2Loose '55 Chevy Sport Coupe, 396 LT1, T56

[jaybee]

I love your approach to this project. head scratching and ingenuity...the way hot rodding was meant to be.

[2Loose]

Got my hands on an original '93 Camaro shop manual, these two ports on the right side of the plenum are vacuum ports, the upper one is hooked to the original fuel pressure regulator vacuum port, which I'm going to leave open to the atmosphere for now, and the lower one in the old original pic is hooked to an "Evaporative Emission Canister Purge Solenoid Valve"....
Hmmmmm....




The large port shown below is apparently a connection to the crankcase, and is setup as a "crankcase vent recirculation valve", which you can see in the second pic...
I think I might keep that also, but fitting the crankcase connection to a road vent tube like the older motors used would be ok too....



I think both the upper small ports are just vacuum ports, one is shown in the old pic as a brake booster vacuum connection....

I really have no idea what this hole in the top, front, right corner of the plenum is for, or what the device plugged into that hole in the second pic is....
(scratching the head....)




These rear ports I'd blocked off earlier, they are EGR (exhaust gas recirculation) ports, that I'm not going to use on this car...
The lower pic shows some of the hardware for that device...




More Later...
Willy

[2Loose]

(Correction on above post....)

Got my hands on an original '93 Camaro shop manual, these two ports on the right side of the plenum are vacuum ports, the upper one is hooked to the original fuel pressure regulator vacuum port, which I'm going to leave open to the atmosphere for now, and just plug this port, and the lower one in the old original pic is hooked to an "Evaporative Emission Canister Purge Solenoid Valve"....
Hmmmmm....

[2Loose]

Messed around some more with how the fuel hoses were laid out at the pressure regulator...


And bolted in a new optima red top in the trunk...


MORE pix here....

[2Loose]

I put a 90 hose end on at the inlet side of that fuel filter, looks a lot better now...
I'll mount that filter on the side of the inner fender when I put the fenders back on...

[SonomaZ]

Your mystery ports and sensor located at the top front corner are for the MAP sensor.

https://www.google.com/search?q=LT1+...hrome&ie=UTF-8

My stock cube LT1 envies your 396.

[2Loose]

Have one port on the right side open for a vent to the Optispark...


New parts are on order for the crankcase vent system, which uses
those two lower ports, plugged the upper ones for the time being...


A MAP sensor is what this top port on the plenum is for...
Thanks SonomaZ !


Pulled out all the wiring and electronic gear, and started scratching my head...


More later....
( I hope !)

[2Loose]

My local Napa auto parts store had what is supposed to be
the correct MAP for this motor....


But it obviously needs a seal of some kind, which did not come with it...
So the search continues...


Pulled the new throttle body off the shelf to mount...


And found that there is a part missing underneath, now I need to
find out what else is needed and go find it. It did come with a
gasket for whatever is missing...
Hmmmm....

[2Loose]

Here's a pic of an original '93 LT1 MAP sensor and seal,
looks like some kind of soft sleeve...

[2Loose]

Found an old original MAP seal, but would much prefer a new one...
Will go back and hit up my local Napa store...


Found a piece of 1/8" aluminum plate in the scrap pile...


Cut out a cover plate for the throttle body hot water passages,
now I need shorter screws...

[2Loose]

Managed to find some (metric) m4 size ss allen head screws for this cover plate, still a little long, had to trim them slightly to get a good fit, but it came out pretty nice, also used flat and lock washers under each screw....



More pix here (scroll down)

[2Loose]

Worked up a list of sensors needed for this
'93 LT1 speed-density efi system:

1. MAT
Manifold Air Temperature
This fits in the air ducting in front of the throttle body,
I need to find one.

2. ECT
Engine Coolant Temperature
Not sure what this looks like or where it goes.

3. IAC
Idle Air Control
I think this goes on the end of the throttle shaft
on the throttle body, I need to find one.

4. TPS
Throttle Position Sensor
Again, I think this goes on the throttle body someplace,
I need to learn more about this one.

5. MAP
Manifold Absolute Pressure
Bought a new one from Napa,
it needs a special seal that did not come with it,
might have to just use silicone sealer.

6. Knock Sensor
I need to find the correct one and
where to mount it.

7. O2 (Oxygen) Sensor
I have one, need to weld a bung
on one of the header collectors for it

[SonomaZ]

Although specific to '95, this should help with your sensor locations:
http://shbox.com/1/component_location_views.html

[2Loose]

I've been slowly finding the parts I need online, most of them from Rock Auto...
but still need a body (housing) for the IAC (Idle Air Control) on the bottom of the throttle body.
My cover plate I fabbed isn't going to do it...

Found this on the evilbay site, but they refuse to ship to Hawaii/Alaska...

They must think we're not a part of the USA yet....

[2Loose]

I contacted the seller, they agreed to mail it to me in Hawaii...

[2Loose]

Finally located some O-rings for the MAP sensor probe that will fit snugly in the plenum hole,
four fit nicely on the probe, it should be ok....


Cut the water heater off of the IAC housing, and got a new probe to fit it,
and cut my cover plate to fit around the IAC housing....


And with a lot of shopping around, I think I finally have all the probes and sensors I need....


I'm learning a lot, I just hope I'm learning enough to not make any serious mistakes,
Merry Christmas everyone !!
-Willy-

More pix here (scroll down)....

[Larry Callahan]

Things are looking great! Thanks for all the updates.

[2Loose]

Living on a small island has it's disadvantages....
Searched every store that has bolts and screws, and could not
find the ss allen head metric screws I wanted, so drilled it to the next size
for the 3 screws for the IAC and tapped it for 10-32 ss allen heads
with ss lock washers....



And the same for the TPS, with ss flat and lock washers....


Both installed with anti-seize, as this is ss and aluminum, want that anti-seize in there....

[2Loose]

Decided to re-tap the threads in the plenum for the throttle body with 5/16"-18 NC,
and to use the ss allen head bolts I have....

All of my taps are sets of three, with different starting tapers,
the one on the right is a bottoming tap for blind holes....



I like to use a cutting fluid to prevent any galling when cutting new threads...



Taped off all holes where debris from the work could get in....



The metric threads that were in this plenum very closely matched the
new 5/16-18 threads I cut. I'm not happy about doing this, but there's
enough solid threads here that it will work out just fine....


I considered bumping it up to a 3/8" fine thread, redrilling and tapping,
but that much bolt seemed like serious over-kill, and the way I did it still
had enough solid threads in there that it will be just fine !!

All mounted up with never-seize and ready to go....



HAPPY NEW YEAR TO ALL !!
And maybe I can get this rig running this year !

[2Loose]

Swapped out the fixed pressure return line fuel pressure regulator for an adjustable one. I've used them on these motors in the past with good results.