TheSamba.com :: View topic - Engine won't start after manifold/boots/end casting replacem

Wed Jun 10, 2015 10:33 pm

Hello all,
I had a small leak from the left side boot, since both boots found very dry/hard and cracked (14 years old!!), I replaced the them both.

While I was there, I removed the original VW dual port manifold, I found the heat riser colgged as expected, So I replace to a brand new manifold, it's paint black from factory, I bought it 8 years ago in the states, I think it's genuine VW Mexico, not sure, maybe aftermarket, I don't see VW logo on it nor part number.

I replaced also the two end casting to a brand new ones made by VW Mexico. Replace the gaskets.

I start the engine, but it won't start, until I rev the engine, and if I don't keep my leg on the accelerator, the engine will die.

Any idea?

Thanks in advance

Wed Jun 10, 2015 11:42 pm

Sounds like a classic vacuum leak.

Does the manifold have a vacuum port on it? My SCAT manifold has one for using SVDA distributors with carbs that don't have a port. Make sure if you have one on your new manifold that its plugged.

And of course check your gaskets and boots.

You can check for vacuum leaks by getting your engine running by whatever means you have to and then spraying every possible leak area with carb cleaner/starting fluid, if you have a vacuum leak you will hear a change in RPM when it sucks in the cleaner.

Thu Jun 11, 2015 12:47 am

If the center piece is not slotted straight into the end-castings, it can be leak-free and yet present enough of a lip in the airflow to "catch" the fuel.

I assume,of course, that you changed intake manifold gaskets, didn't re-use the metal ones...

Hope this helps.

Thu Jun 11, 2015 1:46 am

FreeBug wrote: If the center piece is not slotted straight into the end-castings, it can be leak-free and yet present enough of a lip in the airflow to "catch" the fuel.

I assume,of course, that you changed intake manifold gaskets, didn't re-use the metal ones...

Hope this helps.

I first connected the preheat screws, than I closed the end casting screws of the intake, that new manifold is not sitting perfect 100%, maybe that was my mistake and the end casting is not sitting firmly, although I closed both 13mm real good from each side.
Yes, center piece is not slotted straight into the left end-castings.

I did replaced to new intake manifold gaskets.

I guess I will put back the original VW German manifold and clean the pre heat, and put it back instead the "new" but I probably junk manifold.

Thu Jun 18, 2015 1:53 pm

O.K Some good news! :)
After returning back my VW German manifold (I had a chance to clean and open the heat risers that were totally clogged) and installed the old german end casting, the engine is happy and running very strong.

Probably my mistake was that I closed the heat risers first, instead the end casting. now the center piece is slotted straight into the both end-castings.

While I was there I replaced to new VW oil cooler and new oil seals, the old ones found hard as a rock! (14 years old...)So I fixed also small leak I had from there.

3 majors things that I did for my VW bug 1966:
- Brand new VW oil cooler and seals.
- New VW red silicone dual port boots.
- Clean the clogged heat risers.

Thanks to everyone for the help!
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