The Cal-look Lounge

I've now built two very streetable engines to my -72 bay window doppelkabiner, and here are the recipes for them. I haven't dynoed the bigger motor yet but hopefully this summer after I have the time to enlarge acc.pump jets. As good and easy these were, next engine I build will be much more aggressive as these are so civilized and well-behaving...

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1641cc, 78hp / 125nm
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Basic ingredients:

- Stock AS41 engine case with two oil pressure valves.
- AA-piston's 87mm cylinder/piston set
- Stock crankshaft
- Stock connecting rods
- Stock dualport 1300 heads
- Engle W100 camshaft
- Stock about everything else also: pushrods, 1,1:1 rockers, valves, doghouse cooling, thermostat, flywheel, clutch etc.
- Small / basic equal-lenght exhaust header (not merged or any other fancier stuff). Stock heat exchangers.
- Self-built 2" exhaust with one glasspack and two bigger turbo-style mufflers in-line)
- Dual Dellorto DRLA 40's
- Aircoold.fi 043 breakerless ignition
- 30mm oil pump with spin-on filter

Machining made:
- Line-bored to 1mm / 21mm.
- Heads bored to accept 1600 cylinders
- Heads lowered for about 1mm from stock
- Crankshaft and flywheel dynamically balanced

Head porting:
- Area around intake and exhaust valves opened from their sides to blend nicely into larger cylinder walls. Not so much work here done.
- Head volume 45cc after combustion chamber port work and lowering
- Steep corner on exhaust port rounded
- Intake port just a bit cleaned, not really ported at all
- No match-porting for the manifolds

Build notes:
- Cam thrust bearing slot is too tight for the bearing, had to grind the bearing a bit to fit into cam. This was not the first time with W100, and the same bearing was OK when tried to stock or a couple of another camshafts. The machining of the bearing slot in W100 was just too tight.
- Deck height without shims was 1,6mm -> STATIC COMPRESSION RATIO = 8,5:1. That's a bit over internet suggestions as I like it to be.
- DRLA specs, tuned with narrow-band lambda which is just fine in my opinion for carb tuning:
   - 28 main venturies (e.g. "quite small")
   - .2 emulsion tubes
   - 52 idle jets (25% smaller than "stock" 60's!)
   - 130 main jets (4,6 x main vent diameter)
   - 180 aux air jets
   - X acc.pump jets, don't remember, "stock"
   - no velocity stacks this time

Usage / riding notes:
- Max ignition advance around 32 degrees with vacuum hose taken off.
- Using normal 95E gas, no pinging.
- Steady idle from around 600rpm
- Pulls from 1000rpm to around 5000rpm
- Very easy to drive, very streetable
- Picks up easily 100-105 km/h speed in normal traffic
- Really a bit boring for T2 bay :)
- Stock 200mm clutch is fine with this engine
- Can't do any burnouts in second gear - with first gear usually spins just another tire ;)
- Could be a really fine engine for a much lighter beetle (around 400kg's less weight)
- I drove this engine for about 5000km's as daily driver. Pretty much no problems whatsoever.
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1956cc, ??? hp / ??? nm
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Basic ingredients:

- Stock AS41 engine case with two oil pressure valves.
- AA-piston's 90,5mm "B" stroker cylinder/piston
- CB's 76mm 4340 crankshaft
- Stock connecting rods "stroker-clearanced" from the bottom end
- Stock dualport 1600 heads with new stainless valves and single HD springs
- Engle W100 camshaft
- Stock 1,1:1 rockers, doghouse cooling etc.
- Small / basic equal-lenght exhaust header (not merged or any other fancier stuff). Stock heat exchangers.
- Self-built 2" exhaust with one glasspack and two bigger turbo-style mufflers in-line)
- Dual Dellorto DRLA 36's
- Aircoold.fi 043 breakerless ignition
- 30mm oil pump with spin-on filter

Machining made:
- Line-bored to 2mm / 20mm (should have been 1mm/21mm but machine shop made a mistake, oh well)
- Oil galley plugs opened and cleared, NPT threads made and plugs installed
- Heads bored to accept 90,5 cylinders
- Heads lowered a bit, not sure how much though
- Crankshaft and flywheel dynamically balanced
- Engine case's cylinder holes enlargened
- Case also milled down around holes: the ridge cut down and then cut into case for about 0,5mm. This was done so that I could use non-shortened barrels and still achieve the deck height I wanted.
- Case opened inside:
   - Surprisingly large slots in the cylinder holes for connecting rod bolt clearance
   - Slots also in the top of the case
   - One camshaft bearing support cut a bit down
   - ...this is why I don't usually use "HD cam bearings" as then I would have to had cut the bearing also as the thrust type bearing's wall may touch the con rod bolt
- Some aerodynamic mods done to bearing supports "under" the cylinder holes
- Stock alu pushrods shortened for 5mm. This was actually quite easy when enough heat was used.
- A total of four head bolts grinded down as they touched rocker shafts.
- Welded an steel AN10 bunge to oil filler and aluminium one to the air cleaner lid to make a sweet black breather hose. Biltema sold these quite cheap and they weren't thankfully the red/blue colored.

Head porting:
- Area around intake and exhaust valves opened from their sides to blend nicely into larger cylinder walls.
- Head volume 55cc after combustion chamber port work and lowering
- Steep corner on exhaust port rounded and the whole port opened up a bit
- Intake port cleaned and ported a bit
- Intake match then ported to manifolds (manifolds were bigger as stock)

Build notes:
- As I used "stroker" pistons with only 76mm stroke, it was natural that this engine would be narrower than stock. That made a few problems but nothing that couldn't be solved easily.
- Stock pushrod tubes were really a tight fit but they went OK
- Engine tin fit just about perfectly!
- As with earlier engine, cam thrust bearing slot was too tight for the bearing, had to grind the bearing a bit to fit into cam. Tested this time that the W100's slot was too tight with different bearings (silverline, kolbenschmidt, mahle)
- Deck height tuned via case machining to 1,5mm -> STATIC COMPRESSION RATIO = 8,6:1. Suggestions for W100 on the net are around 7,5 - 8,3.

- DRLA 36's specs, tuned with narrow-band lambda:
   - 32 main venturies
   - .2 emulsion tubes
   - 54 idle jets (a bit over 20% smaller than "stock" 60's!)
   - 135 main jets (4,2 x main vent diameter)
   - 180 aux air jets
   - X acc.pump jets, don't remember, "stock". These are too small for this engine and have to be changed.
   - 60mm velocity stacks

Usage / riding notes:
- Same ignition and timing as with earlier 1641 engine, no pinging here also
- Steady idle from around 600rpm
- Pulls from 900rpm to around 5200rpm
- Way more grunt than in earlier 1641cc.
- Very easy to drive, very streetable
- Picks up easily 115-120 km/h speed
- Way better for T2 bay than the earlier engine :) Got a 19,5s / 106km/h quartermile.
- Short burnouts can be done with second gear. Although my rear tires are 235/65 R 16's so pretty much contact area.
- I used a Kennedy stage 1 clutch with kush-lok disc this time. It's quite light and easy on T2.
- As this stroker is narrower than stock engine, this could fit fine also in older beetle's engine bays where usually it's a tight fit around head tins and heat exchangers.
- Oil temp sender installed on behind distributor: 1/4 NPT -> 1/8 NPT adapted ordered from ebay and cheap 1/8 NPT sender installed.
- On a pretty day, oil temps creeped up to 100c when driving more than 20km's and when speed was around 85-95 km/h. Then I took off the plywood plate I have over my doppelkabiner's engine room. Oil temps dropped 10-15c even if I then picked up speed onto 105 km/h steady. It really makes difference to have more air in the engine bay even if you don't have extra oil sump or any other than stock DH cooling.
- This engine has now been daily driven, for about 2500 km's now. Only problem I noticed was that one rocker shaft spring washer was broken when I adjusted valves, maybe I should upgrade to bolt shafts...

Great summary, thanks for sharing!

Best rgs
BB

I guess 105HP/180NM
I have a similar engine ;)

Small carbs on the big engine and bigger carbs on the small engine??

Recently finished a 1915 for my dad with a 100 cam. Kadron's (tried to talk him into buying my 36's but he said his fat hands wouldn't have it ::)), ported stock valve heads, CW crank, blah blah. He likes torque, so I think it should suit him nicely.

The carbs in 1641 were from my friend when I was rebuilding my own 36's. I tried the new engine first with 30 and now 32 main venturies, the difference was well noticeable in 3500-5000rpm. Maybe additional few ponies to the top but nothing missing from the bottom. I would be very happy with 105hp/180nm as my target was 100/160 :)

One statistics more - fuel consumption was just about 10 litres / 100km on normal 80-100kmh travel. This was about the same in both engines even if the transmission and tires were the same.

Mine is 87x82. Modified 1641 pistons. W100 cam. Stock 1600 heads, same compression ratio as yours. This is the dyno result. Same result on two differnt dynos.
I now have this engine in my split buss, driven thousands of kilometers, and it`s the best engine I ever had! :)