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Cracked plenum

  • Thread starter Thread starter DadLife0724
  • Start date Start date Apr 3, 2026
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DadLife0724

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Mar 22, 2024
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Cooperstown, PA
Apr 3, 2026
#1
  • Apr 3, 2026
  • #1
 

DadLife0724

Active Member
Mar 22, 2024
262
189
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Cooperstown, PA
Apr 3, 2026
#2
  • Apr 3, 2026
  • #2
This has been repaired before. Well . Any recommendations on plenums?
 

KRUISR

10 Year Member
Apr 16, 2015
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Apr 3, 2026
#3
  • Apr 3, 2026
  • #3
Yup. Will need to be welding back on. Crack probably goes all the way through.

Should be able to reweld it. Key will be creating a groove along the crack to be filled by the new weld.
 

DadLife0724

Active Member
Mar 22, 2024
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Cooperstown, PA
Apr 3, 2026
#4
  • Apr 3, 2026
  • #4
KRUISR said:
Yup. Will need to be welding back on. Crack probably goes all the way through.

Should be able to reweld it. Key will be creating a groove along the crack to be filled by the new weld.
Click to expand...
It definitely goes all the way through. I'll probly just throw this on the shelf and go for something new...er.....better condition. Still tryin to work through this thing since last owner. Rather not have to worry about a twice welded plenum.
 

TOOLOW91

If you're the village idiot what's that make me?
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Nov 29, 1999
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#5
  • Apr 3, 2026
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It cracked because of the spacer under it. The spacer is softer then the Intake just mated to the lower.
So a lot of people including myself many moons ago over tighten and the ear cracks because it actually crushes the spacer enough to flex it.
 
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AeroCoupe

lube between the nut and the face. I know my lubes
Founding Member
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#6
  • Apr 3, 2026
  • #6
I cannot suggest an upper and lower as I have no idea what all has been done to the motor or/or your goals…you really want me to post up the dart board don’t you?
 
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DadLife0724

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Mar 22, 2024
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Cooperstown, PA
Apr 4, 2026
#7
  • Apr 4, 2026
  • #7
I agree about the spacer. I thought about that when it happened. I was only torquing to 18.5.
@AeroCoupe , my plan for now is to get all the bugs out of this thing from the last guy. I am a slow mover cuz of kids and sports practices and anything they decide I want to do. Maybe a Facebook exploder intake is my best option until I actually get the car where I want it. As deep as I've been in the motor, which is down to the valley, it seems to be stock explorer heads, lower, and upper with a mild cam. Headers, no cats, x pipe, flowmaster 40s. Bbk intake with 70mm MAF, 70mm throttle body and spacer plate.

I guess I should start a progress thread.
 
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AeroCoupe

lube between the nut and the face. I know my lubes
Founding Member
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#8
  • Apr 4, 2026
  • #8
Yes you should and I agree if all you have is GT40 or GT40P's with a stock bottom end and mild cam then the Explorer upper and lower will work great with that combo especially if you can score them cheap.
 
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TOOLOW91

If you're the village idiot what's that make me?
20+ Year Stangneter
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#9
  • Apr 4, 2026
  • #9
If that’s an explorer id just put another back on it , If you don’t need the spacer remove it or be mindful when tightening it down
 
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Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
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Apr 7, 2026
#10
  • Apr 7, 2026
  • #10
Later explorer uppers were prone to this…even without the spacer. That spot just isn’t reinforced adequately. Spacer just increases the likelihood.
 
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General karthief

wonder how much it would cost to ship you a pair
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#11
  • Apr 8, 2026
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Many DIY tighten the upper to lower bolts too much so I glue the gaskets on both sides with blue RTV and and just snug it evenly and then again after a heat cycle, it only flows air in there but needs a good seal and the blue RTV ain't so hard to remove.
 
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DadLife0724

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Mar 22, 2024
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Apr 10, 2026
#12
  • Apr 10, 2026
  • #12
Picked this up yesterday for 150. Didnt think it was a bad deal. Gonna test and clean injectors. Might have an extra set of 19s. Throw extra lower on shelf for a later build possibly. This upper is gonna take some elbow grease.
 
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idareu

20+ Year Stangneter
Jan 6, 2004
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Apr 10, 2026
#13
  • Apr 10, 2026
  • #13
DadLife0724 said:
Picked this up yesterday for 150. Didnt think it was a bad deal. Gonna test and clean injectors. Might have an extra set of 19s. Throw extra lower on shelf for a later build possibly. This upper is gonna take some elbow grease.
Click to expand...
Not a bad deal at all. I have an intake on my 93 that looks close to that. What's the best way to clean them up?
 
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DadLife0724

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Mar 22, 2024
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Apr 10, 2026
#14
  • Apr 10, 2026
  • #14
I used different wire wheels on my drill. And used an entire spray bottle of degreaser on interior. Had to get another bottle to finish the job. Picking up kid from school currently. Will post pics of finished product when I get home. Haven't done mating surfaces yet.
 
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DadLife0724

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Cooperstown, PA
Apr 10, 2026
#15
  • Apr 10, 2026
  • #15
General karthief said:
Many DIY tighten the upper to lower bolts too much so I glue the gaskets on both sides with blue RTV and and just snug it evenly and then again after a heat cycle, it only flows air in there but needs a good seal and the blue RTV ain't so hard to remove.
Click to expand...
That would be a lot of rtv. I have a half inch spacer so throttle cable will clear coolant tubes.
 

AeroCoupe

lube between the nut and the face. I know my lubes
Founding Member
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Apr 10, 2026
#16
  • Apr 10, 2026
  • #16
I have a 1” aluminum spacer to clear the tall valve covers and have zero issues with sealing with just dry gaskets.
 
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DadLife0724

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Mar 22, 2024
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Cooperstown, PA
Apr 10, 2026
#17
  • Apr 10, 2026
  • #17

Cleaned up pretty good. Any ideas on how to get the crap inside? You can see it in the right side. It was completely black and coated with oil. Im surprised it turned out the way it did. Would like to get that last little bit in there. Thought about plugging vacuum tubes and dumping some marbles in there with a bunch of degreaser.
 

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gkomo

now i can hopefully expect to receive the shaft
Aug 2, 2024
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San Diego, CA
Apr 10, 2026
#18
  • Apr 10, 2026
  • #18
Big ass pipe cleaners with soft metal bristles and attack it from both sides??
 

General karthief

wonder how much it would cost to ship you a pair
5 Year Member
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Apr 11, 2026
#19
  • Apr 11, 2026
  • #19
DadLife0724 said:
That would be a lot of rtv. I have a half inch spacer so throttle cable will clear coolant tubes.
Click to expand...
Your not building a wall, just a skim coat, thin, just enough but not too much,
That sounds dumb, "now just enough Bobby Joe, not too much"
 
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DadLife0724

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Mar 22, 2024
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Cooperstown, PA
Apr 12, 2026
#20
  • Apr 12, 2026
  • #20
Went with dark gray. Gonna have my son's buddy black the inset lines on the plenum and gray the inset background on the plaque.
 

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