Our Beetle 1600 Twin port is getting tired. It has done 50K miles since we got it, and that was unknown second hand condition.
We don't want to race, but above standard would be nice.
If we can keep the 34 PICT/3 carb and the SVDA distributor, that is ideal, as they are rebuilt already. It will cost the same to have 1640 barrels and pistons. 1776 may be a bit much for the stock carby, and need a little extra machining.
What about a slight cam or ratio rockers?
I know it all goes together in an engine build, but I just want to see what the most an original 34 PICT/3 carbied rebuild can do, even if it is 10% above original power.

You won't have any trouble at all tuning the 34 pict to a 1776 a stockish 1915 will also run on a 34.
1641s are said to have over heating issues due to thin walled cylinders.
I also have heard you can fit a sub motor in there ? 8)

Mitchell

I stock carb and manifold can still make more power. Upgrade the exhaust and rockers. heads etc...there's a million combos out there, some better than others.
Personally I have no problems with 87mm 1641 as a slip in kit. One of my engines back in the 90's running Kadrons (not my carb of choice) out performed and out lived a similar 1915 built by a very reputable VW Engine specialist.
I'd actually be tempted to leave your engine together if it's still going strong. Just do some external improvements. If a full freshen is in order, the budget goes way up and you need the upgraded stuff anyway.
So the question is how tired and is the bottom end also sad.

Have you done a compression test on it?
I've seen stock carbs used on 1916s, but they are only good for torque not power, vws by nature are very undercarbed and it will always be the part holding it back.

You will get much better value bolting some twin carbs and a header to a stock 1600 for say 20-25% increase over splitting it for cam and a 55cc capacity increase which may only give 10-15%.

No. 3 was down 15psi about 4 years ago, and it is sluggish and using about 1 litre of oil every 500 miles (per month) now. Very tired. I just want a touch more power if I am rebuilding. It is an every day 7 days a week driver, not a race car in any way.

You can get thick walled cylinders for 1641's...

Lets say I get a totally stock 1600TP fully rebuilt with no mods.

Just by adding 1640 barrels would not increase the price.
1776 barrels would add a bit cost with machining
Ratio rockers would not cost much extra

So what I am looking is long term reliability and ease of maintenance. An 'improved' stock engine, rather than a performance engine.

I've had a few of this type of engine, each to their own but personally I like them.

To give you an idea, a 1584 with home-ported stock heads (iaw the How-To book, but less grinding) with 8:1 comp, stock bottom and cam, 1.4 rockers, cheap nasty 4-1, and a 34-3 with a 28mm venturi in a '63 Beetle runs a mid-17 pretty easily, or 0-100kph in just under 10 secs, so it's a really nice improvement.
To go a bit harder, a 1641 with 9:1 comp, ported 041 heads, Engle W100 with 1.25 rockers, better 4-1 pipes, and a single BX Stromberg (with 39.6mm throttle blade compared to the Solex 34mm) on a ported stock intake and ported end-pieces, ran into the 15.7sec range but revs to 6000, and has a big hole under 3000rpm, really peaky.
It also got hot while cruising at 70mph when the temp went over mid-30s, so you might want to re-think that much compression!

Try and locate an ex-army industrial motor if you can. Its a 1600SP but they are torquey, run forever and are all german components. I have 3 of them, I picked one up recently for $200. I put one in my splitty in 1999 which has been my daily driver for most of the last 15 years and its still going strong, and thats pulling a bus with a camper interior.

If you are leaning towards a bit more pep, then a 1600TP is a better proposal.

Cheers

Steve

I have run 1776's and 1916 with a stock carb will pleasant results

For a stock carb these look interesting
http://vwparts.aircooled.net/Super-Stock-34-PICT-3-34-3-Carburetor-12V-Bocar-...

Personally I would stay away from rockers for a trouble free motor.
Too many stories about lash caps coming off and the like. Happy to be corrected but I have seen more unhappy that trouble free happy

My opinions would run to
A well built and balanced motor
1600 or 1641 or 1776
the above ACnet or similar carb
proper manifold with heat risers hooked up to a Vintage speed exhaust
head work and 8.5 to 9.0:1 CR
slight warming of cam
healthy electronic ignition
Stock filter set up with K&N filter

Ask yourself these questions? Are the main bearings ok? Do I need to split the case? Are the heads cracked? Are the valve guides worn? Are the pistons and cylinders serviceable?

Depending on what you have to work with, the easy option is a new set of big end bearings, a new set of rings (if the pistons and cylinders are serviceable), face the heads (if not cracked) and give it a valve grind, with new gaskets and seals. You would be amazed what a difference good compression makes to a 1600 twin port.

If you have to split the case, Crack test it and then tunnel bore the case. Does the crank measure up? regrind it. Are the piston and cylinders serviceable? NO? Get a set of 90.5mm and open up the case. Whilst you have the case apart, put in an scat C20 or 25/engle 100. Cam will work well with std valves and 34 pict. you can add a better exhaust when the one you have now wears out.

There are more combinations for VW engines then any other type of engine. You just need to know what you want out of your engine before you start? and what do you have to start with?
Dave

I am already assuming I will need line bore, crank grind, main and big end bearings, piston, ring and barrel sets. New heads. The small extra for the 1641 or 1776 barrels, and the 100 cam would not be too much. Or ratio rockers?

I just want to keep the rebuilt 34 Pict/3 and near new SVDA distibutor, and all the other stock parts that are working well.

Just want to see what heads are suitable, and if a Vintage speed exhaust is really nessesary, as the current one is still good.

Trying to think daily driver with about 20% improvement over the original 1600TP engine

call a 1600 as having 40HP at the wheels

my 1916 with a mild cam, stock exhaust and 34 pict dyno'd at 50

Mike VVDS had a 1600 with dual 40 IDF's that dyno'd at 50HP

so - you are in the ball park

Who is it with a 1776 at 90 something at the wheels?
Hellbugged?

You can get a 1916 that delivers 50HP as said above, or you can get downright stoooopid like JPM and make 180-odd at the tyres from a 1600 and run easy 11s.

50-60HP in a Beetle is a nice smooth little runner that keeps up with traffic easily, and peppy enough off the mark to surprise most. All the recipes above will work fine.

That is all we want to do. Have a nice sooth runner that keeps up with traffic.

my motor is a 1600 i bought for $250, bought new 1641cc barrels and pistons off Vollks, new dual port heads off Mick Motors, twin HPMX 40's and 1.25 ratio rockers.
never split the case just cleaned it and bolted the new bits on. Goes good keeps up with the traffic and can cruise at 120 all day long. Its only a stepping stone motor for me as its an upgrade from my old 1200. 2336 fool injected and turbo coming soon

Hmm it has all got me thinking. So many options.

Maybe
Don't split the case
1641 barrels and pistons
new heads
1.25 rockers
Keep the rebuilt Pict/3 and SVDA distributor
Time it to run on 95 or 98 fuel

Just so you know, it will not run on 98 fuel at the moment, as it does not have the compression to ignite the fuel properly, and goes half speed if 98 is put in it. It must be running on about 7:1 ratio at the moment

What is the end play on the crank like?

^ I was told from my VW mechanic, that it should be about 6 cigarette papers thick of end play?

.005" / .08mm is about what you want

Just waste of time doing top end if bottom end shagged

.005" is about .125mm

I suppose the end float is one of the main factors in regards to whether the bottom end needs rebuilding.

Oooop - brain not working

40 thou to a mm so am 1/8 of a mm

No point building a motor if the crank is moving back and forth

The problem with main bearings is you can not see the centre main. Thats where most of the wear is.
If the crankshaft is flopping around in the worn bearings that are moving around in a flogged out case, the bottom end won't last long.
Retention the centre main bolts on the case. If they are loose, the centre main is moving around.
After you retention the centre main bolts check the crank still spins. If it doesn't you need to split the case for sure.
If the motor is still running, when you first start it up in the morning, if the main bearings are worn,
you will hear a 'rumble' for the first 2-3 seconds until you get oil pressure.
Dave

Great advice from David ^^

Does anyone have a single progressive Weber fitted they can report on?

This is my setup, but haven't had it running nicely yet.

Nice set up but that's not a single progressive Weber.
Have you got a massive flat spot and stumbling on acceleration?

Oh sorry.
We've had it running, and accelerates nicely, but having trouble to get it to idle nicely..

you would be surprised how much better a recondition 1600 goes compared to a old tired one.
The Newer parts these days, electronic ignition, better grade oils, all make it a bit better.
They are real nice to drive in traffic and pull up hills no prob .