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Port Matching with Carb intake

4K views 30 replies 4 participants last post by  garryt 
#1 ·
I was a bit surprised to see how much off my manifold is from the head port.
What's even more surprising is that the gasket is a closer match to the manifold than the head.

What have others done for this issue? My head is already ported, I don't want to hog it out too much more, but I certainly can't leave this big step mismatch in there.

I can certainly grind it to match, but I'm wondering if anyone has come across this and maybe used JB Weld or something similar on the bottom of the manifold to blend the shape better?






 
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#2 ·
Just an opinion.

I wouldn't use JB weld. Im not sure what constant temp change and fuel will do to the JB weld in the long run. It could deteriorate or flake off ending up in places you don't want it.

As i said just an opinion.

Do you have any other manifolds you can compare against what your working with?
 
#4 ·
I went with JB Weld. I read a LOT of opinions on many different forums, there's a lot of people with long standing (years) good results.
Very common with intake manifolds.

Some guys with bad experiences, and those bad experiences can be blamed on prep and how it's used. Moral of the story, don't use it on a part that's already been soaked in gas.

I'm doing this on a brand new casting, and it has a rough internal surface, and is no thicker than a spray can red straw.
All the ingredients for success.

I am considering coating the epoxy with POR-15.

I have a science project in progress.
A couple pieces of metal with a skim of JB, and partially coated with POR-15, soaking in E-10 gasoline.
Been 2 days so far. No issues yet, but I'll take them out and see if the material is soft or rubs off or anything.
 
#5 ·
Science project was a little bit disappointing.
Neither product came off the test parts easily, but it did come off with scratching at it. POR-15 is a very hard paint, and after being submerged for a few days, it made it softer. But both the epoxy and paint could have used more cure time too.

The intake ports are at an angle, will never be sitting in a pool of fuel.
I'm going to proceed.

Just wanted to give honest results for anyone thinking of doing this.

If this was a conventional fuel injection car, with the intake being only for air, there should be no hesitation if the metal was cleaned really well.
 
#6 ·
A few questions. Why do you thing POR 15 is good for fuel? My understanding is that it's good for covering rust. They do make a fuel tank sealer.

If you look on JB Welds website, they say it's gasoline resistant. If you want something that is gasoline proof, they recommend something else.
"When fully cured, J-B Weld is completely resistant to water, gasoline, and about every other petroleum product or automotive chemical. For wet-surface or submerged water or gasoline repairs, try our SteelStik"
https://www.jbweld.com/faqs

Since the intake manifold or any other part of the engine is never submerged in fuel, your tests are way to extreme and therefore probably worthless. I do understand that you cannot trust anything on the internet so trusting someone that you do not know that JB Weld is the way to go, may be difficult to accept.

I know that I would just port match that head. Then you do not have to worry about anything coming loose.
 
#10 ·
I appreciate everyone's input.
Sometimes, a combination of other's advice, and just letting a dilemma "soak" for a while brings clarity.

I've removed the JB Weld, and decided to port match the head. I elongated the stud holes, moved the manifold up so I wasn't taking off too much in any one section. The bottom of those ports are a water jacket, so a tiny bit is all that's allowable.
At this point, I'm happy with it, and I won't be stressed about the epoxy softening up through the years.
It's almost done, and I'll show results soon.

Again, thanks for the replies. Like Butcher said, my testing was very extreme for how it's used, but I was, like all of you posting here, concerned about long term. I can not guarantee I will use Ethanol free fuel all the time, and the ethanol added is really what's causing the trouble.

As to "For wet-surface or submerged water or gasoline repairs, try our SteelStik"
https://www.jbweld.com/faqs
I think they're saying to use those if using it while the repair is actually wet or submerged, WHILE repairing, because it's more like a putty. But I could be off base there.
 
#14 ·
I did not realize that you had access/skills for welding, that is the option I would take.

Not that this idea applies but I was trying to align a Audi Turbo intake manifold to my JH head. The ports did not align. I eventually thought about using a spacer that pushed the intake out far enough that helped with the alignment issue. It worked out right.

Gasket differences. Notice the ports vs the mounting holes

Port matched to head

Port matched to intake.
 
#15 ·
Nice work there. Adapter plates are sometimes the only way.
Popular with other non-VW stuff I'm involved with.

As for access to welding, I can only do steel, not aluminum.
I have a master welder buddy across the country, but nothing local.

Money is getting a bit tight right now for this build, as anyone who's done a full rebuild and car restoration can appreciate. Hence, epoxy. But that's all gone, it's looking beautiful in just metal.
 
#17 ·
All smoothed out, all metal. Like I mentioned above, I elongated the holes in the manifold slightly, moved the manifold up a bit, and ported to match.
Very happy with the results, it is very smooth, with no step either coming or going. Pictures make it look rough, but it's very smooth. Passes the finger test very well. One less thing to worry about.



 
#20 ·
decent exhaust/some mild cams and a tuneable em will easily double your original hp:) what size/make are the carbs? my dads got about 3 sets of old side draughts and I was thinking of using a pair as throttle bodies on an 8v. injectors are in the head, so it wouldn't be too difficult.
 
#23 ·
Well, honestly I don't know. I know that I'll be leaving some power on the table initially, as I'm planning 100% "true" old-school with points ignition.
I won't debate whether a sophisticated computer controlled system would be better. Of course it would be. That's just not the flavor I'm going for on this car.
We'll see if I stick with the points or not. But for now, I'll get it running on that.

So, with all that said, it's just a weekend toy that won't be raced, or depended on for a daily driver with good mileage. I like old stuff, and I enjoy making old stuff work well. I'd be happy with anything at the stock horsepower of the 9A, 134hp, plus/minus a few. I'm guessing it will be on the plus side.
 
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