1835 Single port build!

baked beetle · Posted: Sun May 26, 2013 9:18 pm Post subject:

If you went to dual port heads and this modified pict 34 it would be worth it. 20-30% more power if you went to something that will supply it with fuel i.e. weber 40's or kadrons and better mileage as well.
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These days people like me are hard to find- we don't give a damn what you think, about what we think. - JR
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66' His
57' Theirs
63' Hers
62' Drag Bug - Theirs 13.1 @ 101 mph (GONE)

modok · Posted: Sun May 26, 2013 9:30 pm Post subject:

The heads are 37x32 valves, some porting, 8.5-1, cam is similar to engle 100, single dellorto 40 DRLA with 29 vents.
Part of the key is the intake manifold, which is a CB center section with and larger diameter tubing (about 29mm ID VS 27 of stock manifold)
not a high revver but mucho torque and very smooth powerband, probably 10,000 miles on it by now
Interesting my vents ended up the same size as the runners, this works great with the dellorto but I don't know how well a cheap solex would run like that Shocked

Kadrons also work very well on such an engine, if it was a street engine then it would have kadrons, but it is in my "mountain buggy".

JRKman · Posted: Sun May 26, 2013 9:55 pm Post subject:

I see they have one for the carb I plan on using as well. Seems like I could get single port end pieces and use that. If I could find some single port manifolds for some ict's I could also go that route. The c35 cam I have is actually a c25 also so that actualy works out perfect.

modok · Posted: Sun May 26, 2013 9:57 pm Post subject:

type-3 fuel injection manifolds have tubing that is a good diameter AND the right bends already, just have to add the ends Wink

Of course, if you are going to fabricate stuff then perhaps use the dual ICT carbs. Could always do that later anyway, with that mild cam it will work OK with most any carb setup

JRKman · Posted: Sun May 26, 2013 10:19 pm Post subject:

There are a few people actually selling the pieces for $15-20. Do you think this is a waste of time combo or do you think it'd actually make a decent daily driver engine that's reliable?

Danwvw

Ok so here are some Ideas for single port but dual carbs!
New Just for Reference and here are some used Manifolds Weber ICT Manifolds Used. These might let you run more cam? When you think about it. What's so bad about single port heads and manifolds? After all the intake valves don't open at the same time so why not share the same intake!
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

modok

Danwvw · Posted: Mon May 27, 2013 12:44 pm Post subject:

Yeah, I was just looking at what mine does with the 284' cam, I see what your saying. But it would look like as far as flow goes, as one intake valve closes. the other. opens, so flow is maintained nicely through a single port, guess that's the whole idea of running a single carb too.
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

modok · Posted: Mon May 27, 2013 2:42 pm Post subject:

Danwvw · Posted: Mon May 27, 2013 3:29 pm Post subject:

That makes sense! These are things I have never thought about before. Looking at my cam, which I just happen to have installed in a case half here next to the computer on a very rainy day, it is easy to see how one of the intake lobes, leads the other then the intake lobes switch heads. The first cylinder on a given head to intake air/fuel has the disadvantage of having to start the air moving in its manifold again.
There must be various resonant combinations in manifolds and carbs that can capitalize on the ram effect. I think the W-100 camshaft and the stock type 1 single port manifold with a single matching dia carb is one of them. When I put a single Solex 32PBIC on that little 1585 cc Single Port the car got twice as loud. The Mid range Torque increase felt quite significant.
Solex 32PBIC 1956 Porsche 356 Carbs:

Image may have been reduced in size. Click image to view fullscreen.

_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

JRKman · Posted: Mon May 27, 2013 3:31 pm Post subject:

Can you tell me a little more about the "ram effect". Also, I have a mild scat c25 cam in my hands I plan on running. Might throw some 1.25 rockers on the intakes down the road as well.

Danwvw · Posted: Mon May 27, 2013 3:46 pm Post subject:

I was thinking of running a C-25 with 1.25 rockers for a while, I think it would be easer on the valve train than the W-100, Be sure to use larger Push Rod Tubes when you run the ratio rockers. I just order these: CB-1565 Racing Push Rod Tubes just in case I put on ratio rockers in the future.
Scat C-25. Looks like the C-25 is good for 8 to 1 compression ratio and with the 1.25 rockers it's going to be between the W-100 and W-110 camshaft.
But I think your going to need to increase valve size and manifold size if you run the 94mm Piston & Cylinders. The thing about increasing valve and manifold size is, well as I am understanding it, it will decrease ram effect.
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

JRKman · Posted: Mon May 27, 2013 3:58 pm Post subject:

I think I'll end up making the venturi of the 34 pict the same diameter as the manifold tubing.

This one is slightly larger for more flow: http://www.cbperformance.com/ProductDetails.asp?ProductCode=3151

I might be able to hog out the singleport end pieces as well. We'll see once I get them.

Danwvw · Posted: Mon May 27, 2013 4:17 pm Post subject:

The thing to do here is to keep this blog going and get more information out of the people that have actually played around with 94 mm pistons on a single port.
The link to the first photo with some very useful info.
My favorite looking single manifolds are ones like these:

or these:

_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

JRKman · Posted: Mon May 27, 2013 6:12 pm Post subject:

Those manifolds are for double barrel single carbs which I'm sure would be overkill for single port heads. Maybe I'm wrong idk

Danwvw · Posted: Mon May 27, 2013 6:31 pm Post subject:

Yeah I know, But they look nice! The problem I see with 94 mm p&c's is that they can't be filled above some RPM perhaps (3600) with SP heads. If you run a big carb and a big venturi the smallest point in the system is going to be the heads and the valves. You want it to be the Venturi, I've been reading and take a 35.5 mm intake valve for example, it should be used with a 32 mm or even smaller venturi. And the intake manifold either needs to match the heads or be even smaller to keep the Fuel/Air mix moving fast for the ram effect.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

modok · Posted: Mon May 27, 2013 7:54 pm Post subject:

JRKman · Posted: Mon May 27, 2013 8:27 pm Post subject:

If its all in by 4000 rpm that wouldnt make a difference to me. I never cruise at any speeds faster than 3200 rpm and i dont ever shift later than 4000 rpms. Plus with the stock crank I dont dar rev it higher anyways. Seems perfectly acceptable to me to not have an power past that point.

Quokka42 · Posted: Mon May 27, 2013 9:36 pm Post subject:

With dual carbs and a little port work the engine can easily rev past 4000rpm in a single port 1904. Trying to put enough cam in to make it work with a single carb becomes a problem though, as you tend to be trying to time the engine for revs it can't achieve.
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There has only ever been one man who was perfect, and they nailed Him to a cross.


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1835 Single port build!
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