Rocker Geometry Woes

[Diseazd]

It's always better to center wipe patterns with the actual lash pads you're going to use. Just order 5 or 6 lash pads .150, .160, .170, .180 etc. With a stock cam, it should be .120, .130, .140 etc. No telling with the company that built your head though. Valve retainers have different hat seat depths. Stock valve retainers are only deep enough for lash pads that are less than .170 inches.

[rossiz]

so if stock valve retainers are only deep enough for lash pads less than .170, any recommendations on an aftermarket set to hold thicker ones?

[grannyknot]

rossiz or anyone, are the lash pads the only way to adjust the wipe pattern on the rocker?

If the wipe pattern is off to one side does that mean the cam or the rockers have not been ground properly?

[240260280z]

More info here>>>> Reference: http://atlanticz.ca/zclub/techtips/valvetrain/index.html

[rossiz]

started getting a little depressed at the prospect of spending another bunch of cash on lash pads + aftermarket spring keepers, especially since i'm re-building another motor for this car...

 

took a moment to think about it and realized the one thing i hadn't measured was the cam... turns out it was the problem - it's a re-grind with higher lift and smaller base circle, and they dropped it into a stock cam setup. i measured every lobe and compared them to the cam in my original N47 head (the one that came with the car) and put all the data in a spreadsheet to figure out how they related to each other. 

 

then, just for kicks, i pulled the cam, rockers and lash pads from the original head and put them in the new one and see how the geometry worked. i kept all the assemblies together (lash pad & rocker w/same cam lobe) and marked the rockers with sharpie to check the wipe patterns. the result: perfect! every rocker wipe pattern lined up exactly as it was on the original head, right in the middle, as set up by the factory in 1978.

 

so i went with it - cleaned everything up, slathered it in the "z paste" that came w/the re-surfaced rockers from delta cams and did a quick polish on the combustion chambers.

 

the N47 cam is internally oiled and the N42 is set up for a spray bar, and i didn't want to mess with doing both and wondering if i had enough oil pressure, so i decided to block off the spray bar outlets with some small aluminum plates and just rely on the internal oiling. 

 

i'm hoping to get some time tomorrow afternoon to put humpty back together and see if it all works...

 

the measurements

Cam Measurement Comparison.pdf

 

spray bar block-off plates

 

chambers all cleaned up

[siteunseen]

That's great news, now something positive is happening.  Is this the "nail in the coffin" for DP,LLC?

[rossiz]

well, i don't know if it's the "nail" or not... i was worried that the valve job was done poorly or that the valves were dressed improperly, which in my opinion would have been worse, but the issue was one of somebody grabbing the wrong cam, assuming it was a stock grind and slapping it together without checking the geometry. still a big QC issue, but a more understandable mistake i suppose.

 

fwiw - i've been in touch with them during this whole fiasco and he's been very open to hear about it and wants to know my findings so he can discuss w/his machine shop. i'm sure he has a shop that does all his heads so hopefully the feedback will assist in keeping this from happening to others...

[rcb280z]

Still should have never happened and EVERYTHING should have been double checked before sending it back to you a second time! I thought I was the only one with such luck. Can't wait to see the end results.

[S30Driver]

Good job!

Hope it all comes together for you.

 

(Don't forget with the turbo head bolts, it is recommended to use the higher final torque of ... I think it is 65 ft/lbs.)

Edited February 23, 2015 by S30Driver

[rossiz]

the turbo head bolts are for the F54/P79 i'm building - this motor has new NA head bolts, which i've been torquing to 62

 

i brought all my tools out to the car, set up the towel over the fender and brought out my newly set-up head with hopes of hearing her fire up before dinner maybe even drive her to work tomorrow - but it was not to be. instead, today was another day of green-eyed Lilith testing my resolve... 

 

i got the head installed, torqued up and then went to put the cam sprocket on, only to hear one of the most miserable sounds - that little "click" from inside the timing cover when the chain tensioner pops.

 

yup, that one little click turned a 2hr. job into a two day job. the good news is this happened the first time i replaced the head, so i shouldn't have to deal with rusted, broken bolts. the bad news is the car is parked in the dirt and i can't jack it up, so i'm crawling around on my back in the filth to get at all the stuff that needs removing from underneath. damn, this car is lower to the ground than i thought. tomorrow i might have to get some wood under it and put it up on ramps to get better access.

 

tonight i pulled off the splash pan, drained the coolant, pulled off the hoses and fan, removed the radiator, pulled the distributor, alternator tensioner brace, then when i went to remove the crank pulley i realized that since the valve train wasn't connected to the bottom end, i had to take the head back off or risk bending valves. head back off, crank pulley bolt removed, loosened about half of the front cover bolts and called it quits for the night since it was pitch black out and getting cold.

 

tomorrow i'll have to pull the front sway bar so i can drop the oil pump and pull the dizzy drive shaft, then hope like hell i can get the timing cover off without further mishap.

any good vibes would be greatly appreciated...

[Zed Head]

Man, I really appreciate the way you keep going once you get started.  I've had a few start at 10 am, WTF it's 1 am days myself.  I hate to leave things undone.

 

I didn't even know about the "little click" until now.

[LeonV]

"Application Note: Aftermarket spring retainers are required for any lash pads over .160" thickness."

 

why is this, and what is the issue with going with what i've got? i don't really want to spend even more on this head if i can avoid it...

 

Don't worry about this, you will have no problem running .200" lash pads in stock retainers. I've run bigger.