How to Build a Honda Engine

The instructions in this article assume you have the necessary tools and basic mechanical ability necessary to complete an engine rebuild. It is impossible to cover every Honda engine; however, these details will be common to all Honda engines. This also intended to make the rebuild as inexpensive as possible while still maintaining professional results.

Things You'll Need

• Torque wrench
• Digital calipers
• Ring compressor
• Ring installer
• Valve spring compressing tool

Instructions

1. Remember that everything in this process that is removed must be returned to its original position. It is recommended to take an egg carton and number it in relation to cylinders and put all valve parts in this. Get a box ready and it will be used for the pistons.

2. Remove the exhaust and intake manifold. Take the belts and the accessories (power steering pump, alternator, air compressor). Remove the crankshaft pulley.

3. Remove the sparkplugs, the valve cover and the timing belt covers. Remove the timing belt tensioner and the timing belt. Remember to not turn the engine by the crank or camshaft sprockets when the belt is off as to prevent the valves from hitting the pistons.

4. Remove the camshafts by loosening the bolts. Loosen the outside bolts first, working toward the middle bolts so you do not warp the cam. Keep all cam caps in order as you remove them---they must go back on in the same location from where they were removed. Inspect everything for wear as it is removed. This will determine what is worn and whether it will be better to buy a used head at the junkyard.

5. Look at the lands on the head where the cams sit and at the caps. Look for wear such as groves, scoring or discoloration.

6. Replace the cam caps and loosely install the bolts. Look at the cam shafts one at a time and see if there are any grooves on the bearing surfaces that are visible. If so, they cannot be deep enough to feel with your fingernail. If you can feel them with your fingernail, they are ruined and must be replaced. Measure all the lobes of both cams (or the cam if it is a single cam engine) with calipers. On a single cam, one lobe will be exhaust and the next the intake and so on. Measure all the exhaust and then the intake and they should all be the same within .02 thousands of an inch. On a dual cam, one cam is the exhaust cam and the other is the intake cam. Look for wear on all of the lobes.

7. Remove the head by loosening the bolts from the outside first and move inward. Use an X pattern. Now lay the head on its side and pour water in the intake ports and look for leaks at the valves. Mark any valves that show leaks so the seats can be inspected when the valves are removed. Turn the head over and do the same with the exhaust.

8. Remove the valves and inspect the valve seats for excessive wear. Look for cracks between the intake and the exhaust valves. Look at the valve guides and see if they look perfectly round. Remove one of the valves. Put the valve guide in the empty spot (upside down) and see if it has side-to-side movement. If there is side-to-side movement, the guides are bad. If they are not too loose or just barely noticeable they can be knurled at the machine shop. Call the machine shop and tell them what condition the head is in and get a quote on the price to repair and compare that to replacing it with a used head.

9. Remove the pistons and put the connecting rod caps back on their respective pistons. Have the machine shop hot tank the Honda engine and bore the cylinders. If you go for turning your crank or buy a used refurbished crank remember this important fact: You don't want a crank that is more than 10-10. If it is cut more than 10 thousands of an inch, there is no tuffride left. Tuffride is the hardening material put on the journals. With no tuffride, the bearings will wear at a faster rate. Make sure you have the rods sized to the crank whether you use the old crank or buy a new or used crank.

10. Purchase a set of pistons and rings for the appropriate over-size that the machine shop cut the block. Purchase a new set of bearings. Install the crankshaft and the bearings. Install the pistons and the rings. Install the oil pump, making sure you prime it with oil first. Install the oil pan.

11. Install the head and torque it down in the proper sequence. Install the water pump, belt tensioner and the idler pulley. Install the timing belt and check the timing marks to make sure they line up.

12. Install the timing belt covers, the crankshaft pulley and accessory belts. Install the intake and the exhaust manifolds, then install the rest of the accessories in the reverse order they were removed.