JBA Headers
Installed on Friday....
Turned a 16.1 (16.39) best previous time at the strip.
To install we:
Removed battery box , cruise control servo and air cleaner.
We were also changing motor mounts at 53,000...hint...one can tell
a bad mount by looking at the point where the "saftey retainer"
contacts its stop....it should be flat, not rounded from being
used repeatedly.Or broken as ours was.
Removed the rear stud of the pair of studs in center of the manifold.
Installed that stud in rear most manifold bolt position.
This is easier to do before you discover the studs contact the tubes.
I coated the heads and headers with the hi-temp copper Permatex rtv.
Using the studs makes it easier to install the other header bolts and
also nicely holds the gaskets in place.
There are one or two bolts that are "must install first" bolts.
These are the bolts that have a tube cross over top of them.This
is probably very obvious to everyone else, but I guess it has been
too long since I fought with headers.
I also went to Checker Auto parts and bought several "99 cent
special" 7/16 combo wrenches.Grinding down the open end and shortening
one makes it less difficult to get to the bolts that you can only get to
1/64th of a turn at a time.
Fired up vehicle...is that an exhaust leak or just the way headers
sound????
To the strip...about a thousand degrees out but cooling to 100 later on.
First run...a 16.27/84.767mph.....a new record for the truck..
2nd run 16.239/84.887
3rd run 16.138/85.010
It is now obvious that we have an exhaust leak...
later runs produced a 16.316/16.355....the truck usually gets faster
as the evening cools off....we decided the leak might be affecting the
Ox sensor ...so we called it a nite.
Sun PM 115 degress...west facing car port.....we track down the leak.
Pass side header/pipe joint.In fact it has blown rtv onto the oil
filter.
We go under the truck.....
The cross-over pipe is touching the tranny pan on the pass front.
We decide this is not good....
We remove the flange bolts...it looks like we tightened them past the
end of the threads....we compare them to the stock bolts and find they
have more threads than the stock...they should have allowed us to have
more range when tightening....
We pulled the slip joint apart in front of the cat convertor.
This made it easier to handle the Y-pipe without the weight of the
exhaust system.
We took our 40 oz adjuster to the cross-over pipe, also to the corner
of the tranny pan (very gently and with compassion) where we had the
interference problem.
New grade 8 bolts with the same thread range as the JBA bolts were
aquired. Also a hand full of washers and new lock nuts.
The bolts were installed with two washers on the top.A single washer
was used at the locknut end.
The flanges were cleaned and recoated with permatex hi-temp copper
rtv.
Torquing to factory specs we still had about two threads showing above
the bottom flange.
We ended up with plenty of clearance between the pipe and the pan.
I suspect we had over tightened the topmost flange bolts (or had the
Y-pipe pushed up too high) when we installed it the first time.
We started the truck...no leaks...seat of the pants seems to show
better throttle response .
No track time this week so will be two weeks before "1/4 mile dynos"
can be run again.
Sorry for this being so long...Any questions shoot off an e-mail.
rob
phx az
charger69rt@inficad.com
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:09:11 EDT