wouldnt whoever spec'd his cam out know what it should have?
Announcement
Collapse
No announcement yet.
hp/tq/ and 1/4 with a 76mm/78mm turbo
Collapse
X
-
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.Doing less with more

Comment
-
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."
Comment
-
Post Slut
- December 9th, 2011
- 5919
- Michael H
- 1989 Iroc-Z Convertible/1998 Z28
- Lowell, MI
- Meat Processor
- Send PM
My thoughts exactly. Any tuner can set it to unlock over any TPS% you'd like.Originally posted by c0ncEpT View PostI wouldnt lock it @ WOT but lock it on the street for sure.
1998 Camaro Z28 - Bright Red, 6.0 TR224, 4l60e, 3.42 Eaton TrueTrac
1989 Camaro IROC-Z Convertible - 355 big tube TPI, WC T5, 3.42 Zexel Torsen, CTS-V/C4 brakes
1955 Bel Air 2 Door Post - 357 TPI, Muncie M20, 4 wheel disc
2006 Saab 9-7x 5.3i Daily Driver
Comment
-
Thx guys. Im just doing some research and see that non lockups are cheaper. I know everyone says dont cheap out on the converter. Do I need a triple disc over a single disc for a daily driven car? Itll go to the track once in a while, but 90% street.
Engine is ready so im starting to figure out the trans. Stock rebuild with z-pac and hd2 kit. Should be good for the power ill be making?sigpic
11.84 @ 117 w 1.66 60' (previous na best)
- - 5.3/4L80e/T7875 - -
- Huron Speed Turbo Kit -
1998 Formula
Comment
-
Also there are some single disc's on the market that can be locked @ WOT.
TCS sells them - 9" converter 11" clutch. They hit as hard as any 3/5/7 disk I've ever felt.
Mike - keep it simple - if the converter is spec'd right a single disc will take you where you need to be.2000 Formula
fixed slow junk
Comment
-
Only reason you should lock it is if you need a few more RPM at the stripe IMO. If the converter is even close there really isn't any ET to be gained. No matter how badass the converter company tells you there converter is the lock up clutch will only last so long when you start locking it @ WOT.
Comment


Comment