TheSamba.com :: View topic - Late Model - replacement Intake Manifold

Sat Mar 02, 2019 8:40 pm

Hi all,

I recently replaced the dual port intake manifold on my 1973 Super Bug with an aftermarket manifold. It went in decently well but I just realized it is missing the vacuum port for the later model air cleaner setup.

There's a plug to put one in the manifold but I cannot seem to find any information on where to get the proper vacuum port. It would basically be a metal nipple that screws into the manifold.

Does anyone know where to get the right connector?

Any help or advice is greatly appreciated.

Photo below of the hole in the intake where it would go.

Sat Mar 02, 2019 10:52 pm

Why do you need that port? Is it an autostick?

Sun Mar 03, 2019 7:39 am

Jimbo, the missing port is for the '72+ oil bath and paper element air cleaners that had the vacuum-actuated flap in the air cleaner snout. In temps I *think* below 70* or so, the valve's bimetal strip is in an "open" position that allows vacuum from this port pull open the flap for the carb to get intake air from the stove pipe that comes up thru the right side of the rear engine tin. I'm not sure if fuel-injected models had this port.

Sun Mar 03, 2019 9:26 am

Victor. Thanks for the slap on the back of my head. Sometimes I forget stuff and need the reset.

OP
Here is a picture of a properly routed vacuum line.

Sun Mar 03, 2019 9:59 am

You'll need an appropriate sized thread to barbed end connector
Appropriately sized for the plug on the manifold (for the threaded size- "Pipe size")
and sized for the vacuum hose ("hose size") (5mm is stock 3/16" is very close size)

https://www.mcmaster.com/hose-fittings

You would need to:

1) remove the intake (to prevent drilling shavings from falling down into your engine cylinders)

2) Drill out the plug

3) "Tap" the drilled plug for threads of the nipple

4) Screw the adapter in (might be good to locktite the threads as well)

5) Make sure you get all shavings removed from the intake

6) Re-install intake

Happy bug'n

EDIT: alternatively you could do a 'friction fit' port. Drill the hole just undersize of the tube you are inserting. Place a dab of JB weld on the end and tap it into the manifold drilled hole.

Sun Mar 03, 2019 11:29 am

Coat the drill bit with axle grease to enable drilling it on the car. Drill a small amount. Stop, wipe off the bit. Reapply grease. Drill a small amount more. Repeat. If you drill the port about 1/64” smaller than the outside of the tubing, it will set with a friction fit, as AlmostHeaven has stated. I like to use the brass nipples in a plastic tubing coupling. I bet the 1/8” (3mm) one would work well. The 1/4” one would be 6mm, too big, I believe. After you pound it in, cut the flare off the end.

I would still remove the carb and shove a few paper towels down below the level of the port. Put a small amount of grease onto the towels after they are shoved down it there, so the shavings stick. That way any loose shaving will be caught by the towels. You can tie a fender washer onto a string and drop that washer down into the manifold. That way you can pull the towels out really easy. Just be sure to do a good job tying the knots. You could also use a long nose pair of needle nose pliers.

If by chance you drill the hole too large. You can always solder in the fitting. But you will need to remove the manifold and get some Inert gas within that camber, to replace any oxygen inside there.

Sun Mar 03, 2019 11:48 am

VW_Jimbo wrote: Coat the drill bit with axle grease to enable drilling it on the car. Drill a small amount. Stop, wipe off the bit. Reapply grease. Drill a small amount more. Repeat. If you drill the port about 1/64” smaller than the outside of the tubing, it will set with a friction fit, as AlmostHeaven has stated. I like to use the brass nipples in a plastic tubing coupling. I bet the 1/8” (3mm) one would work well. The 1/4” one would be 6mm, too big, I believe. After you pound it in, cut the flare off the end.

I would still remove the carb and shove a few paper towels down below the level of the port. Put a small amount of grease onto the towels after they are shoved down it there, so the shavings stick. That way any loose shaving will be caught by the towels. You can tie a fender washer onto a string and drop that washer down into the manifold. That way you can pull the towels out really easy. Just be sure to do a good job tying the knots. You could also use a long nose pair of needle nose pliers.

I think I'd just use a rag strip. Other than that, agree.

Mon Mar 04, 2019 4:02 pm

Hey all,

This is helpful. One thing I probably should have been more clear on is that the intake does already have a hole in it. I'm just lost on how to find the right fitting.

It doesn't seem like anyone makes one.

Mon Mar 04, 2019 5:03 pm

UrbanTreeFarmer wrote: Hey all,

This is helpful. One thing I probably should have been more clear on is that the intake does already have a hole in it. I'm just lost on how to find the right fitting.

It doesn't seem like anyone makes one.

Nope, no one is making them. You have to get creative. That's how I came up with my port tubing. I am a Plumber, well that is one license of four I have. So, I have a bunch of the brass nipples for tubing sitting in a tool box. When I drilled my Kadrons out for a vacuum port, that is when I learned that they work!

Tue Mar 05, 2019 9:25 am

Gotcha!

And dang! What a pain! But thanks for taking the time with this info.

And to think, I just put the damned thing in there. Had I known I would ah e just cut me dirilled out the carbon in my original manifold.

VW_Jimbo wrote: UrbanTreeFarmer wrote: Hey all,

This is helpful. One thing I probably should have been more clear on is that the intake does already have a hole in it. I'm just lost on how to find the right fitting.

It doesn't seem like anyone makes one.

Nope, no one is making them. You have to get creative. That's how I came up with my port tubing. I am a Plumber, well that is one license of four I have. So, I have a bunch of the brass nipples for tubing sitting in a tool box. When I drilled my Kadrons out for a vacuum port, that is when I learned that they work!

Tue Mar 05, 2019 9:47 am

You are welcome. It may be easier and cleaner to remove the center section of the manifold. You can remove the drivers side end casting and then remove the center. Couple of other details there, but fully doable in an hour or so. Would make the job easier and cleaner!

Tue Mar 05, 2019 11:52 am

Just a note... Beetle vacuum hose is typically 3.5mm ID. So you need a nipple with 3.5mm OD.

Just to give you some size comparisons:
1/8" = 0.125"
3.5mm = 0.1378"
4mm = 0.1575"
3/16" = 0.1875"
7/32" = 0.2188"
1/4" = 0.25"

I couldn't find a 3.5mm barbed nipple, but here is a 4mm one:
https://www.belmetric.com/barbed-hose-adapters-c-1...3k2i8bgus3

I would consider putting the 4mm fitting in drill press and shave the OD down a bit with sandpaper until the 3.5mm hose fits nicely. Just a thought should you really want to stick w/ stock 3.5mm hoses.

Tue Mar 05, 2019 1:48 pm

I thought the manifold take-off was 4mm, like the vacuum retard diaphragm or late FI vacuum system hoses.

CB Performance makes vacuum take-off adapters for their electronic distributor vacuum sensor.

It might be easiest to make your part like theirs, out of an adaptor flange on the bench.

Take one of these spacers, and drill into it (way easier than a manifold) then use some JB Weld or Loctite anaerobic sealant to finish the job.

[img]https://cdn.shopify.com/s/files/1/1902/3741/products/[email protected]?v=1493918513[/img]

https://www.thegansmann.com/collections/isulators/products/late-pict-ict-phenolic-spacer

I'd much rather goof up a $7 spacer than an installed manifold…

See you on the road!
Robbie

Tue Mar 05, 2019 3:54 pm

asiab3 wrote: I thought the manifold take-off was 4mm, like the vacuum retard diaphragm or late FI vacuum system hoses.
Ahh, good point. You could be correct. If so, this green larger ID vacuum hose is what you need, and the 4mm brass fitting would be perfect!

Tue Mar 05, 2019 4:32 pm

If it is 4mm you can use a 3/16” brass nipple. It will work great.

Tue Jul 16, 2019 11:28 pm

Any updates on this issue?

Wed Jul 17, 2019 2:28 pm

Another alternative would be to replace the intake with the OEM version without the small vacuum port and switch to the end-casting that has the small vacuum port on the driver side.

I had to replace my 73 intake to get one with clear heat tubes and switched to the vacuum port on the end-casting for the air cleaner line to attach to.