hp/tq/ and 1/4 with a 76mm/78mm turbo

[hoogiesngrinderz]

I wouldnt lock it @ WOT but lock it on the street for sure.

My thoughts exactly. Any tuner can set it to unlock over any TPS% you'd like.

[c0ncEpT]

I wouldnt lock it @ WOT but lock it on the street for sure.

[sman]

Deff lockup

Sent from my VS980 4G using Tapatalk 2

[Formula Z]

Lockup vs non lockup 4l80e turbo'd street car and occasionally track time??

[1999Black_Z28]

Here is what I use: Shane at Thunder Racing gets the credit.

"The TDC method is NOT always accurate. Try the EO/IC method to check pushrod length. I have posted directions on this forum numerous times... Here it is again:

FWIW, EVERY cam install I have done using the LS7 lifter with a cam with greater than .600" lift (read smaller base circle) AND stock heads w/GM MLS gaskets has taken 7.425" pushrods for ~.050"-.060" preload. We measure lifter preload on each and every cam install we do. I have never had a lifter failure nor do we end up with the dreaded "sewing machine" noise.

Its very simple, If you change ANY of the following:
valve sizes, valve job, head milling, thinner/thicker head gaskets, decked block, cam with an altered base circle, etc... YOU MUST CHECK FOR PROPER PUSHROD LENGTH.

I have helped countless numbers of individuals with this process over the phone, via email, and PM's. I've posted the process on at least 3 occasions.

Here it is again in a nutshell:

1. Using the EO/IC method, get the lifter to the base circle of the cam.
2. Using a known length pushrod (7.400" is a good start with stock rockers) run the rocker arm bolt down to zero lash. This is easily done with your fingers "wiggling" the rocker, the point at which the "slack" is just gone is zero lash.
3. Set your torque wrench to 22 lb./ft. Tighten the rocker to full torque and count the number of turns it takes to get there. 1 full turn wtih a stock 8mm X 1.25 bolt is ~.047" preload as measured at the pushrod/rocker interface.
4. I normally shoot for 1 1/4 to 1 3/4 turns with stock type lifters like Comp 850's, LS1, LS7 etc.

For an example, if you use a 7.400" pushrod and come up with 3/4 of a turn, you will need at least .025" longer pushrod to get into range. If you end up with 2 1/4 turns, you will need one .025" shorter...

I might not know everything but I will tell you that this method has worked for me year after year cam swap after cam swap. We average 3 cam swaps a week here so you can do the math.

If you are not familiar with the EO/IC method for determining valve events in a 4 stroke engine, its very simple:
For a given cylinder as the Exhaust valve is Opening, the intake lifter will be on the base circle of the cam and lash/preload should be checked for that intake valve.
For a given cylinder as the Intake valve is Closing, the exhaust lifter will be on the base circle of the cam and lash/preload should be checked for that exhaust valve.

THIS METHOD ALWAYS WORKS!!!

Check it using the above method and see where you are."

[DETROITMUSCLE]

Larry gave you a method, number of turns will give you a measurement. every rotation adds x amount of pushrod length but I don't know them off my head.

[Formula Z]

I emailed martin with what I have and hopefully he will tell me. I need to know how to double check though

[1BADAIR]

depends. heads, gaskets, cam, pushrod manufactuer( not all 7.400 are actually 7.400 ie trend)

[kammi10]

wouldnt whoever spec'd his cam out know what it should have?

[1BADAIR]

yes. base circle no lift. Or this is the proper way to check base circle and preload
phone 031.JPG

[Formula Z]

Lobe base? Lowest part?

[1BADAIR]

get the the lobe base. then slowly tighten the rocker with just the socket while rocking it. when you get to slack thats 0. put on rachet and count the turns till tight( around 1)

[Formula Z]

I need help figuring out if my 7.4 pushrods are proper length. I dont understand the math and all that goes with it. Im pulling my hair out trying to understand. Please help

[1BADAIR]

Typically ported heads can expose the rocker bolt holes on the intake side, true?



Mine are stock 317's, rocker bolts torqued to 22 ft-lbs, rotated crank 180* and checked again. Not going to pull the covers. I just overlooked the service manual and nowhere does it state to use thread lock or sealant.

the sealant/loctite comes on new bolts. like the main cap and crank bolt. its on the bottom of the bolt head

[OIF1VET]

Typically ported heads can expose the rocker bolt holes on the intake side, true?



Mine are stock 317's, rocker bolts torqued to 22 ft-lbs, rotated crank 180* and checked again. Not going to pull the covers. I just overlooked the service manual and nowhere does it state to use thread lock or sealant.

put yella terra rollers on my car 7 years ago. No loctite here. Not saying it is right, didn't know any better. No issues in 7 years.