Reading/Fixing My RR To Valve Stem Contact Patern (FootPrint) [Pics]

I am using LS7 lifters, CC Chromoly Stock Legnth PushRods, CC 1.6 7/16" NSA RR, My block was decked to put the slugs .010" in the hole (Cut .017" - .018") and I am using a .026" head gasket.

first I took apart a lifter and shimmed it to make it almost a solid lifter (Still a tiny bit of play in there). Then I asembled it. Tightned the lock down until the lifter was fully colased onto my shims (small ammount). then rotated the enigne a few times.

Am I doing this correct?..

Here is what I come up with:




ftp://test1:test11@web171.ixwebhosting.com/KYLE/KylesStuff/Picture%20011%20(Custom).jpg

ftp://test1:test11@web171.ixwebhosting.com/KYLE/KylesStuff/Picture%20012%20(Custom).jpg

So, these look prety discusting do they. I can understand why its not centered (pushrods not right) but I dont get why its ofset to one side. there is almost on contact on the left and all kinds on the right.. How do I fix this?

your pushrods are a little too long.

get checking springs to put on that cyl. and an adjustable pushrod.

the side to side is not that bad from what I see, but isky adjustable guideplates are the only way to fix that. they are a huge PITA to set up.

What rocker arm studs are those? if they are not ARP pro ones I woul upgrade right away.

REALLY, side to side is not that bad?..

I will get an adjustable pushrod, but I cant use it on the heavy springs?.. shyt. I didnt want to have to buy a test spring..

So just try to get the contact patern close to center then stop worryin about it?..

Thanks

is my method ok? I did need to make a solid lifter right?.. to get an acurate mesurament.. Is it ok that its not complety solid. there is still a tiny bit I can puish down.. or should I try to get it solid?.. I could pack a few peices of paper in there to take care of the little bit left..

checking springs are only $5. they are soft and you will not need to make the lifter solid.

the checking pushrod will bend if you try and use it on regular springs.

you can worry about the side to side later, thats in the guide plates. No sense in messing with that until you get the right pushrod.

I think what he means to say is that the roller tip on the rocker is not in plane (parallel) to the valve tip. Seems like its making contact on one side much heavier than the other. The root cause of that will probably be the cheap studs that are likely bent.

Another thing that you can do to correct alignment is to back off the rocker studs and shift the guide plate around while you're tightening it up. This will give you a decent amount of adjustment if both of them or off or one is slightly off, letting you split the difference.

Pushrods are too long, I would venture to say somewhere between .050 and .100.

Now this is more like it:

http://i16.photobucket.com/albums/b38/subdude17/Picture016-3.jpg

its definatly improving. I made a adjustable pushrod and to make it look like this I had to make it alot shorter than stock. To get this patern I had to use a 6.950" pushrod.. thats .250" shorter.. that seems like to much..

the way I am measuring is with a dial indicator on a magnetic base. I then put it on a piece of metal and welded a washer the side of the pushrod on a spot on the metal. I then made it so the dial indicator was vertical of the washer and i put the stock size pushrod in and zero'd my dial indicator. I then put the adjustable pushrod in the same place (making sure not to bump the stand at all, then I compared the diffrence. I realise that over legnth is not how all pushrods are measured. but I am using CC chromoly rods that say 7.200 on them. so I figure - who cares how they take there measurment. If i subtract what I need form that and order comp pushrods It will be correct since I measured using comp pushrods. get it?..

so, I am going to check a few more and remeasure a few times.. but It look like I might be ordering some 6.950's tonight.




forgot to consider that my lifter is colapsing .036".. so does that mean I need to subtract ANOTHER .036"??..

Well, you definitely got it on the center. On my car, with the same stuff you are using, a 6.950 wouldn't work. The bottom of the rocker was hitting the big part on the stud.

Most people on here would sh*t if they saw how close mine are to the edge with the 7.200s! :lol:

2,000 miles and not the hint of a problem

As a shot in the dark to get me started with finding the right valve length I usually just use the adjustable pushrod to set the center of the rocker trunion half the valve lift down from the valve tip. Usually it results in a pattern thats super narrow and just slightly offset toward the exhaust with most rockers. Crowers usually check out the best all around for me but they are definitely nice and definitely $$$ :yes:.

As a side note, all rocker arms are not created equal. Actual ratio will vary from advertized with geometry and manufacturer. Have to check them on the engine you plan to run them on to know for sure. I know a guy who killed a big block by swapping rockers and just trusting the advertised ratio.

Not sure how its really relevant to the thread, but I thought i'd toss it out there.

That's not very good pattern. Like said above, the pattern should be narrow and slightly off center towards the exhaust. The sweep of the rocker is way too much and I think it could cause unusual guide wear.

Think of the rocker like a hammer and the valve tip a nail. You don't want to be hitting the nail all over the head cause it won't go in straight and will probably bend or something. Same thing for a valve, you don't want to be pushing on it all over the tip because the side loads that creates will wear out your guides.

If you go taller your sweep will get shorter and closer to the exhaust. There was a great thread recently about determining pushrod length. Search for it.

so. Should be looking for a thinner sweep or trying to center it, or a good mix of the 2?.. I made my rod a little longer to bring it close to the exhaust and it may have gotten a tiny bit smaller, but not by much.

http://i16.photobucket.com/albums/b38/subdude17/untitled-137.jpg

As a shot in the dark to get me started with finding the right valve length I usually just use the adjustable pushrod to set the center of the rocker trunion half the valve lift down from the valve tip.

Same here, kinda. :)

Seems like it's half and half on the people who put it in the center and small sweep.

Mine are about .080-.090 from the edge of the valve and no problems yet. :)

heres somehting that throwing me off. Do i compensate for the preload?.. or do I asume that the lifter will be FULLY extended all the time (it wont).. so should I consider the .036" that the rocker compressed (cuz its not shimmed tight) the preload setting and just order the legnth pushrods my checker tells me is good?.. ahhh?

I wouldn't worry about the preload too much as much as getting a good pattern. When you set everything up where is the rocker contacting the valve? In the center and your sweep is that wide or is it offset one side or the other? You're defintely getting closer, what length are you at now?

6.950" in the picture in post #7, 7.050" in picture in post #11.

Yeah, keep going and it should get better. As you get the rocker higher it will push down more vertically instead of laterally.

with a longer pushrod you mean. It needs to be ever further toward the exhaust side that that?.. I will try, but it does not seem to be gettin smaller as it moved towards the exhaust.. I mean I dont want it to far off center do i?

Yes with a longer pushrod. In the first pictures see how narrow your sweep was with a stock length PR (7.20). Then you decreased it A LOT and see how wide the sweep got. You want something narrow like the first pictures just on the exhaust side of the valve centerline. That's why I said in my first post you are probably about .050 - .100 too long because your pattern looked good to me it was just too far on the exhaust side. Try 7.10 to 7.15, no reason to shorten your PR by a lot unless your block is zero decked and your heads were milled a lot.

7.100"

http://i16.photobucket.com/albums/b38/subdude17/S3010494.jpg

I tried again with stock 7.2 and its really not that bad.. It is the narrowist weeep I can get, but its prety offcenter.. Think this is to offcenter? (its the same thing is each picture, but one had a glare.

http://i16.photobucket.com/albums/b38/subdude17/untitled-138.jpg

Where does the rocker rest on the valve tip? I've never seen the black line in the middle of the sweep before. What did you do differently between the first go around with the stock length pushrods and the last time around?

here is settin it on, tightning the lock down and rotating the roller tip to make a good line. here is where it sits with stock pushrods.

I think the line is there because I rotated the tip before I rotated the engine over.


http://i16.photobucket.com/albums/b38/subdude17/untitled-139.jpg

the red is BLOOD, I covered the flash with my finger. lol\

but other than the line in the middle. hows the sweep look?..

Just keep the sweep narrow and relatively centered. Thats as good as you're probably going to get from a comp rocker, they are not designed correctly for the type of geometry you are trying to achieve without doing something radical. You will do just fine and not wear anything out or hurt it, and its not your fault thats just how its designed/made.

To me the sweep still looks wide and it gets close to the exhaust side of the valve tip, but sitting on the valve it looks pretty much perfect. Based on the pictures I would go with the 7.1. Hopefully some other people will chime in with their opinion. Have you searched for the thread about determining pushrod length? Also I think Speed_demon had a thread when he was going through some of his issues with pics.

yea. I read threw a 5 page thread about it from almost a year ago. took me a long time, but it was great info there..

I used this thread

http://www.camaroz28.com/forums/showthread.php?t=462630&highlight=pushrod+legnth

but the pictures didnt work.. grr

IMHO that looks pretty good. Without spending money that is probably the best you are going to do.

Just for general information Crane makes rocker arms that are set back .050" for just such situations where you want to get the geometry correct. Basically the more sweep you have the less lift you are going to have.

89TransAm, your talking about the pitcure in post #20 correct?.. cus the one in post number 21 is not a sweep, its just where it touches when on the base circle of the cam.

it thats the case, then im just going to use therm. I did spend money on the. they are CC chromoly (sp?), but I got them used for a prety good price. so yea. not having to spend more money would be great. I think i will be ok with 7.2

Here is where mine are riding with a 7.200 PR.


Closed

http://i80.photobucket.com/albums/j169/black_z_/valvetop.jpg


~Mid lift.. closest to the edge the roller goes

http://i80.photobucket.com/albums/j169/black_z_/valvemiddle.jpg


Max lift

http://i80.photobucket.com/albums/j169/black_z_/valvebottom.jpg

I know the middle one looks REAL close to the edge, but it you find the actual contact point, it ain't that bad. :)

My mistake. I was looking at post 22 and reading it wrong. Sorry.

Here is where mine are riding with a 7.200 PR.




thats about how mine looks with stock 7.2.. I think im just going to use stock 7.2 legnth CC pushrods I have.. its not to bad. well.. maybe..

everything I see and read tells me to put in as centered as I can.. no one really mentions trying to make the sweep small. but I can definatly see that being an advante from a lift and longevity point of view. But. as for the lift thing. my rotating asembly says safe to .600 lift.. and with these rockers and cam I get .600 lift. so I dont want to go over but being slightly under is ok. so I am willin to sacrafise a littele lift for a more centered patern.. as for it being a big sweep.. nothing I can really do about that. I might just use the 6.950's I ordered and be done.. I dono.. lol.

everything I see and read tells me to put in as centered as I can.. no one really mentions trying to make the sweep small.

You're just reading all the wrong stuff! ;)

Just keep the sweep pretty small with 1st priority on being small and 2nd priority being getting it centered. Keep the 2nd within reason.

If you really want to learn something... put a dial indicator on the retainer and write down max lift displayed changing the pr length every .025-.05" It will probably be a bit of a shocker if you just assume a 1.6 rocker is a 1.6 rocker. Record your sweep size and position along with this for added benefit.

I've seen 1.6 rockers be closer to 1.75 before. I have a set of bbc rockers on the shelf that are supposed to be 1.7 but will check out nearly every time right at 1.95 All rockers will change ratio based on geometry, the ratio will even change during the sweep :eek:.

I have gone so far as to move studs in the head before. I have even designed and built my own set of shaft rockers before because I wasnt satisfied at all by what was offered for the application.