1988 Monte Carlo SS
LS1/T56 Change-over page
2001 Project Updates
04/04/01 Fuel lines again
While I am waiting for the weldments to be completed so
that the T56 can be properly located I am moving on to the fuel lines.
- The stock lines (current 3/8" supply & 1/4"
return) will be discarded. I
removed the current hold down bolts on the existing 5/16" vapor return line so
that I can mount the new 3/8" driver side supply line next to it and then I will
reconnect the frame fasteners.
- This pic
compares the 3 fuel line sizes (3/8", 5/16" & 1/4").
- I ran into a problem when carefully reviewing the existing
flared end of the fuel line at the filter. I believed it to be a standard double
flared end, however, upon
closer observation it is a unique high pressure connection utilizing a rubber o-ring for
proper sealing at the filter. So much for my new $50 double flaring tool!
- I stopped by a local fabricator of Industrial high pressure
hydraulic lines to review the tubing end. They assured me that it wouldn't be a
problem for them to duplicate this special connection. Unfortunately they don't sell
a tool for me to make my own.
- One other snag has surfaced with the C5 dual inlet fuel
rail. No one has just the connectors available to fabricate hose ends to. I
stopped by the local Chevy dealer and the stock '97-'98 C5 inlet/return lines list for
about $70 each! I will research this one a bit further before breaking the bank here
for two 18" long flexible fuel lines!
I am proceeding now with finalizing fuel filter location
on the left side frame rail (opposite of the stock TBI filter passenger location) and
running the forward portion of the fuel line to the engine compartment. Once
finalized I will have the new connections made.
04/18/01 Fuel lines & Motor Mounts
Good progress on the fuel lines & welded motor mounts
- I finished bending the
supply and return fuel lines and had a local fabricator add the correct "bump
tube" ends with the brass connectors and rubber o-rings on the ends. I now have
the solid pipe tubing complete (w/fuel filter) and ready for re-installation on the frame
- The welding
has been completed on the motor mounts and I applied POR-15 as a surface finish to protect from rust.
- I spent several days making wood mock-up motor mounts which
I believed could be used as master
models for use in sand casting a pair of high strength steel mounts for follow-on
motor mount sales for those interested in purchasing a bolt-in set of mounts.
Unfortunately I discovered from a local Foundry in Seattle, WA that it would cost a
minimum of $200 just to cast a "test pair" for me to validate the configuration.
In addition to this, the set-up cost for a permanent double mold for a small
production lot run of about 10 sets would run close to $500 plus the cost of the castings
which would run just under $50 each. Too expensive! Oh well, I'll look into a
two piece weldment next before I pass on this idea.
I'll be bolting the motor back in again and start work on
the Crossmember, floor modification and finalizing the clutch linkage.
04/23/01 First fit-up of the T56
I installed the T56 transmission while the motor was in
the car and would not recommend installing it this way. It's way too heavy
installing from underneath the car even though I used a hydraulic jack! When I pull
the motor out again I will haul out the tranny out with it (especially since I have the
engine sling on the hoist to tilt the load).
- I tried to establish two
reference centerline (C/L) scribe marks on the underside of the transmission tunnel
floorboard before I cut anything and drilled 4 pilot holes in a circle as a starting
point. I made about a 3.5" circle to simulate the shifter tower/boot
- This view shows the same
reference pilot holes from the pic above except from inside of the car. After
making the first
cut using a 4" diameter hole saw blade and test fitting the T56 for the first
time it became obvious that the reference side to side scribe line was about 1/2" off
center. In hindsight, the center tack weld mark of the 200R4 shifter/console rear
bracket in the first pic above actually is ideal as a reference for centering the T56
- The reference measurement from the
driver inside Crossmember frame rail to the C/L of the rear trans mounting bolt is
22.5", not 23" as I had originally scribed (must have been up too
late!). I had this measurement written down but somehow didn't transfer it
correctly. Fortunately no problem encountered because I knew that I would make
multiple cuts to get the final hole size "just right".
- I could see that the hole cutting was going to be much
larger than I had originally anticipated so to make it easy on myself and to facilitate
using a die grinder for cutting the floor I went ahead and removed the drivers seat,
detached the aluminum rocker molding holding the carpet down and pulled up the carpeting
surrounding the entire work area and just laid the carpet and attached backing material on
the passenger side seat to keep it out of the way for now.
- After making several parallel and perpendicular cuts to the floor to clear the shifter
tower I had to message the floor area (take a hammer and pound the metal for final
clearancing) around the reverse solenoid and two rearward topside transmission bolts
located just forward of where the tailshaft housing attaches to the main case.
In order to do this, I had to undo the motor mount bolts and raise the engine/trans
assembly up and forward about 12" with the help of the tilting engine hoist sling.
- To get the proper clearance for the two rearward topside transmission bolts I used a
4" wide wooden block on a hydraulic jack then raised the transmission tunnel with the
jack until the floor was slightly stressed (in order to form and help contour the metal)
and then gently hammered around the block to stretch the metal. I reinstalled the
engine/trans assembly and bolted in the engine motor mounts then used the transmission
with the hydraulic jack it and repeated the process using the bolt heads to stretch the
metal slightly further.
- This view of the passenger side rear of the T56 shows the final clearance and location
of the right
rear topside transmission bolt and the remaining 200R4 shifter/console hold-down nutplate.
- I created a locating tool for determining the correct rear height of the T56 by using a
1-1/2" diameter wooden dowel with a nail head exposed 3" (this touched the
floorboard at a pre-marked location) when I had the dummy 200R4 housing still in the car.
To obtain this reference measurement the dowel slides through the rear seal of the
dummy housing as a perfect fit and also matches the diameter of the T56 rear yoke.
This shows how I used this locating
dowel to place the T56 about 1/2" higher than its final height (just touching the
floorboard) to ensure proper clearance (notice that the dowel doesn't align exactly with
the tailshaft by 1/2" because of this).
- Here is the final shifter tower/boot hole configuration with the shifter/boot
properly centered and located for height.
- This view shows the reverse
solenoid with its clearance close to 1/2" to the sheetmetal to account for
drivetrain torque under load.
I will start the Crossmember fit-up next along with final
contouring of the rubber boot which will cover the shifter hole in the floor.
04/29/01 T56 Crossmember Fabrication
I had a very productive weekend and finished locating and
tack welding the Crossmember for the T56! This was a relatively easy job.
Afterwards I wished that I would have put a T56 in my car sooner, however, I knew that the
SBC & LS1's have a different T56 so I knew that I would have to replace transmissions
(or at least the input shaft since the LS1's is 0.400" longer) had I attempted this
- After carefully measuring the area for the mounting plates
to "hang" the Crossmember from I decided to use a 3.5"W x 0.25"T x
6"L steel plate on the drivers side and one with the same dimensions except 12"L
for the passenger side since the frame area didn't quite extend rearward enough based on
how I want to set the Crossmember. My decision was also in part swayed by the fact
that 3 existing holes were already in this frame location thus minimizing my cutting on
- This view shows the drivers
side frame holes and general location with the 1/2" diameter bolts in place that
I will use for the mounting bracket. These holes were drilled this size from the
factory. No mods here! This view shows the passenger
side frame rail where only the far right hand bolt hole existed. I added the two
left side bolt holes and the far left hole on the bottom of the frame for access to the
bolt. The right two bottom holes already are drilled from the factory.
- Here is the left
side bracket tack welded and hung in place at the frame location noted above.
This view shows the right side bracket installed where it cantilevers past the frame rail
to the rear by 4.5". This is why I used 3 bolts on this bracket to minimize
- These views show the individual Crossmember mounting
brackets out of the car (left side and right side).
Here is the tack welded Crossmember
with brackets temporarily assembled out of the car.
- The stock T56 rear Crossmember mounting pad seemed to have
way too much play in it for me. I went to the parts book and found an early '70's
Chevelle "A" body SBC manual transmission rear mount with the same mounting hole
location to the case and with two bolts mounting to the Crossmember instead of one.
The rubber also seems firmer on this mount over the stock T56 unit. I elected not to
use a polyurethane mount due to the potential problems it could cause the sensitive LS1
engine knock sensors which may retard the timing if they sense driveline chatter.
view compares the tops of the mounts (the stock T56 mount is on the right with the
single mounting bolt) and this
view shows the bottom of each.
- This view shows the installed
center section of the Crossmember mount with the metal mounting tab looking toward the
The great news now is that the physical fitment of the
LS1/T56 is virtually complete (less the passenger side coil bracket & drivers side
exhaust manifold oxygen sensor)!!! I will drop off the Crossmember and mounting
brackets tomorrow to have the final welds placed on them and then the Crossmember
complete (less paint)!
04/30/01 Fuel rail connections
I have researched trying to find the correct stock type
fuel fittings to connect the flexible fuel lines to the metal hard lines which will
terminate just above the frame with little success even though I even received e-mails
with suggested potential sources. I finally located what I believed I need at Street & Performance, however,
they wanted $80 for just the two fittings! NO WAY!
- I went back to my local Industrial Hose fabricator today
and had them solder on a metal -5 & -6 male fitting onto my C5 fuel rail after
trimming about 3/4" off of the ends of the fuel rails to ensure that I don't have
Fuel Rail Cover clearance problems in the future when I install them. The killer
deal here....only $15 installed (parts & labor) and they finished them in 15 minutes
while I waited. Talk about customer service! A far cry from $80 just for
- I also removed the existing passenger side fuel &
return lines. The upper rear hold-down bolt located just above where the tailpipe
goes over the axles is a real pain to get loose based on very limited access.
I received my special 16MM drill bit in the mail today
along with a cobalt 3/4" diameter drill bit so that I can finish drilling up the
necessary clutch pedal and associated components.
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© 2001 by John Bzdel