1700, 1800, 2000 - What do you prefer? Why?

[Wasted youth]

If this has been discussed (or argued, massive thread derailment, etc.) just let me know and I'll delete it.

I have three spare engines. One 1700 and two 2.0 liter engines. All three turn over by hand; all are considered high mileage cores. The 1700 was torn down for rebuild, but project stalled. Everything for that is labeled and boxed.

I understand there is a preference of the 1800 engine over the 2000, but am not exactly clear why. I have read the exhaust valves are bigger in the 1800 heads than the 2000, but cannot verify that today. I also understand there is a preference for the shorter (?) rods of the 11.7/1.8 over the 2.0, but I do not understand why that is better.

If you were to build up an engine for a bus using any/all of these, which path would you take and why?

FWIW my goal is to build up an engine for our 1973 bus. It is currently a daily driver with a 1700 mated to the Type 3 autotrans. We plan to use the air conditioning system by updating it with all new components and I also want to make the engine with California emissions. I understand that is not a requirement, but I believe in the emissions system and like clean air.

I would like to make this engine operable with Vanagon engine management controls and marry it to a 090 autotrans.

That being said, I am leaning towards the 2.0, but would like some input.

Or thrashing. Or thread wreckage. Either way... whatever...

[timvw7476]

1800 does rev higher in stock form, has a little more top end in every gear
compared to a 2.0L.
But that applies to operating a four speed manual trans, I would think the 2.0L
and it's small torque bump would come in real handy powering an A/C compressor & automatic transmission, which are both notorious power
gobblers.
I have no experience running a 1700.
People say they rev real nice but again that really helps with a 4 speed manual..

[airschooled]

For your setup, I would want a totally stock, hydraulic lifter, balanced and blueprinted 2.0L with mostly stock fuel injection. I think the lower horsepower peak and increased torque of the 2.0 will work nicely with the daily driver aspects of your bus. With a torque converter AND an air conditioner compressor, you’ll want a way to increase your idle speed electronically based on load. Does the later vanagon system have this ability?

Robbie
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[Wasted youth]

[danfromsyr]

you could add a VW spec idle solenoid to open and bypass a little air around the throttle plate when the AC is triggered.
VW used this on CIS injected cars and the 83-85 Digijet
page 80 in this vanagon fuel systems manual
https://www.thesamba.com/vw/archives/manuals/vanag...ystems.pdf
it essentially acts like you are holding your foot on the throttle a little bit,

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[Wasted youth]

Nice! That might work perfectly. Thanks for the tip.

[Amskeptic]

[raygreenwood]

Just be sure which type of idle air stabilizer you are thinking of.

The main differences in "digi-jet" (early vanagon) and digi-fant (later Vanagon and a whole lot of Golfs and other cars).....is that they both have ignition control in teh ECU...but digifant still used vacuum and/or mechanical at the distributor to control advance. Some still had points and some very early digijet systems went to hall effect. All digifant were hall effect completely controlled by ECU

But...the idle air stabilizer on the digi-jet engines used a digital module between distributor and the ignition control module to control idle stabilization.

The later digifant used an idle control air valve...basically a fancy version of an AAR. It was controlled partly by pulse width from a control module.

But...my impression of it was that it only really had a narrow time frame within which it was controlling anything...mainly start up and warm up. Yes...its pulse width controlled...but only seemed to respond to the pulsewidth settings that were in play during warm up. After that it always seemed to be either fully closed or at a set point. Like I said...pretty much an electronically controlled AAR.

One thing I always meant to do but never got the chance...was take the idle air control valve from my 90 model cabrio...and see if it could be actuated by a potentiometer signal...to be controlled from the dash like a choke. Thought it could be a good replacement for type 4 AAR. Ray

[Wasted youth]

Thanks guys.

FWIW... I plan on using the same system that is in my air cooled 1981 Vanagon which has California emissions with Hall effect and the digital idle stabilizer using part number 251906083

This one: http://www.busdepot.com/251906083

The engine management system also uses an O2 sensor. My spare engine has a York compressor, but I do not have the ECU for that engine. When we upgrade the air conditioning, we will upgrade the compressor to the Sanden SD508.