My motor has 150 miles on it. On the last test drive, which was moderatly spirited, I noticed oil dropplets under the hood and I found I had blown out the front intake gasket. It was on the drivers side near the head.

What would cause this? I am running a PCV on the passenger side and a breather on the drivers side, but there is no room for baffles with my roller rockers. Im going to try replacing the PCV valve. I just dont want to replace this gasket and have it happen again shortly.

http://www.easymoney69.com/Images/gaskrt.jpg

Maybe try some Silicone sealer in the corners? I think its an area that does see some weep over time. Maybe also make sure that your PCV and breather actually can flow air, because if they were clogged they could certainly cause this.

Also make sure you have the correct pcv valve for your engine, the wrong valve can cause problems.

Dan E.
69 SS396 4spd. 4.10 posi. x66 coupe

Was there a post on choosing the right valve? I saw references but the links were old and broken.

further explain "blown out"?

Are we talking a few weeps, or the gasket or sealant physically "Blown OUT"?

I use a bead of RTV across the valley rail (Like GM does now) and I take a punch and make a row of dimples across it to give it some bite. I have never had a leak (or Blow out) using this method.

further explain "blown out"?

Are we talking a few weeps, or the gasket or sealant physically "Blown OUT"?

Hey Jim, Check the link in my original post, the pic was too big, so I linked it. It looks to me like it blew out. But this is my first build... So Im like a newb.

idoxlr8: I will do this tonight when I put things back together. Thanks for the tip.

Make sure the surfaces are clean and dry. Use some brake clean on a rag.

to answer your question, why; to much internal pressure. How does that happen? Leakage past the piston rings. New engine? "Break" it in before any really "spirited" use.
High mileage engine? Um, there is no tellin' the condition of the rings. Cure for the "blown" front intake gasket ? As stated above the dimpling of the gasket surface on the block AND the intake is good. A beed of silicone and let is set for a bit, then put a light skim on top of that and set the intake in place. DON'T run the engine at all for a couple of hours to let the sealer set up. You should be "good to go". Relieve the internal pressure, breathers, PCV ect.

most people don'[t even use thoise gaskets- they go straight into the garbage can.
i don't know why they even put them in the gasket sets any more- GM hasn't used them since the early 80's, and none of the big name engine builders have used them since probably the early 70's.
istead, a 1/4" bead of good silicone is used across the front and rear of the intake valley.
use some brake cleaner to get everything all squeaky clean, lay down the beads on the front and rear, set the side gaskets in, and drop the intake straight down and tighten it.
wait for the silicone to dry before running it- i personally like the "Right Stuff" gasket maker that comes in the squeeze cheese container. that stuff is ready to run in about 5 minutes.

most people don'[t even use thoise gaskets- they go straight into the garbage can.
i don't know why they even put them in the gasket sets any more- GM hasn't used them since the early 80's, and none of the big name engine builders have used them since probably the early 70's.
istead, a 1/4" bead of good silicone is used across the front and rear of the intake valley.
use some brake cleaner to get everything all squeaky clean, lay down the beads on the front and rear, set the side gaskets in, and drop the intake straight down and tighten it.
wait for the silicone to dry before running it- i personally like the "Right Stuff" gasket maker that comes in the squeeze cheese container. that stuff is ready to run in about 5 minutes.

Follow this advice and you won't have any problems. I don't know anyone that uses the intake rail gaskets.

Ditto on the end gaskets.

Extra blowby is typical with a new engine until the rings seat. That is probably most of the issue. A PVC does nothing at wide open throttle -- that is when crank case pressure can build up and make things leak.

Do not use the end seals. They are not as reliable as the bead of RTV method. The mating surface where the end seals go can vary with milling of the heads or deck. I personally like the set up time of the Blue RTV. It gives you time to get everything in place before it sets. And it seals well.

I align my intake before torquing. Have you ever slid the intake around to see how much play there is? With a Victor Jr. style single plane you can see the ports by looking down the plenum. You can move the intake fore or aft a bunch. You can actually bolt the intake down and leave a lip if not properly aligned. I have heard of people making alignment dowels for the intake mating surface. Its a little excessive, but you can see why they do it if you bump the intake around before the bolts are all the way down.