1.7 case mods

[rich]

I have never seen the 1.8 and 2.0 cases apart. Can the windage tray be retro fitted to a 1.7 case? What other case differences are there? If the 1.7 case is bored to accept the 2.0 cyl., can a guy use a 2.0 bus crank and rods to convert a 1.7 to a 2.0? I heard the crank is not as strong. If that is so, whats the difference? (case vs forged?)
I have a bus 2.0 crank and rods i've thought about fitting into my 1.7 case. Can a guy use 1.7 heads and injection With this combo?
(After boring to fit the over size cyl.of course) What would be the performance gain if any? Any and all imput is welcome.
Thanks

[JP Noonan]

Without beating it into everyone's head....
Buy Tom Wilson's book How to rebuild VW aircooled engines. Ask Pelican if they have it (they sell Haynes manuals), I got mine before PP was around through Barnes&Noble online.

The 2.0L P/C's will fit right into the 1.7L case, the hole (spigot bore) is the same on all of them. Either 1.8L, 2.0L heads or "flycut" 1.7L heads can be used. The vavles on 1.7L and 2.0L bus heads are very small so at least use 1.8L 914 heads (not the same as 1.8L VW heads, the 914 heads have bigger vavles). I have heard that 2.0L bus cranks are not heat treated or "hardened", and when I had mine ground down to the first undersize (-.25mm) the machinest said it was not hardened. This isn't really a problem, it only shortens the life of the crank, you get what you pay for. The 1.7L cases I've seen don't have the "bosses" neccesary to put in a windage tray, the case is cast different. Maybe find a blown 1.8L 914 motor use the case and heads and chuck the crank. The other thing is the bus flywhell will not work (I've heard people have used them with modification but that's beyond me) so you will need to have the 1.7L flywheel balanced with the 2.0L crank rods and pistons.
For comparision
1.7L W,EA 80hp (8.2:1 CR)
1.7L EB 76hp (7.6:1 CR)
1.8L EC 76hp (or 72hp, I don't remember)
2.0L GA 100hp (euro, 8.0:1 CR)
2.0L GB 95hp (USA)
2.0L GC 88HP (75-76 all kinds of emissions BS)

Forgot to mention that the pushrods may be longer, I haven't got that far in my rebuild yet. The reason is the 5mm longer stroke means the jugs are also longer so I "guess" the pushrods must be longer.

[This message has been edited by JP Noonan.]

[rich]

Thanks JP, Does that mean a 2.0 big bore P&C set will fit the 1.7 caes as well? Well Wayne,do you have the book? How about a part # cross reference for the push rod question? Anyone out there know the answer to that one? Does anyone know if the cylinders are measurably longer on the 2.0. (or is it a wrist pin thing?)My reason for asking is, that may require using the 2.0 push rod tubes. My haynes and lash international don't seem to specify.
Thanks

[Dave at Pelican Parts]

The way they increased the stroke was to make the rod bearing journals smaller, and offset them toward the outside. In effect, they ground away the part of the crank that the rod rides on that "faces" the crank main bearings. This moves the center of rotation of the rod on the crank outward. A 2.5mm offset results in a 5mm increase in stroke.

They didn't increase the overall dimensions of anything that I know of. If you check the 914 catalog section of this page (Cylinder Head page), you'll find one listing for "push rods, 1970-1976 914-4 ALL". One length, all 914s.

The different-length pushrods generally come into play when you're monkeying around with valve train geometry.

So, yes. You can build your 1.7 out to 2.0 if you desire. I personally would start with a later 1.7 case (I think at least some of them came with the "windage tray" built in) or a 1.8 or 2.0 case.

Your car, your motor--your money.

--DD

[Wayne 962]

Yup, we have that book. You can even see a sample page from it in our technical documentation section of the 914 on-line catalog.

As for installing all this 2.0L stuff into a 1.7L case, why not just buy the 2.0L case? We have a number of them sitting around here at the shop, and I believe that our current price here is about $110. Much less headache than machining your 1.7 case, and you may indeed end up with a stronger motor in the long run as well...

Gee, this fast connection sure is good...

-Wayne