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View Full Version : Intake Manifold Gasket Matching



Some Kind Of Monster
09-24-2004, 11:45 AM
It looks like the "How To" section isn't getting much action so I decided to add my .02 to the equation. I recently had my heads done and the intake ports opened up to match the gaskets so it is only natural that I open the intake manifold ports as well! Here are the steps I took to complete the process. Please keep in mind that I have never done this before and I am going off of a few articles that I have read.
My tools of choice:
Makita 13mm double gear reduction spade handle drill :D This thing has so much torque, I don't thing a vise could stop it. I started with a dremel but it couldn't handle the abuse. I suppose a die grinder might have done a better job, but my air compressor is out of commission right now.
Dremel 60 & 120 grit drum sanders.
Various grit sand papers
600 grit wet/dry sand paper.
Large surface permanent marker.
2 Drill bits that are slightly smaller than the ID of the bolt holes.
Spare intake gasket.
Wire wheel.
http://www.***boat.com/image_center/data/500/1683CIMG0423-med.JPG
I began with a used and abused Performer 2-0 intake. There was nothing wrong with it, it had simply been used a LOT! It looked like someone had cleaned up the imperfections in the ports of the manifold but didn't do much else.
http://www.***boat.com/image_center/data/500/1683CIMG0417-med.JPG
I started by cleaning up the entire gasket surface with an engine degreaser. It didn't do ao very good job, but good enough for now.
I next marked up the outer gasket surface of the intake ports with a blue permanent marker. There is no need to go crazy with the marker. Just make sure that when you put the gasket up to the manifold that you don't see any un-marked surface. It should look something like this:
http://www.***boat.com/image_center/data/500/1683CIMG0418.JPG
Next I selected two drill bits that were just smaller than the ID of the intake bolt down holes. These are used to keep the gasket from sliding out of place during the next step. I chose drill bits because they fit the holes snug instead of the intake bolts which were loose and allowed the gasket to move around.
http://www.***boat.com/image_center/data/500/1683CIMG0419.JPG
Next I placed the gasket on the surface and used the drill bits to align it so that it would be in the same position as if it were actually being installed on the motor. I took a scribe and traced int inside diameter of the gasket around the intake ports. This will give you a guide as to how much material needs to come off. The scribe marks should show up real well over the marker from previous steps.
My scribe marks:
Sorry the pic is fuzzy..
http://www.***boat.com/image_center/data/500/1683CIMG0420.JPG
Next take the template gasket off and make sure that your marks are good and visible. If they are, start grinding away. I used a makita drill with lots of torque because I couldn't stand my dremel slowing down every time I applied pressure. It seemed to do the trick with a 60 grit sanding drum. I was able to take material off at a very good pace while maintaining control very well. I suppose a die grinder would have done the same job, but my air compressor is down for the count.
I took material off all the way to my scribe marks on all the ports and then began to taper the ports in. You don't want any bumps or sharp drops anywhere in there. Take it all down. I took material off pretty deep and made everything flow nicely. I also opened up the inside of the ports a lot, especially near the corners od the ports. Be careful not to take too much material off though. There was a lot of material to work with on my manifold so I didn't have a problem with taking too much off. When you think you have removed enough material, line up the gasket again and make sure. I ended up doing this many times until I got it just right.
http://www.***boat.com/image_center/data/500/1683CIMG0421-med.JPG
Half Done:
http://www.***boat.com/image_center/data/500/1683CIMG0422.JPG
I next went in with a 120 grit drum and re worked the insides to take out the roughness that the 60 grit drum left. When I was happy with the 120 grit, I went in with 200 grit and so on until I had a nice smooth surface.
I next took a 600 grit wet/dry paper on a sanding block and sanded the entire gasket surface along with the engine degreaser. This combination worked very well and made the surface look almost new.
Finished!
The gasket now matches the ports exactly:
http://www.***boat.com/image_center/data/500/1683CIMG0432.JPG
While I was at it I took a wire wheel with a cordless drill and cleaned up the top of the intake to make it look new as well. Except for the hard to get to spots, it looks good as new, and performs even better.
Like I said i have never done this before so if anyone has anyting to correct or add to what I have done, please do so. This was the best I knew how and it turned out great. I am very happy with it. I put about 8 hours into the job. Good Luck!

Infomaniac
09-24-2004, 07:48 PM
Cool man.
How does it match the cylinder heads? Do the heads match the gasket already?

Some Kind Of Monster
09-24-2004, 08:13 PM
Yeah, I just got my heads done professionally and they match the gasket perfectly. The motor goes back together tomorrow!! I can't wait!

SSTSleakcraft
12-21-2004, 04:49 PM
First off, how much your block has been decked and heads milled has a great effect on port alignment. Picture this, the more they have been machined the "lower" they get (moving down). This also moves them closer together. This in turn causes your intake to rise up causing port alignment problems. Ever had to use a thick bead of silicone on end seals? Anyways, here's my .02. Your heads were gasket matched, good. When gluing down an intake gasket be more concerned with port alignment than bolt holes. You can trim bolt holes in gasket. The marker on the intake was good or use machinist layout fluid. Next put non drying prussian blue on intake gasket facing intake, around intake port holes. Carefully set down intake. Put in all bolts and push back on intake before tightening. Remove bolts and carefully remove intake and set upside down. You will be able to see exactly how the ports line up. Lay another gasket (always same brand and thickness) on intake and scribe the impression outline from prussian blue. Go to town with a die grinder and a non-ferrous carbide. Install intake using new gaskets and sealer of choice and remember to push back before tightening. This ensures same alignment everytime. Or pull forward in both steps....

dregsz
06-04-2005, 02:29 AM
I'm down with Sleekcrafts advice.
Milling changes head alignment big time.
If you want to see where you stand, attach the intake and look down the runners w a flexible tipped flashlight.
On my newest SBC race motor I lined up 5 manifolds and tried them all out to see which gave the best alignment on my block's ports.
Setled on a Victor Jr CNC, model 2900
Good Luck
Evan
http://community.webshots.com/album/353002926DVWWwu