First Drive With the Singer

News - Singer

Written by Administrator Monday, 19 November 2012 23:22

The Singer has basically been in running condition for quite a while but I just have not even tried to drive it. The main reason perhaps being the fact that getting it out of the garage required a little bit of manoeuvering and I have also have had something else to do, like repairing the SAAB engine. Yesterday I finally took the Singer out from the garage and tried to drive it the first time. The engine had been running already earlied and so it fired easily on the first try and I let it warm a little for a while.

First Drive With the Singer First Drive With the Singer First Drive With the Singer

Then I realized that there was something wrong with the clutch because it did not release properly. It took a while to find out that it did in fact release but the adjustment has something wrong since the clutch is properly engaged when the pedal is up, released when the pedal is about half way down and again engaged when the pedal is fully pressed. I need to check the adjustment, hopefully the problem is there and I do not need to open the clutch. However after this finding I was able to give the car a little spin on the yard by just pressing the clutch half way down while shifting gears.

First Drive With the Singer First Drive With the Singer First Drive With the Singer

The good thing is that beside the clutch everything seems to work as supposed. Of course there is still some adjustments to be done, for instance I suspect the carburettor fuel level may be a bit high because of the black smoke puffs also whet the choke is not on. While doing the checks before the drive I also noticed that the right front brake hose was little wet and I tightened it's connections. I need to keep an eye on that to see if it is the hose itself that has a leak.

 

SAAB Engine Running Again

News - SAAB

Written by Administrator Thursday, 25 October 2012 21:11

It took longer than anticipated to get the SAAB engine repaired and running again, mainly because there were problems sourcing the parts. The engine is bored to 71mm (1mm oversize), has new pistons, new crankshaft main bearings and and connecting rod big end bearings plus all new seals.

The correct pistons are only available from very few sources and when I eventually got a set of the required 71mm pistons I noticed that one of the three was 70mm even though the package was labeled 71mm. It took a while to get the piston changed to the right size. Then I took the engine block to the machine shop for boring and instructed them to machine the cylinders to correct clearance to these exact pistons. The cylinder block top and cylinder head was planed at the same time. I also took the crackshaft to a fellow two stroke Saab enthusiast who has repaired many crankshafts. This crankshaft is different than a four stroke crankshaft because all the bearings are ball or needle bearings and to get them changed you must dismantle the crankshaft in a press. After putting the crankshaft back together with new bearings it needs to be trued for straightness and a special jig is needed for that.

Engine Repair Engine Repair Engine Repair

Because of the crankshaft construction, all pistons must be assembled to the connecting rods and then the whole crankshaft assembly including all three connecting rods and pistons need to be lifted onto the cylinder block at once. It took a little bit of figuring out on how to accomplish that because the piston rings needs to be compressed and held in correct orientation before the pistons will go into the cylinders. Then I got an idea of using short sections of regular fruit tin can to compress the piston rings. The tin can sheet is thin enough to cause no problems and after the pistons are in cylinders the tin can section can easily be cut and pulled away from around the connecting rod.

Engine Repair Engine Repair Engine Repair

When the pistons were in and the engine block bottom half in place, I checked the top dead centre position mark on the crankshaft front end. Bit uncommonly, the SAAB engine uses the middle cylinder (#2) as the ignition reference instead of either end cylinders as usual.

Engine Repair Engine Repair Engine Repair

Rest of the assembly was really straightforward, installing cylinder head, flywheel, clutch plus some smaller items and then lifting the engine back in place. Installing manifolds, carburettor, starter, generator, etc. back in was straightforward as well and it was soon time to try starting it the first time after the rebuild. Below is a video from the first try. The air filter is still off, and thus the loud intake sound.

It appeared that the connection between the front muffler and the exhaust pipe was leaking (hence the smoke) and the ignition timing is still slightly off and need to be adjusted with a strobe.

 

Chassis Plate Fabrication

News - Singer

Written by Administrator Monday, 06 August 2012 19:33

The chassis plate of my car had been lost at some point during the life of the car. I have found out that some Singer clubs have manufactured reproductions at some point but now they are not available anymore. Therefore I decided to try fabricating the plate myself. The plate is brass and it has the texts etched to the surface. First I needed a good protograph from an original chassis plate to create the graphics. When I collected ptotographs from the plates from different sources I noticed that there a different versions of the plate.This is described more in another article here.

After selecting the photograph I would use, I corrected its perspective and scaled the photo to correct chassis plate size. Then I created the chassis plate geometry with a vector graphics program by using the scaled picture in the background as a reference. This way I could get the geometry very close to the original. Then I printed the graphics onto transparent slide as a mirror image to be used as a exposure screen. This is because when you use the screen upside down, the ink side is against the exposed surface and creates more accurate edges.

I cut brass plates that are slightly larger than the final plate dimensions to allow some toerance on the exposure screen placement. Then I protected the backside with wide plastic tape so that it will not be etched later. The front side of the brass plate is then painted with photo sensitive paint (I used Positiv 20 that is widely used in printed circuit board fabrication and is available from electronics stores)

Manufacturing plate fabrication Manufacturing plate fabrication

When the photo sensitive paint is fully dried the screen transparency is placed on the surface and suporrted with a glass plate. This combination is then exposed to ultraviolet light (The exposure time depends on the light used, I used an old alpine sun lamp and a two and a half minute exposure). The exposed plate is then developed by placing it into a solution of mild lye (NaOH) where the exposed paint dissolves and the unexposed is hardened so that it will protect the surface from etching.

Singer manufacturing plate fabrication Singer manufacturing plate fabrication Singer manufacturing plate fabrication

The developed sheet is then placed into etching solution (I used ferrichloride FeCl3 which is also available from electronics hobby stores). The etching time depends on the solution strength and temperature. When the etching is deep enough the plate is taken out of the solution, washed and the remaining protective paint is removed with acetone. Below is a plate in developing solution and a developed plate showing the geometry on protective paint. On the right are two developed plates on the left and two etched plates on the right.

Singer manufacturing plate fabrication Singer manufacturing plate fabrication

The etched plate is then painted black and let to dry. The high portions are then sanded to bare brass while the etched recesses retain the black paint. I still do not master the process throughly but the result seems somewhat decent already, as seen below right.

Singer manufacturing plate fabrication Singer manufacturing plate fabrication Singer manufacturing plate fabrication
 

Engine Trouble

News - SAAB

Written by Administrator Monday, 06 August 2012 19:17

A week ago the engine of the SAAB started to keep highly alarming noise during a drive at a normal city speed. I managed to get the car to a parking lot and concluded that it is better not to drive anymore. Next day the car was towed to my garage and I made some initial troubleshooting. Something had clearly been broken from the engine, possibly a piston ring.

Last Friday I finally had time to take the engine away from the car and open it. This concluded my initial diagnose. A piston ring had indeed been broken and the broken ring parts had been stuck on the exhaust port on the cylinder, as is bound to happen in a two-stroke engine, and broken also the piston. There are also grooves on the cylinder walls so the block needs to be bored to the next oversize.

Engine Failure Engine Failure
Engine Failure Engine Failure

Now I need to find new oversize pistons and get the block bored to that dimension. I think I will rebuild the crankshaft with new bearings at the same time.

 

Side Screen Restoration

News - Singer

Written by Administrator Monday, 06 August 2012 17:52

The side screens in my car were in original but very deteriorated condition as shown in the pictures below

Side Screen Restoration Side screen

The side screen frames made from D-section tube were in quite decent condition and shape.I sandblaster the frames and painted them black. The sceet metal paltes inside the screens were obviously originaly non-painted and they were so rusted that I needed to fabricate new plates.

Side Screen Restoration Side Screen Restoration

The side screens are attached to the fixtures on the top edge of the door with conical peg on the bottom edge of the screen. The fixture parts were in good condition because they are chromed brass parts. However the chromed steel pegs were badly rusted so I fabricated new pegs from stainless steel.

Side Screen Restoration Side Screen Restoration

Because of the bad condition of the side screens it was in many places difficult to figure out how the fabric has been sewn on top of the sheet metal plates inside the side screens. I made some paper templates to find correct shape for the different flaps on the screens.

Side Screen Restoration Side Screen Restoration

Sewing of the double duck fabric was quite an effort because the material is so thick. It was also challenging to sew just outside the sheet metal plate insede the fabric, as required in multiple places on the screens. 

Side Screen Restoration Side Screen Restoration Side Screen Restoration

The original toughened windows were in good condition, thy just needed proper cleaning. However the chromed brass window channels were corroded. I fabricated new channels fron stainless steel. Getting the channel lengths and corner miters correct was bit challenging but after several trial fittings I got then adjusted correct. I alse made new pull tabs for the screens.

Side Screen Restoration Side Screen Restoration Side Screen Restoration

Restored side screens. Looks pretty decent.

Side Screen Restoration Side Screen Restoration
 

Instrument Panel Finished

News - Singer

Written by Administrator Sunday, 04 March 2012 00:00

I have now installed the self fabricated start and choke cables. They do look like the originals and were the last components to be attached on the instrument panel.

Start and Choke knobs and cables Start and Choke knobs and cables Start and Choke knobs and cables
 

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