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PostPosted: Thu Jan 10, 2013 10:38 am 
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TBI Slant 6

Joined: Wed Aug 18, 2010 9:05 pm
Posts: 217
Car Model*:
Hey guys,
Gonna be super sixing the slant in my dodge d150 soon and I have a few questions about the manifold I got.
Ive read about the two piece manifolds and how they are known to produce bad vacuum leaks. I believe I have one of these manifold, yes?

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Hopefully the pictures are clear enough. There is a clear line in the middle of each runner. Also, the metal is quite porrous around the top outside edge. Will this be an issue?
Also, what type of paint should I use? And should I paint the sealing surfaces...?

Thanks
Justin


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PostPosted: Thu Jan 10, 2013 11:31 am 
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Supercharged
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Joined: Sun Nov 03, 2002 9:20 pm
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Location: Fircrest, WA
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Yes, that intake is known for leaking alone the bubble seam between the two pieces. I have also seen a number of them that crack on the floor of the intake directly below the carburetor next to the EGR port.

If I were going to be using one of these intakes, I would bolt some flat iron to the ports on the ends of the runners, the EGR ports, and over the carb mounting plate and install an air hose fitting in the #6 runner hole. I would then pressurize the intake to 5-10 PSI and submerge it in a bucket or tub and check for air leaks at the seams and around the EGR port below the carb. Anywhere bubbles come out of is an air leak.

Leaks on the seam can be cleaner up by someone who knows how to weld aluminum and an also be cleaned up using epoxy paint.

I would media blast the whole intake and then powder coat it.


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PostPosted: Thu Jan 10, 2013 12:38 pm 
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TBI Slant 6

Joined: Wed Aug 18, 2010 9:05 pm
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Unfortunately I don't have access to the tools to pressurize the manifold, or even access to metal to block off the runners.
I guess what I'll do is paint it or powder cost it (if I can find a place to do it here) and hope that it doesn't leak.
If it does Ill go back to my old manifold I suppose.
Any other ways to check? Pressurizing is obviously the only sure fire way to know, but is it possible to see significant cracks visually?


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PostPosted: Thu Jan 10, 2013 12:43 pm 
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Supercharged
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Location: Fircrest, WA
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You can see big cracks, but these manifolds are know to leak from the porous welds between the two sections. The cracks in the floor of the intake next to the EGR port are usually fairly visible is you check carefully.

If you can do nothing else, try putting a few heavy coats of paint on the intake to try and fill any voids in the welds.


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PostPosted: Thu Jan 10, 2013 12:45 pm 
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TBI Slant 6

Joined: Wed Aug 18, 2010 9:05 pm
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Gotcha.
I'll put a bunch of coats of paint on and hope that it keeps it sealed. Gotta find me some mopar blue. Id like to do orange but the block is already blue. Might as well keep it matching.


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PostPosted: Thu Jan 10, 2013 12:51 pm 
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Turbo EFI
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Location: Maine
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I wonder if you could locate leaks with a bright light? Shine an intense light into where the carb mounts, then observe carefully for light leaks along the runners (done at night, of course).


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PostPosted: Thu Jan 10, 2013 1:05 pm 
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TBI Slant 6

Joined: Wed Aug 18, 2010 9:05 pm
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That's an interesting idea actually! I think I'll try that tonight.


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PostPosted: Thu Jan 10, 2013 1:12 pm 
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Turbo Slant 6
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Joined: Wed Apr 30, 2003 6:43 pm
Posts: 739
Location: SoCal
Car Model*: Toad Wagon
On the one I'm using I had it sand blasted lightly (mostly to break open any thin-top "bubbles"), then whipped up a batch of JB Weld and filled everything that could be. Followed that up with primer & paint.

Three years on'er so far.

One caveat; I don't run a "heat riser" box on it (I carve those off my exhaust manifolds for SoCal operation), so can't address the floor crack issue, or conceivable long term heat shrinkage in the JB (none observed elsewhere as yet though).

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PostPosted: Thu Jan 10, 2013 1:37 pm 
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Turbo EFI

Joined: Wed Sep 17, 2008 6:48 pm
Posts: 2090
Location: Indianapolis
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an alternative to pressure testing is using vacuum,,
makes the opening sealing job a bit easier as you are pulling in on the covers over the casting openings,,, still need to come up with an attachment bung,, but I have successfully done vacuum testing using a hand vacuum pump intended for bleeding brake lines,,, with vacuum you loose the ability to detect the leak area with soapy water,, but its another down and dirty way to leak test.


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PostPosted: Thu Jan 10, 2013 1:49 pm 
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TBI Slant 6

Joined: Wed Aug 18, 2010 9:05 pm
Posts: 217
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Unfortunately I don't have a vacuum gun either. The cheapo one I had broke and I can't justify a better one right now.
I think I'll try the light thing simply for curiosity, though if I don't see any leaks, I can't confirm if it works until I actually run the manifold.
I may also just buy some high tempt jb weld and smear it along the entire seam just to be sure...I doubt the high temp is necessary, but just in case--since I will be running the heat riser. Definitely a must in Canada. The one one on my current manifold stack doesn't work and driving when cold is near impossible.


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PostPosted: Thu Jan 10, 2013 8:26 pm 
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Turbo EFI
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Joined: Wed Feb 23, 2005 1:50 pm
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Location: Pertneer Nashville TN
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Duct tape the carb flange, and the EGR port. Submerge in water withe ports down. Look for bubbles. :?:

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PostPosted: Thu Jan 10, 2013 11:24 pm 
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EFI Slant 6

Joined: Wed Jun 13, 2012 4:39 am
Posts: 484
Location: Australia
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Clean the manifold then spray the inside surfaces with penetrating oil then dust the areas of concern on the outside with talc powder....the talc will "wet" if there is a leak or porosity.... Poor mans dye penetrant check!


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PostPosted: Fri Jan 11, 2013 3:10 am 
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EFI Slant 6

Joined: Sun May 23, 2010 8:38 pm
Posts: 454
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Not sure if this was said, but you could use your old manifold (assuming it is 1bbl and you just want the 2bbl) and the base plate of this one and adapt it. A how too is on this form. I've done it myself with good results cost was around $20.


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