L88 Hood Fresh Air Chamber

[Richard F.]

Re: L88 Hood Fresh Air Chamber

Anybody know the diameter of the road draft tube canister? I can measure the hole in my hood. There would have to be a lot of clearance and the line-up would be critical when the engine torques over.

[Henry J.]

Re: L88 Hood Fresh Air Chamber

Richard:

You make an excellent point which didn't occur to me. It would be interesting to have these dimensions.

[Joe C.]

Re: L88 Hood Fresh Air Chamber

There are no baffles or diverter. I suppose if you are racing in the 24 hours of LeMans you don't stop because it is raining.

Unless the engine dies because of all the rainwater being drawn in.

Did the L88s use foam air filters, or paper?

In any case, running those cars in the rain was an easy way to remove any carbon from the chambers.

Anybody know the diameter of the road draft tube canister? I can measure the hole in my hood. There would have to be a lot of clearance and the line-up would be critical when the engine torques over.

Is that hole sealed, or open into the plenum? Sealed, I hope.

[Michael M.]

Re: L88 Hood Fresh Air Chamber

Joe, the hole is open into the plenum. That's why I am perplexed by it. Like I said earlier in the thread, could it be a hole that allows the air to flow thorugh the plenum like a cross breeze? I have to say though that it sure does match up with the road draft tube from the 67's.

[Dick W.]

Re: L88 Hood Fresh Air Chamber

Unless the engine dies because of all the rainwater being drawn in.

Did the L88s use foam air filters, or paper?

In any case, running those cars in the rain was an easy way to remove any carbon from the chambers.



Is that hole sealed, or open into the plenum? Sealed, I hope.

Foam in the hood, wire screen over the carb to keep the rocks and rodents out My memory is failing fast, but I seem to remember my '69 did not have the extra hole for the road draft tube? Indentation was there but no? hole.

[Richard F.]

Re: L88 Hood Fresh Air Chamber

The hood pictured is a 68. The towel show that the hole is open to the plenum. I don't run the stock air cleaner since the time the carb blew back and set the foam on fire.L88 Hood 002.jpgL88 Hood 001.jpg

[Joe C.]

Re: L88 Hood Fresh Air Chamber

Here are some more photos and comments:

http://forums.corvetteforum.com/c3-g...-l88-hood.html

[Michael M.]

Re: L88 Hood Fresh Air Chamber

Yes, some good pictures there and a good article too but, unless I missed it, no real explanation for the extra hole to the side of the air cleaner opening.

[Charles C.]

Re: L88 Hood Fresh Air Chamber

Here's an underside pic of the hood on a 68 Coupe I sold a while back. Always wondered what the "hole" was used for?

L88 hood inside.JPG

[John H.]

Re: L88 Hood Fresh Air Chamber

Here's an underside pic of the hood on a 68 Coupe I sold a while back. Always wondered what the "hole" was used for?

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Charles -

Knowing how Chevrolet Engineering worked in those days, I'd say the initial design for the '68 L-88 hood inner panel was done based on the re-use for '68 of the '67 L-88 road draft tube. The road draft tube on the '67 L-88 was technically illegal (PCV was required by Federal and California regulations in '67), and the decision was made during '68 L-88 development to incorporate both PCV and A.I.R. so it complied. Rather than spending the money to re-tool or modify the L-88 hood inner panel molds to remove the recess for the road draft tube canister, they just left the recess in the mold and ignored it.

[Richard F.]

Re: L88 Hood Fresh Air Chamber

Keep in mind it is a hole as well as a recess.

[John C.]

Re: L88 Hood Fresh Air Chamber

Richard

I have to agree with John on his concussion. Just the recess does not give enough clearance to fit the road draft tube. You need the hole. The hole is molded into the panel and not cut. It was just easier to leave it than retool.

John

[Joe C.]

Re: L88 Hood Fresh Air Chamber

Charles -

Knowing how Chevrolet Engineering worked in those days, I'd say the initial design for the '68 L-88 hood inner panel was done based on the re-use for '68 of the '67 L-88 road draft tube. The road draft tube on the '67 L-88 was technically illegal (PCV was required by Federal and California regulations in '67), and the decision was made during '68 L-88 development to incorporate both PCV and A.I.R. so it complied. Rather than spending the money to re-tool or modify the L-88 hood inner panel molds to remove the recess for the road draft tube canister, they just left the recess in the mold and ignored it.

Another job well done by engineering!

I shouldn't be so tough on them. I realize that they had their hands tied by the bean counters;HOWEVER, it would have been a better design, with very little cost added, to have molded the round "hole" all the way up to the outer hood skin and then have it sealed with the same sealer (gumdrop adhesive) as was used on other parts of the inner hood bond tabs to the skin. This would have sealed the plenum from hot engine compartment air.

I could not have worked for Chevrolet Engineering in those days. The compromises that they made in the name of cost savings would have been more than I could have swallowed. Would have quit forthwith.

[Dick W.]

Re: L88 Hood Fresh Air Chamber

I could not have worked for Chevrolet Enginnering in those days. The compromises that they made in the name of cost savings would have been more than I could have swallowed. Would have quit forthwith.

You think it was bad then, try now!

[Richard F.]

Re: L88 Hood Fresh Air Chamber

Why have the hole at all? Why not just mold the recess all the way up to the outer hood skin? It still makes no sense to me.