Metal pan missing under intake Issues????

[Al R.]

Just discovered this PM when the cast iron intake ( from a 67 327)I'm using on my 59 283 was removed, it is missing the metal pan, which I assume is to keep hot oil from splashing up in the carb plenum area. I can possibly take 1 off another intake I have ( a holley spread bore type) and install it on this one if need be. Just wondering what the possible consequences are if the pan is just left off as it is now.

[John H.]

Re: Metal pan missing under intake Issues????

Just discovered this PM when the cast iron intake ( from a 67 327)I'm using on my 59 283 was removed, it is missing the metal pan, which I assume is to keep hot oil from splashing up in the carb plenum area. I can possibly take 1 off another intake I have ( a holley spread bore type) and install it on this one if need be. Just wondering what the possible consequences are if the pan is just left off as it is now.

Al -

That shield is there to keep oil from splashing directly on the bottom of the very hot intake manifold exhaust crossover passage and "coking" on the surface; those "coked" oil particles can then fall into the circulating oil. Most cast iron intakes had the shield, and many aluminum intakes didn't have them.

[Joe L.]

Re: Metal pan missing under intake Issues????

Just discovered this PM when the cast iron intake ( from a 67 327)I'm using on my 59 283 was removed, it is missing the metal pan, which I assume is to keep hot oil from splashing up in the carb plenum area. I can possibly take 1 off another intake I have ( a holley spread bore type) and install it on this one if need be. Just wondering what the possible consequences are if the pan is just left off as it is now.

Al------


The purpose of the heat shield is to prevent oil from splashing onto the underside of the manifold and "coking" due to the high heat caused by the exhaust cross-over. However, not all original GM manifold had this shield. So, apparently, some GM engineers felt it was not necessary, at least in certain cases. I'm not 100% sure your manifold used the shield but I expect it did.

If I were you, I'd install the shield. There were several different configurations of these shields and the one you transfer might not be the exactly correct one. However, you can usually modify the shield to perform the designed function although it might not be pretty.

I would not use the drive pins to retain the shield, though. I would drill and tap the pin orifices in the manifold for small machine screws. Then, use the screws (with Locktite thread locker) to retain the shield.

[Al R.]

Re: Metal pan missing under intake Issues????

Thanks Joe. There are remnants of the pins in the usual locations. Looks like the heads were ground off of em, why it was removed is anyone's guess. I will probably try to install it on Sat. Hopefully it will not interfere with the breather can in the valley

[Joe L.]

Re: Metal pan missing under intake Issues????

Thanks Joe. There are remnants of the pins in the usual locations. Looks like the heads were ground off of em, why it was removed is anyone's guess. I will probably try to install it on Sat. Hopefully it will not interfere with the breather can in the valley

Al------


Often these shields are removed in order to clean the manifold, either by bead blasting or chemical. There's really no way to adequately clean the underside of the manifold without removing the shield and there is usually a large amount of "coked" oil under the shield (but protected by the shield from falling into the engine).

Another reason for shield removal is if the manifold is used for an engine that has blocked heat cross-over (e.g. no heat riser on the right side).

These shields were used on engines that had the breather in the lifter valley. However, it's possible that the shield you have was not designed around that requirement. Still, you should be able to modify the shield to fit.