Single Port Intake Manifold Questions

[StefansBus]

Hi guys,

I have done a quick search but not found answers. Apologies if I have missed them.

After fitting a new stock exhaust on which the preheat plumbing didn't quite line up requiring some brute force during install, I now have an intake leak around the right cylinder head intake area. I have the crush metal ring gaskets and will attempt the fix in the next few days. Hoping to be able to replace the gasket without having to remove too much stuff. I also hope I don't have a cracked intake manifold.

Would it not be a good idea to modify the pre-heat pipes on the intake manifold by making a part of it on each side from flexible metal tubing? This should make installing exhausts very easy in the future, at least as far as the pre-heat is concerned.

Also, If I do have a cracked intake manifold, I was considering ordering the aftermarket three piece manifold which is similar to those used on the dual port engines. In fact the center section is a universal part for 30, 31 and 34 carbs and the end pieces are sold as either SP or DP. The thing is: The internal diameter of these is apparently larger than the stock single port manifold. Will this be detrimental to torque? Of course the intake port and valves in the heads remain unchanged as does the 30 PICT 2carb. So will the larger diameter between carb and heads make any difference at all (good or bad)? This is the kind of part I'm talking about: https://www.csp-shop.com/en/?func=detai ... tnr=12379a

Cheers

Stefan

[Pruneman99]

When you said "new stock exhaust" are you talking a German unit, or some aftermarket unit. The aftermarket exhausts are nortoriously bad when it comes to alignment of the preheat tubes. Last one I did was at least a 1/2" out. Aweful. I ended up using a torch to heat the tubes and slowly persuade them into position.

[StefansBus]

[Pruneman99]

That actually looks like a quality exhaust. Well better than most of the crap out there. The preheat tubes are actually set up to flow correctly.

If it was mine, I'd probably pull the intake and exhaust and marry them together off the engine. Maybe a bit of heat and quench to get the parts to realign, and stay that way. Hopefully this would allow you to bolt them to the engine without putting so much force on the intake to cause a leak.

Unfortunately, even with "quality" aftermarket parts, they need a bit of a work over to get them to play nice. These parts are made all over the word, by different manufacturers, with different quality control methods, and measurements.

[Pruneman99]

Oh and if these are used heads, make sure the old crush gaskets have been removed from the heads before installing new ones. Once they get crushed in there, the old gaskets look like part of the head. Many times I've seen people put new gaskets over the old, and get leaks. I usually have to us a pick, or a small screwdriver and hammer to remove the old gaskets.

[Danwvw]

Yes, probably just need to get the right muffler. The Dansk are on sale. Often the heat sink bonding on the preheat of the intake manifolds is cracked but they don't leak. Usually the intake manifolds are stopped up anyhow. ACN usually carries better quality parts and has some refurbished german intake manifolds as well as new ones. Oh, Nevermind I see your in Germany but wait that is where they are made.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[StefansBus]

Thanks guys. Coming back to the "super stock" aftermarket center section plus single port end pieces: Would they actually improve performance compared to the stock single piece single port intake manifold with everything else remaining stock? Here is a different shop that sells them: http://vwparts.aircooled.net/Super-Stock-Intake-Ma...nifold.htm

They say that some guys use them on SP engines. They mention better flow and they also mention the option of using a 34 carb instead of the stock 30 or aftermarket 30/31. Any thoughts on using this manifold on a SP engine with either the stock carb or a 34?

Thanks again

Stefan

[Danwvw]

The nice thing about the stock single port intake manifold is that it has a nice integrity also the PICT 28 and 30 carbs fit and provide good torque and the best MPG's even with a W-100 cam the single port engine in a bug and a PICT 28 can average 32 MPG. If I wanted more performance and was going to change manifolds and carbs I would go with dual carbs on the single port. You have several carbs to choose from when doing that. ACN carries the single port dual manifolds and the Weber ICT 34 carbs the EMPI Clone comes in this KIt with everything EMPI-EPC-34 or the Kadron carbs could be used. This being said I have not tried any of these combinations. Just the PICT 28, 30 Solex's on the stock single port manifold as well as a PCIB-32 Solex from a 356A that when fit to the stock single port manifold woke the 1600 single port engine up big time. Got to plug the Air correction Jet on them though. Then the Gas Milage goes down to 24 MPG.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[EVfun]

I've been searching this section for information on aftermarket replacement intake center sections (or maybe dual carbs.) I have a quality aftermarket exhaust system built with a working heat riser system that I had ceramic coated black. I have this nice fresh stock 1600 single port engine I intended to install the reproduction '73 Thing exhaust onto and then stick it in my buggy, quiet, out of the way, and should just work.

The heat risers on a clean German intake are not cooperating. I bought a replacement.The bends are ugly, but more importantly it fits the same bad way. It is not close enough to start the bolts and nuts and force it. I have pretty well concluded it is the exhaust. I think with the slip in heat riser tubes of an aftermarket intake center I could cut them a bit shorter and roll them down slightly to fit.

Who using the aftermarket center sections and what is your experience with the fit and function? I notice the aluminum heat transfer area is quite a bit shorter. Is anyone using these with single port end castings on a largely stock singleport? My goals are driveability below 4k rpm so I'm concerned with a larger stock intake.

As an alternative I'm also considering a small dual carb setup like ICTs. It isn't a cost issue, more of a driveability issue, no matter what way I go the cost shoud be under $500. It all just dressing for a stock SP long block.
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[modok]

I usually cut the flanges off and re-weld, to get them to line up.
The idea that these things will line up must be.... some kind of shared fantasy. Seems to me that it would be quite rare that they could line up correctly, change any part, ANY part of the engine, and it changed the alignment.

[Coyotemutt]

[StefansBus]

Thanks Coyotemutt. I appreciate it. The plan has changed slightly in that my engine will become a 1776 dual port with the high flow center section and a Solex 34 PICT 3 with a 28mm venturi. CR9:1, CB2239 cam, I will be running a 123 USB dizzy. The exhaust will be an Ahnendorp CustomSport. Will open separate thread for this engine at a later stage.

Stefan

[EVfun]

I have a nice Dansk 1973 VW Thing exhaust that I had ceramic coated black. My exhaust simply is not going to line up with a stock single port intake manifold and I know running a single carb without heat is not a realistic option in western Washington, even in a summer use beach buggy. I bought a new intake manifold to compare to the one I had and it puts the heat risers in the same place. I like the split look on a buggy but wanted something quiet.

Honestly, I still haven't decided between switching to dual Weber 34 ICT carbs or running a single port end castings and a manifold center with slip in heat riser tubes that I can modify to fit. My goal is drivability in an engine that will rarely, if ever, exceed 4000 rpm. Thanks for your input on the single port end casting option.
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