Engine Casing

[Bug Maniac]

When I was at the Volksworld show and watching this guy build this engine it was so interesting that only now do I have questions. He was using a case from a 1300 engine and obviously everything else to match, now lets say it was my engine and I wanted to upgrade the engine size to say 1700 what parts of the old engine could you still use, and at what point do things in general change. And then for example say you wanted to increase the engine to 2000 what would have to be done then, I hope this makes sense to someone as it confuses the F*** out of me.  

[Bruce]

I think this is a question better answered by guys over there.  I'm assuming you are starting with a factory 1300 dual port engine?  The only 1300 we got was in 1966, and with that as a start, you use nothing when you build an engine larger.
The 1300DP engines you got in your Super Beetles may have a case that's the same as a 1600, and therefore may be a good base to build any engine.

[Bug Maniac]

  The only 1300 we got was in 1966, and with that as a start, you use nothing when you build an engine larger.
.

Ok so next question is what size engine determins what case you use, and how many different types of cases are their ???Hope that makes sense  

[Bruce]

For a really mild perf engine you could start with a 1500 case, however that would be only if you are on a tight budget.  Anything else, use a 1600 case.  I think the 1300 case you got in your Super Beetles is the same as a 1600 case, meaning it has the larger oil passages and the two pressure relief valves.

[Bug Maniac]

.  Anything else, use a 1600 case.  I think the 1300 case you got in your Super Beetles is the same as a 1600 case, meaning it has the larger oil passages and the two pressure relief valves.

So say for example I was wanting to build a 2000 engine what case size would that need, and what other components for the engine would be required, no great detail required just curious.  

[Bruce]

Start with a dual relief valve'd 1600 engine case.  (maybe a 1300DP is the same??)  Then you need a 78 stroke crank and a set of 90.5mm pistons and cyls.

[Bug Maniac]

Start with a dual relief valve'd 1600 engine case.  (maybe a 1300DP is the same??)  Then you need a 78 stroke crank and a set of 90.5mm pistons and cyls.

Thanks so far Bruce, heres some more questions, what are the relief valves for??? and why are there two.
I know what a crank is but dont understand what 78 crank means etc etc can you explain???
And as for the pistons and cylinders, what do they go up in ie 92mm 94mm etc etc,
I hope you see where I am coming from???

Also what is meant by dual port?

Thanks for now

[Bruce]

Wow, you really are new at this.  Lets start with the easy stuff.  
First, the engine is in the back.............

The relief valves are part of the oil plumbing.  The cases that have 2 relief valves have superior passages compared to the earlier cases to provide better oiling.

If you imagine what motion is caused by the crank rotating, the connecting rod causes the piston to travel up and down the cylinder.  When you use the stock crank, the distance from where the piston is at the top to the bottom of the cylinder is called the stroke.  A stock 1300/1500/1600 engine has a 69mm stroke.  78mm is obviously longer.  That means that the parts of the crank where opposing rods hang on are precisely 78mm apart, center to center.

There are many different sizes of pistons for VWs.

Stock sizes I can think of for Type 1 engines right now are:  (mm)
70            985cc    (betcha didn't know the first ones had such a small engine?)
75          1131cc
77          1192cc and 1285cc
83          1493cc
85.5       1584cc

Aftermarket:

87          1641
88          1679
90          1756
90.5       1776, et. al.
92
94

And for Autocraft cases:
96.5
98
101.6

[Bug Maniac]

Yeah I am sure a engine/car virgin

Shit did you say the engine is in the back, ,no wonder I was getting through some oil.

Whats a autocraft case?? is that aftermarket.
 
So with the really big engines that some of you guys run for the strip is that still a 1600 case.

OK sir please please another question before school ends, with regards the cam shaft, when people say mild cam whats the difference between that and a normal cam, hope that is a logical step in my quest to learn something.

Thanks again Bruce.

[Bruce]

Autocraft = aftermarket

Big engines always start with a 1600cc case.

There's no such thing as a \"normal\" cam.

Cams come in various sizes from tiny (stock), to really big (full race).  When someone says a \"mild\" cam, they mean one closer to stock than full race.  Since there are no numbers associated with the phrase \"mild cam\", it doesn't mean much.

[Bug Maniac]

OK so whats the difference between a stock cam and a race cam, is it that the lobes are bigger to allow more fuel / air to be mixed in the chamber???
A question about the flywheel, Lightened and balanced does that mean they use the same flywheel and reduce the weight and I have no idea about the balancing??

Thanks tony

[Bug Maniac]

There endeth the lesson I guess  

[dannyboy]

essentially you got it right, the race oriented the cam is the bigger the lobes are. but asking about cam design is  a huge topic....
a lightened flywheel is usually a stock flywheel machined to make it lighter (or a new flywheel thats just manufactured lighter than a stock one)  

[silas]

a lightened flywheel is usually a stock flywheel machined to make it lighter (or a new flywheel thats just manufactured lighter than a stock one)

yup.

it's also easier to rotate. a lighter flywheel requires less force to turn and keep turning. a lighter flywheel reduces inertia (the resistance to motion).

balancing is required so that all the rotating mass (flywheel, crank, et al) is not turning like an egg down a hallway.

 

[Bug Maniac]

OK thanks all for your input, really think I have learned something new