I have an intake question

[dubie]

This is the bottom of a 4 barrel intake. The plate in the middle of it......what is it and do I need to have it on there? This is a spare intake that Stingray had given to me. The intake I am using has already been tanked, sand blasted and painted but doesn't have this plate on it. If I do need it, how do I fasten it? I will also include a pic of how this one is fastened. it looks like it's rivotted on.
Thanks

[dubie]

here is the fasteners

[Alexis]

heat shield?

[68 Stepside]

I can't remember wtf that is, but I do know I used a screwdriver and a hammer to take mine off, and clean under there. Just take a flat screwdriver, and tap it lightly with a hammer, while prying up on it. I always put that "thing" back on, even though I don't know if it's necessary or not, I do believe it might be a heat shield.

[dubie]

Yeah I think it is a heat shield. I just wanna make sure because i had a dream last night that I was out cruising and cooked my fresh engine so i wanna be safe rather than sorry

[COBALT]

It keeps oil from baking into crusty garbage in your lifter valley, so yes, it's a heat shield.

Any machine shop who comes across an old cast-iron intake should offer to pop the rivets out, remove the plate, and once they clean the intake put it back on with new rivets. Some shops even have those plates sitting around, but usually they'll bake it along with the intake...

I usually keep mine on.

[Long Knight]

LOL! I forgot about that from my rebuild. Always wondered what that was! Figured if it was on there it must do more good than harm, so we left it on. I never could find any literature on it though.

[Mixup]

It keeps the hot oil off the bottom of the intake.

[Alexis]

edit.......I made no scence like normal.

Ok when you take a manifold off you got the area on top of the motor. Was there or not a plate that was factory in place to keep oil from jumping up toward the intake manifold???

[crazy longhorn]

Ditto", its a heat sheild. You can tap the holes, & install allen heads, or screw heads.......then just grind the corners off the fasteners so there is no interferance with the heads. I would use locktite on the threads. Good luck,crazyL

[1970 CST Short Wide]

Aftermarket manifolds (Aluminum) don't have it.

[ddsmith]

Okay here is my take on this shield and a helpful tip on removal. The factory setup has an exhaust crossover that pushes hot exhaust gas through the intake manifold crossover ports when the engine is cold. The purpose is to heat the manifold floor during cold starts faster preventing fuel from pooling on the manifold floor once it goes through the carb. If you have the factory setup you'll notice that one side of the exhaust manifold has a temperature controlled damper/valve that is closed when cold. This forces half of the cylinders to exhaust under the carb to the other sides exhaust pipe until temperature rises. As temperature builds up in the exhaust system this valve opens allowing exhaust flow from both exhaust manifolds back their respective pipes for dual exhaust or to join back together into a single pipe for single exhaust downstream of the valve. Most people block the crossover port because of concerns that it robs horsepower because of heating the intake manifold. This is probably why most aftermarket manifolds do not have them. If you block the crossover then ensure you remove the valve or wire it open otherwise half your cylinders will not have a path to flow when the engine is cold.

Now for the heat shield. It is there to prevent cooking the oil that splashes up on the underside of the manifold while the exhaust gas is flowing through the crossover. Believe me that some oil still cooks because the shield doesn't totally stop oil from getting to this area. I wanted to remove my heat shield on a 454 engine. I found the rivets actually have a thread to them. They were initially hammered into the holes but it is hard to turn them out because of no slot to grab onto to remove them. I used a pair of vise grips. A small pair and got a grip on the heads. The I just turned them like removing a screw and out they came. Maybe yours are different but I doubt it. The 454 was from my 71 Corvette. This puts it into the same time frame and the General made money using one type of part on as many things as they could.

[ratfreak888]

it keeps hot oil off the intake so the air charge stays cool

[tom hand]

ddsmith has most of the answer...the reason for the sheild is the heat riser system will turn the motoroil into crusty little dingleberries. The shield keeps them from falling back into the motor.

[Randy70C-10]

Originally posted by 1970 CST Short Wide
Aftermarket manifolds (Aluminum) don't have it.

I always install a lifter valley baffle any time I use an aftermarket intake. It's just a bent piece of sheetmetal with holes cut out for the pushrods to go through, and springs that press against the intake to keep it from rattling around.

[dubie]

would regular rivets work on this? I have a set of 1/8" x 1/4" rivets here that would probably work. wouldn't it??

[dubie]

Wondering if anyone can help with this. It's kind of a slow day at work and I would like to get this intake on. Just wanna know if a regular rivet would hold that plate on

[JimKshortstep4x4]

We tap the holes with 8-32 threads and use stainless screws to hold the plate in place. The holes are not tapped all of the way so that the screws lock in place when they are screwed into the shallow threads. It is not good to have the fasteners fall out!

Jim