Ok so my heads and cam car is together and I got my straub bolts so I went to measure for pushrods todsy and I'm massively confused. I HAVE to be doing something wrong.


I'm using EOIC so as I see the exhaust start to open about 1/4 or maybe Half way I placed a .003 feeler guage under the Valve stem in between the rocker tip and torqued the rocker to 22 lbs. I used known length push rods on my checker as verified by my calipers and kept going up until I could no longer pull out the feeler guage.

As I see the intake go full open and then start to close about 1/4 of the way I measured the exhaust the same way. Feeler guage while torquing the rocker with a known length pushrod.


I have only measured one piston so far and I made sure I was in the lifter cup as I pushed it done withy fingers several times and witnessed it return to where it was many times.


My concern is my results.

The exhaust was slightly less tight then the intake but I couls get my feeler guage out with some decent force all the way up to 7.450.

This seems blatantly wrong to me as this would mean with my 0.40 pre load on my johnson lifters imma need a 7.490 or 7.500 push rod.

My heads are milled to 62 cc and I have a cam which I'm sure has a smaller base circle then oem


I was totally expecting a shorter pushrod not longer. What did I do wrong and is anyone in socal who's not an idiot like me able to help me finish this and tell AI what pushrods I need.


:/

P.s
As I'm threading in the bolt by hand with my socket I csn see the pushrod tighten a bit to the rocker and move down which leads me to believe I'm generating pre load even though I can slip the feeler guage out

 

Start here at post #13: https://ls1tech.com/forums/generatio...l#post19085422

You need an adjustable pushrod and 8" calipers. The 22lbs doesn't come into play with measuring. And I assume your preload needs to be .040 and not .40. You know that already, so just don't mix up your math

 

Ok so you were pulling on the feeler and it slips out with some force? You really need to just go to zero lash the lifter preload isn't going to have enough force to hold the feeler gauge that tight. Try to tighten it down till you can't wiggle the rocker up and down. Then check your pushrod length and see what you have that way.

 

I do have an adjustable pushrod. What I was doing is starting at 7.300 and going up until I couldn't get the feeler out anymore. Ended up at 7.450

 

Oh shoot. I skimmed over that part. Ok I would read through that thread a few times and try some more. I had to stop and start several times and moving to different cylinders helped get me on the right track.

 

I feel like in need to play with it more. I must be going past zero lash. Am I looking for the point where I can no longer separate the rocker and stem on top of the spring after the rocker is torqued ro 22.

Maybe I should ditch the feeler guage idea and just go up 0.025 until I can no longer tick tick the rocker by hand.

I was using the feeler cuz I was afraid of compression the lifter and skewing measurements but my Johnsons seem pretty tight when I push hem in by hand so I think if I'm careful I can be ok.

 

Don't torque it at all. No feeler needed, either. Follow the guide above and it will work fine. Read it through a few times before doing any of it.

 

Ok guys I feel much better now that I took the measurement on 4 valves and came up with pretty consistent results. Also I have a better idea of true zero lash.

To Sum it up when I got into what I believe was the right length the tick tick woukd dissappear while torquing the bolt and once fully torqued I sill had some slight lateral movement of the rocker as I moved it around with my hands so I'm pretty confident I was at zero last plus or minus a few thousandths.

I was also able to get the 0.003 feeler guage under the rocker tip all the way until I started torquing the rocker so I gotta be damn close.


Measurment of my 4 valves I checked the checker
As measured by calipers was

7.245
7.243
7.248
7.240

johnson 2110 lifters call for preload @ .040" +/- .010".

So with all this guage length, theoretical bull **** what pushrod should I order

It does seem shorter then I see most people running though but I have milled heads, decenter aggressive cam and new lifters so is it normal? Or did I screw something up again lol.

 

Sounds really short. Again, why are you worried about a feeler gauge? There shouldn't be a gap. Did you follow the guide step by step? Sounds like no, so I'm not sure how many other people are going to try and help.

My heads were also milled with 62cc chambers and I have a cam with very aggressive lobes. My measurements came out to ordering 7.525". Not that it means you will too, but the longer length shouldn't scare you.

Once you're happy with the measurement, you call the vendor and tell them the length "as measured by calipers" and they will handle the difference. That is also in the guide. Good luck.

 

I was just trying to put it in to see if I had play.

I tried the method in the walkthrough but others told me I did need to find zero lash at 22lbs. And others said no.

I'm off all day tomorrow so I'll keep at it.

Not sure what I might be doing wrong so I will re read the walk through a few times.

Thanks !

 

Just re read everything and I know what I did. Thanks so much for being patient with me and kicking me in the *** to keep re reading it


Thanks again

 

Cool man, hopefully it works out perfect like I think mine did. I started the same way as you too. After reading and reading, trying and trying, finally got it with Darth's help. Let us know how the rest of it goes.

 

I noticed in his right up he is using a johnson with the exact pre load I'm looking for and he achieved 1/2 turn of preload so thankfully I have a sort of control to measure against.

Gonna stick to it tomorrow until I can duplicate his results.

 

Mike try this as a double check

Take your adjustable and add the 040 preload to it. Install the PR and rocker. Find dead soft touch. I use three "taps" to verify no preload at all just zero. Then mark the bolt and tighten it. Don't torque it just tighten it until it stops. The rocker bolt should rotate just past 180 degrees. The bolt torque doesn't figure in

If that comes out right, you've got it

For comparison mine were near 7.7, but that's aftermarket heads, shimmed up rockers so I expected longer.

 

Ok so I have 3/4 of a turn before it gets tight and I can tell I'm just stretchching the bolt if I go further.

I will verify that this works on the rest but it woukd seem I'm pretty close.

This is with a caliper length of 7.300

I turned the bolt by hand juuuuust until I could no longer get a tick from the stem before getting my 3/4 turn

 

That's about perfect. At 3/4 turn, that's about .055 preload doing math in head. Whatever .75 x .076 is.

When you order make sure you tell them that is the length as measured with caliper.

 

Thanks so much for the help everyone. I think I was second guessing cuz I don't see too many people going down to a 7.300. Although this is only .085 smaller then my stock ones I measured and I do have lifters that want less pre load, new bushed rockers with different then stock trunions, as well as milled heads around the 0.025 mark so that could be the difference right there.

I measured with eoic and switched to tdc of compression stroke and measured again. And both figures worked out ok.