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Two piece intake manifold

 
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duval67
TBI Slant 6


Joined: 18 Aug 2010
Posts: 237

Post subject: Two piece intake manifold (Thu Jan 10, 2013 11:38 am) Reply with quote

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?







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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Reed
Supercharged


Joined: 03 Nov 2002
Posts: 9825
Location: Fircrest, WA

Post subject: (Thu Jan 10, 2013 12:31 pm) Reply with quote

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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duval67
TBI Slant 6


Joined: 18 Aug 2010
Posts: 237

Post subject: (Thu Jan 10, 2013 1:38 pm) Reply with quote

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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Reed
Supercharged


Joined: 03 Nov 2002
Posts: 9825
Location: Fircrest, WA

Post subject: (Thu Jan 10, 2013 1:43 pm) Reply with quote

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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duval67
TBI Slant 6


Joined: 18 Aug 2010
Posts: 237

Post subject: (Thu Jan 10, 2013 1:45 pm) Reply with quote

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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Slanted Opinion
Turbo EFI


Joined: 22 Feb 2005
Posts: 1088
Location: Maine

Post subject: (Thu Jan 10, 2013 1:51 pm) Reply with quote

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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duval67
TBI Slant 6


Joined: 18 Aug 2010
Posts: 237

Post subject: (Thu Jan 10, 2013 2:05 pm) Reply with quote

That's an interesting idea actually! I think I'll try that tonight.


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old6rodder
Turbo Slant 6


Joined: 30 Apr 2003
Posts: 505
Location: SoCal

Post subject: (Thu Jan 10, 2013 2:12 pm) Reply with quote

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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DadTruck
Turbo EFI


Joined: 17 Sep 2008
Posts: 1454
Location: Indianapolis

Post subject: (Thu Jan 10, 2013 2:37 pm) Reply with quote

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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duval67
TBI Slant 6


Joined: 18 Aug 2010
Posts: 237

Post subject: (Thu Jan 10, 2013 2:49 pm) Reply with quote

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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Rug_Trucker
Supercharged


Joined: 23 Feb 2005
Posts: 2775
Location: Pertneer Nashville TN

Post subject: (Thu Jan 10, 2013 9:26 pm) Reply with quote

Duct tape the carb flange, and the EGR port. Submerge in water withe ports down. Look for bubbles. Question



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SlantSteve
EFI Slant 6


Joined: 13 Jun 2012
Posts: 250
Location: Australia

Post subject: (Fri Jan 11, 2013 12:24 am) Reply with quote

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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Brussell
EFI Slant 6


Joined: 23 May 2010
Posts: 458

Post subject: (Fri Jan 11, 2013 4:10 am) Reply with quote

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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