Valve adjustment video

[brad hibbard]

we are attempting to add some informational videos with our written recommendations on our FAQ page
this valve adjustment video was just our second video of hopefully many more to come.
it will be posted on our website and FB page by Monday but I thought I would get some early reviews from my 4M friends
take a look ---I hope it helps some people understand some things.

https://www.youtube.com/watch?v=r_4HUSP3vYA

Brad

https://www.race-1.com

[SRXSRULE]

Good video.
One question for you. do you use the same amount of preload on the 602? 5/8-3/4 of a turn? If you do, have you ever played with preload on the dyno? would you seen any change running zero preload?

[brad hibbard]

that zero stuff is a recipe for failure when the clip holding the lifter together is pushed out

as for actual power gains with less pre load the answer is no we do not see a gain at any point
actually (depending on lifter condition) you will see a loss in power

lifter condition----let me explain
the actual clearance inside of the lifter between piston and lifter body have a tolerance just like anything
if that clearance is on the loose side you have "squishy" lifters
also coming into play is the seal between push rod cup and piston and then we have that pesky check ball in the bottom that really has an influence on lifter performance----all of that information is pertaining to the "guts" of the lifter and whether we have firm lifters or squishy lifters

the fix for a squishy lifter is pre load----this limits the amount of squish
by the way---I am not sure if squish is a real word but it works in my head

this whole premise of lifters pumping up and holding the valve open (the reason for zero lash)
comes from the aftermarket world where hydraulic lifters are performance oriented with a different set of tolerances and in many cases a completely different design inside.

the 602 and 604 engine has stock design lifters and at 3/4 of a turn preload will not pump up and hold the valve open

special note----
we do not recommend more than 3/4 turn of preload because of geometry issues

we can get into this deeper but that should make it a little more clear

Brad

https://www.race-1.com

[SRXSRULE]

interesting. lots of good info there.

I will say that I run zero pre-load on my 602's, have done that for years. I start with new engines, run them 30-40 nights and sell them. Never had any lifter failures, but I do know that is a possibility with running the valves like that.

Now you have me thinking about this. I'll be on the dyno in a few months with a new engine and I will do some testing between zero preload and 3/4 turn.

[brad hibbard]

sounds good---I am all about input from independent sources

for apples to apples testing your temperatures (especially oil temp) need to be the same

when you test do you A--B--A ? or A--B--A--B ?

many tests are only A and then B not even back to A

our testing procedure is a minimum of A--B--A--B sometimes repeated a 3rd or 4th time

just my 2 cents

Brad

https://www.race-1.com

[SRXSRULE]

My normal testing procedure is 3 pulls, record results and temps. then average out the result of all 3 and thats the number. Not just hp,tq numbers.... several numbers. acceleration time is big for us.
Make adjustment, bring up to test A temps, 3 pulls, record results and then average out.

We dont repeat the process unless we feel there was an error or see something we didnt like during the pulls.

I have to pay for Dyno time, per hour. I normally have around a dozen things I want to test and changing those parts multiple times just isnt a good use of my time.

I should also add this is chassis dyno testing. Its not as quick and easy to make changes as using an engine dyno, but I prefer to do it this way because over 1/2 of my testing is parts in front and behind the engine. water pumps, pulleys, fans, shrouds, transmission, drive shaft, gear, fluids.

[50j]

That can be helpful but you sure need to have the right person running the dyno and monitoring things like water and oil temperature. Chassis dyno sessions are rarely as controlled as an engine dyno usually is.