valvetrain geometry
#22
RE: valvetrain geometry
Here is some more good information from Joel at s.b.f. tech
PR length allows setting of the valvetrain geometry, by changing its length , it will affect the "sweep" pattern, location with respect to the valve stem, or its contact pattern through the valve open-close cycle. This has an effect on valvetrain, wear and tear.
To check your pushrod length you will need a pushrod length checker (make one or buy one) and some light duty checking springs. Install the light duty checking springs onto your cylinder heads and then install the adjustable pushrod into the pushrod slot making sure that it seats in the lifter. Mark the valve stem tip with a sharpie or other dye and set your rocker arm following the instructions above for adjusting your stud mount rockers (or pedestal rockers if that is your bag). Once the rocker arm is set, roll the engine over by hand several times and remove the rocker arm. Then check your wear pattern. Adjust according to the guide pictures below.
PR length has to be set/determined providing for the lifters preload....or the additional .020" - .060" needed for it.....
[IMG]local://upfiles/89883/AF07D6B387B94BB48F35294321236128.jpg[/IMG]
[IMG]local://upfiles/89883/C281909F252146D1A37F762B1D82AF64.jpg[/IMG]
pushrod short
[IMG]local://upfiles/89883/4483BDDD3FA34F16A53AB77083943F07.jpg[/IMG]
pushrod long
[IMG]local://upfiles/89883/73CCCB1EC3164BD19012761F54D15A7B.jpg[/IMG]
pushrod correct
[IMG]local://upfiles/89883/74F81353340845B592A2EF10AA187E25.gif[/IMG]
Lifter preload
#23
RE: valvetrain geometry
Check these...
http://sbftech.com/index.php/topic,317.0.html
and
http://sbftech.com/index.php/topic,57.0.html
Replace "****" with "s b ftech" (no spaces)
For some crazy reason this site filters it out like it's a four letter word...
http://sbftech.com/index.php/topic,317.0.html
and
http://sbftech.com/index.php/topic,57.0.html
Replace "****" with "s b ftech" (no spaces)
For some crazy reason this site filters it out like it's a four letter word...
#24
RE: valvetrain geometry
Yall, seriously, take a geometry class. The technique I described works just fine. I have used it several times (just recently used it with aluminum rockers instead of comp stainless ones), and have always had good results. A local race shop owner showed it to me, and he swears by it also. Anytime you check geometry, you are basically eyeballing, unless you break out the micrometers. It is easy to see weather or not the tip of the rocker is in the middle of the valve stem seal when the cam is rotated. The only thing that I can say in your favor is that this method doesn't allow for the .030" of preload, but the solid lifter technique doesn't either, so how the hell is it any better? Truth is, it isn't. Don't be afraid to try something new. I guarantee that if you do it your way and then do it mine, the results will be the same.
#25
RE: valvetrain geometry
Let me guess, the local race shop owner who showed you this has been doing this forever.A"race shop" that does not measureand eyeballs things is a shop that I would not be customer of.Without checking for the tightest pattern on the stem, how do you know the pushrodlength is optimal? You don't. It's not about not wanting to try new things Tyler, it's about doing things correctly, the first time.
#26
RE: valvetrain geometry
Well, considering that they build up to 20 dirt track and drag race engines per week, I would say that they know what they are doing. It isn't a guy that works under his shade tree or in his garage behind his house. This guy gets paid big big money to build high quality race engines at Race Engine Design here in Chattanoga (Rossville). He is a valid resource, and if you don't like the way he does it, then fine. You can continue doing it the hard way, and waste time and money to do it the *cough* "right" way. Its not sweet off my back or money out of my pocket, so do it however you wish.
I haven't bent any pushrods, or messed anything else up, and everybody else on here said that theirs make noise too. So does this mean that everybody on here is a dumbass and did it wrong? Are you the only one who knows how to do it "right"? I think not. Thank's for the links, if I ever build an engine "right", I may try your way to see how big of a pain in the neck it will actually be.
I haven't bent any pushrods, or messed anything else up, and everybody else on here said that theirs make noise too. So does this mean that everybody on here is a dumbass and did it wrong? Are you the only one who knows how to do it "right"? I think not. Thank's for the links, if I ever build an engine "right", I may try your way to see how big of a pain in the neck it will actually be.
#27
RE: valvetrain geometry
No Tyler, I am certainly not the only one. Just read the repliesto your post from others on here. And there are many, many, others. If you really want to learn some in depth tech information about Ford engines, I recommend you read through the site dudeboy (Jason) was trying to post. Here it is a gain but the link will not work here (it's blocked) so you will have to type it in (but take out the spaces):
www. s b f tech. com
www. s b f tech. com
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oxfordgt
4.6L (1996-2004 Modular) Mustang
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12-04-2008 04:06 PM