So here is my dilemma PLEASE READ ALL TO UNDERSTAND ISSUE........I am building/currently assembling a 400 with the kit purchased from T meyer..........cam is degreed, it's a lunati 255he cam, heads are 351c open chamber heads basically same a 351m heads just no emission provisions. heads were set up to spec and all stem heights adjusted to factory spec that T meyer recommended. So I'm mocking up the valvetrain currently and I'm using the stock 1.73 stamped steel pedestal rocker arms and stock length push rod. I have the no 1 cyl set so the intake valve is on the base circle/heel and I screw the pedestal bolt down until I hit "0 lash" and from there it roughly takes me 1.5 turns until I seat the pedestal to the head/reach 20 ft lbs of torque. According to this I need a shorter push rod? = 9.440 ?: Setting your torque wrench to 18 to 20 ft.lbs., turn the screw until the torque is reached. The screw should turn one half to one full turn between zero lash and torqued. This will give the proper lifter preload. If there is less than one half turn, a longer pushrod is needed. If there is more than one turn, shimming of the rocker stand or a shorter pushrod is needed. However, since the next shorter push rod is a .060 difference from stock, there may be a chance that this will be too much a jump and I'll have too little preload?

Now I've read until I was blue in the face and have spoke a few times with Tim and he states that shimming is for geometry and changing the push rod length is to correct preload.......Now I agree with such since the rockers are bolted down and in a fixed position........now I did for test purposes install a .020 shim under the pedestal and this brings the preload to 3/4 of a turn to reach specified torque, however the claim is this also alters geometry........as it is it appears the rocker is sitting on the back half of the valve stem and watching it as I roll the motor over with checking springs installed of course, you can see the travel of the rocker tip go from the back half, cross center, then at full lift it's on the front half of the valve tip.......this looks and verified by the witness mark like a huge travel path, way greater than the .080 recommended.......What I'm not sure is: Is this just a characteristic of the stock stamped steel pedestal rockers? or is it a cause for concern? adding 1 or 2 shims under the pedestal didn't seem to make a difference in the size of the travel/witness mark. I'm almost regretting using the stock pedestal rockers and wishing I'd of gone with a set of pedestal roller rockers at the very lest as it's easy to see the witness marks the rollers make. According to ford racing if I have to turn more than 1 full turn it's as simple as add a shim and move on.......SO WHY DOES fORD RACING recommend such but all the reading I do states shiming is for geometry and to correct preload push rod length is to be changed?? This has my engine build at a stand still........personally I think a .020 shim under all the pedestals will do the job and I doubt it will seriously affect geometry enough to make a difference.......anyone agree or done such? One other thing Tim said I could do was measure the dry clearance between the rocker tip and stem by collapsing the lifter/bleed it down with the rocker torqued down and no shims under it.....basically with all stock stuff in place, I measured roughly .145 and Tim says to strive for .125........this would have it install a longer push rod for even more preload to get to .125.......which they don't come in a 9.520. WHAT would you guys do in regards to my dilemma or have you all done in the past when confronted with a similar dilemma?

 

Tim is the pro, and may well be along soon here to clear this up.

But, my $.02: If push rods are not available in a length to get the preload correct then you have to shim. And, it seems you've proven that shimming .020" gets you the right preload and the correct geometry - as shown by the witness marks being basically centered on the valve tip. Further, your measurements say that .020 would bring you to the recommended .125. In other words, to me everything points to .020" being exactly what you need.

 

at rest with cam on base circle, you can tell the tip of the stamped steel rocker is on the back half, it's not falling off by any means but using a solid lifter as mock up so as to not skew the results, I rotate the motor over 2 times and while doing so I watch the tip of the rocker go from the back half, over center, then to the far front side, when all said and done it appears the witness mark is centered, however it's width /travel takes up nearly 2/3 of the stem........I'm use to seeing a narrow pattern = best for geometry yet still staying in the center 1/3 of the stem on either side. not this huge pattern..........now I rarely ever use the stock stamped steel rockers, I always in the past have used roller rockers............there in may lie the issue in that this may be a characteristic of the stamped steel rocker.......Tim never has used such on his builds and didn't seem to know as he's never mocked such up with oem steel ones.......let me clarify my reading, I think you have it opposite.....with no shim from 0 lash it takes me 1 1/4 turns roughly to reach 20 ft lbs of torque on the pedestal bolt, when I measure the collapsed lifter gap/valve clearance with a feeler gauge it comes in around .145 spec is .125-.175 so it'd appear I'm okay. when I add a .020 shim it jumps it all the way to almost .190 valve clearance which I assume is because I affect geometry as well.........while I'm not loosing sleep over the 1 1/4 turn as it appears my collapsed lifter gap is acceptable, what concerns me is where the rocker sits on the valve tip and the wide pattern although centered, it's a very wide pattern which may be a characteristic of the stock stamped steel rocker......this just concerns me as a wide pattern will spread the load over the tip and possible contribute to guide wear?? or maybe it's just a function of the rockers I'm using........anyone ever run into such using stamped steel ones?? most probably just bolt them down and go...lol and aren't OCD like me with specs......guess that's the tech in me..lol

 

I did have it backwards. Anyway, I've never checked a standard stamped-steel rocker's travel so, like Tim, don't know. And, given that, I'll bow out and hope others can answer your question.

 

I appreciate your insight.........while .020 shim gets me to the desired preload, it takes valve clearance/collapsed lifter measurement outside the recommended .125-.175 range......which makes me think using stock stamped steel rockers and or pedestal roller rockers won't allow me to dial it in.......heck the oem stuff went over 100k....so I should be okay?? hopefully..lol block has not been decked, nor heads milled but has had a valve job and machine shop set stem height up according to specs Tim gave me so all things point to using the oem stuff with no changes.......I just don't want to have issues when the motor is fired up....it will be broke in on a engine run stand

 

Different length pushrods = different preload. Shims are for geometry. I can't find your cam in the Lunati book but I'm supposing it's not far from stock lift.. ...0.428"/0.483"? Give or take0.020"? Installed spring height of 1.80" and stock springs should be ok if you're not going over 0.505" lift...check for coil bind when you get set up. Did you dump the rotators?

Stock lifters have 0.1850" of collapsed clearance. That means you can run as much as 0.090" of preload and still be good. Use an oil can with a small tip to fill your lifters through the side hole. Snug down your rocker bolt such that the stock pushrod (9.500") has NO up and down play....Count the number of turns to torque 'em down to 20 -22 lbs. The range is somewhere between...0.75 and 1.75 turns.

From what I've read of your description, you should be fine. Remember, the stamped steel rockers will slide over the valve stem...making it a little difficult to judge geometry.....but you should be OK. Roller rocker are a different story altogether. They (from my farting around and checking the lift between rollers and stamped steel rockers) seem to have about 0.020" higher lift. Could have been the stamped steel rockers were old....tried 3 different sets

 

I understand all of that, and I have 1.25 turns from 0 lash until they torque down......cam is a lunati 255he all stuff was purchased from t-meyer.........my main concern was where the rocker sat and how wide it scrubbed a pattern......I'm use to roller rockers........but it appears stock length push rods will be fine as well as geometry, springs match the cam as well as locks and retainers are from comp so no rotaters.

 

I understand you have a Lunati 255he....what I meant was I couldn't find the particulars on it in the book - lift, LSA, etc....no matter.

I think you're good to go with what you have..the oem rockers slide over the valve stems...just adds a bit more friction (side to side, front to back stress) on the valve stem/guides than the roller rockers would. The oem rockers last quite a while so, again, I think you're good to go with what you have.

 

YEAH I'm SLOWLY coming to that conclusion. I just don't like the pattern these oem crap leave and potential for guide wear, but if that's what it did on the oem 351, it seemed to last for 144k doing such..lol

 

Hello again....I think valve/guide wear would be minimal...and take quite a while.....especially since you had a buck forty four on the oem.........hahahaha

I know on one of the 460 sites they're happy with the stamped steel rockers...and run "bigger" cams than you.

Good luck.

 

so mocking it up over the weekend with adding 1 to 4 shims then using my adjustable push rod to take up/compensate for preload allowed me to move the placement of the rocker tip forward more on the valve , however the overall pattern stays wide and off centered it towards the front side so it brings me to the conclusion and after having looked at the wide wear mark on the stock old rockers that the travel/wide sweep pattern would be a function of the design of stock rockers. When I added more shim and maintained proper preload, each time a shim was added it seemed to increase dry/compressed lifter (valve clearance) with no shim No 1 cyl came in at .127 intake and .135 exhaust , 20 ft lbs is reached in 1 1/8 turns, with one shim it jumped up to about .185 and .190 respectably and 20 ft lbs reached a 3/4 turns. so it would appear that no shims is the ticket, the block has not been decked, nor heads shaved, however a valve job and new valves were done and the machine shop set the installed stem height in accordance with what Tim recommended.........So, my conclusion would be of course checking them one by one as I install them.....is to bolt the suckers down and run with it!!!!

 

Yes, I think you are on the right track.

 

So spoke with Tim at T-MEYER LAST NIGHT, He agreed that I should be good to go!! so build is moving ahead full steam, for the most part all checks are done, so final assembly is moving forward. Hope to have it on a engine break-in stand fired up before the end of the month

 

Tim's THE MAN. So, you should be good to go. Let us know how it goes!

 

will do, hopefully soon I can get some pics up, truck is apart and I'm flipping between doing body work and engine assembly .