Camshaft Installation in a 1971 Super Beetle

snipped-for-privacy@yahoo.com escreveu:

Since you don't any idea how to improve your engine (cam and carbs) and no clue how they work, I do think that you are not ready to start right away. For a few hundred bucks you will able to rebuild it stock if you case is ok. For a performance engine you need cam crankshaft heads carb distributor a good case and a lot more.=20

Jo=E3o

Don't start with too much modifications. Anyway, if you want a little bit more power, look at this config:

- stock 1600 parts, with new bearings, piston rings.

- stock rebuilt heads ( you can do it yourself) with HD valve springs

- camshaft: webcam 218, if you have time, order the one with a smaller LC, f.i. 105°.

You put this together and then, you shoud use a dual empi 40mm carbs kit with a bosch 009. This works great (80 hp with "cleaned" heads), has power under 5000 RPM

a écrit dans le message de news: snipped-for-privacy@r2g2000cwb.googlegroups.com...

Thanks for the information, how exactly could i rebuild the heads myself? What parts do i need to get for the operation and what exactly does rebuilding the head do for performance or power? I would like to try to rebuild the heads but as i have said before, i am a beginner and would like some instructions or a website that says how. thanks.

before you dive in over your head do some research.... it will save you alot of heartache and money in the long run...start here:

You can't, unless you have a machine shop at home, set up to do headwork. You can do some of the work, if you have enough experience, but it sounds to me you don't. Otherwise you wouldn't be asking us :) Leave it to the pros, the heads are one of the most important and critical part of the engine, and easy to mess up too.

Head rebuild:

1. clean the combustion chambers of all carbon deposits. (Doable at home)

1. inspect cleaned chambers for cracks between valve seats and spark plug hole (doable at home) --> Bring cracked heads to a machine shop for welding, it will last a while but it will crack again. Sorry for the bad news. (Shop required)

2. inspect valve guides for wear - hard to determine on your own if you dont have the experience, tooling, or "feel to it". (Shop recommended)

1. inspect valves: stems for wear; measure diameter in 3 places, and inspect keeper grooves for possible "mushrooming" that would allow the keepers to move up and down. That means the valve should be replaced. Check straightness. Look for discoloration, "blue" is baaaad. Measure valve lenght, especially exhaust valves. Stretched valves are a time bomb. Inspect valve stem end for pitting or cracks or grooves. You don't want any.

2. all valves should be lapped to the seats, to make sure they seal well. If new guides were installed, the seats need to be re-cut to match the guides by a shop. In fact, I wouldn't recommend valve guide replacement at home either unless you were really experienced, knew the tolerances and had the tools to verify them.

1. The seats themselves may need to be replaced. Some free ponies and less carbon buildup is possible to achieve by blending the seats into the head, they usually have a step in the port where the seat ring ends and the head aluminum begins. Steps are bad for flow.

2. Combustion chamber shaping and matching: Worn engines usually require head flycutting, to smoothen out the cylinder mating surface. This makes the combustion chamber smaller, raising the compression ratio, which in turn makes the engine less resistant to pinging (which, if you didnt guess yet, is baaad). You need to bring the CR back down by either using shims under the cylinder, or removing material from the chamber to make it bigger again. I'd recommend shaping the chamber, there's a few free ponies lurking in there to if you know what you are doing. Same with the intake and exhaust ports. (Better leave this for the shop, although not all of them know what to do to them). if the engine was rebuilt before, who knows what the heads have gone through already. You need to measure them anyway. (Combustion chamber volume, on all 4)

1. Broken off or rusty intake and exhaust port studs need to be replaced. Stripped threads repaired in the head. Need to get the new threads cut STRAIGHT. Helicoil thread inserts should be installed for added strenght, and to get back down to original size after having to drill the stripped stud holes larger.

2. especially in the case of aftermarket heads: the gaps and holes in between the cooling fins are sometimes covered in casting residue and they need to be cleaned out, even drilled out.

1. intake and exhaust sealing surfaces need to be inspected, old gasket remains removed without scratching the head.

2. valve cover sealing surface needs to be inspected and smoothed out where needed. No room for sloppy work here either.

1. valve springs should be inspected for straightness and proper tension under load. If any of them stand crooked when you set them on a table all on their own, I'd say replace them.

2. Although not a part of the head, the rocker asembly should be inspected too. The shafts and rockers may be worn, and they sure as heck are usually covered in KRRRAP. Inspect the adjuster screws and nuts too. They need to move with ease once broken loose, screw heads should be shiny and not pitted or cracked. Nuts preferrably should not be mangled by incompetent wrench holders.

1. There's more but I'm too tired to go any further. maybe this gives you an idea of how muchg stuff is involved. Most of it requires special tools and skills, and HEAVY duty machine shop equipment.

Jan