I am trying to find out which push rod length I should run with, and verify I'm doing it correctly.
My set up 5.3l block bored to a 5.7l W/ -3.2cc valve relieves in the piston, tsp 225CC heads, LS7 lifters, TQR V4 cam. 26190PT felpro headgasket. (.048 thickness) please ask if I forgot anything.
I just tried to get my pushrod length with a push rod length checker from COMP cams.
my problem is it seems that I'm getting proper pushrod length for 2 different sizes and have no idea how.

when I first started to check for pushrod length. I placed the head gasket, put head on and placed 4 bolts around the cylinder in and just ran them down to be snug. from there I put my rocker arm in WITHOUT the push rod in to see how many turns on the rocker arm bolt I was going to have before it bottoms out on the seat. and to make sure its seating properly later on. I marked the top of the bolt with a marker when it first starts to thread into the head. From there I put the push rod I got from Texas speed (which are 7.450) in and reinstalled the rocker arm and bolt. I got the correct number on the rocker arm bolt and then went to push up and down on the rocker arm to see if I had any clatter and I wasn't getting anything so I figured that was proper pushrod length. from there I checked my PTVC (keep in mind I have a 5.3l block bored to a 5.7l W/ -3.2cc valve relieves in the piston) and didn't read anything on the clay I put on the pistons. so to me that's telling me I have more then enough clearance when it comes to PTVC. so out of experimenting I was thinking about what would happened if I bumped up the push rod length from 7.450 to 7.55 just to see what the result was for proper pushrod length. and turns out I am actually getting the same reading when it comes to pushrod length. theres no chatter. and I'm getting the same amount of turns when it comes to the rocker arm bolt seating properly... can anyone tell me why this might be?
because in my mind I'm thinking I need a base pushrod length of 7.450 but with the ls7 lifter preload of .060-.090 I was told from TSP. I'm thinking running with a 7.500 push rod length because by the time I actually torque my head gaskets down and the rocker arm down It should add up to .060 lifter preload. and when it comes to PTVC I have more then enough clearance so running a longer pushrod if I can shouldn't hurt. (I did make sure I was on the base of the cam aswell many times. I was looking at the cam from the top of the valley cover to verify)
If I left anything out please let me know I'm kind of confused I feel like I'm doing something wrong. but at the same time I feel pretty confident for some reason lol.

 

Trying to follow but not sure I completely understand so will make a few points. First, pushrod length should have no affect PTV unless you are bottoming in the lifter. It will affect the lifter preload.

As for the gasket, it will compress some. Not sure what your original gaskets were, but I had the MLS gaskets and replaced them with a thinner gasket when the new heads went on. I found that I could remove the rivets from the old MLS gasket and remove one layer of the gasket and I ended up with 0.040" gasket as a result. This allowed me to set things up using my final gasket thickness without using my new gaskets.

How are you measuring PTV? If you use a new lifter and the actual valve springs you likely are not getting the right value as the lifters will compress. If you have an old lifter, remove the snap ring in the top and use some washers to make it solid. Use check springs on the cylinder and an adjustable pushrod set to zero lash and check the PTV. Make sure the lifter doesn't turn when doing any of this.

Once you check PTV, put in your new lifter and use the adjustable pushrod. Measure zero lash and add your preload. Don't count bolt turns as it doesn't matter. You just get zero lash with your bolt snugged down in the head.

 

I'm measuring PTV with clay, I have a -3.2 cc reliefs in the piston, and I know that I need a solid lifter. but I honestly i have no idea where to even get a solid lifter. lol
and I'm using a .048 size head gasket.
the reason for counting the bolt turns was to verify that the rocker arm was going to going into the pedestal fully.
And thank you for replying.

 

ok so I went back out there in the heat to try to figure out this pushrod length...

when I go to put my TSP push rod in which is a 7.450 length I'm thinking that I'm getting that as the base pushrod length... because when I screw the bolt down and grab the rocker arm and try to lift it up and down it doesn't chatter. but I can pretty much push the hydraulic part of the lifter down. which is kind of confusing me. is this normal? I know its a hydraulic lifter and its suppose to move. but it pushes down rather easy. (I'm running with LS7 lifters) and when I put my push rod checker in at 7.400 length it slightly clatters. but barely. for LS7 lifters how much lifter preload should I have? ive heard .075 lifter preload.

 

If the lifters are new, then the plunger will easily depress so you have to be careful when taking measurements. That is why measuring PTV with this lifter won't work.

Do you have your old lifters that were in the motor from before? You can make a solid lifter to do the job, I have some photos if you have the lifters.

 

oh ok, yes I have the old lifters still.

 

Pull the snap rings on a couple of the old lifters and get some washers to fit inside. Just add enough washers to make the old lifter solid. I seem to recall that a couple of washers had to be filed thinner to get a good tight fit of the snap ring so there was no slop in the lifter. You might be able to use shim stock as well, goal is the reassemble the lifter so the lifter cup doesn't move.




This shows the washers I added along with the lifter internals.



View down the throat of the disassembled lifter.

 

That is a great idea for a testing lifter! Thank you for posting that!

 

Are there washers inside of the lifters?


And I went back a couple times to see which pushrod length I was going to need. And i went 12 turns on the comp cam pushrod checker​​​​​. And the rocker arm was taping so I went 12.5 turns on the checker. And it wasn't turning and more so I moved down to 12.25 turns on the checker And the rocker arm wasn't tapping so I called that my base pushrod length. Which gives me a 7.4125 base push rod length. So I'm thinking a 7.475 pushrod should be the correct size with lifter preload? Which should give me .0625 lifter preload?

I think before I was just over thinking it LOL...

 

No, those are washers I added to keep the plunger from moving and thereby making the lifter solid so I could check PTV, degree the cam, etc.

 

oh ok.
So before you stated that I wasn't going to be able to check PTVC because I didn't have a solid lifter.
If I'm using the clay method should I still be able to get a decently accurate reading without a solid lifter? I'm just curious.

 

No, your new lifters will compress. You should use solid lifters with a correct thickness head gasket.

 

Why not just buy 2 solid lifters and use some light mock up springs. The washers was a great idea though, it is confusing when you’re buying a package and they ask you to select push rods before you even have the cam.

 

Because depending on which solid you buy, the PR cup could be slightly higher, or slightly lower, which probably wont matter for degreeing, but would for setting PR length. Sometimes problems arise when converting/compensating. Perfect example were my AFR 225 Mongoose heads. Someone at AFR made an error while converting metric to SAE, and my installed height ended up .100" too short/stiff. So I try to use the actual components when mocking something up. I'm with Vettenuts on this one.