Designed to Scare

This post is specifically designed to scare.

Not you. Me.

This is what is known as an engine 'blueprint' or build sheet. Rather than simply slinging together parts that 'should fit' from the manufacturer, we document what the measurements SHOULD BE on all of the parts, and then ACTUALLY measure every stinking part to make sure they they are how big they say they are on the box, and have the material properties the spec says they should have. Essentially, you trust nothing. It is very time consuming to be paranoid.

Many of the engines that you buy from resellers are assembled from new components that are assumed to be 'made correctly' from the manufacturer and unfortunately, the customer winds up being the Quality Assurance department. So I'm taking the extra time to blueprint. And it scares me because the measurements drive far into the 1/1000ths of an inch range and being out of tolerance by 1/50th of an inch can mean an engine that lasts 1 lifetime or 1 minute.

The following is the specification for the Type4 engine, as well as my measurements of (update: My new VWoC case.) Original GD case specs will be left below in case I ever get the ridiculous idea that I want to rebuild another engine.

Note that my measurements will be in inches because in this benighted country, metric has yet to catch on with the good old boys.

Designation New (mm (inches) Wear Limit MINE


Crankcase bores

+ Main Bearing Bores

- Bearing 1-3 dia. 70.00-70.02 (2.7559-2.7567) 70.03 (2.7808)

- Bearing 4 dia. 50.00-50.03 (1.9685-1.9696) 50.04 (1.962)

+ Flywl seal Bore dia. 95.00-95.05 (3.7401-3.7420)

+ Fan seal Bore dia. 62.00-62.05 (2.4409-2.4428)

+ Cam bores dia. 27.50-27.52 (1.0825-1.0833) 1.083

+ Oil pump Bore dia. 70.00-70.03 (2.7559-2.7570)

+ Lifter Bores dia. 24.00-24.02 (.9448-9456) 24.05 (.9467)

Crankshaft

3 undersize grinds of

.25mm (0.00984252 aka ".010 inches")

.50mm (0.019685 aka ".020 inches")

.75mm (0.0295276 aka ".030 inches")



+ Crankshaft

- Main Journals Diameter

1-3 59.97-59.99 (2.3609-2.3617) (2.35975)

4 39.98-40.00 (1.5739-1.5748) (1.573)

- Con-rod journals Dia. 49.97-49.98 (19677-1.9681) (1.967)


Out of Spec

- #2 & #4 main journals runout 0.02 (.0008)

+ Crankshaft unbalance max. 12cmg

+ Main bearing journal out-of-round 0.03

+ Con-rod journal out-of-round 0.03


+ Crankshaft main journals

(taking housing preload into account):


- Bearings 1 & 3 radial 0.05-0.10 (.002-.004) 0.18

- Bearing 2 radial 0.03-0.09 0.17

- Bearing 4 radial 0.05-0.10 0.19

+ Crank main end play 0.02-0.07 0.15

+ Con-rod journal / Con-rod radial play:     0.1-0.4          0.7


Designation New (mm (inches) Wear Limit MINE


Crankcase bores

+ Main Bearing Bores

- Bearing 1-3 dia. 70.00-70.02 (2.7559-2.7567) 70.03 (2.7570)

- Bearing 4 dia. 50.00-50.03 (1.9685-1.9696) 50.04 (1.9700)

+ Flywl seal Bore dia. 95.00-95.05 (3.7401-3.7420)

+ Fan seal Bore dia. 62.00-62.05 (2.4409-2.4428)

+ Cam bores dia. 27.50-27.52 (1.0825-1.0833)

+ Oil pump Bore dia. 70.00-70.03 (2.7559-2.7570)

+ Lifter Bores dia. 24.00-24.02 (.9448-9456) 24.05 (.9467)

Crankshaft

3 undersize grinds of

.25mm (0.00984252 aka ".010 inches")

.50mm (0.019685 aka ".020 inches")

.75mm (0.0295276 aka ".030 inches")



+ Crankshaft

- Main Journals Diameter

1-3 59.97-59.99 (2.3609-2.3617) (2.35975)

4 39.98-40.00 (1.5739-1.5748) (1.573)

- Con-rod journals Dia. 49.97-49.98 (19677-1.9681) (1.967)


Out of Spec

- #2 & #4 main journals runout 0.02 (.0008)

+ Crankshaft unbalance max. 12cmg

+ Main bearing journal out-of-round 0.03

+ Con-rod journal out-of-round 0.03


+ Crankshaft main journals

(taking housing preload into account):


- Bearings 1 & 3 radial 0.05-0.10 (.002-.004) 0.18

- Bearing 2 radial 0.03-0.09 0.17

- Bearing 4 radial 0.05-0.10 0.19

+ Crank main end play 0.02-0.07 0.15

+ Con-rod journal / Con-rod radial play:     0.1-0.4          0.7