Wednesday, April 20, 2011

Isetta - Stripped Threads

It would be extremely rare (if not impossible) to restore a vintage vehicle and not encounter stripped threads at some point. Up until now, I had only encountered two stripped threads on my white Isetta. The drain plug on the chain case was stripped, and one of the threads on the engine case that holds the coil was stripped. As I had mentioned on an earlier post, I had a lot of problems with the quality of manufacturing and fit of a muffler and heat exchange that I had purchased from Group Harrington. I had never completely tightened down the muffler system because I thought I might either try to salvage the extremely poorly made heat exchange or do some additional tweaking of the bend on the header pipe. I finally decided to give up on the heat exchange and just use the header pipe that came with the muffler. After some additional tweaking of the fit of the header pipe and muffler, I decided to tighten down the muffler system. That's when I encountered two more stripped threads. The bottom two threads of the cylinder head that hold the header pipe on were stripped.

Thankfully there are a couple of styles of thread repair systems that work very well. For repairing the cylinder head threads I using a helical insert style of thread repair kit. Most people refer to these as Heli-coil which is probably the most popular brand of helical inserts.

To give myself a little better access to the stripped threads, I removed the cooling shrouds from the engine which also meant removing the carburetor.

Repairing a stripped thread with a helical insert involves drilling the stripped hole out to a slightly larger specified diameter, and then tapping the hole to accept the helical insert.

After the hole is tapped, the helical insert is thread into the hole with a special tool that has a slot that fits over the tang of the insert. After the insert is threaded to the correct depth, a punch is used to break off the tang at the rear of the insert. I then blow air into the hole until the broken piece of tang comes out of the hole.

A photo of the repaired threads.

For the stripped threads in my chain case drain plug hole I used a different style of thread repair called a Time-Sert. Time-Sert's are more expensive than helical style inserts (unless you borrow it from a friend like I did) but Time-Sert makes kits specifically for drain plugs and spark plugs which I felt might give me a better seal than a helical style insert.

Road & Track - February 1958

Saturday, April 16, 2011

Microcar Papercraft

In the United States papercraft or paper models are not as popular a hobby as they are in Japan and Europe, however the internet may be changing that. Since papercraft models can be easily downloaded and printed at home for little or no money, their popularity has sky rocketed worldwide. There are numerous websites and blogs devoted to a wide variety of papercraft model making. In Japan it is very popular for manufacturers of consumer goods to have a section on their website where you can download models of whatever product it is they might manufacture. Whatever your interest, there's probably a papercraft model available.

A great resource for micro and mini car paper models is Ichiyama's Paper Cards. Ichiyama's website has an excellent selection of micro and mini car paper models available as free PDF downloads. Not only is there a nice selection of cars, most of them are available in many different colors. Domo arigato Ichiyama!!

Wednesday, April 13, 2011

Isetta - Spark Plug

The most commonly recommended spark plug for the Isetta 300 is the Bosch W7AC (WR7AC new version). It used to be the Bosch W4AC, however many people feel the W4AC does not work as well as the W7AC with modern fuels. Speaking of modern fuels, if you live in the US or Canada and you're concerned about using ethanol blended fuels in your vintage vehicles, there's a website called that list gas stations by state that sell ethanol free gas. Of course there are many other brands of spark plugs that work in Isetta's. Another popular choice is the NKG B6HS. People have also reported good results using plugs with a longer reach (thread) such as the Champion N6YC. If you're wanting to use a brand other than Bosch, NGK, or Champion, a good resource for cross referencing spark plug brands is Club Plug USA. Another useful online resource for diagnosing engine/spark plug related problems is NGK's "How To Read A Spark Plug"

The spark plug recommended in the Isetta 1957 Export Owners Manual and Repair Manual is the Bosch W240T1. These NOS W240T1's recently popped up on ebay. They're not cheap, but if you're planning on entering your Isetta in the Pebble Beach Concours d'Elegance these babies will probably score you some extra points. If you're planning on actually driving your Isetta, I'd go with some much less expensive and better performing Bosch W7AC's.

An old Lodge spark plug cross reference chart. It shows the Bosch W240T1 being interchangeable with the Lodge HH14, Champion LA10, and KLG F80.

Monday, April 4, 2011

Kansas City Area Microcar Meet

Spring is in the air which for midwest microcar and minicar enthusiast means it's time to bring your babies out of their winter hibernation and start enjoying them. The premier event for microcar-minicar enthusiast in the Kansas City midwest region is the Kansas City Area Microcar & Minicar Meet and Swap Meet. This year the date is Sunday, May 15th, 2011 from 1:00PM to 4:00 or 5:00PM. The event is held in parking lot of Westwood City Hall located at 4700 Rainbow Blvd, Johnson County, KS. (near KU Medical Center). The event is organized by Jack Vetter. For more information about this years meet, contact Jack at: Last year mother nature did not want to cooperate, but as you can see in the following pictures from 2 years ago, the event does draw a nice group of microcar-minicar enthusiast.

Photos - Evin Moore