Exhaust manifold plug/plate

03black · **Posted:** Wed Apr 07, 2021 11:45 am

So when I rebuilt the top end of my motor I had fabricated up a plate out of T6 aluminium, molded it around the exhaust flange used the exhaust clamp to plug up the hole. This was easy to do with the manifold off the engine. Well after about 6 months of use it blew a hole in the plate.

I tried to fabricate another plate but with the manifold installed on the engine I can't get a good seal and the plate keeps blowing out. With the tight space, taping it for a NPT plug is not an option. Putting the original tube back in is not an option since I also removed the cooler on the other side of the engine and it'll be near impossible anyway with the tight space. I do not want to remove the manifold either if I can help it.

Looking for options on how to plug the hole. Or does anyone have the block off plug from a weeks stage 2 laying around that I could get.

Thanks!

WWDiesel · **Posted:** Wed Apr 07, 2021 12:56 pm

03black wrote:

So when I rebuilt the top end of my motor I had fabricated up a plate out of T6 aluminium, molded it around the exhaust flange used the exhaust clamp to plug up the hole. This was easy to do with the manifold off the engine. Well after about 6 months of use it blew a hole in the plate.
I tried to fabricate another plate but with the manifold installed on the engine I can't get a good seal and the plate keeps blowing out. With the tight space, taping it for a NPT plug is not an option. Putting the original tube back in is not an option since I also removed the cooler on the other side of the engine and it'll be near impossible anyway with the tight space. I do not want to remove the manifold either if I can help it.
Looking for options on how to plug the hole. Or does anyone have the block off plug from a weeks stage 2 laying around that I could get.
Thanks!

You have a few options!

This is what I did, and it is still holding going on 9 years now. Whenever I pull head to install new exhaust valves on next timing belt change, I will tap and install a proper pipe plug.

Plug needs to be made out of STEEL, not aluminum!

03black · **Posted:** Wed Apr 07, 2021 1:41 pm

WW, interested in option 1, just having a hard time visualizing the fix?
Understand the washer ground down to fit inside the clamp, but what's the purpose for the nut and bolt? Is it just to fill the washer hole? And the bolt head goes into the manifold?

What's the difference between this fix and me making another plate plug out of steel to fit inside the clamp?

Thanks

WWDiesel · **Posted:** Wed Apr 07, 2021 2:00 pm

03black wrote:

WW, interested in option 1, just having a hard time visualizing the fix?
Understand the washer ground down to fit inside the clamp, but what's the purpose for the nut and bolt? Is it just to fill the washer hole? And the bolt head goes into the manifold?
What's the difference between this fix and me making another plate plug out of steel to fit inside the clamp?
Thanks

Yes, the bolt head goes up into the inside of exhaust manifold.
Yes, the bolt/nut is for sealing up the hole in the washer.
If you have the means to make a solid plug out of steel, it would be no difference. Really need a lathe to do this properly which I don't have, so I used thick steel washer so I could put a bolt in it and chuck it up in a drill press to turn it down to the correct size. :wink:

03black · **Posted:** Wed Apr 07, 2021 2:35 pm

Did you have to "bend" down the edge of the washer to meet up/match the angle on the flange on the manifold and to get it to "fit into" the clamp better?

WWDiesel · **Posted:** Wed Apr 07, 2021 3:12 pm

03black wrote:

Did you have to "bend" down the edge of the washer to meet up/match the angle on the flange on the manifold and to get it to "fit into" the clamp better?

I may have a little bit, I really don't remember, it was over 8 years ago. :ROTFL:

Exhaust manifold plug/plate

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