Vortec intake manifold pitting

[97-2door]

Hi all. I'm in the process of putting a new crate engine in my 1997 Tahoe. I'm going with a stock 5.7 Vortec (L31), but I need to re-use the intake manifold from my old engine. The intake manifold was not leaking when I removed it. After cleaning it up, I noticed pitting around most of the ports, but especially around the front driver's side water port. I tried to get a few good pictures. I really don't have a good frame of reference, as I've never done this before. Is some pitting okay? The one corner around the water port definitely seems excessive, but I'd like to get some other opinions. I'm planning to use the Fel-Pro gaskets that are metal with black rubber molded on them. The Fel-Pro instructions say that if pitting is "severe" they recommend having the manifold re-surfaced. They state you can use epoxy. I just want to make sure I do this right the first time. If I need to get it resurfaced, I'm not even sure there is a machine shop near me (eastern NC) that I would trust to do this right. I guess I could try to find another manifold in a junk yard or eBay. Pictures I've looked at on eBay tend to have some pitting also. Really just looking for opinions on how bad this is and what my best options may be. Thanks in advance!

 

[Komet]

Run a thin layer of rtv around the ports and send it.

 

[RichLo]

I'm a fan of epoxy but for that I also would just run RTV.

Milling would be best but if you dont trust local machine shops, they can F up the angle and you'll be worse off. Junkyard manifold will be a gamble.

Dont think too much, RTV has sealed up way worse surfaces with much less prep work than you've done.

 

[Orpedcrow]

That dosent looks terrible, I’d run it with some rtv or permatex no.1.

 

[97-2door]

If I go for the RTV, would I just smear a thin amount around the water ports then pop it together with the gaskets like normal?

 

[Charles Matzelle]

mine was pitted also, I filled it with jb weld

 

[Orpedcrow]

If I go for the RTV, would I just smear a thin amount around the water ports then pop it together with the gaskets like normal?

Yep. And don’t forget the corners where the China rail, intake and head meet. Also, the matching coolant ports on the head probably look similar. I would rtv both the heads and the intake.

 

[Schurkey]

1. I'm concerned about the swirl-marks on the gasket surface. Did you use a Scotchbrite surface conditioning disc "cookie" to clean the gasket surface? Scotchbrite on a gasket surface is a Really Bad Idea. GM and other manufacturers specifically state not to do that. They'll wear into a cast-iron surface, they're really bad on soft metal like aluminum. And the 'active ingredients" in those Scotchbrite pads are aluminum oxide, titanium dioxide, and quartz silica, which gets EVERYWHERE including in your lungs. The abrasive dust inside an engine will destroy bearings and embed into aluminum pistons.

2. Yeah, I've used RTV to seal manifolds worse than that. But I have not used RTV to seal manifolds that use the "hard plastic/metal carrier and a silicone sealing bead" style of gasket. If this was me, I'd thoroughly clean the gasket surface, fill the pits with epoxy, and then sand the epoxy flat using sandpaper and a backing-pad for flatness.

 

[Road Trip]

Based upon personal experience I can recommend the Permatex Ultra Gray
for use around the coolant ports & the front/rear end seals:

You must be registered for see images attach

NOTE: 'Sensor Safe' = Oxygen Sensor Safe
(Mandatory no matter what sealer you choose to use!)

If you follow this link you will see some relevant info
having to do with 8-hour cure time, etc. (HERE)

****

The above has never let me down, and no doubt
be able to handle the pitting shown in your photos.

Having said that, I think the idea of a thin layer of JB Weld,
sanded flat, filling in the pits surrounding the coolant ports would
result in a 'good as new' solution.

As others have mentioned, your manifold is in better than average
shape, and with proper prep & this gasket sealer you should have
no problem getting a 100% seal between the manifold & heads.

Best of luck --

 

[GoToGuy]

Since it's metal I chose to use the JB weld two part to fill the pitting areas. And made sure after curing was absolutely flat smooth. If those swirl marks have created any peaks and valley's that could create a sealing problem. Mating surfaces should be absolutely flat and level.