Saturday, April 15, 2017

Tuesday, January 10, 2017

1949-54 Chevrolet Passenger Car Starter

1949-54 Passenger Car Starters

Little is known about the 1949-54 Chevrolet passenger car starter.
Starting in 1949 Chevrolet passenger cars started using a push-button/solenoid actuated type starter. This was a two field style starter, which was used on all 1949-54 manual transmission cars (see pic.).

With the introduction of the Powerglide transmission in 1950, Chevrolet decided they needed a stronger starter to turn over the engine with its heavy transmission torque converter attached. So in 1950 Chevrolet introduced the 4 field starter for this application. (Sorry, no picture, but the second “shoes” in the picture above would also have windings around them).
This is a fairly rare starter as most parts stores did not show a difference in the two applications, and would just give you what they had on the shelf.
This 4 field starter is not even mentioned in the 1954 or earlier GM parts books. I do not have a 1955 GM parts book, but my 1956 GM parts book is the first book I have that shows the Powerglide starter separate from the manual transmission starter.
There are two ways to identify the 2 and 4 field starters.
First is by the tag on the side of the starter. The problem is that a lot of starters are missing the tag.   
The 2 field starter tag is, 1107109.
The 4 field starter tag is, 1118035.
The second way to identify a 2 or 4 field starter is by the position of the terminal coming out of the field housing, (there is a copper strap from this post to the solenoid).
The 2 field starter will have the terminal coming out of the housing next to an open area of the housing (see pic. Below).

The 4 field starter will have the terminal next to a solid area of housing.

 If your Powerglide car is starting fine for you do not worry about the difference between the two starters, but if you find your car turns over slow, this would be a good place to start checking.

Thursday, January 14, 2016

Saturday, August 15, 2015

Wednesday, April 29, 2015

Friday, April 3, 2015

235 Rocker Oiling Evolution

1953-57 full pressure 235’s (full pressure started in 1953 in the Powerglide cars) had a 1/16” oil restrictor fitting which screwed into the block at the beginning of the rocker oil supply tube under the side cover.

They also used a rocker connector that looped over the top and then dumped excess oil back on the head. The shafts were only supplied with gravity oil pressure with this design.(picture of early and late design)

 Starting in 1958 the tube under the side cover was discontinued and the engines now had a 1/16" orifice in a cast in the block galley. This received oil directly from the center of the lifter oil galley.
 Starting in 1959 the orifice size was increased to 11/32", see picture.(this was scanned from a 1960 manual, but stayed the same through 1962).

This larger orifice offered almost no oil flow restriction.
At the same time the overflow tube on the rocker connector was pinched off. This pressurized the shafts.
Sample of the three styles used
 At the same time the groove inside each rocker was offset 1/4" so it did not line up with the supply hole at each rocker. This prevented oil from squirting out of the vent hole on each rocker.

If you use 1958 or earlier rockers on a 1959-62 engine you will have the best luck preventing oil flooding to the top end if you restrict the oil supply to the rockers. Chev did this on replacement short blocks by selling you a plug to put in the block to block the original oil path and a special drilled head bolt drilled with a 1/16" hole for the oil to pass through.
 I have experimented with several designs, if a plug and drilled head bolt was not available. This orifice I designed drops in the head right below the connector supply tube and seems to work well.

 The orifice I make is 5/16" OD, .400" long, with a 1/16" hole drilled through the center. It is installed in the head under where the rocker supply tube fits in the head. I then use a rocker connector with the overflow tube.