Steps to scratch build a VW

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Pops

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My guess is the coil power wire. From the factory they had no fuse in that circuit. Wire to the points often fell off and then the whole wire loom melted from the dead short. Common fix was too move the wire with a jumper to the other side of the fuse block. At least then when the wire came loose all it did was blow the fuse to the horn.
Fix the loose wire put in a new fuse, or wrap the old one with a gum wrapper, and keep driving.
Exactly --
About a year ago a local man bought a VW that wouldn't start. Stopped by my place and ask if I would look at it. The coil power wire was shorted out somewhere from the front to the rear. Just ran a new wire. Lot of times the power to the coil also jumps from the coil to the reverse switch on the transaxle for the backup lights. Wire falls off the switch and shorts out and burns the wire out to the coil.
 

Hot Wings

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That isn't a blown up engine. It's just a bit worn. A 'blown up' VW has a nice little hole where the red circle is.
blown up.jpg

edit:
Was a little quick to brand the engine in post #644 as a 356. Looks more like a mid 60's 912.
 
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Pops

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I was running about 75-80 ? mph on the interstate one winter when the 1966 VW beater I was diving had a head of a valve break off. Made 3 large bangs and the rear wheels locked up. Almost rolled it before getting the clutch in. Not much of the engine left. Engine parts on the interstate. Only part of the engine that was use able was mostly the distributor , carb, generator. One side of the engine case was mostly not there. All rods bent, etc.
 

jeffwalin

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I just finished reading this whole thread. Good read!

I do have two questions though....

Pops....what is an SSSC? I assume one you designed and built yourself?

And Little Scrapper....what is/was you conclusion about engine size, and are you still doing the V-Witt?
 

Map

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I have my VW engine apart at the moment because some parts were very worn/broken. I had a problem with the mechanical fuel pump drive, the plastic guide of the drive rod broke. I don't have the ignition on the pinion drive gear, not sure if that made a difference. I have modified this installation and hope it will last longer this time round.

I use a magneto on it, and the drive (on the flywheel end) has given me problems. The original part (drive puck, phenolic) supplied by GPAS did not fit and after I modified it broke quickly. A replacement I had made from aluminum worked for a while but wore out fairly quickly. I have now redesigned this drive with a steel interface to the magneto, I think this will be more durable.
 

Pops

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Are you sure that the mag mount housing is centered to the end of the crankshaft well ? If it is off center a little, it will tend to wear the drive puck. I always remove the drive puck at each conditional inspection and measure for wear. Still using the same phenolic puck.
 

Hot Wings

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I had a problem with the mechanical fuel pump drive, the plastic guide of the drive rod broke. I don't have the ignition on the pinion drive gear, not sure if that made a difference.
There are 2 different length pushrods for the fuel pump - depending on the pump version.
The pump/distributor drive tends to like to climb out of it's bore. The stock VW uses the little spring to keep tension on the drive when the distributor is in place. If this is left out, or the distributor hold down nut comes loose it can move enough to break the pump pushrod guide. It can also make a mess of the brass gear if it is moves too much.
I like to set the mesh of the distributor drive gears, and the distributor depth during the build before closing the case to make sure everything lines up properly. Some combinations need a custom spacer between the case and the drive to get things right.

One other problem, that I havent seen in several decades, is the plastic/Bakelite guides sometimes were not properly cast and needed some sanding on the oversize and off center shaft to relieve a bending preload that would inevitably snap the guide if not corrected. The guide should slide in snugly, but with little force.
 

Pops

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One time I was going down the interstate when the VW engine quit running. Pulled off and the nut holding the distributor bracket down came off and the distributor jumped out was laying on the engine tin.
Have seen several fuel pump bakelite pushrod guides broken.
Had a fuel pump fail one time. Ran fine uphill, each time when I got to the bottom of the hill I would have to coast to a stop and prime the carb to restart. Found an old beer can on the side of the road and pulled the hose off the metal fuel line behind #3 cylinder to get a little gas. Made it about 30 miles that way, got to town and called my oldest to get me a fuel pump from the workshop and get it to me.
 
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