Intake Manifold Removal Question

[KJL]

I thought I could remove the intake manifold without the need of the service manual. I removed all the bolts, hoses, wire harnesses, air intake, throttle cable etc. without issue. When I went to carefully lift it off I discovered a wire harness attached to the underside at the rear of the intake and also noticed some other stuff attached underneath as well. My goal is to check the torque of the injector housing bolts as they are leaking oil at the gaskets. Having the intake lifted up enough I can see the reason why. Anyway, there appears to be a bolt holding one of the harnesses in (the large one) and the other looks like just a push in plug. I am not sure about the other stuff. It seems odd that that anything would be attached to the underside of a component that would need to be removed to service what is under it. Can anyone shed some light on this? Thanks!

PS I did order a manual but like an idiot I ordered one for the 1995 corvette not the ZR1. I have a service supplement but it does not show all the wiring harnesses nor anything at all that attaches to the underside of the intake. Looks squeaky clean simple from the diagrams.

[Dynomite]

I thought I could remove the intake manifold without the need of the service manual. Can anyone shed some light on this? Thanks!


A. Tools for Plenum Removal.

Two Allen Head wrenches (6mm and 3mm),
Two flat head Screw drivers and ...................................1/4 inch socket wrench with 1/4 inch socket
TB bracket wrenches (7mm and 9mm)..........................and short extension for DIS Connector
http://i287.photobucket.com/albums/ll142/dynomite007/Maintenance%20ZR1/cd1f898d-6255-439d-af9e-ab8bfbaea4b9.jpg (http://s287.photobucket.com/user/dynomite007/media/Maintenance%20ZR1/cd1f898d-6255-439d-af9e-ab8bfbaea4b9.jpg.html)http://i287.photobucket.com/albums/ll142/dynomite007/Maintenance%20ZR1/7d184269-e7b8-4563-bb79-10ded592ab5c.jpg (http://s287.photobucket.com/user/dynomite007/media/Maintenance%20ZR1/7d184269-e7b8-4563-bb79-10ded592ab5c.jpg.html)

B. Plenum Removal Steps (assuming you have TB Coolant Blocked). If not.....remove some coolant before you start.
1. Disconnect Battery (Check Battery Condition and Jumper GOOD Battery as FIRST CHECK).
2. Remove Samco (or stock) Air Duct (large flat screw driver).
3. Remove Oil Catch Can Hose (If Oil Catch Can Installed) to Plenum and PCV Dual Connector on back of Plenum (small flat screw driver).
4. Remove Trottle Body Cables (two including TB Shield and two top (I have 3mm SS Allen Head) screws on Plenum) and TB Connector (7mm and 9mm wrenches).
5. Remove Fuel Regulator Vacuum Hose "L" rear of Plenum.
6. Disconnect MAP Vacuum hose from MAP (Manifold Absolute Pressure) and from rear of Plenum.......
(in case it gets intangled with other wires/hoses as MAP is not disconnected from Plenum).
7. Disconnect Passenger Side Plenum Vacuum (and Drivers side Plenum Vacuum if secondaries not removed).
8. Disconnect Brake Boost Vacuum line Drivers Side Rear of Plenum.
9. Remove three 6mm Allen Head SS Fuel Line Bolts and two fuel lines (6mm Allen Ball Head Socket) or Torx-40 stock bolts.
10. Open gas cap to prevent fuel lines from leaking when removed from fuel rail.
11. Remove 12 Allen Head SS Plenum Bolts (6mm Allen Ball Head Socket with Extension) or Torx-40 stock bolts.
12. Lift Plenum from Gasket (front only) and remove two Cam Cover PCV Vent Rubber Connectors to Air Horn.
13. Disconnect two DIS (Distributorless Ignition System) Connectors front of DIS.
14. Disconnect large Purge Vacuum line under front of Plenum (91')......
(90' has small vacuum line only under front of Plenum going to Charcoal Canister under left head light).
15. Disconnect two small electrical connectors rear under Plenum (MAP and DIS).
16. Unscrew 1/4 bolt in Main DIS Connector rear of Plenum.
17. Remove Plenum.

C. Starter Removal.
18. Remove Coil Pack Connector and 4 bolts (two pairs 8mm hex heads 6mm bolts front, 10mm hex heads 8mm bolts rear).
19. Remove Coil Packs with plug wires attached (remove all 8 plug wires from Cam Covers).
20. Check starter with hot wire but then disconnect Starter Solenoid connector.
21. Disconnect main HOT wire from Battery to Starter.
22. Remove two starter mounting bolts (13mm Hex Head 10mm bolts) and lift starter out of Valley.

http://i287.photobucket.com/albums/ll142/dynomite007/D%20Engine%20LT5/f6da30fd-c4c0-4c81-9e31-f7510aaf14f2.jpg (http://s287.photobucket.com/user/dynomite007/media/D%20Engine%20LT5/f6da30fd-c4c0-4c81-9e31-f7510aaf14f2.jpg.html")

Removing Plenum (including the 10 minute Plenum Removal) (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-4.html#post1581663365)

[PhillipsLT5]

Dyno. ROCKS!

[XfireZ51]

It's a plenum not an intake manifold. That's your problem ;)

[KJL]

Yea yea....old school. I can strip down my 72 without hesitation. Well it came right off without a problem. Thanks for the tips. I noticed that the small vacuum canisters to not align well with the linkage mounting pins. The actuator arm looks as if it is slightly offset and if the units were turned 180 degrees they would align better. I noticed in some pictures they appear to align better than mine. I have a 95.

There is some oil in the motor valley and I was wondering if it would be possible to jack the front of the car up a bit and carefully wash some of it out with simply green and a gentle stream of water or something.

[Dynomite]

I noticed that the small vacuum canisters to not align well with the linkage mounting pins. The actuator arm looks as if it is slightly offset and if the units were turned 180 degrees they would align better. I noticed in some pictures they appear to align better than mine. I have a 95.

There is some oil in the motor valley and I was wondering if it would be possible to jack the front of the car up a bit and carefully wash some of it out with simply green and a gentle stream of water or something.

The general concensus is to leave those vacuum canisters just as you see them unless you are installing new canisters...then I aligned them "straight".

I would remove coils and starter........When you are at it.....clean up starter solenoid contacts with wire brush.
Then clean out the valley drain by blowing compressed air up from bottom tube between the oil pan and bell housing. Then pressure wash if you have to :D

Do not laugh...but I soak paper towel and paint brush in gas and clean out all oil (with coils and starter removed)....then HOT pressure wash ;)

The Starter Solenoid is shown in the left photo with slight burnt contacts in right photo.
http://i287.photobucket.com/albums/ll142/dynomite007/Maintenance%20ZR1/bac49725-6086-4f07-a929-9f1f498e4d50.jpg (http://s287.photobucket.com/user/dynomite007/media/Maintenance%20ZR1/bac49725-6086-4f07-a929-9f1f498e4d50.jpg.html)http://i287.photobucket.com/albums/ll142/dynomite007/Maintenance%20ZR1/e8886408-e5b8-40d3-a5d2-199e22f85e0a.jpg (http://s287.photobucket.com/user/dynomite007/media/Maintenance%20ZR1/e8886408-e5b8-40d3-a5d2-199e22f85e0a.jpg.html)

The Solenoid contacts in left photo were wire brushed clean in right photo.
http://i287.photobucket.com/albums/ll142/dynomite007/Maintenance%20ZR1/95a2d94c-6e14-4206-ab39-e157c17fc6a2.jpg (http://s287.photobucket.com/user/dynomite007/media/Maintenance%20ZR1/95a2d94c-6e14-4206-ab39-e157c17fc6a2.jpg.html)http://i287.photobucket.com/albums/ll142/dynomite007/Maintenance%20ZR1/e6b04516-3ebb-49ab-9f32-1da552901435.jpg

[Blue Flame Restorations]

Dyno. ROCKS!


Agreed 100% :cheers:

[mgbrv8]

This might help also feel free to contact me.

https://www.facebook.com/media/set/?set=a.10201021415884459.2217036.1439230280&type=1&l=bf12a0aa41

Dave

[KJL]

Thanks for all the help. Finally got to check the injector housing bolts and found just about all were 30 to 50% low on torque and some were just finger tight. I hope this solves my oil leak at the mating surfaces. I will put back together after some cleaning. If not, I guess I will need to replace the gasket. Now all I need to do is figure out how to replace the battery.... I replaced the transmission in my wife's Jag in the garage with car on jack stands and a cheap scissors lift, I cant figure out how to replace battery. Maybe I will need service manual after all!

[PhillipsLT5]

http://www.youtube.com/watch?v=gk03-roWP2A

http://www.youtube.com/watch?v=jgMa-J8Gqks

[Paul Workman]

Just to add:

To keep the IH bolts in place, some BLUE Locktite on the threads will keep them from backing out again.

While you have the plenum off, now would be a good time to check the vacuum harness for the secondary port throttles and replace any dry rubber or cracked plastic tubing.

As for the oil in the bottom of the V, a new breather box gasket from Jerry's Gaskets might be a consideration too. And, as were the IH bolts loose, so too might the bolts on that breather box be loose (mine were). The blue Loctite will keep them in place.

As for the connections to the Digital Ignition Controller*, you want to take care to align that long connector (with its many small pins) carefully. You should be able to easily push it in place by hand to be sure the pins go "home". It isn't often that a pin gets bent, but it happens - especially if the connector is started in at an angle and snugged into position with the force of the clamping (center) bolt! [-X

* The "DIC" was mounted where it is - underside of the plenum - for cooling of the internal circuitry, which generates a lot of heat and requires some serious heat sinking. If for any reason the DIC is removed, such as for porting or perhaps powder coating the plenum, there must be a thin coat of that white (zinc oxide) heat sink grease between the DIC and the plenum. AND... be especially certain there isn't so much as a grain of sand or other debris/grit sticking to the "grease" when placing the DIC against it's heat sink surface. Such debris - even a grain of sand - will prevent heat transferring properly to the plenum and the DIC will be in danger of overheating and failing. (And, they don't make those anymore; a critical piece of equipment, that fortunately doesn't often fail...if properly installed.) If the "grease" gets contaminated, it is best to remove it completely and replace it with some fresh heat sink goop (Radio Shack and other electronic supply stores have it). KEEP THE NEW COAT THIN!

Another tip I learned watching Marc Haibeck remove a plenum is the throttle cables don't necessarily have to be removed if only dealing with something else under there. The plenum can be rolled over on its back to rest gently on the driver side of the engine/wheel well out of the way, and rolled back into place afterward; throttle cables intact.

When installing a new plenum gasket, I first spray the top side of the gasket with silicon spray as a release agent to ease removal in the future (taking precautions to keep the spray the hell away from the open IH ports and the car in general). The bottom side remains dry, and the mating surface of the IH is first cleaned with a razor blade, followed by a scrubbing with (CRC Brakleen; non-petroleum) brake cleaner - getting the metal sterile and dry.

The next time the plenum is removed, the gasket will usually stick to the IH well enough so that removing the plenum only requires me to slip a thin putty knife between the plenum and the gasket and sliding the knife down the length of the gasket, the plenum comes free and the gasket usually remains intact for at least 2 and sometimes more uses (or at least Jerry's gaskets do!), depending on the number of heat cycles or how long the interval between plenum pulls has been.

I like to remove the rubber collar gasket from the "Weatherpak" connectors and with a dot of dielectric grease between my thumb and finger, massage the gasket to coat it with a thin layer of fresh grease before reinstalling the connectors. It will prevent moisture, of course, but also facilitates removing them next time and lessens the chance of one tearing.

Hope something here is useful.

P.