i have no vacuum!

[tomst9]

ever since i put my cam in, my brakes haven' worked very well, especially at idle. I threw a vac. guage on today and when the car is fully warmed up i got 8 in.hg of vac. Is that ok. What should it be?. I checked all my vac. lines, but i didn't find any leaks. I know that with the cam i will lose vacuum, but my cam isn' that extreme to lose my power brakes.
thanks
tom

 

[dastang2]

summit sells a vacuum canister with a gauge on it.

 

[tomst9]

ttt

 

[Idwitheld-1`]

I have a stock motor and stock cam....had the gauge on today and I have 18 In/Hg hot at idle (900rpm).

Not sure if this helps you....

 

[dastang2]

aftermarket cams lose vacuum but when you had the vacuum gauge on it did it read steady or what.

 

[tomst9]

yes it was steady. I tried playing with the idle some but in order to get 15in.hg i had to have it idle at 1500rpms.

 

[dastang2]

if it was steady then i believe it is fine for that cam but i don't really know. i have a real lopey cam and it has plenty of vacuum.

 

[blown5.0]

sounds normal to me. why do you need 15"hg?. if you list the cam specs I can say whether or not 8" is normal, probably is. is the car an auto or stick?

 

[tomst9]

its an auto

 

[blown5.0]

thats real low vacuum for an auto, hope you have at least a 2500 stall convertor in it, or its going to be a real dog. you still didnt list the cam specs?

 

[tomst9]

i'm going to a five-speed in the summer and its not that big of a dog off the line anyway. Cam specs are in the sig. 516in/531ex, 217in/226ex
thanks
tom

 

[HISSIN50]

Tom, just a thought, but have you checked the brake booster? if the vac is decent, and you have no assist, then i would look at that possibility.
or run a vac canister as someone mentioned. good luck.

 

[tomst9]

how can i check the booster?
thanks for the replies,
tom

 

[dastang2]

well when you push the brakes does it sound like a loud vacuum leak or are your brakes hard to push

 

[tomst9]

i do hear a loud vacuum sound

 

[HISSIN50]

how can i check the booster?
thanks for the replies,
tom

i would try to check it like a FPR. put some vac on it with a miti vac, etc, and see if it holds steady or bleeds off. im not sure exactly how a booster works, but that is my best guess on how one could test it.
good luck, Tom.

 

[PrimerdFury]

I just have an E-cam and have always had a low vacuum problem. That coupled with a leak in the break booster (denoted by the "loud vacuum sound") forced me to finally do something about my brakes not working well since the cam install. To solve the problem I replaced the brake booster and installed a vucuum reservoir canister thing and haven't had any problems since. Good luck