The Ford 2300 engine has proven...
The Ford 2300 engine has proven itself reliable for four-cylinder racing classes and delivers strong performance at 7,500 rpm.
In our January issue, we introduced you to a Mustang Mini Stock project undertaken by Steve Smith Autosports and Esslinger Engineering. Our previous effort focused on the suspension, and now we look at the engine that puts the power to the ground. This buildup is also covered in a video called Ford 2300 Engine Building, and the complete buildup can be found in the book, Building the Mustang Ministock. Both are available from Steve Smith Autosports Publications, 714/639-7681, www.stevesmithautosports.com.
Wherever you find Mini Stocks, you are likely to find the Ford 2.3 OHC engine in the pit area. This powerplant has proven itself worthy of the challenges of the four-cylinder racing wars. It has been offered in a number of Ford and Mercury products since 1974 and remains plentiful. A 2-liter version was introduced in truck lines in 1983. Bore diameter is the only difference between the two engine types, meaning all parts are interchangeable.
With any engine project, a solid foundation is necessary. When considering a Ford 2.3 block, look at the junction of the breather boss to the block (on the left side). This is prone to cracks if the block freezes. The valve covers and pan should be pulled to look for cracks, heavy sludge, or cylinder wall wear. Connecting rods should be inspected for discoloration. The cylinder bores should be free of scratches.
A micrometer is used to measure...
A micrometer is used to measure the piston diameter 90 degrees from the pin centerline. With this number and the expected piston-to-bore clearance, cylinder honing size can be determined.
If it has been faced with excessive heat, the head will crack between the exhaust seat and the intake seat. The cracks are generally not visible to the naked eye and require magnafluxing.
Look for physical damage to the engine. Any damage could indicate it ran out of oil at some time, causing internal woes. A damaged crank pulley could indicate severe internal damage from a blow to the front of the engine.
The block and head should be disassembled with freeze plugs and threaded oil gallery plugs removed. The engine should be hot-tanked and then cleaned with high-pressure steam and a good degreaser. Use compressed air to blow dry the block.
A dial bore gauge can determine...
A dial bore gauge can determine the finished size of the cylinder.
Since castings don't have a uniform thickness, sonic testing is a good idea. You can determine if the block is good enough to proceed, especially if overboring is involved. Your block will face several machining operations, including align-boring the mains, milling the block deck, boring the cylinders, and finish-honing the cylinder bores.
A used block needs overboring to clean up the cylinder walls and to ensure the bores are perfectly round. It is not advisable to overbore a 2300 block much beyond 0.040 inch due to thin cylinder walls. Too much boring can cause cylinder wall flex.
Before the cylinders are honed, piston-to-bore clearance must be set. Check the piston manufacturer's recommendations. Clearance for racing will generally fall between 0.003-0.005 inch. A closer fitting piston will support the rings better and seal better. However, a piston that is too tight will result in friction and damaging heat.
Studs with steel support straps...
Studs with steel support straps can outperform main cap bolts, especially in high-rpm applications.
To find clearance, mate each piston to a cylinder and number them according to their cylinder position. Measure piston diameter 90 degrees from the pin centerline. Add the desired piston-to-bore clearance to get the honing size.
When the cylinders are honed, a torque plate must be installed. The block will twist and distort as bolt torquing brings internal stresses. Having the torque plate in place and the main caps torqued and in place will represent the stresses of the block similar to final assembly. Cylinder bores will be round and free of distortion. Crank bearing bores will be square to the cylinders. Since the cylinder bores are perfectly round, the rings will seal much better in the cylinders. Using the right head gasket in this process will make a difference in how the bolt pulls into the block. Finish-honing of the cylinders is done in four steps with four different grit ratings, starting with 150-grit and then 220-grit. A 280-grit stone sets the crosshatch, which creates a finish that is too rough. A 500-grit stone and plateau brush smooth out and finish off the crosshatch. Finish-honing is done to remove only 0.005 inch diameter.