Lifter valley oil splash shield in a BBC

Mike Harrington · May 28, 2020

I'm putting a new cam in my 454 TBI engine and when I removed the intake manifold I noticed it did not have the sheet metal oil splash shield that keeps hot oil from getting on the underside of the intake manifold. I'm not talking about the one that rivets to the bottom of the intake...im referring to the one that lays down inside the lifter valley.... GM part number 12555320. Is this some thing I should install in the engine even though there wasn't one to begin with?

bucket · May 28, 2020

GM didn't put one in there. At least none that I've opened up.

Mike Harrington · May 29, 2020

Is there an actual benefit of putting one in there? The part number I gave is an actual GM part so they might have had an afterthought?

nvrenuf · May 29, 2020

I’ve never seen on on a gen IV bbc. I can’t imagine you’d see much benefit unless it’s a high hp motor that you’re racing.

Shorty81 · May 29, 2020

My BBC is a 1976. It does not have a splash shield.

idahovette · May 29, 2020

I agree with Andy, never seen one. Haven't opened up too many BBC's but I did have an LS6 in my Chevelle and it never had one. If Chevy used them anywhere. you would think it would be in that engine!

Bextreme04 · May 29, 2020

It is OEM on the Gen VI Vortec 454... I had one on the donor 1997 K2500 454 I opened up when I sent it off for rebuild.

Markmx6 · May 29, 2020

My gen 6 motor had one too.

I don't think it would hurt to have. It may not really help though.

Bextreme04 · May 29, 2020

Markmx6 said:
My gen 6 motor had one too.

I don't think it would hurt to have. It may not really help though.

I agree. It may or may not help. The Gen VI is MPFI, and has no exhaust crossover to heat the intake, so having the heat shield makes a lot of sense to keep the intake manifold colder. With aa Mark IV or Gen V having the exhaust crossover and fuel injected before the intake, i'm not sure if it would help or hurt it. There is also a supplemental oil cooler, roller cam, and it runs 5W-30 from the factory.

Catbox · May 29, 2020

You can see the mentioned valley pan in this photo of my Gen 6 454.
It just lays in the valley.
I would think it would be a benefit to keeping things cooler on the intake in any build.

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Mike Harrington · May 29, 2020

Catbox...yes that's what my understanding of the purpose of the shield is.....to keep the hot oil from splashing up on the intake and heating the fuel and air mixture up. The intake I have right now is the stock TBI intake that doesn't have any kind of plate that's riveted on the bottom of it like the intake on my generation IV does. So maybe that full length oil shield over the lifter valley would be beneficial in this case. I guess I'll go ahead and put one in there and see how it plays out

nvrenuf · May 29, 2020

How is the gen VI valley pan secured? Is it part of the intake gasket? If it is, need to be sure all of the holes line up correctly if you’re using it on an older gen block.

Mike Harrington · May 29, 2020

The block is a gen VI but it's set up for hydraulic cam and such not roller. It has provisions for roller but just not used.

nvrenuf · May 29, 2020

Do you mean flat tappet?

What roller provisions? Unless a gen VI is very different from a IV the lifters only have link bars joining pairs as opposed to the big spider-like retainer that (I think) small blocks use.

Bextreme04 · May 30, 2020

nvrenuf said:
Do you mean flat tappet?

What roller provisions? Unless a gen VI is very different from a IV the lifters only have link bars joining pairs as opposed to the big spider-like retainer that (I think) small blocks use.

A Gen VI is very different from a IV and has the same hydraulic roller provisions as the Vortec small blocks got. It has the cam thrust plate on the front of the cam and the lifter Valley is tapped for the same style of retainers and spider assembly as the small block vortecs. The cooling passages, oil galleys, and several other things are different as well. The timing cover only has 6 bolts, all of them are 4 bolt mains, and it is a one piece main seal.

Lifter valley oil splash shield in a BBC

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