Fix That Exhaust Leak; Make NEW Exhaust Gaskets at TechShop!


Introduction: Fix That Exhaust Leak; Make NEW Exhaust Gaskets at TechShop!

Finding Land Rover parts *can* be an enjoyable an alternate universe; in this one, its a, lets just make them ourselves.  

I have made aluminum and copper exhaust gaskets with very effective results in the past.  Back then it was a pretty manual process (i.e. Time Consuming); but, I was broke, so it worked.  Now, I have TechShop Menlo Park...this steps up my game. 

These gaskets are called "exhaust flange gaskets" and they seal the primary pipe to the exhaust manifold on a Land Rover Discovery 1  (1989-1998).  I bet your car or truck has something similar to them.

Lets get started!

Step 1: Tools & Materials

This is a really simple process; all you need are the following:

                      Metal Bandsaw
                      Rotary Punch (Rotex)
                      Flat File
                      Round File
                      Scribe (anything narrow and sharp will work, like a nail)
                      The old gasket (or whats left of it)
                      Metal (aluminum or copper of the appropriate size)

Step 2: Scribe

Lay your old gasket on top of the new material (I use untempered, pure aluminum when possible).
Pressing firmly on your old gasket, scribe an outline of it onto the material.

Step 3: Punch (POW!)

Using the rotary punch, select the appropriate sized punch dies for your application (don't forget to match the top and bottom!), punch out the holes. 
          Note:If you need to punch a hole larger than the die set on the rotary punch, you can use the largest punch to remove the material until the desired size is obtained (I needed to make the holes slightly larger than one die but smaller than the next, so it took a few extra operations for me).

Step 4: CUT!

Using the bandsaw, cut your outline...  do not try to follow the path exactly (its metal, not foam :-),  instead, make multiple slices to obtain cut pathways that will deliver your desired outline.

Step 5: FILE

Clean the edges with a file; I recommend a half-round or a rats-tail file for the inner curved parts.

You may need to use a hammer to flatten the material a bit, depending upon the shape and type of material you are working with.

There you have it!  :-)



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    High temp RTV works great in many applications :-) It is not that great for flange gaskets, although it works fine in conjunction *with* flange gaskets. This demonstrates the making of a metal gasket; not the replacement of a gasket with a non-gasket material :-)

    On those other applications; a couple of guys at TechShop Menlo Park made a pewter casting mold out of High Temp RTV...and made wine bottle stoppers with it! Very cool (or rather: hot)! I think they were able to make about 6-8 castings before the HTRTV was burned out :-)
    Thanks for the comment :-)

    1 reply

    I used high-temp RTV for the catback to y-piece(not really a Y-piece, since it's duals but you get the idea). The stuff in Aus is rated for 350C tops, I assume degree figures above are in F. For this area, it seems to work well and holds. For areas closer, I'd be willing to guess it won't last for a terribly long time.

    Hopefully this method will solve my gasket problem, since I can't seem to find any that fit the part. Doesn't help when manufacturers don't include any markings on their product....

    This is why they make high temperature RTV. The stuff works, try it.

    11 replies

    High temp RTV will retain a seal even when exposed to exhaust gases from a flange on a cylinder head? Really? Look on YouTube at a Honda or Renault F1 engine in test room. 15.00rpm+ creates cherry red exhaust. Your RTV must be something amazing.

    Like I said in my previous comment, the stuff works, try it. I have, and it does. I don't live my life vicariously through YouTube so RTV isn't the only amazing thing I've personally experienced.

    High Temp RTV is solid until ~600 degrees.

    I know for a fact: the turbo on my diesel rover can hit 1400 degrees (I never run it above 1050! :-)... High temp RTV does not live long and prosper in that environment, but you are welcome to try :-))

    Use you head for more than a hat rack will you? I didn't say smear the outside of the part with RTV, put it where it belongs, between mating surfaces. It works, I've done it, end of story. Go annoy your stupid friends and quit bothering me.

    A friend of mine builds competetion tractors for pulls. (Not living viacariously) through him. The diesel can hit 80psi plus under boost. I do not know what his egt is but I know that RTV will not hold up in this enviroment for more than a few seconds. Maybe on the flanges of your Briggs&stratton it might.

    How many square inches do you think are exposed in a flange fitting? Or rather I should say what fraction of a square inch. The flanges on this hold up just fine, the head is shaved 3/8s of an inch so that boosts up my compression somewhat I'd imagine.


    I agree with TechShopClay that this 'discussion" could go round and round aimlessly. Nice VolvoP1800. I am amazed that the Swedes provided so much meat on the head deck surface for a .375" milling. Link to Site to aid in calculating new compression ratio:

    Don't know which engine you have but your probably in diesel territory with that "shave' Perhaps a typo on the 3/8" claim? Most guys will deck block .020' maybe.
    Where did you obtain the new con rods to accommodate such a radical milling? Anyway nice Volvo.


    This guy milled .020 and bumped up 1 point. .375' mill about 9 points...diesel comp territory

    I like math..



    There are different tactics to *similar* challenges. Having used RTV to seal exhaust flanges in the past, with mixed results, I do not recommend the method for high heat and pressure turbocharged environments. If it works for PFred, then more power to him. For sure: there is *NOTHING* wrong with making proper gaskets either :-) This Instructable is about those gaskets. I recommend PFred writes up a "how to make a proper RTV Exhaust Flange Gasket" Instructable :-) I will gladly attempt to learn from it.

    That said; comment flames are petty, shallow, and stupid... The comments in the Instructableverse seem to be intended for Q&A, improvements, enhancements, safety, and recommendations... not flames and petty ridicule.

    Notice the "Be Nice" comment policy, right there below your comment editing window?

    You'll know when I cease to be nice.

    Probably a good thing pffred2 was not consulted when o-rings on the now retired shuttle were being looked at. He would have offered some permatex ultra as a fix before they rolled it back into the hangar.