Intake horn corrosion

[secondchance]

I always thought the LT5 under the hood was the prettiest part of a ZR-1. Being a daily driver, after 14 years, motor is beginning to look a bit messy. So, I am thinking about refinishing valve cover and intake plenum/horn - either Ligenfelter paint or powder coating.
I would love to solve corrosion issue (adjacent to cover plate on top of throttle body) before refinishing.
It seems different metal and presence of current is causing this. One thought I had was figuring out a way to insulate 3 electrical pieces connected to throttle body/air horn:
1. IAT sensor - simply relocate to plastic air intake above air filter housing.
2. Throttle position sensor - I got to disassemble and figure out.
3. IAC motor - Insulate bolt from bracket.

Has anyone figured out how to stop this corrosion?

Another thought is to purchase "Counter Act" electronic corrosion control unit and apply the patch to underside of throttle body. However, heat may make this impractical.

Any thought or info would be appreciated.

[GOLDCYLON]

Well im not sure how to stop the corrosion however The old paint was not that durable on our motors from the factory. For PCing I recommend Jeffvete a forum member here who did the PCing on my car. He could have your plenum, Cam covers and Airhorn seen to in no time.

Heres a couple of Photos of Jeffvettes work. I took these about a year ago still need to snap a few with the Samcos upgrade.

[QB93Z]

I will offer a cople of suggestions:

There is a vendor on the Net/Registry web site that sells an aluminum Throttle Body cover plate that is engraved with ZR-1. That plate being aluminum should not cause a galvanic corrosion problem, which is what i think you are talking about. There are a lot of other components connected to the throttle body that are dissimilar metals that can not be removed. If you keep the area clean and dry, the corrosion should not be a problem.

The part you refered to as a valve cover is called the cam cover. There is a lot more to it mechanically that just a valve cover on a standard V-8.

Once you start powder coating or painting engine components, you will end up wanting to do all the top-end components, because the newly finnished parts will stand out against the old pieces.

Jim

[flyin ryan]

Jim is 100% regarding dissimilar metals/alloys. i've never mentioned it but have thought in the past about trying metallic ceramic coating. more commonly known as header coating. it's tuff stuff.

[secondchance]

Thanks to all of you for your input.
Also, I notice coolant in/out tube for heating the throttle body during warm-up. Does coolant flow below the plate? I was thinking coolant possibily acting as electrolyte.

Also, I didn't know the plate was non-aluminum. Perhaps replacing the plate is the solution.

Thanks again!

[PhillipsLT5]

Bypass coolant

[flyin ryan]

Originally Posted by flyin ryan

Jim is 100% regarding dissimilar metals/alloys. i've never mentioned it but have thought in the past about trying metallic ceramic coating. more commonly known as header coating. it's tuff stuff.

sorry, i guess i should have been a little more clear. when i'm talking about using ceramic metallic, i, myself, would only do the inside surfaces. want to try keeping the outside relatively factory looking. maybe not on my serious engine, but on these ones anyhow.

[QB93Z]

Originally Posted by secondchance

Thanks to all of you for your input.
Also, I notice coolant in/out tube for heating the throttle body during warm-up. Does coolant flow below the plate? I was thinking coolant possibily acting as electrolyte.

Also, I didn't know the plate was non-aluminum. Perhaps replacing the plate is the solution.

Thanks again!

I believe that the original equipment throttle body plate is aluminum. I was referring to the plate shown in GoldCylon's pictures, it is aluminum also.

I don't think you need to be concerned about galvanic corrosion because of the coolant in the throttle body. If it was occurring, it would have to be on the wetted surfaces of the coolant passages, not on the exterior surfaces. (Provided the engine surfaces are clean and dry.)

Still, coolant bypass modification may make sense for other reasons such as easier maintenance and possibly performance improvement due to cooler (denser) air charge.

From what I have learned about the LT5, the biggest causes of stained or darkened engine surfaces are stains from spills of engine fluids and inappropriate cleaning solutions.

Jim

[secondchance]

Originally Posted by QB93Z

I believe that the original equipment throttle body plate is aluminum. I was referring to the plate shown in GoldCylon's pictures, it is aluminum also.

I don't think you need to be concerned about galvanic corrosion because of the coolant in the throttle body. If it was occurring, it would have to be on the wetted surfaces of the coolant passages, not on the exterior surfaces. (Provided the engine surfaces are clean and dry.)

Still, coolant bypass modification may make sense for other reasons such as easier maintenance and possibly performance improvement due to cooler (denser) air charge.

From what I have learned about the LT5, the biggest causes of stained or darkened engine surfaces are stains from spills of engine fluids and inappropriate cleaning solutions.

Jim

For sure. But over a period of time, inevitably stain accumulate, especially when driven everyday.

[tomtom72]

I would just offer up this suggestion concerning that corrosion on the T/B cover plate.

Upon dissassembly use some baking soda solution or white vinegar and a very stiff tooth brush on the bare metal gasket lands in that coolant cavity. I had to spend a good bit of time to remove all the white looking residue from those areas using even a brass bristle brush (gently) and a tooth brush, using the vinegar as a lube & cleaner. I even used some crocrous cloth wetted with paint thinner and eventually I got it all off of all the surfaces, the gasket lands, coolant cavity & plate, screw threads and screw holes clean. I wonder if CLR would be the best thing to use???

Anyway, after cleaning I then washed all the fromerly corroded surfaces w/steam distilled water & dish soap and then rinsed and used acetone as a final de-watering wipe. I used the LPE paint to refinish my stuff. I also didn't have any pock-marks than required any body work to make smooth.

I didn't paint the gasket lands, I masked them off on the T/B and the cover plate I only painted the top side. I used rtv to coat the gasket on both sides and reassembled. It's been since October of '05 and I haven't had the corrosion come back....but I do use steam distilled water to mix down my coolant and it gets done every two yrs without fail.


Tom