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Author
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Topic: cobra intake vac fittings and roller rockers
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z pyro
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Member # 3745
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posted
 
 
This is how my cobra upper looks
obviously there's a bigass hole in the lower back of it, and there's one more opposite the main runner from that vac tree that's on it.
now on my stock upper
there's the same vac tree, except this time there's an actual fitting in the big hole, with a hose going to the PCV valve and the main runner, as well as another fitting on the main runner that's capped off and one more that isn't capped off.
does anyone have a pic or diagram of what goes where on the cobra intake, since there's one more (2, counting the capped one) vac fitting on the stocker than the cobra?
also along the lines of cobra...I tried using cobra roller rockers on a completely stock valvetrain and heads, but the pushrods are too short. I've been told by some people that these simply bolt straight up, did they run too short of pushrods and not know it or not care, or are there different length pushrods from year to year of engine? for those who have used the rockers on stock everything else, if new pushrods are necessary, what length did you use? wouldn't everything else from the 93 cobra engine (springs, lifters, cam base circle) be the same as the regular 5.0 HO? if so, what is the length of a 93 cobra pushrod? and I know that I can get an adjustable pushrod checker, I'm just wondering what others have done. I'll likely just run the stockers until I get the money for new springs and pushrods, cuz I already have a b-cam in it.
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'95 Integra LS
'08 Buell XB12R Firebolt
'65 Mustang 289 - soon to be 306
Posts: 1732 | From: Fresno, CA | Registered: Nov 2003
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BlackNGold
CaliforniaFords.com
Moderator
Member # 655
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posted
Buy some metel plugs at OSH and plug the PCV line in the middle of your intake and just run the line that is in the lower left of your picture to the PCV valve...Sorry, I don't have a vacuum diagram....
As far as your Cobra Crane rocker go, are you sure you installed them correctly?(no offense)....On a 5.0 HO the push rod are all the same length as far as I know...If you're taking them off a another car you will probably need the shims to get the correct lifter preload...If you bought the Crane Cobra rockers as a kit then you already got the shims....When I installed them I actually milled my pedestal mounts down to get the correct preload....
Good luck
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-SLOWER TRAFFIC KEEP RIGHT-
Posts: 5132 | From: Bay Area, CA | Registered: Dec 2001
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FasterDamnit
Bad Attitude
Member # 442
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posted
"Unbolt the stock rockers and remove them from the heads. Clean all the metal guides that go underneath two adjacent rockers as it will be reused (at least w/ the Omegas). Once the old rockers are out it is time to bolt in the new ones.
Pedestal mount rocker arms have a 5/16" bolt passing down through the pedestal and into the head. The Omegas are assembled two rockers at a time placing the pedestals in the stock guide piece (see photo.) Put a pushrod in place and then lightly assemble rocker arms on the heads.
Start by setting the the #1 piston at top dead center on the compression stroke. You can confirm this by checking to see if the rotor is pointing directly at the #1 spark plug terminal on the distributor cap. If it is not, rotate the crankshaft until it is. If the distributor is out you can remove the #1 spark plug, and rotate the engine until you feel air rushing out of the #1 spark plug hole, indicating that the #1 piston is coming up on the compression stroke. Then observe the timing marks on the harmonic damper and continue rotating the crankshaft until the 0 degree, or TDC, mark lines up with the pointer. At that point in crankshaft (and camshaft) rotation, both the intake and exhaust valves will be closed and the cam will be on the base circle.
Working on the #1 piston, slowly spin the pushrod, of the intake rocker, between two fingers while you tighten the 5/16" bolt with your other hand. When it becomes difficult to spin the pushrod, indicating that all clearances have been taken up, torque the 5/16" bolt to 20 ft-lb. If more than one full turn of the bolt is required to achieve the torque setting, you will need to shim the pedestals. Unlike a stud-mount rocker, the only adjustment possible is adding or subtracting shims under the pedestal.
Pedestal shims.
Shimming: Back off the bolt, add a .015” - .020” inch shim under the pedestal, and try it again. Keep adding shims until the torque applied to the bolt reaches 20 ft-lb with between one-half and one full turn of the bolt after the pushrod stops turning. If however the pedestal bolt reaches 20 ft-lb and the pushrod can still be easily rotated, the pushrod is too short and must be replaced with a longer one.
Repeat the procedure for the exhaust side. Then move the crank counterclockwise so that the rotor is pointing at the next cylinder in the firing order and adjust the rocker arms for that cylinder. Continue through the firing order until all rockers are adjusted."
How to make a pushrod length check tool-->
http://www.fordmuscle.com/archives/2000/03/quicktips/index.shtml
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'92 LX T5
Looked stock, went 11's 11.90 at 115mph.
'65 Mustang 347
www.fordmuscle.com
Livin' in the Carolina Pines
Posts: 2971 | From: NorCal | Registered: Sep 2001
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z pyro
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Member # 3745
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posted
quote:
Originally posted by BlackNGold:
Buy some metel plugs at OSH and plug the PCV line in the middle of your intake and just run the line that is in the lower left of your picture to the PCV valve...Sorry, I don't have a vacuum diagram....
As far as your Cobra Crane rocker go, are you sure you installed them correctly?(no offense)....On a 5.0 HO the push rod are all the same length as far as I know...If you're taking them off a another car you will probably need the shims to get the correct lifter preload...If you bought the Crane Cobra rockers as a kit then you already got the shims....When I installed them I actually milled my pedestal mounts down to get the correct preload....
Good luck
for the intake...so I only need that vac tree that's on it, and a line going to the pcv valve? nothing more? what about the other hole right next to where the tree is?
and the rockers...I've installed them right (like FasterDamnit posted) with absolutely no shims, and there's still some play. I can put a .024 feeler between the roller tip and the valve tip, and there's still room for more. is this ok? it seems like it'd make a bunch of noise and wear on the parts with them being that loose
[ May 12, 2005, 07:21 PM: Message edited by: z pyro ]
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'95 Integra LS
'08 Buell XB12R Firebolt
'65 Mustang 289 - soon to be 306
Posts: 1732 | From: Fresno, CA | Registered: Nov 2003
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BlackNGold
CaliforniaFords.com
Moderator
Member # 655
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posted
I'll try and make this short since I just typed out something and my son hit ESC and erased it all...I'll try again...
I think the port in the intake you might be thinking about is for the charcoal canister fuel vapor line...There is a solenoid (canister purge valve)with a T fitting toward the front of your car....Well, the line from your intake connects to that....
Check the rest of your valvetrain and make sure it's up to spec...I'd recommend buying all new lifters, springs, and pushrods, but that's just from my experience...
Good luck...
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-SLOWER TRAFFIC KEEP RIGHT-
Posts: 5132 | From: Bay Area, CA | Registered: Dec 2001
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z pyro
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Member # 3745
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posted
john b told me that the roller rockers need longer pushrods because the cup is deeper or something to that effect. but others have said that they're bolt-on and go
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'95 Integra LS
'08 Buell XB12R Firebolt
'65 Mustang 289 - soon to be 306
Posts: 1732 | From: Fresno, CA | Registered: Nov 2003
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Blind
2.3L
CAFords OG
Member # 3052
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posted
quote:
Originally posted by z pyro:
john b told me that the roller rockers need longer pushrods because the cup is deeper or something to that effect. but others have said that they're bolt-on and go
I'm gonna have to say trust johnb ![[patriot]](graemlins/patriot.gif)
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89 LX Notchback ex 4cyl, 14psi
02 Harley F150, 15psi
Posts: 8521 | From: Fairfield | Registered: Jul 2003
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h8louzn
¯
Member # 1075
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posted
You don't need longer pushrods.
I have done many of these and never bought longer pushrods.
Good luck!
Posts: 593 | From: Sac. | Registered: Mar 2002
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z pyro
¯
Member # 3745
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posted
quote:
Originally posted by h8louzn:
You don't need longer pushrods.
I have done many of these and never bought longer pushrods.
Good luck!
so having some play in the pushrod doesn't make any difference? seems like it'd make a bunch of noise, and not be very good on the lifters/rockers
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'95 Integra LS
'08 Buell XB12R Firebolt
'65 Mustang 289 - soon to be 306
Posts: 1732 | From: Fresno, CA | Registered: Nov 2003
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JohnB
Tech Moderator
Member # 969
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posted
If you are using stock pushrods on 1.7 "Cobra" rockers, you are asking for trouble. The pressed tip on the stock pushrods is not the same diameter of the Cobra ones. What will happen? You will have incorrect pre-load and the pushrods will eventually knock the cups out of the rockers. The only way you will not notice the problem is if the heads have been milled...or you have the correct pushrods. Most, if not all replacement or aftermarket "stock" pushrods are the correct ones. As for Cobra specific valvetrain items, here goes..
Heads: different, GT40's vs. stockers- the valves are longer on GT-40's, hense the reason why you're finding there is slop once you're torqued your rockers to 20ft-lbs.
Springs: different installed height and rates
Cam: different specs
Rockers: obvious one here...
For your intake- run the vac tree, hook it up just like the stocker was. Big hose to the firewall tree, two smaller ones...FPR and AC controls. If you have any other ports under there open, plug/cap them accordingly. You don't need to use any of them. For your cannister Evap, the hose hooks to the port on the neck of the intake, just inboard of the throttle body. You need a 90* elbow for the PCV (the 3/8" hole in the plenum) if you're going to run stock valvecovers. If you've got Cobra ones (stamped steel) you only need a straight nipple for it. Do not use your original PCV hose, it will crack, due to having to bend it differently. Get ALL new hose/caps.
Any other Cobra questions? ![[Wink]](wink.gif)
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1965 Shelby Cobra
1993 Cobra
2012 F150 Raptor
2020 GT500
Posts: 6523 | From: Orlando FL/Redding CA | Registered: Mar 2002
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