Help! L98 intake gasket re-install questions

[pdeason]

My son and I are in the process of replacing the intake gasket on his 1991 Corvette with the L98 engine. Since the car has 100k miles we have also removed and cleaned the radiator and are replacing the thermostat, EGR valve and valve cover gaskets. We are also refinishing the valve covers. My questions are:

1. What kind of thread locker to use on the intake and plenum bolts?
2. Do I need a sealant around the water ports and if so what kind?
3. Do I need a sealant on the bolts next to the water ports and if so what kind? Also, do I put thread locker and sealant?
4. What is the proper sequence of torquing the intake bolts? Some have suggested not torquing them all the way to 45 ft lbs for fear of bolt failure but that does not seem like a lot of torque to me.
5. When we took the injectors out (Bosch III) we lost one of the little plastic spacers under the o-ring. I saw where some people just put two o-rings instead. Is this ok or should I try to source the spacer? I think I bought the injectors from someone named John that I saw on here about 5 years ago.
6. What is the correct color for the valve covers? I have seen conflicting information. It seems like the early C4s were some sort of nickel color but these definitely looked bronze and it did not appear to be discoloration. Are there any sources for the textured paint with the correct color?
7. Is there anything else we should replace or do while everything is off?

Thanks in advance!

 

[Schrade]

Bolts? ANYthing but dry. Jaguar used to buy new Ford auto trannys, and re-build them RIGHT to install in Jags.

In the end, it's personal preference tho'...

And good for you workin' with your son

When I did L98, and LT1, and LT5, I used a LIGHT film of grease on gaskets. Some say to not do that. I've NEVER had a leak on re-builds. Light grease also helps hold the gasket in place, and makes dis-assembly easier if you to have to break it back down.

Only time I've ever used threadlock was on TB butterfly shaft bolts. All others just get anti-seize, or grease. STERILE clean bolt threads, and CLEAN bolt holes. I hate it [NOT] when the clean bolt won't catch with a ratchet, cause it's so clean and feels like it's going in on ball bearings!

Silicone for coolant hose ends (Armor-All is LOADED with Silicone). Stops the hoses from binding on the metal coolant ports.

LOTS more here, although it's different Tuned Port Injection...

 

[mr.beachcomber]

I concur with all of Schrade's recommendations above especially that of clean threads for the bolts and holes. I use a light coat of anti-seize on all steel bolts threaded into aluminum. Remember to reduce your torque values by roughly 50% to account for the less friction generated by the anti-seize coating. As for the light grease on the intake manifold gaskets, I've used this procedure for years going back to the 60's w/o any problems. The biggest challenge for intake manifold gaskets is making sure that you use enough silicon sealant at the front & rear of the intake to seal properly. Try to make the silicon bead's height even across the block, allow it to "skin" (about 5-10 minutes depending upon the temperature), and then set the intake down gently to avoid squeezing out the silicon and leaving a gap in the coverage.

1. As far as torque sequence for the intake, I've attached a copy of the 1989 FSM page regarding the torque sequence.
I didn't remember ever using 45 lb-ft on the intake bolts. Here's the recommended torque values from my 1989 FSM:

intake manifold attaching bolts - 47 Nm (35 lb-ft) (The 89 had aluminum heads just like your Vette)
intake runner to intake manifold - 25 Nm (18 lb-ft)
intake runner to plenum - 25 Nm (18 lb-ft).

2. I'm not sure of which part you're missing from your Bosch III injector, but I think that Jon at Fuel Injector Connection is the individual you're looking for.

3. The valve covers should be a light, tannish-brown from the factory. Here's a link to a blog regarding repainting the valve covers. If you need to remove old paint that's cracked or blistered, it's best to use a hand-held copper wire brush or plain old sandpaper as the valve covers are made of magnesium which will burn if subjected to too much heat. Only way to put out the fire is smothering it in sand (or dirt). Don't use water as the magnesium will explode! (There are chemical strips that won't hurt magnesium, but they are expensive. I've done two sets by hand w/o any problems.)

Hope this info helps! Good luck with your rebuild.