Rebuilding a CA code 1.7 into something better?

[Benno]

Hi there,

I just got my 1972 1300cc Beetle back from welding and painting and I’m intending to replace the original engine with something sportier.

I’ve gotten a hold of a type 4 CA 1.7 long block. It apparently runs but it’s a bit smoky and apart from that doesn’t have much in the way of history.

The reason I picked this up is because I want to learn how to strip and rebuild air-cooled engines and in my opinion there’s no better way than getting something intact to dismantle. That way you get to see how things are put together, rather than starting from a pile of parts and an empty case. Plus, this happened to be around at the time and was cheap. I also got hold of the Jake Raby type 4 engine DVD’s for reference.

So, the question is, do I sack the engine off and go type 1 or stick with it and go type 4? If I’m going type 4 what would be the best route to take to get to 150-175hp? I accept that there will be a need to spend (cooling, exhaust, heads), however if its planned right with a clear goal some the re-buying could hopefully be avoided.

I assume the first step would have been to rebuild as stock and as cheaply as possible to check that its worth hanging onto. If its good, then start looking at making it bigger/better.

Thanks

[cal 67]

You have a budget in-mind? The headwork is going to be the single most expensive part of the build. 120HP doesn't need much, but 150 requires port and chamber work by a skilled head porter.

Some of the easier mods to accelerate faster are flywheel lightening, using lighter H-beam con rods, and lighter pistons than stock. Using 42x36 valves with a ~85% port-to-valve size, and 75% INT/EX ratio should get you there. Run a tight .040" deck and high compression for whatever cam you'll run. For a 71x96mm engine, you'll probably need a powerband of around 6500 rpm to make 150hp, so pick your cam accordingly and learn about dynamic compression. With the Web 86B for example, you'll need around 10-10.5:1 compression and 91 octane fuel. Lots to learn. Just remember, keep it light and make compression high.

[Benno]

Thank you. I'm assuming you based that on maintaining a 1700cc capacity? how about upping the stroke/bore, does that make things more easily achievable?

I've not thought about maximum budget yet but have a fair idea of major component costs so I'm not underestimating what may be required. I'm trying to figure out at what point does the spend go crazy in relation to the returns, I would assume there is a cross over point at some stage.

I just found another thread stating that 2056cc is a good bang for buck combination. Maybe 150hp is stretching it a little as I don't have benchmark to go off. I don't see the point in building something too small, otherwise i may as well stick with stock.

[cal 67]

Yeah, that's the 96x71 engine. For whatever combo you choose, headwork still still be at the top of the list, as far as priorities. Price/returns is all relative. It depends on the person, and how much they value the gains. My upcoming T4 project would be considered extreme by most, but for me, it's absolutely fine. Also 6500 rpm is not extreme by anyone's means. In the Type 1 world, that is very mild for large engines.

[Clatter]

Check the build in my sig?
Using mostly good stock parts scan get you a motor of far better quality than aftermarket China stuff..

[Benno]

Thanks guys, I'm still reading around various threads trying to pick out relevant bits of information.

[Ephry73]

Love to see progress on this build.

I got the type 4 bug back. Will be playing around with a 1700’cammed and high cr as well better ignition.


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