I have have dana lifters(hydrualic) which are basically just a stock replacement. How high of rpm can stock lifters or dana take before the power falls of dramatically? Also can one bad lifter or all of them cause such a dramatic power drop? The car is peaking around 6300 and was designed to peak around 6800 or so. The hp is dropping off by about 30 horse from 6300-6700. Also the tuning is the best it can get, a/f is 12.9 all through, andd spark advance pretty aggressive. We tried alot of things up top, but nothing helped. thanks guys

 

Whats the cam and whats the valve springs, rockers, studs, pushrods etc...

Let me see if I can help ya out here.

Bret

 

Yeah it would be helpful to know what kind of additional valvetrain hardware you are running.

 

Bret the cam is one of yours in sig, my name is chris falcone if that helps, springs are beehives, rockers are comp pro mags(steel or aluminum?)comp pushrods

 

Do you know your spring pressures and install height?

 

Chris,

Yeah I looked up your setup

AFR's, big stall and TH400, big hyd roller. It should peak 6500-6900rpm.

The spring setup is good to 7500rpm with those cam lobes.

Did you zero lash these lifters?

The motor most likely doesn't like all the spark advance you can give it, a lot of guys throw it at the motor till it's not knocking but most times the motor makes best power with less total advance.

Lloyd and I talked about the setup too. Sounds like a weird dyno setup, the really fast pulls are killing you in terms of inertia eating up the power.

The lifters might cause a issue. With the springs you are running more PR might even help (3/8ths) or better lifters. I've never run the Dana's, the OEM ones and the Comp replacements along with the old R's and the Morel's now are what I'm used to.

I'm a big fan of the Morel's BTW that's why I use them in my motors.

I'm thinking you need to run it at the track before anything. Or try another dyno just to see what it says.

Send me the charts either way.

Bret

 

Bret,
The rockers were adjusted about 1/8 of a turn past zero lash. I did try a different dyno and the results were alittle higher because it was a dynojet. We tried taking timing out, adding it, increasing and decreasing fuel, but no major difference. Do you think that is too much cam for thoseheads they peaked at about .650 flowing 288 cfm, and 286 at .600 lift.?

 

something else, what about my tranny? i went from a sixspeed putting 160 to the wheels on a 150 shot, then going to th400, 3800 stall and only put 130 to the wheels on a 200 shot, nothing else changed. Does the type of tranny you run (m6 or th400) depend on what rpm the power PEAKS at?

 

You want to try zero lash, not 1/8th past it. Thats where they will make the most power.

The tranny you are running now is eating up more power by a lot. The much smaller gain from the N2O shot shows that bigtime. As for the RPM it's doubtfull it's going to change the HP peak RPM of the motor but at the tires it might.

Bret

 

Bret, I sent you that graph at bauer racing. Also, any body else runninh morel lifters, if so what are they set at?

 

.030" is the spec, but I'm doing a engine dyno test here soon to see where they make the best power.

 

I'm a little confused, maybe you can straighten me out. From the Comp Cams catalog, .030" (+/-.010") is also the spec that is suggested as the preload on their lifters. With 3/8-24" studs, that works out to almost 3/4 turn past zero lash (1"/24=.042"; .030"/.042"=.71). Using the same method, figuring out the preload at 1/8 turn, that works out to .005". That's how I set the lash on my Elliott LE1 head/cam(Bret, it's your cam spec) and it runs great, but it sure is noisey. It sounds like I'm running solid lifters. As soon as I break in my new clutch, I'm going to put my Datamaster on it to see if I'm getting any knock retard from all the valve noise. Wouldn't setting the lash at 1/16 turn or zero even make the valve train even noiser?

Chris

 

Usually they get better with going to zero lash.

Bret

 

So, if I understand you correctly, if I readjust them back from 1/8th turn to 1/16th turn or zero (where there is no detectable up/down movement of the rocker arm), the valve train noise might decrease?

Chris

 

Yep..... it's still going to be noiser than the stock setup.