Power assist gone when stopping...blew through a stop sign yesterday!

[69hemibeep]

All you can do is timing and see what happens. Something tells me your in for a cam change or some kind of vacuum pump which I know nothing about. http://www.summitracing.com/search/...eet?tw=Vacuum Pumps, &sw=Vacuum Pumps, Street

 

[Ranger]

I was in the same boat (but no power brakes), 3" of vacuum. A milder cam brought it up to 18".

 

[droptop]

OK, reporting back....I was getting about 3" of vacuum at idle. After messing with the idle and air/fuel screws, I am now getting about 5.5" of vacuum at 950 RPM. What else should I adjust to get the vacuum higher?.....

14-16 inches of vacuum is what you need to get full benefit of your brake booster. Change the cam or add a vacuum pump.

 

[69hemibeep]

Has anyone suggested changing the cam? LOL. It will make the 6bbl work better also

 

[mac]

still would like to know what the timing is. can make a huge difference in vacuum. timing first then air fuel mixture. timing for torque, mixture for horsepower.

 

[moparchris]

Its the vacuum line to the trans, very classic problem found on all the Dodge Roadrunners. Go ahead and find the line in the trunk that comes through the floor. Look there for vacuum. That should fix it.

 

[69hemibeep]

:nachos:

 

[Ranger]

What's a "Dodge Road Runner"? :huh:

 

[Ranger]

timing for torque, mixture for horsepower.

Can you elaborate?

 

[Big John]

Ignore Chris, pay attention to Mac.

 

[mac]

Can you elaborate?

whether or not the cam installed was a good choice, first step in my opinion is to have a timing curve, base timing and total timing considered. basic carb adjustments will get it to run but timing is first and then carb mixtures. it has happened twice to me that a person had a car that would run but not well. both cars were for what ever reason were set at zero degrees base timing. all it took was a timing light and a little time and both cars were running great. so i have to ask again what are the timing settings for the OP car? not saying this is what his problem is but not having this info makes it hard to help. advancing timing can increase vacuum but i don't want him to advance it too much so there are problems on the other end of the scale.

 

[69hemibeep]

5.

 

[Ranger]

I meant elaborate on "timing for torque, mixture for horsepower". I had not heard that before.

 

[mac]

something i have heard before when engines are tuned on a dyno. they start with timing and when they reach a top value, they then start to play with jetting for peak horsepower.

 

[moparchris]

Ignore Chris, pay attention to Mac.

Now that just hurts. BTW you shouldn't let your child smoke.

 

[ACME A12]

Now that just hurts. BTW you shouldn't let your child smoke.

Nice Dodge Road Runner in your avatar pic. :basketcase:

 

[utahcarguy]

whether or not the cam installed was a good choice, first step in my opinion is to have a timing curve, base timing and total timing considered. basic carb adjustments will get it to run but timing is first and then carb mixtures. it has happened twice to me that a person had a car that would run but not well. both cars were for what ever reason were set at zero degrees base timing. all it took was a timing light and a little time and both cars were running great. so i have to ask again what are the timing settings for the OP car? not saying this is what his problem is but not having this info makes it hard to help. advancing timing can increase vacuum but i don't want him to advance it too much so there are problems on the other end of the scale.

OP here....I have not had a chance to take a timing reading. The car has a serpentine belt setup and I haven't seen any timing marks. I'm getting my garage floors done with epoxy, so the car is in storage for a few days. I can report back when I can get a better look!

 

[utahcarguy]

OP here...timing was at 10. Bumped it to 12 with no noticeable difference other than the car seems a bit more responsive. But it might be in my head! I'm going to try every BEFORE having to switch out a cam and pulling a motor!

 

[69hemibeep]

Lower timing gives you more vacuum but more timing makes it faster to a point