Building a 74 mm Stroke by 88 mm bore with 042 or 044 heads?

[Saul Koll]

Cool stuff!

[Danwvw]

Oct 3 2021 Still Running, No problems at all. 27217 miles on the engine so far.
UTube link to Fuel Pump Safety override switch: https://youtu.be/HzBVho5b-Xc

[Danwvw]

The 74mm X 88mm Engine is still running perfectly.
Made my own Turn Signal Relay: Running Stock Turn Lamps etc LED Indicators though. Works Great!
This is my own design feel free to use it!

Prototype 2:

A Trench Mosfet is gated at 19 Volts to work as a solid state relay between +12-14 VDC and the Turn and Emergency Flasher Lamps to ground.

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

[Danwvw]

[calvinater]

Are you using a doghouse shroud? Any fitment issues with the manifolds/ carbs?
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"Albatross"!

[Danwvw]

Built in 2013:
Miles on the engine as of Feb. 4th 2020 is 24637 and STILL GOING!
1800cc Type 1 Engine Build Sheet: Special thanks to everyone here on the Samba that participated.
Machine Work: Local shops,
Misc: Parts and service: Bug Germinators, North Bend OR and 2nd Street Foreign Car Service Coos Bay Oregon.
Engine Case: 1971 VW Bus AS-41 Magnesium, Inserted for 10mm studs, Full Flow oil return and block off, Stock 1600 Cylinder Openings.
88mm Bore, 74mm Stroke,
Dual 36 DRLA Dellorto Carburetors, May 2017 Removed and cleaned new gaskets and orings clean and lube bearings
Cam Web-Cam 163 with 284' 250' at .050" and .422" Valve Lift with 1.1:1 Rockers, Web-Cam 163 Profile
Heads German 113 Dual Port cut for 90.5mm cylinders (with step), 3 angle valve job and port matched using stock VW 35.5mm(used german intake) x32mm(new exhaust valves) with new Single HD Valve Springs,
Solid Rocker shaft from CB-Performance, 1.1:1 Ratio stock VW rockers,
CB-Performance Elephant Feet Adjusters,
Bug Pack Aluminum Push Rods (Stock Length)
Push Rod Tubes are CB Performance 1565 Large ID Racing,
Lifters are cb-performance 1537 UltraLightWeight 28mm,
Valves Springs Single HD Racing. Valve guides Stock VW
CR 8.5:1
Rods 5.325" H Beam Racing Rods from Aircooled.Net,
Crankshaft: 74mm Counterweighted 4340 Forged from Aircooled.Net,
Piston and Cylinders 88mm AA ThickWall from Aircooled.Net
Flywheel Stock VW Surfaced and drilled for 8 dowels,
Pressure Plate: Sachs 200mm Porsche style 1971 and up CB-1324, Clutch is starting to slip on take-offs unless babied
Throw Bearing OEM,
Disc Kush Lock Solid,
Scat Aluminum degree pulley, Everything Balanced by part and Dynamically with clutch and flywheel mounted to the crank,
Electric 12 volt Fuel Pump: 3 1/2 lb Rotary CB-Performance 3193,
Oil Pump 26mm Schadek with Empi Steel Full Flow Cover Plate,
Oil lines and remote filter CB-Performance 1732,
Oil Filter VW Rabbit Type Mann W719/5 Others I have tried include WIX 51342, HASTINGS LF493F, WIX 51515, (ECOGARD Synthetic oil filter S4670), Bosch 3400
Castrol GTX 5W30 motor oil with Lucas TB Plus Zinc Oil Additive, Mobile 1 full synthetic 0W40,
German Bosch .009 with points, Mechanical Advance Distributor set for Max advance of 33', 30',
Bosch Blue Coil,
Empi Spark Wires, New old stock Bosch Spark Wires
Spark Plugs are Bosch Super Plus WR8AC+ 14mm X 1/2", Changed twice except for #2 just once
Motorola 12 volt Alternator with Aftermarket External Regulator, I think one phase of the Alternator has burned out 02/04/2020
Intake Manifolds: CB performance off-set with hex bar linkage Linkage wore out and had to be up-dated using rocker arm parts for bearings in it. CB Performance air-cleaners.
Current Air Correction are : 1.80
Mains: 1.32 1.35
Idle: .60 tried .55 Went back to .60
Venturi: 30mm
Extractor, BugPack 4 into 1 1 1/2" single Empi Muffler", Stock Heater boxes New Muffler Feb 2018
New Battery Sept 2019

Link

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

[Danwvw]

Installed it finally, and it works!
Also rewired the fuel pump and all to run directly off the battery.
Updated Schematic:

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

[Danwvw]

My Dell 36's are sometimes leaking gas through overnight and the engine will be hydro locked with gas the next morning, one time it filled the crankcase with gas. This problem started about a year ago and I got it cleared up by changing a float but the problem has returned.
The CB-Performance 3 psi Rotary Electric fuel pump does not shut-off the gas from the tank when stopped so I have an Idea here to solve the problem.
Cheap $10 Solenoid Valve from eBay:

Current Limit circuit to keep the valve from overheating during driving.

Prototype:

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

[Brian_e]

Back cutting the intakes is very common and can be done by most any engine machine shop with a valve refacer. It takes about 1min. per valve.

I have also seen guys chuck the valve stem in a spinning drill press and use a dremel tool with a steady hand.

You can gain more combustion volume by dishing the pistons, but it's hard to get much more then 7cc's safely, and that's on a 92mm bore. With some proper valve unshrouding you might be able to gain another 2cc but it's a pain in the ass to do.

Brian

[AlteWagen]

Ive done it on my 1699. I set up zero cylinder deck height and let the step provide the .045 quench area which provided 9.2:1 compression. On the first refresh I replaced the cylinders and noticed a length difference of .020. With the shims I had (.090 and .010) I removed the .010 shim which left the piston down in the hole .010. Even that small amount caused the engine to run a tad warmer and I lost some MPG.

Next go around Ill adjust DH with rod lenth/shims and run heads with no step or have them removed from the 043 heads when rebuilt.
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Grapes of Wrath $200 Engine Rebuild
Official Dual Carb Thread
Cylinder Head Quick Reference Sheet

[bugguy1967]

[Danwvw]

So my method here is based on 1 TableSpoon being 14.787cc and 1 Quarter being .8092595cc
3X14.787=44.36cc
13X.8092595=10.5cc Note Error somewhere as 85.5mm dia by .047" Height calculates to be only 6.8cc's
For these VW heads we are evaluating, I got a chamber volume of exactly 3 tablespoons or 44.36cc and to the top of the step, I measured 54.88cc Total.
http://cbperformance.com/v/enginecalc.html
So 44.36cc chamber would be a 9.4 CR even using .060" Deck with the step out. So I think I will forget this whole step thing for now.
But thanks for all the input. Still looking for more info. on undercutting the intake valves as per "Brian" here: Quick easy 18.4cfm gain for old Single port heads.



L3 Heads without the step are shown in the photo 53.26cc:

Replacement head for Evaluating my measurement 54.88cc:

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

[Frank Bassman]

Sorry about the minor hijack, but since we are on the topic now is the time to ask!

For a stock 1600 where the cam and all is the same, if one wanted one could actually run the piston into the step with no adverse effects? The piston will reliably clear the step with the stock 85.45 mm bore? I'm putting together a stock 1600 with a few tricks, and my heads have the steps too. I don't see the need to change heads since these are fine, and I DO have the means to mill the cylinders shorter to achieve a desired deck height.

Thanks in advance

-Frank

[sled]

What’s really going on here is you have a huge “squish” or “quench” gap. All the deck terminology aside, you want to have the piston be close to the quench pad of the head at TDC. That part you understand? The step in the heads is currently preventing this. If you cut the step out completely and run shims, you will need to run way too much shim stack to keep the compression managabale. What we are saying is the chambers on those heads are too small for your application and can not be set up for proper squish. Proper squish goes a lot further than you think for over-all engine performance.

While you may have gotten a decent deal on those heads, you’d be MUCH better off selling them and buying a properly suited set of heads.

As mentioned previously, a set of new Tims heads, like the super stockers cut to your desired chamber volume for .040-.045 deck (squish) would be the ticket.
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drive your split.

[Danwvw]

Your help is much appreciated. All of you guys! Got me thinking about it again. I will get the measurements and post. I suppose my machinist could just cut the step to like what 88.25mm ID to flat? I guess that's the Nice thing about L3 heads, they setup nicely cc wise with the 88's.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[[email protected]]

I can't tell you how many engines I have torn down that had pistons bigger than the step ID. That results in a $)*#)& up engine, since it has to have .040" clearance to the step, but the actual deck is that clearance PLUS the step height. So, poor combustion.

The step is somewhat tolerable with stock size pistons, since the piston is smaller than the step, and you can set the actual deck height. But as you found out, on those heads the chambers are often too small, and you wind up with a lame performer.

It's best to CC the heads WITHOUT the step volume, to find out if the heads are usable when (not if) the step is cut out.

I am just trying to help.
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It's just advice, do whatever you want with it!

Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net

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[modok]

I can trim the piston to clear the step, or trim the step to clear the piston. I think it's easy. but, we see this problem SO often, i guess too confusing for anybody to figure out.

[Danwvw]

Well, John as I understand it you want me to have a 30 to 40 thou deck right? Not what .022"deck measurement + .047" step measurement = .069" You know the thick wall 88's almost cover the step.
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[[email protected]]

it's not a volume issue, it's a safe distance and combustion quality issue.
_________________
It's just advice, do whatever you want with it!

Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net

"Like" our Facebook page at
http://www.facebook.com/vwpartsaircoolednet
and get a 5% off code for use on one order for VW Parts ON OUR PARTS STORE WEBSITE, vwparts.aircooled.net

[Danwvw]

Well, When I checked cc's I filled the head to the rim of the step so it at least cc wise does not count as part of the Deck variable of the calculation. Therefore cylinder top to the piston was used as the Deck Variable. I will calculate it the other way but the only difference in volume is going to be the little bit of the step that is inside the chamber.
Yeah, Brian, I was disappointed to see the Knurl job but that's how my guy did it. It's probably ok because the guides were pretty good. Intake guides didn't need anything. I did not ask for a 3 angle valve job as I did last time on the original heads.
What should I do about the back cut on the intakes? Just the intakes get back cut, right?
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1960 Beetle And 1679cc DP W-100 & Dual Zeniths!