Stuck on 405S. 1600 with Solex carbs backfire?

Few things to check. If you have points in the distributor check the gap.

 Fuel filter, and adjustment at the accelerator pumps 

Could it be something as simple as bad gas?  It happened to me once.

Add some Sta-Bil ethanol gas treatment to the tank and see if that helps.

If the engine heats up a bit (and who knows what that is, I'm staring at the temperature gauge and it's just off cold), you still wouldn't expect backfire in the dual carbs?

Back to the basics. Check the plug wires at the cap and spark plugs, check cap an d rotor, check the point gap, carbs sync?  Once warm are both carbs opening at same time? Carbs adjusted correctly, clogged jet?   Fuel bowl dirty?  Not as easily as adding something to the fuel.  Should be running premium fuel!!!!

I will be in Irvine sat.  Call me 1-916-255-9776 

Hey, Anthony,

thanks for the kind gesture!  ironically, on Saturday, i'm gonna be in Hawaiian Gardens to have "Ella" get her 1000k oil change.  I was hoping I might get some insights before i checked with Kirk.

This board is awesome.  i can't believe the camaraderie in this community.  Next time, you're down here, Anthony, I would love to meet up.

Large Dachshund posted:

Hey, Anthony,

thanks for the kind gesture!  ironically, on Saturday, i'm gonna be in Hawaiian Gardens to have "Ella" get her 1000k oil change.  I was hoping I might get some insights before i checked with Kirk.

This board is awesome.  i can't believe the camaraderie in this community.  Next time, you're down here, Anthony, I would love to meet up.

I would scrap the appointment with Kirk and take the opportunity to have Anthony look at it. (No Brainer)

Never pass up a date with Tony.

I'll never forget what happened to the last guy that turned Tony down.

Large Dachshund posted:

Hey, Anthony,

thanks for the kind gesture!  ironically, on Saturday, i'm gonna be in Hawaiian Gardens to have "Ella" get her 1000k oil change.  I was hoping I might get some insights before i checked with Kirk.

This board is awesome.  i can't believe the camaraderie in this community.  Next time, you're down here, Anthony, I would love to meet up.

What they're trying to tell you is if you're having trouble with your car don't pass up a date with Anthony. I've never met the guy but from what I've heard you may even learn something, and the Speedster's oil will wait 'till next week...

Anthony,

You are recommending premium fuel in a 1600, w dual Solex's?  I guess I got all wrong.

Art

Does Anthony's (Tony's) last name begin with an 'S'?

I think Tony sells premium oil too.

Wow!  Uh, I'm going against the consensus. This is about "madness", not stupidity. 

Tony, since you come so well recommended, I'll give you a ring. 

Thanks, guys!

Art, CMC, 1641cc posted:

Anthony,

You are recommending premium fuel in a 1600, w dual Solex's?  I guess I got all wrong.

Art

everyone should be running Premium fuel in their vw regardless of engine size or carbs-single or dual

Anthony posted:

Art, CMC, 1641cc posted:

Anthony,

You are recommending premium fuel in a 1600, w dual Solex's?  I guess I got all wrong.

Art

everyone should be running Premium fuel in their vw regardless of engine size or carbs-single or dual

I've been running premium fuel plus Star Tron Enzyme treatment at every fill-up since I got my car over two years ago and I've never had any carb/fuel related problems. 

I have had one intake manifold loosen up and the car runs poorly.  It makes a chirping sound too.  Try to wiggle them to see if they are both tight.

Anthony;

Thanks you very much.  -art

I had the loose manifold thing, and it drove me bonkers for quite a while.  The gasket failed, and allowed air leakage from outside, as well as vacuum communication between the two intakes.  Ran like shyt, frankly, and no wonder. Here's what I saw when I pulled the manifold:

The proper diagnosis here was to spray the area with starter fluid while idling, and note  any change in the idle speed.  Easy and definitive.  Unless the only failure is the narrow piece of gasket between the ports (totally missing in my case).  This failure mode happens  more often than one might like, and if that is the only failure, then the starter fluid spray test likely would not work.

I had that same issue for a long time - the gasket between ports was so thin that it kept getting sucked out and then it would run crummy.  My head ports (044's) have huge oval shapes so the part between ports is really thin - less than 1/8".  Drove me nuts.

Finally, I called Jake Raby and asked him about it and what to do.  He recommended getting the mating flange on the intake manifold dressed at a machine shop to make it flat and smooth, and then use very thin film of Locktite 510 flange sealant and no gasket.   Never had a problem since.   They're a little tough to get off, but I found that using the manifold and carb as a torque arm and applying gentle, constant and increasing hand pressure at the top, after a short while you can feel them slowly let go.

Oh!  and I found that using Nylon insert Stopnuts (Nylock) on the manifold-to-head studs is a major PITA for me, mostly due to lack of access - Instead I use taller, 11mm manifold nuts with lockwashers and crank them as tight as possible using an 11mm stubby, open end wrench.  I've tried tall sockets, universal joints, 1/4" ratchets, etc, and of all of them, the stubby seems to work the best.

When it comes to intake manifold hardware, I use a aircraft style nut. Heads are 10 mm or 3/8 but with 8mm thread I'd. I have them in stainless also

I used a lot of stainless hardware on my build.

But, stainless nuts sometimes suffer galling and seize on the bolt or stud and have to be cut off. This happened to me on the bolts holding the body support bracket on top of the front beam.

I would hate to have this happen with the intake manifold nuts. It can be prevented with application of anti-seize stuff.