Cheapskate Plenum Gasket fix?

-
dartslantsix

dartslantsix

Well-Known Member
Joined
Mar 3, 2011
Messages
212
Reaction score
108
Location
Klamath Falls, OR
My plenum gasket it blown. I'd like to fix it, but currently, the Hughes plate that fixes the problem permanently is out of the budget. Since I won't be driving this car more than a few thousand miles a year, I'm thinking I can get away with just replacing the gasket.

Is there an improved design gasket that works with the factory sheetmetal plenum? Should I use RTV on the gasket? I think I read somewhere that the factory bolts are too long, so I should make sure they don't bottom before they clamp. Any other tips?
 
I would get the Fel Pro gasket and grind off about a 1/16th off the bolts and call it a day. I have heard both ways with RTV on the gasket and both seem to be fine. There have been long arguments on other forums if the aluminum pan is necessary and the majority says no. I did the Hughes pan in 07 with no rtv and its holding up fine(knocks on wood).
 
The aluminum to aluminum expansion rate is much closer than the aluminum to steel rate with factory steel plate. When they dont expand together, it causes the gasket to walk out between them. We should have an aluminum 6160 .250" plate with bolts and gaskets at about 2/3 of Hughes within a few weeks. It went to water jet about a week ago.

dart. get a fel pro gasket with glue, scuff up steel and manifold with 120 and use new bolts, old ones can break when reinstalling. Torque sequence seems to be important so check fsm or other reliable source. It will work for a year
 
I wouldn't worry too much about replacing the bolts. The torque spec is only about 7 ft/lbs, isn't it?
 
dusterglenn said:
I wouldn't worry too much about replacing the bolts. The torque spec is only about 7 ft/lbs, isn't it?
Click to expand...

its super low but I had one break, when it happened again a few months later they all get bolts. That is out of tons of gasket swaps but... Its an hour to remove broken bolt and $1.50 to replace with good hardware. My time is worth more than $1.50/hr:D
 
I decided to not completely cheap out on this. I was able to fab up an aluminum plate on my own for about $24 and got the intake fixed this weekend.
 

Attachments

  • P1090187.jpg
    43.5 KB · Views: 323
We just had 45 plates water jetted for us, still have to get them from Oakland to Oregon, dress the bolt holes and put in packages but should be ready to go in next few weeks. $99 out the door with gaskets....for anybody not wanting to spend $150 from the big H or spend the weekend picking aluminum filings from dremel out of your hair. :D
 
spend the weekend picking aluminum filings from dremel out of your hair.
Click to expand...

What fun is that? Ha!

Thanks for getting those made up. Hughes makes a good kit, but their price has really crept up. If they would have been available sooner, I probably would have bought one from you.
 
I just replaced the plenum gasket on my 93 5.2 Magnum.
It was using oil mysteriously, and pinging. I removed the throttle body and looked inside. Oil pooled inside.
Once I removed the intake, the old original gasket was rock hard, and wobbled in and out of position, like a snake. Lots of leaky spots.
Someone mentioned to me, to check that the bolts weren't too long. So I did, and guess what?
With the plenum cover and gasket removed, they all bottomed out before contacting the surface. They are a dog point bolt (meaning they have about a 1/4" non threaded tip. So I ground them all off about 1/8".
New Fel Pro blue gasket. It is wider than original, and has sealing strips moulded in place. Nice part.
Sure runs nice now.
Hopefully problem solved.
 
The bolt length was originally intended to prevent overtightening, which damaged the factory gasket.
Hopefully you used a little blue LockTite on those bolts, since you shortened them, and they no longer bottom out securely.
Yours will probably be fine.
The best repair, meaning the longest lasting, is still to replace the stamped metal plate with a thick aluminum one. Versions are available from ebay for about 55 dollars.
 
You must log in or register to reply here.
-

Back
Top