i needed to drop seat height from 1.7 to 1.85 and run springs with the right pressure at that set height

i also had to install roller rocker as the amount of lift on a 1.65:1 rocker to great for standard rockers

so you'll need to speak the cam supplier/maker to find out spring seat rates, can you use different colets to adjust seat height if required?

are standard rockers ok to use, will you need anti-pump lifters/solid lifters or standard will do,

does the cam already have a factory advance on it, so when you install will you need a 9 key way timing chain,

there are also a lot of other things to consider when replacing a cam, not just the valve train,

in most cases you can make more power on a smaller cam, then bigger when all is matched up correctly to create an overall combination

[Bigsix]

Id at least go with diff springs if going to a larger cam. Springs have a max lift they can handle and typically going to an aftermarket cam goes out of their usable range.

Soory if this was already mentioned, didnt read all the way through.

[AUDIOADDICT02]

the correct answer in yes and no,

when you get a cam, that cam will have a recommended seat pressure and valve lift

if and i mean if you new cam falls into the parameters of old springs and valves then yes

but you will always need to resurface lifters of get new ones

normally you cam will say something like 244/244@ 50 540/540"lift 106lc (this is what i run on my 4.2ltr)

and to achieve the lift i needed to drop seat height from 1.7 to 1.85 and run springs with the right pressure at that set height

i also had to install roller rocker as the amount of lift on a 1.65:1 rocker to great for standard rockers

so you'll need to speak the cam supplier/maker to find out spring seat rates, can you use different colets to adjust seat height if required?

are standard rockers ok to use, will you need anti-pump lifters/solid lifters or standard will do,

does the cam already have a factory advance on it, so when you install will you need a 9 key way timing chain,

there are also a lot of other things to consider when replacing a cam, not just the valve train,

in most cases you can make more power on a smaller cam, then bigger when all is matched up correctly to create an overall combination

Short answer is Yes.When running an aftermarket cam,sometimes lift ratios can get extreme enough to need heavier springs.Rockers are not always needed,but again depend on lift and duration ratios,also note that their are different ratios of rocker as well that will change lift stats.Your best bet is to contact the manufacturer of your cam and follow their recommendations.

Yea, after checking in with some of the folks over on the big block forum, I found out that my cam has too much lift(.582/.600) for my stock heads, valve springs alone will not suffice. These stock heads are only good for up to .550 lift.

I will need to swap the iron heads with aluminum heads, but at over $2000, audio is gonna have to wait.

[V8SRSLO]

these are the springs recommended for the cam you listed http://www.summitracing.com/parts/LUN-73815K5LUN/

also i am not big into ford big blocks but i find it hard to believe that a .600 lift is to large for your heads, maybe the valve relief in the piston yes- but heads no i would give a call and ask lunati personally. i think you should be ok on a big block head wise into the .700 lift range. the first thing that tells me somethings up is thats still a hyd lifter cam when lifts become to large for hyd lifters and you have to go solid is when things get sketchy

[AUDIOADDICT02]

these are the springs recommended for the cam you listed http://www.summitrac...LUN-73815K5LUN/

also i am not big into ford big blocks but i find it hard to believe that a .600 lift is to large for your heads, maybe the valve relief in the piston yes- but heads no i would give a call and ask lunati personally. i think you should be ok on a big block head wise into the .700 lift range. the first thing that tells me somethings up is thats still a hyd lifter cam when lifts become to large for hyd lifters and you have to go solid is when things get sketchy

Yea I already checked the rec. valve springs, but I'd have to cut the valve guides in order to get more than .550 lift. The pistons have more than enough valve relief, so that's not a problem, I have enough piston to valve clearance. Also, Lunati said the same thing, that cam will not work with the stock valvetrain. :/

I'm just gonna order a smaller cam with less lift for daily driving while I have enough time/money to get the Super Cobra Jet heads capable of .660 lift.

Based on my research, Ford just could never properly design an engine without major flaws.

[Sean Lorbeske]

usually when you increase the lift of the cam its also wise to get higher pressure valve springs to prevent valve float at higher rpms

[Sean Lorbeske]

these are the springs recommended for the cam you listed http://www.summitrac...LUN-73815K5LUN/

also i am not big into ford big blocks but i find it hard to believe that a .600 lift is to large for your heads, maybe the valve relief in the piston yes- but heads no i would give a call and ask lunati personally. i think you should be ok on a big block head wise into the .700 lift range. the first thing that tells me somethings up is thats still a hyd lifter cam when lifts become to large for hyd lifters and you have to go solid is when things get sketchy

Yea I already checked the rec. valve springs, but I'd have to cut the valve guides in order to get more than .550 lift. The pistons have more than enough valve relief, so that's not a problem, I have enough piston to valve clearance. Also, Lunati said the same thing, that cam will not work with the stock valvetrain. :/

I'm just gonna order a smaller cam with less lift for daily driving while I have enough time/money to get the Super Cobra Jet heads capable of .660 lift.

Based on my research, Ford just could never properly design an engine without major flaws.

just my personal opinion i do not reccommend lunati at all dont get me wrong they make a great product but they are a tad on the pricey side i would reccommend comp cams a good .580 lift max should be no problem with stock heads although different rocker arms and pushrods would be needed as well as different lifters and even diferent springs due to higher spring pressure needed in higher lift camshafts

[Miguels]

every time i do a cam swap i always change everything from springs, push rods, guides, seats and locks(rocker arms when needed). you already took them apart might as well do it correctly then to have failure later

and yes sometimes you have to replace the stock rods for some hardened ones, dont want them bending on you and causing catastrophic failure

[AUDIOADDICT02]

[ just my personal opinion i do not reccommend lunati at all dont get me wrong they make a great product but they are a tad on the pricey side i would reccommend comp cams a good .580 lift max should be no problem with stock heads although different rocker arms and pushrods would be needed as well as different lifters and even diferent springs due to higher spring pressure needed in higher lift camshafts

The Voodoo cam & lifter kit was about $50-60 cheaper than a Thumpr cam kit, so I went for it. As far as lift goes, I'm going to cut the valve guides & replace the springs on new d0ve-c heads. I will be upgrading everything in this engine since I am in the process of rebuilding it due to a broken piston.

every time i do a cam swap i always change everything from springs, push rods, guides, seats and locks(rocker arms when needed). you already took them apart might as well do it correctly then to have failure later

and yes sometimes you have to replace the stock rods for some hardened ones, dont want them bending on you and causing catastrophic failure

Hardened pushrods are a must, so that is not optional for me. I'm actually swapping heads now since I want to bump up the compression a bit especially for the new cam.