Engine building, Looking for suggestions... Options

[Hine62]

I've read "a lot" about the type 4, but still have some questions. My father worked on these engines when they where new, so he's teaching me how. I'm looking to build an type 4 engine with these parameters:

1.8l case
96mm cylinders
78mm crank

Some questions:
1. If the stroke of the crank is increased, how does this affect the cylinders?

Are the cylinders shimmed to the new stroke?
Does someone make "78mm" cylinders"?
Are the pistons/rods shorter/longer to make up the difference?

2. Should I look for a 2.0l case? From what I've read the cylinders fit in the 1.8L case. Are there any other benefits to the 2.0L case?

3. If I decide on 103mm cylinders, where should I send the case? (It will need to be machined for the crank anyway. Unless I decide to take a grinder to it (IMG:style_emoticons/default/biggrin.gif) )

4. There are a lot of 'kits' to buy. Should I go with a kit or buy the parts separately? One advantage is kits come with gaskets, etc...

I have more questions, but this will get me started. Thanks

[Hine62]

Thanks Dave!

Could you explain the reduced base-circle cam? I assume the cam doesn't open the valve as far, but must keep the valve open longer to compensate lack of height. There is also the option to go with chevy or vw journals which would change the thickness of the rod end.

[Dave_Darling]

Could you explain the reduced base-circle cam?

A cam is basically a circle with a bump on it. The lifter (or follower) will ride along the circle, and then get pushed outward by the bump, then ride along the back side of the bump to the circle again.

The circle is the "base circle". So a reduced base-circle cam (-shaft) is made with a smaller circle. The bump is still the same, so the amount of lift and duration can be the same, but the piece takes up physically less space. That allows for more room for the rods and rod bolts.

It also means there is less surface total for the cam, which may speed up wear. It also means that the lifters have to stick out of their bores a little further, which I think also leads to them rocking in the bores slightly, which also increases wear.

--DD