Rocker arms vs Cam

[KingstonX]

Hello everyone, im building my 5.0 engine right now. And im trying to decide what performance parts to pick. So for $300 i can get my rebuild kit, Minus cam and lifters. For $690 i can get my complete kit with a custom cam and lifters.
Or i can get some 1.7 rocker arms for $60. My explorer is going to be a daily driver with some off roading every few weekends. So without losing to many mpg's what would be the best choice? Cam? Or Rocker arms? I would also have to change my stock springs as well with new rocker arms?

 

[techieman33]

your going to have to change your rocker arms and springs with a new cam. A new cam should be at the top of the list too. The cam and exhaust manifolds are the 2 biggest bottlenecks on these motors.

 

[KingstonX]

ok so if i change my cam i cant keep my stock rocker arms? my 98 5.0 has 1.6 rocker arms right? if i change my rocker arms ill have to change my valve covers right?

 

[KingstonX]

ok so if i change my cam i cant keep my stock rocker arms? my 98 5.0 has 1.6 rocker arms right? if i change my rocker arms ill have to change my valve covers right?

 

[techieman33]

It all depends on what size rocker arms the cam designer specs. Even if you keep the same size you should still replace them since you'll be replacing everything else when you put the new cam in.

 

[rookieshooter]

"DD with some offroading"...well this tells me that you will need a cam that has more low end then top end. Or another way of saying that you would want the HP at a lower RPM and not at the upper limit.
For offroading you most definitely do not want the engine to stumble when crawling along in somewhat of a precarious angle or situation that could happen with a cam designed for HP at a higher RPM range. No need for a cam with a lot of Split over lap where both IN and EX are off it's seats for any long time. A cam like this produces HP at a much higher RPM where the dynamics of the velocity of air charging through the intake and exhaust runners at the same time produce HP but does not at the lower RPMs that I think your looking for.
I highly recommend Comp Cams 268 High Energy series cams, this is what I run in my 302 Bronco. It is the second Comp cam I have had. I went with the more aggressive .268 duration and has super low end torque coupled with that slight rumble sound of a "not stock cam".
I get so many compliments on how it sounds.
Also you don't need to change rocker arm ratio.
Here is a link to that Cam shaft.
http://www.jegs.com/i/Comp-Cams/249/CL31-218-2/10002/-1?parentProductId=746636#moreDetails

Summit along with others also sell this cam.
Absolutly follow the break-procedure to the letter including Comp Cams break in oil. I would also ask them about what type motor oil for Flat Tappet cams to run.

Somewhere in the vast latter pages of my build there is vid with audio of the sound of this cam. If you don't find it, I could post a new one.
Now keep in mind what 33 said about uncorking these engines to let them breath. Now mine is carbed not FI but still needs to breath no matter what...hence the Single plane Edelbrock intake for lower torque and L&L headers.

 

[techieman33]

"DD with some offroading"...well this tells me that you will need a cam that has more low end then top end. Or another way of saying that you would want the HP at a lower RPM and not at the upper limit.
For offroading you most definitely do not want the engine to stumble when crawling along in somewhat of a precarious angle or situation that could happen with a cam designed for HP at a higher RPM range. No need for a cam with a lot of Split over lap where both IN and EX are off it's seats for any long time. A cam like this produces HP at a much higher RPM where the dynamics of the velocity of air charging through the intake and exhaust runners at the same time produce HP but does not at the lower RPMs that I think your looking for.
I highly recommend Comp Cams 268 High Energy series cams, this is what I run in my 302 Bronco. It is the second Comp cam I have had. I went with the more aggressive .268 duration and has super low end torque coupled with that slight rumble sound of a "not stock cam".
I get so many compliments on how it sounds.
Also you don't need to change rocker arm ratio.
Here is a link to that Cam shaft.
http://www.jegs.com/i/Comp-Cams/249/CL31-218-2/10002/-1?parentProductId=746636#moreDetails

Summit along with others also sell this cam.
Absolutly follow the break-procedure to the letter including Comp Cams break in oil. I would also ask them about what type motor oil for Flat Tappet cams to run.

Somewhere in the vast latter pages of my build there is vid with audio of the sound of this cam. If you don't find it, I could post a new one.
Now keep in mind what 33 said about uncorking these engines to let them breath. Now mine is carbed not FI but still needs to breath no matter what...hence the Single plane Edelbrock intake for lower torque and L&L headers.

Why are you suggesting a flat tappet cam? He needs a hydraulic roller cam.

 

[rookieshooter]

Oops. Your right.

 

[KingstonX]

what would you guys think about this cam? Comp cam grind number XE250H-14

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=812&sb=0

I have contacted comp cams waiting for a reply. So for off roading you want torque at a low rpm right? I also do some towing ounce in a while.

i wonder if the company im buying my rebuild kit from can do that custom grind

I plan on porting the gt-40p heads myself, new guides etc. Plus some TM Headers ounce i can get enough $$ for them. Since the engine has 300,000 miles on it i should probly replace, springs, rockers, and push rods too right? The engine runs pretty good right now but i want to rebuild it while im rebuilding the trans.

 

[techieman33]

what would you guys think about this cam? Comp cam grind number XE250H-14

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=812&sb=0

I have contacted comp cams waiting for a reply. So for off roading you want torque at a low rpm right? I also do some towing ounce in a while.

i wonder if the company im buying my rebuild kit from can do that custom grind

I plan on porting the gt-40p heads myself, new guides etc. Plus some TM Headers ounce i can get enough $$ for them. Since the engine has 300,000 miles on it i should probly replace, springs, rockers, and push rods too right? The engine runs pretty good right now but i want to rebuild it while im rebuilding the trans.

yes all of that stuff should be replaced with the new cam anyway. Use whatever parts and spring rates are spec'd for the cam you chose. That cam isn't what you want, you need a hydraulic roller cam, not a flat tappet cam.

 

[shucker1]

I am running Comp Cams Magnum 266HR with Ford Motor Sport 1.6 Roller Rockers. New CompCams hydraulic roller lifters and pushrods. Had to use new FMS Valve covers to clear the roller rockers. CompCams ChainSet.

1\2" Phonelic Spacer under factory intake.

19# FMS Injectors, Port and polished heads with new valve job.

Ran it all out to a 3" Gibson exhaust system.

Stock 3.73 Rear End with Carbon Fiber Clutch packs.

By all means bring it to someone who can Dynotune the engine when your done.

Dyno numbers came back at 255 Engine Shaft HP.

Truck gets about 16 MPG on Hwy @ 75 MPH.

 

[KingstonX]

Ok i heard back from Compcams, here is what he said "I recommend you look into one of my XTREME ENERGY camshafts part# 35-512-8,
this cam will make a great low end increase in power to help with any off
roading/towing you may run into"
Ok so looking at http://www.compperformancegroupstor...Product_Code=35-320-8&Category_Code=F50CEFIXE
Part number 35-320-8

Says i need 1.7 rocker arms, Ok so with 1.7 rocker arms i need new Valve covers right? You said with you magnum cam you needed new VC with your 1.6 rocker arms? What Rocker arm stud sizes do i need? I cant find a good cam/lifter/push rod combo for cheap

 

[shucker1]

Cam Kit is CompCams K35-308-8. Be sure to verify correct cam thrust when reinstalling.

If the block is out of the engine bay reseal \ replace the rear cambore cover, cheap insurance here.

Push rods are CompCams with kit. Head Gaskets are FelPro 9333PT-1.

Head Bolts are Torque to Yeild. Pitch the old ones and get new. Don't reuse.

I went with the FMS M-6564-B351 Pedestal mount 1.6 roller rockers. Comes with studs.

I was worried about underside rocker to spring retainer contact with the larger ratio.

It was a major pain setting lifter preload. Lots of time with a dial indicator getting correct preload. Most of the pedestals had to be machined down to get preload.

I work for an industrial engine manufacturing plant so I had access to all machines needed. Our machines are too big to do auto engine heads so a local speed shop reworked them.

I almost used the adjustable rocker arms but I had no plans of going back under the valve covers to readjust every year. That's a major pain.

When you have all your pedestals adjusted like you need them remove the bolts and put a little Locktite Blue on the bolt ends, reinstall and Torque. Always use a good torque wrench and torque to spec. Don't guess.

Make sure you degree in the cam when you do your set up. I ran mine 2 deg retatard for low end torque. I pull a 23 Ft boat with it.

Valve covers were FMS P\n M-6000-K302R. Minor issue here. Oil filler cap barely fits under throttle body but it does work. Your gonna need the intake spacer to get the room. Intake Spacer P\n FMS M-9486-A52.

Valve cover gaskets are FMS M-6584-A50. Rubber coated. The cork ones leak.

EGR tube will need small extension TIG welded into it once you lift the intake. With the spacer you'll need longer upper intake bolts. Fastenal has these.

Factory coil pack support no longer fits with raised intake. Minor welding needed on bracket for proper support.

Keep everything clean, use a good torque wrench, torque to spec and use Locktite Blue on major fasteners.

Carbon Fiber Clutch pack kit for rear end came with .030 shim. Gave me zero end play during installation. This causes broke parts. Had to install .025 shim both sides to get correct axel shaft end play of .003 per side. Yours may be different.

It's a lot of work but you'll enjoy the end results.

 

[shucker1]

I noticed your doing the transmission. Check out www.TCCOA.com for tech articles about doing the J mod to yours.

It's an excellent write up.

I just have not done mine yet.

 

[CDW6212R]

I noticed your doing the transmission. Check out www.TCCOA.com for tech articles about doing the J mod to yours.

It's an excellent write up.

I just have not done mine yet.

Do not do a J mod("Jerry's Mod") to any truck valve body. They are different, and usually don't work right with that mod. If you like that, get a car VB and swap it in.

For a not high powered engine, the TransGo shift kit is the best for all around driving. It has the very best off WOT characteristics, all the other companies have been trying to catch up to TransGo. They are the standard, and the original owner of the "shift kit."

For the engine, set the budget and work around a custom cam. The custom cam should be part of any build, not any off the shelf cam(cam with a part number).

Rebuilding an engine is not cheap, don't try to do it for $1000. Figure out what a typical full rebuild costs, and make a budget. Then find a source for a custom cam, like Ed Curtis(2nd best I know(best available right now)). Work with them on which heads, valve springs, rockers, and intake manifold to use. These parts are the most critical, do not buy them separately without expert consideration for how they will work together. That's what a custom camshaft is all about. An OTS cam will lose easily 1/2 second to a custom cam in a 1/4 mile. For the extra $100 or so it costs, get the custom cam. That does not even account for the much better idle and driveability a custom cam provides.

If a 302 build was done on the cheap by need, bolt on rebuilt GT40(or P as needed) heads with an HO cam onto a stock shortblock. The stock truck cam is the worst OEM part, followed by the intake and GT40 heads. Outside of the engine it's the exhaust, all of it. Look under a decent Mustang at the size of the exhaust(total pipe area). That's what the goal should be for the same sized engine in the Explorers, dual 2.5 or dual 3" pipes, all the way back. Regards,