That piston meltdown had nothing to do with driving over 45 mph during break in. This was ignition timing or maybe mixture related. The head also appears to show some combustion gas leakage past the top cylinder seal. This is often caused by a warped case. The combustion leakage may have contributed to the excessive temps that melted the piston and/or cracked the head. These engines rely heavily on a working EGR system to control combustion temperatures. It needs to be there and working for any extended highway travel.

Keeping these engines alive require a bit of a laid back, slow but steady driving style. When power is needed, let it rev, never lug it. Yes, it can be lugged at 3,000 rpm. At any speed, if more throttle does not make more speed, the engine is being lugged, slow down or down shift.

The control flap over the oil cooler is deceiving. As the t-stat lets the flaps open, it appears to cover the outlet to the oil cooler. Actually, it moves away from the fan housing. There is duct space underneath that actually supplies air to the cooler.

Dennis

-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Kragen Sitaker Sent: Tuesday, July 04, 2006 8:16 PM To: vanagon@GERRY.VANAGON.COM Subject: need new engine for air-cooled van (overheated one)

Short summary: cracked a head (maybe both), scored a cylinder and piston; rods, crank, and case seem good so far. We have an offer for a $700 pig-in-a-poke air-cooled Vanagon engine. What are our other options for a new engine?

Long version:

Well, after we had our magic bus engine rebuilt in Omaha, we made it about 200 miles before losing a lot of power on the freeway. Didn't know you weren't supposed to go over 45 for 300 miles after rebuilding your engine. I guess I would have known that if I'd rebuilt it myself, because I would have read that part of the manual. But we weren't going over about 50 anyway.

Water flicked on the crankcase boiled immediately, even several minutes after we stopped, and the oil smelled like hell. It wouldn't start for another half-hour or so (it had been having problems with starting warm ever since the rebuild), and when it did, we drove very slowly to the nearest town, Galesburg, about six miles away.

Compression test said 45 psi on cylinder #3; the other three were fine at around 100. We rented a U-Haul and towed it up to Minneapolis to take the engine apart.

Looks like that piston and that cylinder are pretty badly scored, and one of the rings is stuck in its groove, and there's a crack between the valves in the head. My wife uploaded photos of the whole removal and disassembly process:

http://flickr.com/photos/blmurch/sets/72157594187260002/

The other piston on that side has a little bit of scoring.

I haven't taken apart the other side of the engine yet. I don't know what I'll find; maybe a good head.

Looks like the thermostat is missing, along with the cooling control flap on the right side; the flap on the left side was covering the oil cooler all the time. I have the impression that the oil cooler is supposed to have air flow through it when the engine is hot in order to cool the engine more effectively, but clearly that wasn't happening. Perhaps this explains why it only ran for 200 miles.

So since I need to replace at least a head, a piston or two, and a cylinder, I'll probably be better off with a new engine altogether. We have a lead on a running air-cooled Vanagon engine with unknown history for $700; how much time would it take me to install some other kind of engine in here, such as a diesel, water-cooled, Subaru, or a Jetta or Golf engine? Would it cost a lot more? Are there other air-cooled engines out there with more-accurately-known history for a similar price?