ssheets

iTrader: (1)

The hydraulic lifter will collapse about .075" I went through the same thing when I was measuring

vettenuts

iTrader: (4)

I'm confused, how would you get less PTV with a hydraulic lifter? I would think the lifter plunger would partially collapse giving a larger PTV indication. What am I missing?

Prerun4fun13

iTrader: (6)

I dont see why it isnt legit to have this in a public forum. I would like to see what happens... Also i have heard alot of good about Pred so im sure he will handle it.

edcmat-l1

iTrader: (10)

If you use a hydraulic lifter with a checker spring, the checker spring doesnt have enough spring pressure to put the lifter piston where it supposed to be, so you end up with whatever preload is supposed to be as a minus in the PTV clearance. In other words you staert with the valve off the seat.
And if you try doing it with the regular valve springs, the lifter bleeds down and screws up the reading.
You can use a hydraulic lifter, but you have to use an adjustable pushrod and carefully set it to zero preload.

ssheets

iTrader: (1)

Yes, so you use checker springs with an adjustable pushrod to determine P to V and your actual pushrod length. You can use a solid lifter or if your hydraulic is fully pumped up and your checker springs are week (mine would barely keep the locks in) it will work too. When the real spring pressure is applied to your hydraulic lifters they will collapse about .075" In my case my valves actually hit my pistons using the 7.400" pushrods with the checker springs. Using an adjustable pushrod I determined my cam gave me .100" clearance on my intake ports and .180" on the exhaust. I measured measured my adjustable pushrod, added .075" for preload and came up with 7.400" for my new pushrod length. It's not rocket science, but if you're not sure it can freak you out. If it turns out you're wrong and predator is right...you need to think about where your finger is pointed before you start pulling the trigger. (I'm talking to Chrs1313, not you edcmat).

ssheets

iTrader: (1)

And I was in your shoes. I knew I may be in a bind though as I was installing an F14 (232/234 .600") cam with 5.3 heads and 2.02" valves. Instead of getting mad at people I learned how to really measure PtoV. So if the shoes of ignorance are the ones you're talking about guys like Predator are the ones that'll help you grow out of them.

chrs1313

iTrader: (24)

i didnt check PTV clearance with the check springs i used the dual patriots...the checker springs were on the other head just to check it another way besides clay...i used a stock hydraulic lifter with the dual spring not checker springs...so i thought that the lifter would blead down and the reading would be less...i was wrong in that case so now i know just to use a solid lifter...but it is just tight actually on the limit tight and i wanted other people to have a heads up...

and what are you talking about pointing the finger... 0.073 is 0.073 no matter what way you want to spin it...i am not pointing any finger...

PREDATOR-Z

Chrs1313,

.073 intake is a good clearance on that cam and I'm happy that you checked your PTVC.

Many of the big cams like MS4, T-Rex, G5x3 (jus naming a few, no direct reference) have less than that on intake depending on LSA/ICL.

If you are uncomfortable with that much on intake, just retard the cam 2* or 4* and it will be more clearance on intake and a bit less on exhaust.

This cam by no means have PTV issues even at 111 LSA and 107 ICL.

Are you measuring 10* BTDC (int) and 10* ATDC (Exht)? this is the danger zone.
Just make sure you do that to give you the clearer picture.

Don't worry about the "red face", I do not mind, this will bring in a lot of readers (this is good info). The poeple who understand "clearances" will automaticaly know that these are GOOD clearances by today's big cam standards.

You can post a thread about the bigger cam poeple and ask for what they run on theirs "measured" , you'll see what I mean and relax a bit.

Otherwise, anyone on this board running a cam with bigger than 232 duration on a 112 lsa better yank their cam out in a hurry, they all have the same or less clearance.

Please do not flame the OP, things can get freaky, but this is a good thread and OP did the right thing in measuring PTVC.


BTW, this cam is now running in a few cars on even tighter specs at 110LSA

PM Patrick G I'm sure he will tell you the same.

Let us all know of the power it makes once properly tuned.

So to recap:
1- Measure 10* BTDC intake and 10* ATDC exht
2- You can retard cam via adjustable timing chain to modify clearances.

MPHmotorsports

iTrader: (18)

My mistake, still would have sent a PM but this thread now has some real good info.
Many people can get value in how to check P/V clearence and also can see that in today's standards you are safe. :-)
It is nice when a thread like this turns out this way.
Jeremy

chrs1313

iTrader: (24)

thank you predator i appreciate it...next time though give me a heads up when it is going to be around .073 clearance haha...again this was no means an attack at you i was just in more shock than anything...i read another post about a cam patrick speced out i think is was for rockws6 and i asked him what his PTV clearance was and he must not have known and told me with stock heads it shouldnt even be close...

thanks again though i appreciate it just was a little shocked...gotta give me a heads up next time

PREDATOR-Z

No problem, you did the right thing.

Just get it tuned properly by a good tuner and show us a graph if you can.

NHRAFORMULA00

iTrader: (2)

Thanks PREDATOR for understanding our situation.Thanks to all that set us in the right direction.We just had a lot of hours in checking clearances and runing around before the holidays.Chris should have some numbers by the end of the first week of January,he has an app. at SPEED INK. HAPPY HOLLIDAYS TO ALL

GMmexican

iTrader: (7)

Just curious how many cams have predator and pat g speced for members here?..........ford and mopar guys must hate you, for giving us the power and knowledge to smoke them so much

vettenuts

iTrader: (4)

OK, missed the part on using checker springs so now I understand. Thanks.

lastcall190

iTrader: (36)

Good info in here. I wont lie, the red face got me looking just as predicted it would

-J

ABQ99TA

iTrader: (17)

Pred is the man.

chrs1313

iTrader: (24)

Thanks again and HAPPY HOLIDAYS!!

patriotformula

iTrader: (28)

completely unrelated... kinda, but I have an MS4 cam...

If you wanna know how tight clearances are on it, I spun a bearing and lost enough ptv that my #6 intake valve slapped the piston!!! lol

Good news, I put the new motor in and have had no problems what so ever with the same cam and clearances.

bad6as

iTrader: (17)

230/230 .613 / .591 lift XFI/X-ER 111+4
Im going with a 232/232 110+3 .595/.595 xer/xer. They are both on the same icl, i have 2* more intake but a lil bit less lift. So my cam will open start to open the valve 1* sooner and close it 1* later, right?

so i will have about the same clearance?

NoMoreFWD

iTrader: (1)

Predator deserves much respect. He shares a ton of info with this board and is always professional.