Thread: Manifold Warped???

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Ok heres the scoop, put an Edelbrock performer intake on last year.

Intake gasket blows out, buy a new set of victor reinz gaskets from carquest and leaks coolant from the front drivers side of the manifold.(around those two bolts)

Buy some new gaskets again, this time ordered from the dealer and same exact problem, leaking in the same spot.

What are the chances of the manifold being warped, my motor has never been overheated or anything and the motor only has about 20k miles on it.

Oh yeah, its a 86 K-5 Blazer w/ a 350

Could be. Are you following the proper torque sequence?

I had the same problem with a dual quad set up that I bought. I finally had to use the thickest gaskets I could find to make it work.

intakes do warp. i cut them it can happen

I did go by the torque sequence, I will probably take it to a machine shop this time to get it checked out.

What kind of sealer is good for the bolts because the only thing I used on them was just some threadlocker to keep them from coming loose?

And Chevy 37, do you remember what gaskets you ended up using to stop the problem?

if the intake bottoms out on the flat part of the block (china walls) there needs to be some gap there if not the bottom part of the intake needs to be mill or you could use thick gasket .if not check for some gap this will keep the intake from going down on the gaskets and sealing up

Occasionally, you may experience a vacuum leak into the intake ports from the crankcase of the motor due to the intake manifold / cylinder head interface not being machined parallel. Here, I'm talking about looking at the manifold from an end view, from the front or rear of the car for instance. Unless you're using all brand new parts, you have no way of knowing if the heads or manifold have been machined by the previous owner, so the interface at the manifold/head could be out of parallel. In other words, the gasket might be pinched tightly at the top of the port and sealing fine, but might be wide open to the crankcase at the bottom of the port. The manifold may also be warped a little. No amount of propane or carburetor cleaner will find such a leak. The best way is to insure the elimination of such a problem while building the motor.

Here's how I set up the intake manifold/cylinder head interface to prevent vacuum leaks from the crankcase to the head ports....Begin with the heads properly torqued to the block for the final time and ready to go. Measure the thickness of your new intake manifold gaskets. Get flat washers or shims that will measure that thickness. With the manifold off and the mating surface on the cylinder heads de-greased, put a dab of RTV on the washers/shims and stick them on each corner bolt hole on the cylinder heads. Let the RTV set up. Stuff paper towels into the ports to keep debris out. Make up 16 pea-sized balls of modeling clay. (Use oil-based modeling clay from a craft store, not Play-Doh). De-grease the intake manifold at the ports. Place the balls of clay on the top and bottom of each port of the manifold, squishing them down well so they stay in place. You want them to be thicker than the shims/washers that are RTV'd to the heads. With your fingers, coat a little oil on the heads where the clay will meet the heads to keep it from sticking to the heads. Now carefully place the manifold into place on the heads and use bolts on the four corners to just snug the manifold down until you feel resistance against the shims/washers. Remove the manifold carefully. Cut half the clay away at each position with your pocket knife. Measure the thickness of the remaining clay at all 16 positions with the depth function end of your 6" dial caliper. You'll know pretty quickly if the manifold/head interface is square. Record the measurements on the manifold with a permanent marker like a Sharpie. The widest measurement will be the standard to which you will want your machinist to cut the other positions on the manifold to make it square with the heads, thusly sealing up the motor.

Pay particular attention to what Pat said about interference at the bottom of the manifold at the block rails front and rear. If you cut the manifold, you'll be dropping it down a little into the valley, so PAY ATTENTION. Also, with the manifold down a little in relation to the head ports, the ports may not line up exactly. On a street motor, I wouldn't be overly concerned about it because the laws of fluid flow dictate that the majority of the flow is right down the middle of the port and the surfaces of the port wall will be relatively slow moving. If you want to be dead-nuts on your build though, you should port match to the gasket.

Get a straight edge and check all the surfaces ,even on the block. Use a angle gauge and check the intake and engine block mating surfaces. Milling on the block and milling on the heads will change the angle of the mating surfaces. If its a used intake it could of been milling in its former life to match another block.

I had a 318 that had the heads planed to run on propane. The intake surfaces were planed at the wrong angle, no way to seal them.

Machine shop could find nothing and did as was suggested to the block and heads and all seemed straight so here we go again (BTW I bought the manifold brand new last year)

Manifold is on, I got some edelbrock intake gaskets this time, so far no leaks, (fingers crossed).

Now I can get it started, but she won't stay running long enough for me to check timing or anything. She'll fire up, sound real healthy, then rev up to about 15-2000 RPM's and shut off.

To me this sounds like a vacuum leak somewhere, but I could be wrong as I can't find any lines not hooked up anywhere

What else could be causing this?

So close to having my truck back, must get fixed

Yeah, I'll try and get a decent pic, there's a lot of emissions stuff in the way, but I'll try.

As for the booster and PCV, they are both hooked up

Could you refresh my memory on checking these for California models,

I just pushed up on the underside of it, and the motor stayed on a bit longer than it has

These pics are really bad, but I tried

Now its back to just doing it what it was...

Isn't it true that if chemicals get into a backpressure type EGR valve, it will ruin it.

The machine shop cleaned up the manifold in the shop and I'm pretty sure they use chemicals when cleaning engine parts....I think....