Intake Manifold leaks Coolant- Could it be too small??

-
Bob Watkins

Bob Watkins

Active Member
Joined
Oct 14, 2018
Messages
35
Reaction score
19
Location
Kent, OH
I bought a used Weiand 7510 aluminum intake for my LA and cannot get it to seal. The rear coolant ports both leak. When I removed the intake, the metal gasket ridges were not flattened, and it does not appear to fit. As a sanity check I compared the fit on the head with a cast iron 2bbl manifold I had and noticed that the Weiand has side to side play of 1/8" to 3/16" without gaskets, while the cast iron has zero play and is flush. Before I spend bucks on a new manifold, I thought I'd ask FABO for comments. Anyone know of a way to tell if the Weiand has been resurfaced? It seems fairly straight front to back on each rail, but it is definitely a bit narrower side-to-side than the cast iron manifold. Will thicker gaskets work? Or should I bite the bullet and buy new? As always I appreciate your comments!
 
Dunno if this helps but I usually run a big bead of silicone on the ends in place of the manifold end gaskets on the block then torque to spec. I would think the aluminum would seal if the water jacket ends are flat. Maybe try run silicone around the water ports with the gasket that sits between the heads and manifold...

what you don't want is antifreeze leaking into lifter valley into oil etc. Good luck.
 
Dartswinger70 said:
Dunno if this helps but I usually run a big bead of silicone on the ends in place of the manifold end gaskets on the block then torque to spec. I would think the aluminum would seal if the water jacket ends are flat. Maybe try run silicone around the water ports with the gasket that sits between the heads and manifold...

what you don't want is antifreeze leaking into lifter valley into oil etc. Good luck.
Click to expand...
I shared the same concern about coolant in the valley, and there was some in there, but don't know if it came when I lifted the manifold off. Sealant is a possibility but the gap seemed pretty large for a sealant fix. That's why I'm gathering thoughts- thanks for yours.
 
Bob Watkins said:
I bought a used Weiand 7510 aluminum intake for my LA and cannot get it to seal. The rear coolant ports both leak. When I removed the intake, the metal gasket ridges were not flattened, and it does not appear to fit. As a sanity check I compared the fit on the head with a cast iron 2bbl manifold I had and noticed that the Weiand has side to side play of 1/8" to 3/16" without gaskets, while the cast iron has zero play and is flush. Before I spend bucks on a new manifold, I thought I'd ask FABO for comments. Anyone know of a way to tell if the Weiand has been resurfaced? It seems fairly straight front to back on each rail, but it is definitely a bit narrower side-to-side than the cast iron manifold. Will thicker gaskets work? Or should I bite the bullet and buy new? As always I appreciate your comments!
Click to expand...
Did you take the locating dowels out of the china walls? What engine are you working with?
 
toolmanmike said:
Did you take the locating dowels out of the china walls? What engine are you working with?
Click to expand...
Engine is a 74 Dart 318. The block had both locating pins for the heads, no locating pins for the manifold- should there be pins for the manifold?
 
Bob Watkins said:
Engine is a 74 Dart 318. The block had both locating pins for the heads, no locating pins for the manifold- should there be pins for the manifold?
Click to expand...
THe stock manifold had pins in the front and rear walls (between the deck surfaces) Most aluminum intakes aren't drilled for those pins and can caust sealing issues. Just spit ballin' here.
 
Never a big fan of using metal intake gaskets with an aluminum intake. I used Fel-Pro intake set #1243 , gasket port size 1.05 x 2.08 And I did not use the cork china wall gaskets. Check your intake port size on your head and your intake manifold and purchase a paper/composite gasket that fits....

fel-1243_xl.jpg
 
I run an Edelbrock performer intake and seem to recall similar issue,it didnt :fit" as well as my Mopar cast iron one Like said I used silicone and proper tightening sequence and torque spec. i am not sure if the aluminum"flexes" when bolted down. I would think to a degree, but aluminum cracks also so you dont want to overtighten etc. Mine sealed up fine but i recall thinking it didnt sit right when i sat it on the engine dry without gaskets. maybe it is an aluminum intake commonality? or a defect?
 
SGBARRACUDA said:
I agree with Dicer. Never like using metal intake gaskets.
Click to expand...
I used the on my 273 for a better fit. (thinner and the intake bolts lined up perfect) but the heads had been shaved. It was a cast intake though.
 
toolmanmike said:
THe stock manifold had pins in the front and rear walls (between the deck surfaces) Most aluminum intakes aren't drilled for those pins and can caust sealing issues. Just spit ballin' here.
Click to expand...
The pins are not in the block china walls, so that's not a problem, but it was worth checking at this point- thanks.
 
Dartswinger70 said:
I run an Edelbrock performer intake and seem to recall similar issue,it didnt :fit" as well as my Mopar cast iron one Like said I used silicone and proper tightening sequence and torque spec. i am not sure if the aluminum"flexes" when bolted down. I would think to a degree, but aluminum cracks also so you dont want to overtighten etc. Mine sealed up fine but i recall thinking it didnt sit right when i sat it on the engine dry without gaskets. maybe it is an aluminum intake commonality? or a defect?
Click to expand...
Cast aluminum is quite brittle, so I was very careful tightening. Your comments help- if all aluminum manifolds are like this, then I need to make this one work somehow.
 
Bob Watkins said:
Cast aluminum is quite brittle, so I was very careful tightening. Your comments help- if all aluminum manifolds are like this, then I need to make this one work somehow.
Click to expand...
New or used manifold? It could have been machined.
 
toolmanmike said:
New or used manifold? It could have been machined.
Click to expand...
It is used and I don't know much about it. The rear water jacket seals on the back of the manifold show some corrosion, so I can assume that it has been used, but the seller didn't know much about it. It could have been machined.
 
Dicer said:
Never a big fan of using metal intake gaskets with an aluminum intake. I used Fel-Pro intake set #1243 , gasket port size 1.05 x 2.08 And I did not use the cork china wall gaskets. Check your intake port size on your head and your intake manifold and purchase a paper/composite gasket that fits....

View attachment 1715713486
Click to expand...
What did you use in place of the cork gaskets?
 
I purchased a tube of this RTV, and a caulking gun, worked great, laid down a nice tall wide bead...

IMG_4318.JPG
 
Bob Watkins said:
Cast aluminum is quite brittle, so I was very careful tightening. Your comments help- if all aluminum manifolds are like this, then I need to make this one work somehow.
Click to expand...
I did use fel pro gaskets and they weren't straight metal...they were blue coated and like said with silicone on the ends and around the water ports at all 4 corners of the heads.
 
Dartswinger70 said:
I did use fel pro gaskets and they weren't straight metal...they were blue coated and like said with silicone on the ends and around the water ports at all 4 corners of the heads.
Click to expand...
Thanks DartSwinger and Dicer- For grins I measured the distance between the rails on both manifolds. The Weiland is exactly 1/8" narrower than the cast iron manifold. 7 5/8" vs. 7 3/4". I am now suspicious of the Weiland, as I look closer, the rails have fairly deep scratches running lengthwise on both rails, like someone used very coarse sandpaper or a file on that surface. Definitely not a machined surface.

20210325_123635[1].jpg
 
Looks like an old sanding belt was used. Definitely not production as they were not even machined flat just flat as cast iirc. Your gonna need to get the heads lower (deck the block) or get the intake wider (1/16 spacer or thick *** fiber gaskets or double up on them) and then you'll have to make sure the ports and the bolts line up. Spacers cut from 1/16 (16 gauge) may be easy to make with tin snips and a jig saw. Your kinda screwed on that modded intake. You may want to try 1/16 rolled gasket material and cut your own intakes out of that as they are not that precision or torqued on and use the tall foam China wall gaskets as they are pretty thick uncompressed. Good call on the dowels. Overlooked them once and cracked a 273/4 intake.
 
Have the intake angle milled to square & depending on how much is taken off, you might have to have the China wall ends of the intake milled also. From there, use good FelPro composite (not shim steel) gaskets & RTV silicone for the China walls.
 
AJ/FormS said:
So are you saying that the intake is sitting ON TOP of the china wall and skating ON it for this distance? Cuz that would be self-explanatory.
Click to expand...
That's correct. It slides on the china wall back and forth, and the cast iron manifold fits with no slide.
 
I would get a different manifold. You may never get that one to work.
 
toolmanmike said:
I would get a different manifold. You may never get that one to work.
Click to expand...
After these discussions I'm leaning that way myself. Hard to justify making mods to an engine to accommodate a bad manifold. I really appreciate FABO and it's members for helping solve problems like this.
 
You must log in or register to reply here.
-

Back
Top