Single Port VS Dual Port

[dbtcj07]

so my main question is, what the difference between the two.
also how can you tell by looking at the block if its a single port or a dual port.
What are the positives and negatives of either one.
Also what the difference between a long block and a short block. i currently own a short block but was thinking of buying a long block engine and rebuilding the long block.
If i were to go this route would i have to buy a new crankshaft, or cylinder heads, or would i have to change anything at all.
What are the positives and negatives of either one.
ive been trying to do research on it online and through the samba but cant find it. i know i saw a topic similar to this a while back, while i was browsing but i just cant find it or anything similar to it.
thx for the help

[jgarcia86]

I can't help you. But I did log on today to search specifically for this topic, so thanks and I hope we get some responses.

[codeMechanic]

dual/single port refers to the intake ports on the heads, these vary a lot in cc size

long block means it has barrels and heads installed
short block doesn't

if you buy a long block all you would have to get for it is all the bolt-ons like fuel pump, carb , gernerator, fan, dist. etc etc.
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[corvette6698512]

Found this picture in the gallery.

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'65 riviera bus

[GB2S]

What is your application? Stock or something bigger? If it's just a family cruiser, it really doesn't matter.

Geoff

[Culito]

Single ports do offer a tad more torque.
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[Sid Vicious]

Single ports are also WAYYYYY easier to work on. I don't have to do Yoga and pray to get spark plugs out.

[jgarcia86]

[Eric&Barb]

Really you need to figure out what you want and more importantly need first!!
A 1600 will not get the MPG that a 1300 can, but of course neither of those will have the drag race ability of a 2000! Then again the latter can certainly suck your wallet dry in both parts and MPG if you do not earn the big bucks.


Personally very happy with a 40 HP 1200 engine in the type 1s.
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[corvette6698512]

Singleports are awesome in a daily driver. I have a unknown displacement singleport in my '67(case says its the original '66 1300 for my car) and it produced 44.6hp and 84ft/lbs on the dyno. Gets 35-38 mpg and just runs awesome. I don't think i have ever had a dual port run as good as my singleport.
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garage:
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'65 riviera bus

[bill may]

[VOLKSWAGNUT]

Good large single port heads, in my opinion, get very little credit. They are very reliable, crack way less often, and have decent street power potential. I try to use single port heads whenever I can, add an Engle 100 cam and it comes to life even with a stock carb.
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Usually and often edited

[bnam]

They can be distinguished from each other by the intake manifold. The SP has a on piece manifold while the DP manifold is made up of 3 parts that are joined together with rubber boots and clamps.

[Shadd]

There are many more facets to an aircooled VW engine than most people realize. The factory was constantly making upgrades, not large noticeable changes but small evolutionary ones. And they do have consequence. If you dissected the majority of existing VW engines you would see that they are Frankensteins. With mismatched parts from many different years. So the trick is to match the best parts for your application.
Follow the advice given above to first decide what you want out of the engine, what you need, and what you can afford. This will dictate which case to use. 1200, 1300, 1500, and 1600. 1200=40 horse; its a great reliable little motor for the vintage enthusiast who is not concerned with all out horsepower. In my opinion 1300, 1500 and some early 1600 cases should only used if they were the original engine to the car and you are keeping them close to stock. They fall short in one critical area, oiling. They were fitted with a single relief oiling system. After 1969 the 1600 cases got a dual relief oiling system. If you are building a 1600 dual port or looking to modify, this is where you will want to start. Essentially this is your "short block." which is an assembled case with pistons and cylinders attached. If you bolted on the heads and valve train it would be a "long block" The benefits of dual port heads are few on a stock 1600. 3-4 hp coupled with better gearing means you can cruise a little faster on the highway but the benefit really comes as room to grow. You can increase displacement and install a larger cam. You can successfully run a 1776 with an otherwise stock intake system and find quite a few more hp.
Basically if you find beauty in simplicity and are perfectly happy with the limitations then single port heads will be fine. If your more performance oriented and your planning to squeeze out every last h.p. then the dual port is the path for you. Sorry about the rant

[Zundfolge1432]

Looking at the block tells you nothing about whats inside as was mentioned earlier parts from various years can be matched or mismatched to build an engine.... The only advantage of using dual port heads`is potential for performance upgrades as they will flow more air, but building a stock engine say a 1600 we use a late case say AE or AK or AB or AS anything preferably built after late 1973 with 8mm studs and dual relief ...Find a good pair of single port heads, use a stock dished cam w/ matching 26mm oil pump, keep the compression reasonable, use the doghouse cooler w/ matching tin and fan , be sure to locate and install all the sheetmetal including the thermostat and last but not least balance the lower end ( DO NOT SKIP THIS STEP AS IT WILL PAY FOR ITSELF IN SMOOTHNESS AND RELIABILITY) Using this combination of parts will make a reliable engine ....... To the extreme we built a 1915 single port using a stock carb and a stock single tip bus exhaust. As you can imagine it was choked down and a simple switch to single pack header and carb jetting worked wonders, low end torque was all there till about 3k RPM, the little carb acted as a governor, Best wishes

Jim-

[Matthew]

[spiderjames]

Everyone has their opinions on what works best for them, usually based on experience. If I am building a high performance motor I go for a later dual relief case with doghouse setup, dual port heads etc... For a stock driver I prefer a single port with a single relief case non doghouse oil cooler for simplicity. I have experienced no discernable longevity issues between the small oil pumps and the larger ones with the dished camshaft.

Although I am running all 1600 single ports right now i really feel that a 40 hp is the easiest to work on when doing routine maintenence. everything is easy to reach and the manifold angle to the heads makes it easiest to reach when fooling with the manifold. They always seemed to have less manifold leaks. Later I plan on building a good vintage speed 40hp for my beetle (volksrod).
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[rustyblue]

I just posted a number of questions about my engine, and one of them was about the strange intake setup, with a single-port manifold adapted to the dual-port heads. There seems to be a lot of knowledge on this thread.

Please take a look, I'd appreciate the help:

http://www.thesamba.com/vw/forum/viewtopic.php?t=386252

[bajababy]

ok ive got a stock 1600 single port from my 1968 standerd bug and i was wandering what all i could do so that i could get more horses out of it with uot spending to much money and not goting over board with it???