Making Exhaust Manifold Flanges Flat

[DirtyBirdRacing]

Hi,

I am currently porting my exhaust manifold, turbine housing, and 02 sensor housing. After I got done porting the parts I wanted to true up the flanges. At work I have seen mechanics use what looks to be a sanding stone/brick to true up these flanges relatively quickly. I have looked around at all the local stores (Home Depot, Lowes, etc.) as well as McMaster-Carr and I have not been able to find anything like this. Does anyone know where I could find a sanding stone/brick like this?

Thanks,
Bill

 

[turboglenn]

What i have and use is a piece of 1/4 inch plate steel that i use some bolts and metal strap to secure some full sheets of sand paper to, then run the part in all different directions while holding it flat across the paper and it will sand the part as flat as you can hold it while sanding.. This is called a lapping table and you can see a pic of it in my htread called "some things i've been working on" in the fab section

Or just google "home made lapoping table" and you'll see how easy one is to make

Another thing you can use but on smaller areas is to go buy what's called a "whet-stone" or wet-stone for sharpening knives the old fashion way..they usually have at least 2 sides , coarse and fine, but i have one with 3 from coarse, to medium and super fine that i use to sharpen my knives with, and you can shave hair off your arms with them when i'm done... I have used these with success to true up some smaller gasket surfaces like waterneck housings and such.

 

[Boosted98gsx]

Your best bet is to pay $10 to a machine shop that has a table belt sander.

 

[debbie]

Your best bet is to pay $10 to a machine shop that has a table belt sander.

If you send stuff out to the shop to have them do it then it makes this part of the forum pretty pointless

 

[My1GLaser]

I use a 1"x3" piece of steel flat bar 8" long wrapped in sandpaper, and I use it as a sanding block. It weighs about 10 lbs so it is heavy enough without having to push real hard and I can concentrate on keeping even pressure.

It takes a while to take much material off the cast exhaust parts even using 60 grit. It works well for a few thousandths of clean up though and I have done it many times.

It great on Aluminum parts like t-stat housing, IM, and I even resurfaced my head with it.

 

[DirtyBirdRacing]

Hi,

Thanks for the replies everyone. I ended up using Turboglenn's second suggestion and used a fine knife sharpening stone. It is about 2 inches wide and 5 inches long. It worked real well on the turbine housing flange, and with the use of a straight edge and feeler gauge I was able to get the head flange "flat enough."

I used the service spec of 0.0059 in. for flatness. I checked it with a 0.005 inch feeler gauge every where. I plan on using the following exhaust manifold gasket so I think this should be good enough.

FFWD Connection - Race Injuns That Will Freeze Your Brain

Thanks,
Bill