Since I did my roller rockers, i have noticed that the brakes require slightly more pressure.

To me, it seems about right because more air is being sucked for combustion, creating less of a force for running the brakes.

I am gonna get a new check valve tomorrow to see if that makes a difference.

It is very slight. hardly noticeable. It is not like sleeping in a different bed, more like your wife getting the pillows mixed up when she does the sheets and you get her pillow.

 

if your theory stands correct it using more air then technicaly you should get more suction and better stopping power since the brake booster runs off of vacuum..maybe a loose connection?

 

I thought your vacuum problem was gonna be like mine after I put my 1.7s in.My vents are messed because I broke the vacuum tube between the 2 tees by the firewall.Yet something else I need to fix.

 

no, it is not like that. More lift means that the valve is open longer based on the longer distance (lift) that was created. The valves are going to always open and close at the same velocity. But the time they are open will cause less vac. since the conbustion chambers are getting more air volume going into them.

Vac loss is something you get with a higher duration camshaft. But the duration has to do with the valves staying open longer in a sense that they are "fully" open longer.

 

hmm my understanding was that the 1.7's gave you more valve lift allowing more air in not changing the duration of which the valve..where as a cam would understandably change vacuum because its changing the duration of time that the valve is open..so in my head it would make sense that a more open valve would create more vacuum..im not trying to insult you..but do you see where im coming from?

 

That is why I asked. I had always thought that duration was the factor for vac loss, I was just checking if i might be wrong and lift can have a part in it.

I think i am just being paranoid. After all, the truck is a lot more powerful with all the mods I did. Maybe it just takes a bit more pressure to stop.

I really hope that I did not put my intake on wrong and have a vac leak out of the intake.

I hear a loud sucking noise, but I am attributing that to the round air cleaner I put on. Maybe I should check to see if a vac line is cracked or not attached!!!

I did notice that i had to play with my vents when flushing my engine (put heat on hi). I noticed that in the beginning when the coolanmt was at temperature (after a while of idling) the vents were blowing outside air. THen I opened and closed the vents using the ****, and the heat immediately kicked on HOT.

 

from what i remember increase of valve overlap cause's loss in vacuum..now that i think about it your right..a higher ratio rocker would bring the lift point sooner in the curve...Since the duration will be larger at this earlier point on the ramp..the effective overlap will increase at this point..

 

i never noticed any change when i did mine.

 

If anything, my brake pedal feels spongier than before.

 

exactly.