6.0L/243/pump gas/carb/Cam Motion LLSR
10-06-2016, 02:14 PM
#8
The common .660" BTR springs I have are not adequate for this effort. Needs something like a PAC1237X. Probably change over the winter, it wasn't happy over 6800 on the dyno. with valve control it probably would have picked up some numbers.
It does have a heavy rocker on it.
10-07-2016, 12:19 PM
#14
11 Second Club
So at what point/rpm do you believe valve float is starting? You did say it feels good to about 7k & that above 6800 on the dyno didn't look so good. Do you have a MAP sensor hooked up to see the reversion or other data?
I'm interested in valve float as my valve train is also not the lightest. From some data I've been looking at it seems my motor is done making, or carrying, power after 7k looking at the MAF values. Although the manifold vacuum, from the MAP, is the highest at the highest rpm. I'd just like to be able to spot it when it happens.
I'm interested in valve float as my valve train is also not the lightest. From some data I've been looking at it seems my motor is done making, or carrying, power after 7k looking at the MAF values. Although the manifold vacuum, from the MAP, is the highest at the highest rpm. I'd just like to be able to spot it when it happens.
10-07-2016, 01:56 PM
#15
The posted dyno sheet only shows the beginning of it (not so bad), but I had others where I pulled it to 7200 RPM and it was much more prevalent.
There was much larger deviations in the airflow. Air was being measured via the mass air meter in the carb bonnet which is very accurate.
Seen this before in engines with valve control issues, normally from the lack of spring pressure, assuming this is the same issue. Only 160# on the seat and about 440# over the nose.
Most people probably don't notice it, it is not audible BUT the HP is affected. For the short period of time that it spends up there before the shift it is not going to cause any major problems, probably only talkin' 10-15 HP loss.
If it was a tractor puller or a sprint car engine I would have been taking it apart to fix right away. I decided to put it in the car and have some fun!
It was a science project and I learned those lobes need a little more spring pressure than the hydraulic roller stuff to be PERFECT>
There was much larger deviations in the airflow. Air was being measured via the mass air meter in the carb bonnet which is very accurate.
Seen this before in engines with valve control issues, normally from the lack of spring pressure, assuming this is the same issue. Only 160# on the seat and about 440# over the nose.
Most people probably don't notice it, it is not audible BUT the HP is affected. For the short period of time that it spends up there before the shift it is not going to cause any major problems, probably only talkin' 10-15 HP loss.
If it was a tractor puller or a sprint car engine I would have been taking it apart to fix right away. I decided to put it in the car and have some fun!
It was a science project and I learned those lobes need a little more spring pressure than the hydraulic roller stuff to be PERFECT>
Last edited by helicoil; 10-07-2016 at 03:07 PM.
10-07-2016, 04:46 PM
#17
11 Second Club
Thanks for the info man.
That thing runs right there. Hurt some feelings with that guy. I'm not the best with older cars. The first thing that came to my mind was an early Chevy II Nova? Awesome car!
That thing runs right there. Hurt some feelings with that guy. I'm not the best with older cars. The first thing that came to my mind was an early Chevy II Nova? Awesome car!
