How do you stop 48idf webers vibrating

[Herbie]

Hope someone can help me here.  My 2165 is about to be back on the road soon and I want to prevent a problem that annoyed me heaps last time it was on the road.  I was forever experiencing manifold/head gasket leaks due to the top heavy 48idf.  I was wondering if anyone has this problem and has made up a bracket to support them.  I am using 12mm nuts and only have 2 bolts mounting the carbs.  The manifolds are pretty standard.  No extra welding.  If anyone has some pics or ideas on how to stop these moving I would love to hear it.

[superdrag]

Never heard of this problem, I run 48 idf's and have never had vibration problems with them, and what do you mean they are top heavy?  They are the same basic carb body as say 44 idf's.  Do you have bolts coming loose, or what?

[Squirmn German]

I was forever experiencing manifold/head gasket leaks due to the top heavy 48idf.

I don't think that is the problem. Are they banging into the side of the engine compartment?

[Herbie]

They seem to loosen the 12mm nuts holding the manifold onto the head which leads to the inlet leaking.  I had to start using thicker gaskets as I was sucking the paper ones into the motor. The 12mm nuts just don't seem to stay tight no matter how hard I tighten them. 

[Herbie]

The carbs aren't noticeably moving either.  I just assumed when the engine vibrates that this would cause the carbs to eventually loosen the 12mm nuts.

[madmike]

Try using a star type lock washer and check often some  guys don't use gaskets anymore because of this problem just a Locktite anarobic(spelling) sealer,Madmike

[fiatdude]

Just pull the batteries out of them.

[John Palmer]

This is a fourty year old problem, nothing new.  If you want to convince yourself just walk through any VW swap meet and you will loose count of how many old manifolds have had their mounting tabs welded back on.  Just pick up a manifold with a carb mounted to it and try to hold it by the tabs, its no wonder the manifolds get loose.  The fact that we port the maniflods and heads only makes the problem worse because the mounting surface area is less.

EMPI (the original one) had a IDA manifold with "a third mounting stud" that really worked.  We ran these for years on both the street and our smaller race motors with great results. 

I'm not convinced that the manifold nuts get loose when using the star washers.  I think its more of an issue of the gaskets compressing after the carbs/maniflods have shook back and forth.

Possible cures.........
Contact cement the gaskets to the manifolds and leave as much gasket material on the outside as the head/shroud will allow.  The thinner the gasket, the less it will be able to compress. 

Use no gaskets and just silicone the manifolds.

Until we started using our Comp Eliminator style heads a few years ago we ran "a support bar" between the two carbs.  The bar was mounted to the back carb stud on each carb using a heim end.  How ever you need to make a provision for the fact that the enginge grows in width as it warms up.  That is why we used a 1/2" aluminum rod and bent it into a radius "like a bow" which allowed it to grow and still have a dampening effect that we needed.

Make "absolutely certain" that when you launch the car nothing on the engine can hit or rub the inside of the engine compartment or deck lid.  If the right carb hits the inside of the fender you will never be able to keep it tight.  The engine will move down at least one half an inch even with a traction bar or frame tie-in.  The last time we had this problem it was traced to a NOS nozzel that was too close to the firewall.


 
 

[Herbie]

You hit the nail on the head.  I will have a look and try a few of your solutions.  This car is a daily driver so the problem occurs more often then a weekend driver.  I couldn't work out why my friends never had issues but i did.  Thanks for the advice.

[ALB]

John- Do you (or does anybody) have a pic of those old Empi manifolds with the third mount?

[Ohio Tom (DdK)]

Also to add to John's statments..
Many times I find that the manafolds and/or gaskets have an interference issue with the cyl tins. the tins get sandwitched and give false tight feelings when torqued down.
Motor vibration just makes it loosen up.

The fix is to make sure that the manafolds sit flat against the head with no interference from the tins. Trim the tins as required to get a good fit.

[Clinton DdK]

Here is what I like to do. Trim off the bottom of the spark plug hole, after doing this you can push in the area between the spark plug hole.






You may have to flatten this area some.






Then following this crease from one end to the other cut and remove this area. This should give you adequate room for even the thickest manifolds.



 

[Ohio Tom (DdK)]

Cool idea Clinton..

[vwracer]

Just pull the batteries out of them.

ROFL... Great minds think alike!  I was just thinking the same thing. 

[youngnstudly]

Hope someone can help me here.  My 2165 is about to be back on the road soon and I want to prevent a problem that annoyed me heaps last time it was on the road.  I was forever experiencing manifold/head gasket leaks due to the top heavy 48idf.  I was wondering if anyone has this problem and has made up a bracket to support them.  I am using 12mm nuts and only have 2 bolts mounting the carbs.  The manifolds are pretty standard.  No extra welding.  If anyone has some pics or ideas on how to stop these moving I would love to hear it.

What do you mean by "two bolts mounting the carbs"? Is this at the manifold to head surface or the manifold to carb surface? Manifold to carbs need 4 studs/nuts. I have been running my 48 idfs for a short while now and I haven't had much trouble with the manifolds coming loose. I only use the 10mm wrench size (CSP brand) nuts to hold the manifolds on with no lock washers or locktite. I use Fel-pro 1/16" gasket material with a thin layer of white grease on all  the manifold gaskets. Also, how loose are the manifolds on the head studs? If the manifold holes are too big (ovaled out or oblong in shape) then that could be part of your problem.

I didn't chop my head tin for clearance as I simply reworked the metal into the shape I needed. I did ,however, grind my manifold bases down some (they were huge!). I left as much material as possible (everywhere) and made my parts just barely clear one another.

This is the tightest spot I have with my setup and yes I am going to trim the body a little to make it clear...I thought I would be able to just fold the metal lip under so I could keep from butchering the body up. Notice my special $50 each K&N air cleaner(s) on this set up so the decklid will clear). The manifolds were simply too tall to run a standard filter.


Here is my tin clearanced with the stock air deflector added. No problems, just lots of time and patience! Notice the copper sleeves that keep the manifold tight on the studs. The other sleeve is stuck in the manifold. As stated, make sure the manifold seats flat against the head with no interference with the tin.


Manifolds after grinding a little off.


Good luck!
Andy

[Greg Ward]

Or you can do this.

"The Third Stud"

Greg

[fish26]

I also like to bush the manifolds to the studs for a nice snug fit, never had a problem with loose carbs.

[jetmanoo1]

Click here: TheSamba.com :: VW Classifieds - 3/8 8mm Nut Exhaust Manifold Carb Header

mine use to do the same thing this is what took care of it

[Clinton DdK]

Or you can do this.

"The Third Stud"

Greg

Greg, I like this idea but how are you able to tighten that down with the cylinder tin on?

[John Palmer]

Greg, I like this idea but how are you able to tighten that down with the cylinder tin on?

Clinton, the original Empi dual port manifolds were made just like what Greg has shown.  However they were cast with the boss "in place" and it ran "higher up" than what he has fabbed but still the same principle.  The boss was for a 5mm stud approximately 50mm tall and threaded at the top of the head port divider.  It was not a problem dropping a 5mm nut down on the stud and tightening it up with a 1/4" drive 10mm wobble socket.  We ran them for years using a stock sized "Thing" dog house shroud modified for a type 4 oil cooler. 

 

[Greg Ward]

Clinton, the original Empi dual port manifolds were made just like what Greg has shown.  However they were cast with the boss "in place" and it ran "higher up" than what he has fabbed but still the same principle.  The boss was for a 5mm stud approximately 50mm tall and threaded at the top of the head port divider.  It was not a problem dropping a 5mm nut down on the stud and tightening it up with a 1/4" drive 10mm wobble socket.  We ran them for years using a stock sized "Thing" dog house shroud modified for a type 4 oil cooler. 

 

No Stud at the head, the head is machined for the corresponding thread,(and deep enough) and a hex bolt used, so all you need is an allen head on a flexy bar (bit of vaso or grease in the hex bolt so it doesn't fall off when you are attempting to insert through the manifold hole, and tighten gently, do the other 2 (with 11mm nuts) and then retighten all to required torque.

Don't have the heads at my place, so I can't take a pic, but you should get the idea.

Greg

[James2]

I ran no gasket, star washers and still had problems on long drives. I had a carb almost fall off when i drove it about 150 miles.

I'm starting to remember why i stopped driving my car.

[markhuebbe]

I ran no gasket, star washers and still had problems on long drives.

At my first rally race I had the carbs loosen up.  Turns out it was the aluminum big beef manifolds that wore down at the nuts.  I smoothed the flange flat with a file and added steel washers and those 3/8s nuts and have never had them come loose since.  I also use a thin gasket and red Permatex high temp flange sealant.  http://www.permatex.com/products/Automotive/automotive_gasketing/anaerobic_gasket_makers/auto_Permatex_High_Temperature_Anaerobic_Flange_Sealant.htm
When I take the carbs off I have to pull hard to get the manifolds off and break loose the seal.

[Bruce Tweddle]

My experience is the same as Mark's.  The nuts don't come loose, the aluminum squishes out from under them, making them appear loose.  I use a standard VW m8 washer with a 12mm hex m8 nut.

[Lanny]

Red Loctite on the studs into the head. Blue Loctite on CSP/Berg M8X10(jet nuts). Everything flat/clean with nothing rubbing or hitting. This approach can allow the use of a 3/8" drive socket/extension combo when using IDA's. Bruce Tweddle said years ago..'why are you messing around with open end wrenches and 1/4" drive stuff..get some torque on those things'..

[Sam]

In a sand buggy its the worst, I have to change the gaskets in mine after every trip. Guys that ran circle track bugs had hell with carbs coming loose. I may have to switch to silicone and no gaskets, what silicone do yall use?

[Greg Ward]

As soon as I get a chance, I'll get a pic of the head end and work needed to do what my old heads that we did this to look like.

But, I don't know why anyone would use washers of any kind under the nuts? I guess it's an attempted cure to the problem, but with a lovely base to my current manifolds, a simple spot face and 11mm nuts and torque with bendy bar and socket, and good to go.
That's even 1000 miles to the racetrack to race, so, it's not a quickfix for a weekend...

With those manifolds I pictured, if they were different at the bottom, and with so much meat like my current ones (that the ones in the pics MB manifolds, don't have) then "The Third Stud" would never be necessary.

And I've always run gaskets, total failure with ones that have ANY sort of silver film on them, just nice non-coated reasonably thick for torque down types, and never a drama there either.

And as everyone has also said, tinware, or non-prefect cut gaskets and all that can totally screw any prepped surface up.


Greg