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max lift with stock valvesprings

Posted: June 26th, 2010, 12:17 pm
by stege123
How much is the max valvelift with stock springs? Due to longlifety of the cam and moderate rpm's i don't need the expensive and cam eating springs, but will i end up with coil bind ??? I will use the comp cam with #68-232-4

Re: max lift with stock valvesprings

Posted: June 26th, 2010, 8:02 pm
by unlimitedrubicon
The factory service manual lists .430" max valve lift, but the third edition of Mopar Performance's Jeep Engines book recommends the factory springs for the P4529229 cam which has .440" lift. Either way, with the Comp Cams 68-232-4 having .460"/.476" lift you would probably be in for some problems with the factory springs. You could do the mopar performance springs for an easy drop-in spring that is rated for up to .525" lift, or go a more custom route such as some of the members here.

Re: max lift with stock valvesprings

Posted: June 27th, 2010, 12:14 am
by stege123
Thanks unlimitedrubicon for your reply. That is a clear answer. I have to bite the bullet, and buy the expensive springs, retainers and locks. Furthermore i will use a differant oil with more ZDDP such as shell Rotella.

Re: max lift with stock valvesprings

Posted: June 27th, 2010, 5:11 am
by 4.whoa
The rotella is good for break-in, but its a bit much to use all the time.

Re: max lift with stock valvesprings

Posted: June 27th, 2010, 9:20 am
by stege123
OK thanks, but what is the downside of using rotella all the time?

Re: max lift with stock valvesprings

Posted: June 27th, 2010, 6:35 pm
by 4.whoa
It's very thick. From what I understand, it put's extra stress on the dist gear, not to say it will be quick or destructive, but it's better to not let there be an opportunity.
for break-in though, you want the additives and thickness to help ease the wear-in.

Re: max lift with stock valvesprings

Posted: July 10th, 2010, 8:56 am
by stroked'73
stege123 wrote: I have to bite the bullet, and buy the expensive springs, retainers and locks.
You can reuse the locks with the MP retainers.

I run rotella 15/40 like alot of other folks - if the thickness bothers you, they have a 5w40 synthetic or synthetic blend that'd work good. I run the 15w cause it's cheap and I can buy it by the pail.
Oil viscosity in multi-viscosity oils changes with the oil temp - the numbers represent the weight range in which they can change. So a 15w40 can't get quite as thin as a 10w30, but gets alittle thicker on the other end. In between, they should act the same, so at normal operating temp, there may be very little difference between the thickness of the two oils. Rotella actually recommends their 15w40 for older engines wanting more zddp.

Re: max lift with stock valvesprings

Posted: July 10th, 2010, 9:33 am
by stege123
Thanks stroked73
I already bought the locks, and yes they are the same.
15W40 is what i use, so switching to rotella should not be a problem. A year ago i bought a litre of ZDDP from an oil blender, and added a little every oil change (2003 Jeep, 1986 Corvette and 1983 Volkswagen Santana all with flat tappets) but the end of the bottle is in sight, and it is very expensive, so i will not buy it again. Personally i like an oil with a "body" like the 15W40. Downside is during wintertime, when you have to warm the engine up very carefully. Thanks again for all the input, i consider this topic closed, and finish my stroker. :banana: