Engine Compartment

Engine Block

In 1934 the 8 cylinder engine was introduced with a water side plate cover. This plate and the core plugs to follow were used to extract the sand from the casting. The side plate style of block ran to sometime early to mid 1935, when at which time the factory introduced a 3 large core plug block in what must have been a fairly short run. Next a 5 core plug block was introduced; with 3 large and 2 small plugs. It also had additional bosses and casting that facilitated moving the supercharger to the right side of the engine, with the intent of a conversion from left to right in the future. [Changes to this paragraph 5/16/18]

All engine block assemblies carry part # A90458.  No other part number has been found for designation of the various types of block.
Five freeze plug engines were superseded by a 3 freeze plug variety which ran until the end of production in 1936, making these rare.

6 cylinder engine A90425 started with a water side plate in 1934 and changed in mid 1935 to a 5 core plug version.
There are no known 6 cylinder 3 core plug engines.

8 cylinder 3 core plug engine

8 cylinder 3 core plug engine

Data Plate

The first line of a data plate indicates the Model

  • 1934 8 cylinder is 850Y or 850X
  • 1934 6 cylinder is 652Y or 652X
  • 1935 8 cylinder is 851
  • 1935 6 cylinder is 653
  • 1936 8 cylinder is 852

1936 6 cylinder is 654
The second line is the Serial Number which is a numerical code followed by an alphabetical suffix.

The serial is derived from the number stamped on the right hand front frame rail, plus a count of 1000.
Example: if a 1934 car frame number is 1100, the serial will 2100.
Example: if a 1935 or 1936 car has a frame number of 3120, the serial number will be 4120 except if it is supercharged.
If supercharged, the serial number is prefixed with a 3, so frame of 3120 would be serial 34120.

The alphabetical suffix indicates body type:

  • A – Sedan
  • B – Brougham
  • C – Touring
  • E – Speedster
  • F – Cabriolet
  • G – Victoria
  • H – Phaeton Sedan
  • K – 7-Passanger Sedan
  • L – Chassis
  • M – Coupe

The third line of Data plate is Engine number: a combination of alphabetical indicator and number.

The alpha-plus-number is found hand stamped onto a boss located on the left front top of the engine.

  • 6 cyl prefix WF and a sequence of block
  • 8 cyl will be one of the following prefixes followed by a sequence number:
    • GA – came with cast iron head. Used in commercial vehicles and in some early 1935 cars, possibly to use the stock up
    • GG – came with aluminum head, standard production
    • GH- supercharged engine


Standard Block

In 1934 the 8 cyl engine had a water side plate cover, used to extract the sand from the casting. This style of block ran to sometime mid to late 1935, when 5 freeze plugs blocks were introduced.

All engine block assemblies carry part # A90458. No other part number has been found for designation of the various types of block.

Five freeze plug engines were superseded by a 3 freeze plug variety which ran until the end of production in 1936, making these rare.

6 cyl engine A90425 started with a water side plate in 1934 and changed in mid 1935 to a 5 freeze plug version.

There are no known 6 cyl 3 freeze plug engines and no change in part number.

Supercharged Block

Engines A90537 were manufactured in the same three styles as the 8 cyl above.

Most differences between supercharged and non-supercharged engines are internal and not covered here.

Details of the supercharged engine internal differences can be found at:


 There are two external identifiers. One is the engine serial number begins with GH. The other is a hole on the bottom of the left side of the block, slightly forward of center, that is for an oil drain back tube fitting.

engine sc


UPDATE NOTE – Since this engine was restored it has become known that the superchargers were delivered to Auburn by Switzer Cummins painted black. Auburn did not repaint them green. All superchargers should be black on the green engine.

Engine Block Paint

All 6 and 8 cylinder engines left the factory a dark green.

If an 8 cylinder was returned for rebuild, typically called a Dallas Windslow rebuild engine, they were painted battleship gray.
If a 6 cylinder was rebuilt, it was painted a dark turquoise.
Any of the three colors are acceptable.

When the engine was painted at the factory it included the following items, already in place:

  • bell housing without the upper and lower inspection covers
  • oil pan
  • waterside plate (if applicable)
  • water pump
  • timing cover
  • front motor mount
  • harmonic balancer
  • oil filler pipe and cap
  • oil pressure relief valve
  • intake and exhaust manifolds on non-supercharged
    • See Manifold Exhaust & Intake sections
  • valve tappet covers
  • Also if an 8 cyl had a tach drive it was on the engine. If not equipped with tach drive, A90390 crank case tachometer cover will be installed instead.

This means all the gaskets, bolts, and washers that secured these items were painted at the same time.

Note: All superchargers came from Switzer Cummins painted black. This site has them mostly painted green in the pictures because we continue to learn as we go.

Oil Dip Stick

Oil level gage A90244 can be gray, black, green or cad plated. How it came originally is up for discussion.


Oil Filler Cap and Tube

These are the same on all cars, body styles and engine types.

  • Oil filler tube A90283
  • Oil filler cap A90003

Cap and tube were supplied by an outside vendor and received painted black. The caps have been black or cadmium plated.

They were inserted in the engine block when it was painted. It is believe that these left the factory engine green, but the black is found under the green over time.

For now in judging green or black are both acceptable.

A90003 A90283

Engine Mounts

There are four upper and four lower motor mounts.

First, the engine mount spacer A90380 must be bolted to the front of the engine.

Next the two rear motor mount brackets A10101, must be secured by six SF708 bolts and lock washers WA7 to each side of the rear of the bell housing.

Now that this hardware is bolted to the block, which is swinging in your cherry picker, we can move to the motor mounts.

Start with the four A10113 uppers in first, putting them in the frame cup-holders. Set the engine down at the rear first, lining up the holes with aligning punches. Place 2 large washers A10104 on top of the front rubber A10113, then lower the engine.

Now for the rear, take two A10103 bolts (shorter) and drop on washer WE10, then lower rubber insulator A10115 or A10116. See NOTE below. Push up from the bottom through the aligned rear mounting holes. Start the castle nut NK8, but do not tighten yet.

NOTE: Rubber insulator A10115 or A10116 must be put on the bolt so the stepped part goes into the frame.

Go to the front with two bolts A10102 (longer), add washer WE10. The next part on is insulator A10115 or A10116. Push up from the bottom through the aligned front mounting holes. Start the castle nut NK8, but do not tighten yet. And see NOTE above.

Begin to tighten all the nuts. When done, add cotter pin PE308 to each.

Motor Mounts

RESTORATION TIP  Prior to engine installation:

  • Have the steering column bolted to the frame
  • Install clutch and brake pedals and the adjuster C10149, but leave LOOSE on cross shaft C10297.

Engine Mount Supercharged

This is all the same as non-supercharged, except for the left front motor mount bolt. The same long bolt is on the right hand side and this and the rears are in, but loose.

Bolt for left front mount A10136 (short) has a hole drilled sideways through the head. The bolt screws directly into the timing chain cover and should be the first one you start to thread. There is no nut or cotter pin on this bolt.  Be cautious not to cross thread!

When all the mounting bolts are secure, go to the left front and using mechanics wire through the bolt head, extend it to a hole in the frame for this purpose.

Additional Pipe Plugs

The two styles of plugs below are  installed on the engine at the time it is painted.

There are 1/8 inch npt square head pipe plugs PF2 on the left side oil galley: 9 on the 8 cyl and 7 on the 6 cyl.

There is a 1/4 inch npt plug on the right side of the engine, square head cylinder water drain, the head embossed A. This functions as a block drain. There is NO drain cock in this location.


Side Plate

These plates can be installed in 4 different ways, and only one is correct.

The 8 cylinder side plate A90363 and gasket A90364 is secured with 26 SH405 round head slotted screws and copper washers 11S1.  If car is equipped with startix there will be two mounting studs, also with 2 more copper washers 11S1. CAUTION: Note one hole is staggered. Ensure side plate and gasket are correctly secured so startix fits into proper position.

A90363 sideplate

The 6 cylinder side plate A90427 and gasket A90428 is secured with 19 SH405 round head slotted screws and copper washers 11S1.  If car is equipped with startix there will be two mounting studs also with 2 more copper washers 11S1. CAUTION: Note that one hole is staggered. Ensure side plate and gasket are correctly secured so startix fits into proper position.

Cylinder Head

8 cyl heads:

850X and taxis used a cast iron head A90403.

850Y, 851, 852 used A90418 aluminum head which was superseded by A90539. The date or serial number of change and the difference between part numbers is unknown.


  • All 6 cyl used A90431 aluminum head throughout production.
  • All 8 cyl head gaskets are the same A90404.
  • All 6 cyl head gaskets are the same A90432.

Fasten 8 cyl heads using 27 SZ730 cap screws and 27 WZ9048 special washers. Opinion though recent times was that head bolts were cad plated, but old factory and era photos depict head bolts as black. We believe black Parkerized is correct.

There are two PF6 3/8″ npt square head pipe plugs marked A in the cylinder head. The front PF6 is next to the thermostat housing and used as an air bleed when filling the engine with coolant. The rear PF6 plug orifice is used for the supercharger heater line if applicable or in some instances if a cabin heater is installed with this as the hot water input.

Water outlet / thermostat housings A1-233 are the same for all cars. Held in place with three SA508 cap screws, typically marked W, lock washers and gasket A1-119. These are dark Parkerized, like the head bolts.

Spark Plugs

All Auburns with cast iron heads, including 850X, taxi cabs and some early 1935 GF-engines came with Champion C7, part K10341.

All other 8cyl and 6 cyl cars, Non-supercharged came equipped with Champion J6, part K10340

All supercharged use Champion J9, part K10740.

All Champion spark plugs from 1934 up through 1947 had two ribs and are called beer bottle style plugs.  These are the most desirable because they came in the cars. After 1947 Champion plugs had five ribs. All had a black or gun blued base. Spark plugs with cadmium bases are 1956 and later and not correct for Auburn.

On top of the spark plug is a brass top K10328, about an inch high with a hex shape on one end which screws onto the plug and wires press into this.  All 6 cyl, 8 cyl cars had this and they are natural brass.

Spark Plug Wires

Wires are all black lacquer.

There are two rubber rings or loops K10350 that hold the wires together in groups on all cars.

6 cyl have one loop on wires 1, 2 and 3. A second loop on 5 and 6. Wire 4 is not included because it is right next to the distributor.

8 cyl cars have one loop on wires 1, 2 and 3. A second loop holds wires 6, 7 and 8.

sparkplug wire

Flywheel And Bell Housing

The flywheel 8 cyl A90299 and 6 cyl A90472 are interchangeable except that the timing mark location differs.

The flywheel housings are not the same between 6 & 8 and left & right hand drive.

  • The 8 cyl left hand drive is A90360. Right hand drive is part A90480.
  • The 6 cyl left hand drive is A90421. Right hand drive is part A90481.

None of these are interchangeable.

Clutch Inspection Cover

Both covers are interchangeable for all models and body styles, 8 cyl and 6 cyl.

The upper cover C2-102, painted semi-gloss black.

The lower cover A10069, painted semi-gloss black.

Total of 10 bolts SF404 marked W or 30 to secure, with WA4 washers.

Chain Case

Applies to 6 cyl and 8 cyl non-supercharged. Cover A90406 with gasket A90383 was painted on the engine.

Working from block outward: Spacer gasket A90381 seals front engine mount spacer A90380. Next A90383 cover gasket and A90406 chain case cover. The A8-403 front crank shaft main seal is a part of A90406 cover, but may be replaced with a modern seal.

Chain case is secured by one SA504 hex bolt marked W or 30, two SN506 flat head slotted screws and two WK5 countersunk shake proof lock washers, ten SA506 hex head cap screws marked W or 30, one NA5 nut, eleven WB5 lock washers

Chain Case Supercharged

Cast iron chain case A90541, superseded after engine #4379 with A90607.

From engine outward, gasket against block A90383 seals the spacer A90547. Next A90546 cover gasket seals chain case assembly A90607.

The auxiliary drive inspection cover A90548 has a gasket with no known part number.

The chain case cover is secured by six SA506 hex bolts, four SA508 hex bolts, four SA528 hex bolts, four SZ902 round head slotted machine screw and appropriate lock washers.
These fasteners are dark Parkerized and typically a W or 30 head.

chain case SC

Vibration Damper / Harmonic Balancer

Dampener assembly A90459 is the same for 6 cyl and 8 cyl. It has accommodation for two V-belts. Secured to crankshaft with WZ9023 flat washer and NH16 Nut.

Vibration Damper / Harmonic Balancer Supercharged

A90562 is shorter and accommodates one V-Belt. Secured to crankshaft with WZ9023 flat washer and NH16 Nut.

Manifold Exhaust & Intake – Non-Supercharged

Intake and exhaust manifold: we have found green paint on the intake, but never any on the exhaust for obvious reasons. It is possible that these were painted off the engine together or possible they were painted on the engine as an assembly. This would mean the studs, nuts and lock washers would all have evidence of green paint, but we have not found that.

RESTORATION TIP: Knowing that the paint will burn off the exhaust manifold, I would suggest a ceramic coating that takes on the appearance of cast iron. Various companies provide this.

There are three different intake exhaust manifold combinations for non-supercharged engines.

For purposes of discussion we will consider the intake and exhaust manifold together as one part.

The heater valve or heat riser will be covered later.

850X used a Swan manifold A90302 for the exhaust and A90416 for intake. This combination would interchange with other 8 cylinder engines as well.

850Y, 851, 852 uses A90414 exhaust and A90465 intake.

All 652X, 652Y, 653, 654 use A90438 exhaust and A90443 intake.

850X uses three gaskets between the block and the manifolds. A5-274 front. A5-275 rear. A90310 center.

850Y, 851, 852 use gasket A90468 front and rear. A90469 center.

All 6 cyl use one gasket A90444.

There is a gasket in between the exhaust manifold and intake manifold. This area is known as the hot spot.
850X uses A90312.
850Y, 851, 852 use A90456.
All 6 cy use A90443.

Manifolds are bolted together.
850X uses four SA 612 cap screws
850Y, 851, 852 and all 6 cyl use four SA610 cap screws.
Screw heads are marked 30.
Lock washers are used with all these fasteners.

Studs: Manifold to Block

850X uses two A90311, ten A5-96, two Washers WZ9010, eight WZ9014 and 12 NF6 nuts. There are 15 total WA6 lock washers used on this manifold assembly.

850Y, 851, 852 use two A90470 long studs in the top two center positions of the block. And there are ten A5-96 studs.

6 cyl al use ten A5-96 studs.

There are two WZ9010 plate washers used on the two top center studs on both 6 cy and 8 cyl.

The WZ9014: all 8 cyl take 10, all 6 cyl take 8.

There are 12 NF6 nuts for all 8 cyl.
There are 10 NF6 nuts for all 6 cyl.

All 8 cyl use 15 WA6 lock washers.
6 cyl use 10 WA6 lock washers.
Finish is Parkerized or natural.