78 Ignition shield Install

[David W.]

I have a L82 that has had the right exhaust manifold replaced due to a crack. The right rear spark plug shield was not put back on and I want to replace it since the car takes a hit during judging (15 points assigned to ignition shielding). I am not sure how the mounting brackets attach to the manifold and what is routed through the large hole in the shield. I believe there is no gasket used on the manifold so bolt removal should be possible. Does the EFE actuator rod that connects to the exhaust heat valve somehow get involved with the shield? A picture would be worth a ton. There are some temperature wires and negative ground cable in the vicinity also. Thanks

[Tom R.]

Re: 78 Ignition shield Install

I have an L82 that had the right exhaust manifold replaced due to a crack. The right rear spark plug shield was not put back on and I want to replace it since the car takes a hit during judging (15 points assigned to ignition shielding). I am not sure how the mounting brackets attach to the manifold and what is routed through the large hole in the shield.

Pictures are tough considering the location...schematics much better. I'll have to see what I may have but the AIM is a must if you need numbers and schematics. Do you have the boomerang looking wire shields for each side? They are the same part number and used to route and protect the wires as they travel from distributor to the forward plugs.

The hole was intended for an L82 temperature sensor, per the tech manual, so presumably the wire routes through the hole. Not sure if this was used and my L82 does not have one. Remember these shields were used for many applications...just not corvette

Does the EFE actuator rod that connects to the exhaust heat valve somehow get involved with the shield? A picture would be worth a ton. There are some temperature wires and negative ground cable in the vicinity also. Thanks

No...the hose from the actuator valve (upper cadmium cover) routes to the EFE TVS switch on the manifold. Its brackets mount to the exhaust manifold and use a couple of different length spacers. The rod drops to the heat riser.

The ground cable mounts to the upper mounting hole of the starter bracket and routes to the frame. Those other wires should connect directly to the starter/solenoid.

[David W.]

Re: 78 Ignition shield Install

Yes Tom I do have the boomerang wire shields. What is missing is the right rear only spark plug shield that bolts to manifold using two brackets. Thanks for the info on the temp sensor. I don't have one either so the hole like you said is apparently there for other applications. Many times the shields were removed to change plugs or like in my case replace the manifold and not reinstalled. All my heat shields are inplace also. Many of the schematics I have seen are too general. I just need to get the bracket kit and go from there.

[Tom R.]

Re: 78 Ignition shield Install

My installed shield shows those quarter 20 bolt heads (GM# 274430). Thought I had an extra shield but I'm missing that particular one. And I don't see wing nuts as shown in either schematic or the Wilcox parts photo below. I'll have to put that on my Carlisle list. I have seen broadcast codes on the brackets when riveted to the shield such as the V shield. I have gone thru parts bins before with exclusively heat shields but its the brackets that make it the correct part for 78 (70-79). If I get ambitious I may pull it...but no time soon.

Wilcox shows the shield kit with hardware:

https://willcoxcorvette.com/corvette-ignition-shields-spark-plug-2-piece-set-70-79

Keep me posted

[David W.]

Re: 78 Ignition shield Install

My shield on the left rear bolts to the manifold brackets (no wingnuts) The judging manual refers to bolts also so wingnuts must be incorrect for 78-79.

[Tom R.]

Re: 78 Ignition shield Install

My shield on the left rear bolts to the manifold brackets (no wingnuts) The judging manual refers to bolts also so wingnuts must be incorrect for 78-79.

So you need the two brackets and the shield...and the 274430 bolts? You've made me curious now...if weather is nice I may get and remove that shield just to see those brackets...once again.

Riks Corvette Parts has the brackets, shields & bolts, sold individually. Look for ignition shielding in the category drop down menu

http://www.parts123.com/parts123/yb.dll?parta~partsort~A2~cadefghb