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Discussion Starter · #1 ·
I decided today was a good day to try and figure out the pushrod length of the V8. In theory, I need a 6.250" pushrod for the 5.0L motor w/ hydraulic roller lifters. I had purchased an adjustable push rod checker for this purpose and set it to 6.250":




To ensure the roller rockers hit dead center on the valve stem, I used a permenant marker on the top of the stem, setup the rocker so there was no slack on the pushrod but not so much that it would pre-load the lifters. Then began rocking the rocker a few times from hitting the piston at TDC to full close; the idea is to "mark" the vavle stem tip so you can ensure it's dead center; too far to the exhaust meant the pushrod was too long. Too close to the intake means it's too short. As you'll see, it's pretty much dead center:



On an interesting side note, when I first bought the cylinder heads and hardware from the guy up in Sacto, I did not ask too much about the hardware. I knew it came with the head bolts and saw some studs but didn't really pay attention. Well today, I discovered I had gotten ARP head studs!!! These are $134.95 at Summit if they were new. This makes this purchase super inexpensive. Recall I purchased these heads with Comp Cam alum. roller rockers and now these ARP studs. Roughly speaking, this setup new, is $1500. My price for slightly used: $500. Now I'm really happy!!!
 

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Aren't you supposed to have them be in the middle of the stem at half lift?

Doesn't matter for yours though, if that mark was left by the rocker dragging from the valve being full open to fully closed.

They drag further on most engines though.
 

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Discussion Starter · #3 ·
Sharky: you're correct as I was reading the CompCam site before going into this:

2. Determine correct valve train geometry
What is the correct length pushrod for your application? The one that produces correct valve train geometry. What is correct valve train geometry? When the rocker arm roller tip rolls from the intake side of the valve tip, across the center of the tip (at approximately mid-lift), to the exhaust side of the valve tip (at full lift) and back. See Diagram A.

However, I went well beyond to see just how much it move towards the exhaust side; it wasn't much but that's the whole point! :) Just needed to be sure 6.250" was in fact the length I need to order. With this info now, I can finally begin to think about building up the engine to a point where I can degree the cam. Once I've verified the cam (or adjust it as needed), I can pretty much begin the task of BUILDING the motor to a point where in theroy, I'd be able to fire it up.
 

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good pics.
 

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Damn, with all these detailed instructions, I might be able to build a FFR Cobra without doing all the research. :p :bow:
 

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Carlos Spicyweiner
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HermanH said:
heh, Postman, it's 8 quarts or 2 gallons of oil.

Sharky: to parapharase: we will server no horsepower before it's time. :)
Do you need that much? What's the redline going to be on this thing when you're done? I assume it probably has a windage tray and all that cool stuff in there? I guess I should search huh? You posted your specs awhile back IIR.

Either way, very cool.
 

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Discussion Starter · #13 ·
Postman: there are guy's running 600, 700 even 1,000 hp (supercharged and nitrous). It all depends upon what you're going to do with it. The 331 kinda "happened" (read my journal around Jan.) Out of the box, this thing was going to instantly produce 350 -375 crank HP w/ FRPP high-performance cams. The Compcams roller cam coupled with a better intake takes me to 400hp.

When you've got the chance to buy new components, you look at the goal first. In my case, I knew 400hp (streetable and reliable) was possible and doesn't cost that much more to go to the next stage or level. Do it right the first time as they say so I said to hell with 350hp, let's go for 400. But the dyno will ultimately tell me if I planned it out right or not.

Warped: no body/chassis until 2007 or very late 2006. Depends how long it'll take me to save $16k.
 

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love the pan!
 

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Holy. 2007? You gotta put that in the Passat for the time being, then. :weirdo:
 

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Carlos Spicyweiner
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HermanH said:
Warped: no body/chassis until 2007 or very late 2006. Depends how long it'll take me to save $16k.
Damn! I thought you already had it. You have the donor car already don't you? I say we put this motor in the donor car for now, that we you can break it in!
 
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