Burtz Model A Engine 5 Main Bearing
Burtz Model A Engine Builders Guide (v2.0)
Congratulations on your purchase of the Burtz Engine Kit (Cylinder Block, Crankshaft, and Connecting Rods) which has many improvements over the original stock Model A Engine.
This new engine can be built as stock, or it can be built for higher performance standards. We ask that you (or your engine builder) follow these guidelines as you undertake new engine build. If you find any conflicts or concerns in the build process, discuss with your engine builder or parts supplier.
Inspection of Parts
- Pcs: 1; Cylinder Block with 4 hard exhaust seats, 5 cam bearings installed.
- Pcs: 5; Main Caps (each with studs, nuts and 2 locating dowel pins) installed.
- Pcs: 4; Replacement Studs (7/16 UNF x 1/2 UNF) “stepped”; for #1 and #3 Main bearing caps (packed separate).
- Pcs: 4; 1/2-20 UNF tall Castle Nuts for top #1 and #3 main bearing studs (packed separate).
- Pcs: 4; 7/16-20 UNF 12-point Nuts for main bearing studs #1 and #3 (packed separate).
- Pcs: 2; 1/2-13×3/8 UNC Setscrew main oil galley end plug.
- Pcs: 5; 3/8-16×1/4 UNC Setscrew oil galley plug.
- Pcs: 1; 7/16×3/8 UNC Oil Galley Plug.
- Pcs: 1; 1/8-27 NPT Slotted Plug.
- Pcs: 2; Dowel for cylinder block/flywheel housing interface.
- Pcs: 3; Thrust Washer half.
- Pcs: 6; 8-32×3/8 Phillips Flat Head Screw – brass – for thrust washer halves.
- ONE balanced crankshaft with 2 rear dowel pins, 4 setscrew oil passage plugs, and 1 Woodruff key.
- FOUR balanced connecting rods each with wrist pin bushing, and 2 dowel pins at cap interface installed; two, 12 point bolts (requires 3/8” thin walled, deep well socket for tightening).
During the inspection process take note to:
- Verify “match marks” on main caps and connecting rods caps (1-4) before disassembly.
- De-burr any machining sharp edges.
On final assembly, replace the #1, #3 main cap temporary studs with FOUR replacement “stepped” studs UNF 1/2” to UNF 7/16” studs (refer to Section V, Part A below). Discard the temporary studs.
1. Cleanliness and Detailing
The new engine parts are dirty and need to be cleaned and detailed before assembly. Light oil has been applied at the factory to prevent corrosion and has attracted dirt and dust. Oil passages and threaded holes may have machining chips and grit that must be removed (see Sec. VII before cleaning).
Detailing includes mild chamfering of holes and elimination of sharp edges with a Dremel tool (or similar). Refer to Pic 201 A-B below.
When cleaning your new parts, please take note of all drilled oil passages and where they go. For a long engine life, all parts need to be “surgically” clean.
2. Notes and Recommendations Regarding Add-on Parts
- Interfaces on the new cylinder block and crankshaft are identical to stock. Parts that fit an original Model A engine will fit the new cylinder block and crankshaft.
- All threads in the new engine parts are either UNC, UNF, or NPT; there are no metric threads.
- Add-on parts, whether new, used, NOS, or aftermarket, need to be cleaned and inspected for flatness. Flatness is critical at the cylinder block/head interface, cylinder block/manifold interface, and cylinder block/oil pan interface.
- Cylinder head which is not within .003 of being flat, will require resurfacing.
- The oil pan upper surface should be checked for straightness before installation.
3. Standard Parts Required for the Build
- Main Bearings: 8 pairs; Type: Clevite CB-745P or Federal Mogul 2020cp; both types are tri-metal. Use standard size.
- Connecting Rod Bearings: 4 pairs; Type: Clevite CB-745P or Federal Mogul 2020cp. Both types are tri-metal. Use standard size.
- Rear Main Seal: National Industrial Seals 415035 (or equivalent).
4. Procedural Requirements for Building the BURTZ Engine:
There are unique aspects to the Burtz Block which require the builder to follow these instructions closely.
Main Bearings: #2 and #4
The #2 and #4 main bearing saddles in the cylinder block each have oil passages from the pressurized main oil galley system. Mark the upper bearing insert in the correct location and drill the oil passage with a 1/8″ drill bit.
See pictures 501 A-C below.
Ensure the oil passage in the bearing insert aligns with the oil passage in the block. Do this for both the #2 and #4 upper bearing inserts.
A. Replace the #1, #3 Main Cap Studs
The #1 and #3 main cap studs in the block at the time of purchase are temporary and need to be replaced with permanent studs that were packed separately. The permanent studs are “stepped” UNF 1/2” to UNF 7/16” studs. Discard the temporary studs. Refer to picture 502.
B. Installing the Camshaft
The engine block will accommodate either, a 3-bearing camshaft or a 5-bearing camshaft. The block is fitted with 5 cam bearings. The #1, #3 and #5 cam bearings have oil passages which direct pressurized oil flow to the cam journal surfaces. If you plan to install a 3-bearing cam, the cam bearings are already pre-drilled for the #1, #3 and #5 journals so nothing further is required.
If you are planning to install a 5 bearing camshaft, you will need to drill an oil passage through the #2 and #4 upper and lower cam bearing surfaces to allow oil to flow to the cam journals (2 and 4). To drill the #2
& #4 cam, remove the oil plugs located on the bottom of the block which provide access to the oil passage system and to the respective cam bearings. See Picture 503 below.
To drill the oil passages through the bearing surfaces, a 5/16” drill bit with a minimum length of 12” will be required along with a jig to support the drill bit after it passes through the lower side of the cam bearing and begins to bore into the upper bearing surface. The jig can be made from a simple aluminum plug in the close approximate width and diameter of the cam journal (1” L X 1.56” DIA) – refer to picture 504 & 505 below.
Once the drill passes through the plug, any deflection on the drill bit from the bearing surface will be mitigated by the support from the jig and prevent the bit from breakage. Repeat this procedure for both the #2 and #4 cam bearings.
Ensure the hole is drilled completely through both bearing surfaces (lower and upper).
1.56” Diameter Drill Jig with Handle and 5/16” Drill Bit
BE SURE ALL FINE METAL PARTICLES ARE THOROUGHLY CLEANED FROM THE BLOCK AND OIL PASSAGES
(This procedure must be undertaken prior to cleaning the block in the pre-assembly stage). Once the cam bearings have been drilled and the block has been cleared of all metal debris, be sure to replace the oil plugs in the bottom of the block at the #2 & #4 cam bearing locations.
C. Rear Main Seal Installation
The rear main uses a radial lip seal (use National Industrial Seals 415035 or equivalent). It is recommended to remove the garter spring prior to installation to reduce friction. The garter spring side of the seal should face towards the interior of the cylinder block. The seal cavity is deep enough for 2 seals. If 2 seals are used, leave a cavity between seals and fill the cavity with a high-quality oil. Refer to pictures 502 a-c.
D. Thrust Washer Installation
There are 3 “half” thrust washers, each with two (2) screw fasteners. Two (2) washer components are located on the rear of the number 5 main bearing cap and block and one (1) washer component is located on the forward facing surface of the rear main cap. Refer to Pictures 504a and 504b below. The Crankshaft “end-play” is recommended to be between .002 and .007”; the forward surface thrust washer (Picture 504b) can be sanded down to acquire the desirable crankshaft end-play tolerance.
5. Clearance Verification
A. Stud and Bearing Clearance #1 and #3 Caps
Install and inspect the replacement studs for #1 and #3 main caps for clearance with the insert bearings. Be certain the temporary studs have been replaced and discarded. The stud diameters have been reduced to provide necessary clearance for the insert bearings. If the corners of the bearings are touching the studs, they should be filed slightly to provide the necessary clearance. See picture 601.
Check Clearance between Stud and Bearings on the 1 & 3 Main Seats
B. Connecting Rod Clearance
Connecting rod surfaces have tight minimal clearances (after installation). Ensure the rods are positioned with the “long side” facing the cam. Refer to Picture 602.
Areas of tight clearances include: 1.) Upper Rod side (facing the cam) and the bottom edge of the cylinder bore; 2.) Rod Cap Bolts Heads and the side of the block casting and inside walls of the oil pan; 3.) Rod Caps and camshaft lobes. Verify clearance by rotating the crankshaft.
6. Various Parts Notes
- Valve Guides: Original two-piece with shoulder, one piece with shoulder, or press-in valve guides can be used.
- Tappets: Single lock tappets (Colony CM1008)
Oil Pump: The stock Model A pump should be modified to increase oil circulation volume. Refer to the website www.burtzblock.com and click “Assembly Guide”; locate and open the tab “Doubling the Flow Area of a Model A Oil Pump”. Also note, the Stipe Oil Pump can be utilized (www.specialtymotorcams.com); refer to website for applications and modifications.
Note: For high pressure oil pumps, a 40 PSI pressure relief valve should be installed within the closed system. Higher pressures may require a heavier oil pump/distributor drive retaining spring. Consider replacing with the McMaster Carr 9657K522 spring.
The stock spring may be too light.
A blind-tapped (UNC 5/16-18) hole on the bottom of the bock can be used for a “dog clamp” to keep the oil pump in place. Refer to picture 701.
7. General Assembly Tolerances (inches)
Follow dimensional specifications provided by parts suppliers. If not available, use these specifications as a general guide line:
Upper ring gap
Middle ring gap
Lower ring gap
0.012 to 0.015
0.010 to 0.012
0.008 to 0.010
Piston to Cylinder Bore::
Measured at the bottom of the piston and at 90 degrees to the wristpin. 0.0035 – 0.004 if using solid-skirt pistons; 0.002-0.003 if using split-skirt pistons.
Intake valve/Tappet clearance
Exhaust valve/Tappet clearance
Main & Connecting Rod bearing clearance
0.011 to 0.012
0.012 to 0.013
0.0015 to 0.0020
0.002 to 0.007
8. Torque Specs:
- Head Stud Nuts
- Main Bearing Stud Nuts
- Connecting Rod Bolts
- Manifold Stud Nuts
9. Oil Filter System (Optional)
The pressurized oil system has been designed to accommodate an external oil filter. There is an exit hole for dirty oil and an entrance hole for returning clean oil built into the design. Refer to the website (www.burtzblock.com) and under the ”Builder’s Guide” tab find “Optional Oil Filter System” for a detailed explanation of how to set up an external oil filter system.
Oil Pressure Monitoring
If you look at the bottom of the valve chamber cavity, there are 2 oil passages from the main oil galley that connect to 2 valve cover bolt taps. Refer to Picture 1101. These passages can be used for an oil pressure gauge or to provide oil for an overhead valve conversion.
Valve Cover Bolts Taps provide Access to Pressure Oil System
To utilize these oil passages, a special bolt needs to be made from 1/2-inch hexagon stock. One end is threaded 5/16 -18 x 3/4 UNC and the other end is threaded 1/8 UNPF. The special bolt is shown in the following picture 1102.
10. Flywheel (Optional Part)
The 30-pound flywheel is machined to use the Ford V-8, 9-inch-Long design pressure plate (48-7563 or 09A-7563). We do not recommend the use of the 8N-7563 tractor pressure plate. The new flywheel is machined to accept the original Ford shoulder bolts (350433-S) that attach the pressure plate to the flywheel. Other 5/16-18 shoulder bolts can be used. Shoulder bolts are much stronger in shear than fully threaded bolts.
The new flywheel does not come with a ring gear installed because the beveled teeth on the ring gear need to be at the rear if using a Model A starter, and at the front if using a gear reduction starter.
We do not recommend the use of a “barrel” starter drive instead of an original Bendix. The “barrel” drive has a shorter throw (distance that the pinion gear moves between its resting position and its full extension). As a result, it will not engage the ring gear completely.
The new flywheel does not come with a pilot bearing.
11. Engine Block - Identification of Key Aspects
Oil Galley Plugs
There are 7 oil galley plugs that must be in place to maintain oil pressure. They are indicated in the pictures below.
The main galley runs front to rear and is plugged on each end with UNC 1/2”- 13 plugs (2); refer to pictures 1301 A and 1301 B. The bottom of the block has four (4) UNC 3/8”-16 plugs which are in direct communication with the main galley; refer to picture 1302.
The right side of the block has 1 UNC 7/16-14 plug located on the mating surface for the timing gear cover. Also note the UNC 7/16”-14 threaded bolt hole for the bottom of the timing gear cover communicates with the pressurized oil system; refer to picture 1303.
This hole also serves as the “filtered oil” return port to the system. It MUST be blocked either with a timing gear cover bolt – or – a return oil fitting to prevent loss of oil/pressure to the system. Refer to the Builder’s section regarding installation of the OIL FILTER SYSTEM.
To download a PDF copy of the Builder’s Guide, please select the download button below.