If the pattern is no wider then .060" you will not side load the valve. If you go wider pattern but put it in the center you will wear the guides out. My teacher was the guy that made roller rockers for Harvey Crane, who was his teacher.

Close enough for street engines, no sir. Street engines this is most critical as they see more time on the engines than other engines. A drag engine with 400 passes will see about 125 miles. A board member may see 1500 to 3000 miles a year. The rocker and valve sees more cycles in a street car than in any HP application just about.

 

Ok, LASH CAPS, Lash caps were developed to protect the valve stem from aggressive lash clearances as ramp rates grew. For years we did not have valve tips that would take the punishment. Lash Caps (hence the name not More Area Caps) protected the valve and was a perishable item. Then someone came up with the idea to use stellite and either fusion weld a protective tip on the valve or drill and pool an area on the tip. BTW, I make these and supply to several companies.

The center of a 11/32 stem valve would be .170". Perfect geometry does not care about lift, I assure you we just had a pump gas 532CID leave here with .760" lift and its pattern was .060". We had pump gas 509 leave here with .670" and it had .060". From .170-.060" is .110". This is the clearance you have to work with. No closer than .020" to the tip. Factoring the .020" you now have an area .090" wide that you want to put a pattern of .060". In engine building that is half mile wide.

If you choose to not read my post then welcome to America. Your fellow forum members that have read, listened, are not tearing down their engines. Whether they have bought product or not from me, we still give tech support.

Do I own a corvette, I don't see what this matters but no I don't. I do own the equipment to properly do check this stuff.

 

Justin,
Any luck?

 

I just checked roller placement last night, but wanted to talk to Scott before I do this and order the pushrods. This photo is with the 7.900 length and just roller starting point - I did not crank the engine over to go all the way through the motion. I bought two of the super thin springs so that the rods wont collapse the hydraulic lifters and have them on cylinder 1 exh/int. I might change them out for every cylinder and test just for kicks.

 

Everybody....."play nice".


This is not a Presidential debate..........


or the Jerry Springer show.




I'm a rookie just trying to learn from the big boys.

 

Just got off the phone with Scott (thanks Chris) - what a cool guy.
Stay tuned...his method is awesome and will be very accurate. Pictures and process to follow...

 

Glad we could be of help.

 

It's understandable as I am a nobody to most. My company has not been in business for 60 years grinding cams. I have been fortunate enough to have grown up in this industry since '88. I have worked for some very smart people over the years. The knowledge I have gain I share on the net to help, whether you bought parts from us or not, I care enough about my industry I don't want to see enthusiast have issues.

 

Chris,

I'll be the first to admit I do have knowledge voids and I am grateful for your posts since they all have information helping me to fill those voids or to purge bad tribal knowledge. I know it can be unrewarding giving away valuable subject matter expert opinion and getting pushback, but some of us are genuinely happy to have you on the board.

 

It's not unrewarding as I look at it this way. If I can help then that person will keep "motoring" and that keeps this industry alive. I give out free lash adjustments all the time so that one can see for themselves with a little sweat equity that a cam is wrong in the engine. In doing this trust is built.

I think Justin got a good education this morning. The way Scott does it using the polylock as your measuring tool is simple, neat, and spot on.

And thank you Gerry!!!

 

Ok, so here it is - the best way (now in my humble opinion ) to measure your pushrod size. Please note, this was all thanks to Chris and Scott at Straub Technologies. We are very fortunate to have their support on this forum as well as others - thanks guys!

STEP 1 - Find out your cam's gross valve lift. In my case, the XE262 lift is .462 on intake (.469 on exhaust, but intake should suffice). Take that number and divide it by 2. This will give you your lift number at half the movement. Now take that number and divide it by .041 if you have 3/8 studs or .050 if you have 7/16 studs. This will give you the amount of distance to travel on the threads. In my case with 3/8 studs, this gives me 5.63. Remember that number.

STEP 2 - Take your rocker and make a mark from the center of the roller folcrum to the center of the rocker tip like the image below. This will give you the geometry line to follow that will show your rocker being perpendicular with the valve at lift.

STEP 3 - Take your rocker and set it on the stud without the pushrod. Thread your polylock on just a few threads and hold the rocker up so that the roller is touching the valve tip.


STEP 3 Continued...While holding the rocker up, look at the line on the side and turn the poly lock so the line is parallel with the retainer cap. *Note - the roller tip will most likely be far over to the exhaust side of the valve tip - this is ok and will change anyway when the valve is pressed down.


STEP 4 - Remember that number we figured out earlier? That is how many turns you will need to turn the poly lock until you reach half lift. Marketing the poly lock, turn it the number of turns you calculated. *Note - if you have an adjustable pushrod, go ahead and drop it in now before you tighten down on the poly lock.


STEP 5 - Once you have the poly lock down the correct number of turns, twist your adjustable pushrod until you are at 0 lash. This will be the correct pushrod length at the correct geometry for your set up.


*NOTE - For hydraulic lifters, you will need to add .050 to your final number. In my case, I added .050 and that brings me to 7.900! Bingo!


Chris and Scott, if I forgot anything or misrepresented anything, please let me know.

 

As i said before that adj p-rod is the most difficult tool i have ever used. The rocker arm tester would be done in a tiny fraction of the time to measure as provided here.

Any how where does any printed information on VTG does it say to off center the contact patch? "justified on the exh side"??? Not the Chevy Power Manual, not Crane Cams tech tips, not D. Vizards "how to" books, not in Smokeys Pwr Secrets. Some how all of those missed such an "important" detail. Not hardly. More likely some one that wants to hide something will make that concept sound as complicated and esoteric as possible to only hide the fact they have a lessor solution. I read posts all the time of setting lifter pre-load that are extremely difficult only because the individual doesnt really know what to look for.

Yea, so if setting the contact patch off center - justified on the exh side - is soo important show us one reference that says so - not some expert acquaintance. Just one printed reference to this.

cardo0

BTW u never explained why Smokey or your Circle Track article said center contact patch was ok. Both state the optimum geometry occurs at a certain amount vlv lift. Not contact patch location.

 

How much difference is that from the length you had?
Pretty cool procedure. Sounds like it would save a lot of time.

Did you run it through to see where the wear patch is now?
I ended up with rods a lot shorter than stock for my aluminum heads shaved .030 and roller lifters.

 

Interesting thread !

 

I was using the stock 7.800 rods. The AFR heads have a raised exhaust port of .100, but with this method, I was at 7.875. Add the .050 for the hydraulic lifters and I get 7.925. Since I have to round, I figure 7.900 would be better than 7.950.

 

If you add plus .050 for hydraulic lifters, is this to compensate for the lifter preload. If that's the case, wouldn't you want the longer pushrod.

 

Either way, the difference will be the same at .025 with either the longer or the shorter rod so it shouldn't really matter, I guess.

 

So you use a stock length +.100.
AFR heads use a +.100 valve so it sounds right.

 

Justin,
How goes it?


Chris

 

The new pushrods came yesterday (http://www.summitracing.com/parts/sum-1457900) and they are WAY nicer than the first set! Got them installed with the Comp full roller rockers and they all seem to fit really well. There are two pushrods - one on each side - that are very close to touching the heads at the top of the slot so I will have to keep an eye on that. Set the lash with the car running by slowly backing off until the rocker clattered and then slightly tighten until it stopped and added a half turn from there.
These oil much better than the last set. I originally thought it was a lifter issue, but after seeing how much these rockers were drenched in oil, I think it was the rods and rockers.

Now I have to get my timing figured out and get the power out of the build that I should be seeing. Either my distributer is off a tooth or so (most likely) or the balancer has slipped. At 16 degrees initial, the car doesn't run as well as it should and vacuum is at like 11/12. If I continue to 20 degrees, it starts to smooth out and run great and vacuum hits around 15. Something doesn't seem right.