Sandrail / Volkswagen / Mazda Hints and Tips

Welcome to the Hints and Tips page.

Disclaimer: I usually don’t know what the hell I’m doing, so most of this advice is probably wrong…. Seriously though, please use common sense with any of the information below and understand that you are at your own risk by following any information on this site, and I am not responsible for the use or misuse of anything contained here.

Volkswagen Starter Problems

Okay, this one was a real pain to figure out. When I purchased the “Green Rail”, it had some difficulty starting. The previous owner had been hooking a battery charger to it to start it, and it had the usual symptoms of a vehicle with a bad battery — the starter spins real slow after the first couple of revolutions. So, I replaced the battery. Didn’t help. Believe myself to have two bad batteries, I purchased a load tester, and the batteries both tested out good. Well, if it wasn’t the battery, it must be the starter, so I went down to autozone and got a new one. No difference. Well, then it must mean that I rebuilt the engine wrong, misaligned the main bearings, and the engine is binding. So, I went down to a VW shop and spun one of their engines by hand and compared it to mine. Felt about the same — good news, it wasn’t a bad engine.To make a long story short, it turned out to be the starter bearing. The VW started armature is only supported on one side within the starter. The other side is supported by a little bronze bearing that is in the transaxle case. If the bearing is in bad enough shape, then the starter will bind or ground out, and rapidly heat up, spinning slower and eventually fail. That’s why the new starter always comes with a new bearing.

So how do you get the old bearing out? There’s a special tool that you can buy just for that purpose. However, if you have a tap and die set, then you can just thread a tap into the old bearing and use that to get it out. That’s what I did with mine — it was so badly gone that the tap pulled it out with no trouble.

Also beware that 12V and 6V starters generally have different shafts, and therefore different bearings. So make sure you’ve got the right one.

Carburetors

I’ve had experience with a few different types of carbs, and I’ll outline them below:Kadron / Solex dual carbs. I didn’t like these. My #1 plug fouled with a flat-black sooty coating approximately every 1.5 hours of driving and had to be replaced. I tried rebuilding, adjusting the mixture, and putting in a different idle jet. No help. I eventually gave up and replaced the VW engine with a Mazda Rotary (which of course introduced a whole new set of issues….)

Weber 34 ICT. These carbs came with the Green Rail that is described elsewhere on the site. They were setup for a type-3 engine. The 34ICT is more-or-less a pretty good carb, and I’m told they’re suitable for engines up to about 1835cc, but not much higher than that. In my opinion, the 34ICT look much nicer than the Kadrons. They performed pretty good on the Green Rail. My only major complaint was the nuisance of having to deal with a dual-carb linkage and to synchronise the carbs. Some people love to tinker with things over and over again, but I’m the type of person who likes to set it up and have something stable.

The “pod filters” that are commonly sold for the 34ICT are glued together, and I’ve had two of them come apart, and require re-gluing.

Weber 32/36 DFEV. I purchased one of these kits new from Chirco, complete with intake manifold. This carb is an excellent performer, and is the smoothest I’ve ever heard a VW engine run. There are a few issues with the kit: a) the intake manifold rubbed against the alternator, requiring minor clearance of the alternator case, b) the throttle cable doesn’t line up quite right, and I had to do a little bit of grinding on the fan shroud, and c) the damn mixture screw faces the fan shroud and is very hard to get to for adjusting.

For the person who wants a trouble-free buggy without any need to dual-carb synchronisation, the 32/36 DFEV is an excellent choice.

Type-1 vs Type-3

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  The type-3 fan is located down low, and sucks up dirt when used on a rear-engine  sandrail, as opposed to the type-1 which is located up high, and fairly well protected on a rear-engine buggy.
  The type-3 cannot take the cheap and readily available sand-seal pulleys that are on the market. To put a sand seal on a type-3, you would have to take the fan in and have it machined (which is probably not that big of a deal if you have a friend with a machine shop)
  The type-3 takes numerous special parts that are hard to come by. A good example is the dipstick which is a real complicated mess on the type-3. There is a conversion available to convert to a type-1 dipstick, but that looks like it might interfere with the fan shroud.
  The type-3 fan shroud is a pain in the ass. It’s held onto the engine case by some small bolts that love to strip out and/or come loose, making a horrible noise. It’s also a pain to tear the shroud off and on whenever you have to work on something in there.
  The type-3 takes different versions of some carbs than the type-1. For example, the linkage/manifolds off a type-3 weber 34ICT kit are not the same as the linkage and manifolds off a type-1 weber 34ICT kit.

Having tried both a type-1 and a type-3 engine, I have come to the conclusion that the type-1 is far superior to the type-3 for sandrail applications. Here are the reason why:

Bent Pushrods

After rebuilding the Green Rail’s type-3 engine, it promptly bent the pushrods on the first time trip around the trail. Not just a little, it bent them lot, even elongating the pushod tubes. The valve clearances were adjusted properly. I never did figure out what caused it (none of the mechanics around here had any idea), but after pulling them out and straightening them, the problem never did reoccur. go figure.

Disc Brakes

Another problem related to the infamous Green Rail which I’m tempted to start calling “Murphy’s Rail”. When I purchased the rail from the previous owner, the disc brakes had trouble holding pressure. They’d be good for a while, but after you drove it around a bit, they would lose pressure and need to be pumped.I tried bleeding them (went through several cans of brake fluid), tore out the turning brake cylinder (because it looked like just that sort of suspicious gremlin that could cause such a problem), inspected all of the lines, tore out the calipers and inspected them. Nothing would solve the problem.

What it turned out to be was the brake system was missing Residual Pressure Valve (RPV). The residual pressure valve is a little check valve that always maintains a small amount of pressure in the system. It turns out the previous owner had never installed one, and the brakes probably had never worked right.

This is necessary for disc brakes because the calipers don’t have any kind of an adjustment to hold the pads close to the rotor (I suppose the lack of an adjustment means they’re self-adjusting!). Hence, as you drive it around, if there’s no pressure in the system, the bumps and bounces can cause the pads to move away from the rotor, requiring a good pump or two to get them back in close. This is not an issue with drum brakes because drum brakes do have an adjustment (that little spring thing that you click with the special drum-brake adjusting wrench).

Things to look at every time you pull a motor

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  Thowout bearing
  Throwout bearing cross arm (especially where the ears attach to the arm, and where the bearing rides in the ears). If you have the weak stock one, buy a new heavy duty SCAT or Bugpack one.
  Pilot bearing. It’s the little bearing in the end of the crankshaft. If you stick a clutch alignment tool in there, it should fit fairly snug.
  Clutch.
  • Clutch disk. Check for wear.
  • Pressure plate. Pay special attention to the “fingers” on the pressure plate. Look for any cracks or defects.
  • Flywheel. Look for any surface defects in the fly wheel surface. Look at the teeth on the starter gear.

Going from experience, there’s all kinds of things that you should check any time you have the motor and tranny seperated. If you don’t check these things, they will break. Yes, I know it’s hard to believe, but the parts do know if you’ve looked at them or not, and they will break if you don’t look. Take it from experience, it’s easier to fix these things when you have a motor pulled, then to have to pull it all apart because some minor part breaks: