Topic: The 40 hp engine
Decided to split this off from other threads, as an ode to what I'm beginning to see as VWs most practical engine: the 1200 40 hp engine of 61-on. The US only saw this engine for a few years, but it continued production for other countries long after that, and now that I'm restoring one I see why. I think it was potentially the longest-lasting VW engine for the stock daily-driver.
Some years back I bought a 62 ragtop to restore that had its original 1200 engine, and repair records did show one rebuild. However, when I tore it down I was amazed at the condition. It had been in daily use in stock form for about 35 years. It had a bit much end-play, so it needed a thrust cut, but the main bearing saddles really didn't need to be align bored, as the stock bearings fit tightly with no wear ridges. Later engines with longer strokes are seldom so lucky, as the crank whip wallows out the saddles, but the short-stroke 40 didn't have that problem.
This case had no sign of heat related problems like cracks, in spite of long use in the Texas heat. With 1200 ccs and low power output it doesn't have as much heat to get rid of; so even the old narrow fan and stale-air shroud could handle the cooling chores.
I got my first license in 62, and Beetle drivers then were wowed by the driveability of the new 1200 compared to the older VWs. It had enough power for most of us at the time. (Life was slower then...) When I bought this one it still felt "right" for the car.
The 40 hp case is dimensionally the same as all later cases except for the cylinder bores. This was much stronger than the earlier cases, but only had to handle the power of the 1200 ccs. (Or 1192 as I remember...) That made for a low-stress case and long life.
The Stale-Air thermostat system that went out of production in 63 may also have contributed to the longevity. The air control stopped air coming IN to the fan instead of going OUT of the shroud, so the fan would spin easier in a relative vacuum when warming up, instead of working to compress air that couldn't get out of the shroud as later cars. During warm-up there was no air forced through the oil cooler, so the oil heated up faster to lubricate sooner. Later, doghouse shrouds force MORE air over the cooler during warm-up, and over-cool the oil in winter weather, since the thermostat doesn't affect air flow through the cooler.
Clancy sent me the air control-ring parts for the stale-air thermostat that were missing from my engine, so I'll get to set it up "right" as I get it back together. Thanks again, Clancy.
I just got the case back from Rimco. They put in case-savers, only because one stud had a deformed thread which damage the case. Otherwise the studs were solid. They did align-bore in order to thrust-cut the #1 saddle properly, and provided a matched cut set of bearings. I'm using a NOS 40 hp crank. They also bored the cam saddles for bearings, as the early cases didn't have them, and the saddles were worn enough to worry about oil pressure. They decked the cylinder openings along with the case-saver work, but it really didn't need it. Otherwise they agreed it was in great shape.
By boring the cam and crank tunnels at once they get them very parallel, which makes for better fit of the cam gears. If their fixturing is good it should be close to nominal pitch dimension, so it will be interesting to see what cam gear fits. (See: I did tie this to another thread!)
The later cases do have a higher-capacity oiling system with larger passages. I think if I were building my "ideal driver" engine I'd use a new case, sleeve the cylinder bores to fit 1200 cylinders, use a 1200 short-stroke crank, and a new Mexican filter-pump. The pump would take more power from the 1200 due to the larger gears, but if I wanted power I wouldn't be building a 1200 anyway.
I know, most of you are wanting to get MORE POWER from your engines, but I'm getting old, and my priorities are different. I think the 1200 had the best engineering balance, and the later revisions to increase power gave up something in the process.
Here's to the 1200, and the engineers who designed it.