This is topic low vacume bad brakes HCI 5.0 in forum Tech Talk at Northern California Ford Owners  .


To visit this topic, use this URL:
https://californiafords.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=010359
Posted by Coupe (Member # 3001) on :
 
I did a HCI swap on my 5.0 and put it back together and all of a sudden my car runs like crap.

It gets about 10ish # of vacume and the car stumbles down low, anyting under 3g it stumbles but after 3k the car just pulls and the brakes get a little better (obviously its getting more vacume)

my cam is basically identical to aaronc's cam and the lift is like 496 I belive (ill have to double check)

I thought maybe my booster was bad so ive swapped my booster and MC. Didnt make a difference my brakes are still hard as a rock. It takes a good 1-2 second with all my weight on the brake pedal to fully stop or lock up the brakes.

I also sprayed propane basically all over the engine and It made absolutly no difference the only time it made a small difference was when i sprayed into my stock airbox.

My timing is at 12 and Fuel Pressure is at 38 unplugged.

Im really at the end of my wits with this no idea what to do next. Im open to all opinions.
 
Posted by FasterDamnit (Member # 442) on :
 
List the cam specs.
Did you do any brake work? Sure all the vac lines are correctly attached?
 
Posted by Coupe (Member # 3001) on :
 
looking at the cam specs at 50 it is 224 intake 218 exhuast
gross valve lift is .556 on the intake and 528 on the exhuast, I guess i was off on my guess, long day.

I intalled it straight up.

as for the vacume lines correctly I did remove my smog equipment and I thought I had plugged in the vacume correctly I could be wrong i guess.. If you know of a chart onliine that shows were exaclty the vacume lines go it would be greatly appreciated.
 
Posted by mtbaughs (Member # 4052) on :
 
http://www.veryuseful.com/mustang/tech/engine/88Stang5.0Vacuum.gif
 
Posted by Coupe (Member # 3001) on :
 
Thanks a lot mtbaughs, Any ideas one why you think the car has such low vacume?

How would I know if my lower gasket has moved?
 
Posted by CDT (Member # 5004) on :
 
you have to have a leak somewhere, spray carb clean at the gasket areas.
 
Posted by blind (Member # 3052) on :
 
quote:
Originally posted by Coupe:
...I also sprayed propane basically all over the engine and It made absolutly no difference the only time it made a small difference was when i sprayed into my stock airbox...
quote:
Originally posted by CDT:
you have to have a leak somewhere, spray carb clean at the gasket areas.
propane would do the same thing, no?
 
Posted by CDT (Member # 5004) on :
 
yes it should, I did miss that, the only other thing would be if the cam is way outta time or the valves are too tight, I would lean toward cam timing it would also explain the powerband of above 3k
 
Posted by Coupe (Member # 3001) on :
 
The cam was degreed and installed dot to dot.

I remeasured my pushrods and they seem to be to short by .1875 do you guys think this would cuse my problem?

Im going to be ordering new pushrods today.
 
Posted by 93PONY (Member # 60) on :
 
What heads & what pushrod length are you using?

That cam should have 14-15inches of vacuum at idle.
 
Posted by Coupe (Member # 3001) on :
 
The heads are AFR 165's with 1.6RR and 6.500 pushrods.
 
Posted by blind (Member # 3052) on :
 
ttt
 
Posted by 93PONY (Member # 60) on :
 
Pedestal mount or stud?

6.500 is longer than what is typically used on that setup. If you're running pedestal mount rockers you've got WAY too much preload. If you're running stud rockers you'd better check to make sure the rockers aren't bending the studs at peak lift.

6.250 (stock length) is what 95% of the inline 20 degree heads require on a roller 302. The other 5% is 6.200-6.300.

[ February 23, 2005, 10:57 PM: Message edited by: 93PONY ]
 
Posted by Mr JoCo (Member # 1549) on :
 
cool

[ February 23, 2005, 11:06 PM: Message edited by: Mr JoCo ]
 
Posted by JoeT (Member # 298) on :
 
lower intake vacuum leaks that leak towards the lifter valley (center of the block) can not be detected by the ol 'spray carb cleaner' technique or more serious ghetto techniques of feeling around with your fingers [Razz]

I had a leak like that that worked exactly as you describe, drove me nuts for 2 weeks.
 




Fueled by Ford Mustang Owners
on CaliforniaFords.com