Toyota Vista 1.8 4S-Fi (1990): Cylinder Head Resurfacing

Part numbers are from the manufacturer's original catalogue. Check them against your VIN before ordering.

• Socket and wrench set
• torque wrench
• hex bit for head bolts
• straightedge and feeler gauge set
• gasket scraper (plastic or brass)
• valve spring compressor/stand
• coolant drain pan
• engine tester or hoses for leak testing

1. Let the engine cool down completely. Drain the coolant from the radiator and from the cylinder block, and it is best to drain the oil as well. Disconnect the negative battery terminal.
2. Remove the air filter with its ducts, and disconnect all sensors, connectors and hoses from the head and intake manifold. Photograph or label every connector and hose. Remove the fuel rail with the injectors, after first relieving the pressure in the fuel system.
3. Remove the intake and exhaust manifolds. Disconnect the downpipe from the exhaust manifold. Remove the throttle cable or linkage and the cooling system hoses.
4. Remove the timing cover and the timing belt. Before doing so, set the crankshaft to top dead center on the compression stroke of cylinder 1 using the mark. Do not turn the crankshaft with the belt removed until the head is off and the crankshaft and camshafts are secured.
5. Remove the camshaft pulleys and the valve cover, then remove the camshafts together with their bearing caps. Be sure to mark the camshaft bearing caps and lay them out in order: they must not be mixed up.
6. Loosen the head bolts in the reverse of the tightening sequence: from the edges toward the center in a spiral, in 2-3 passes. This is important: on an aluminum head, loosening the tightened bolts in the wrong order causes additional warpage. Remove the head. If it is stuck, tap it with a rubber mallet, but do not pry between the mating surfaces with a screwdriver.
7. Clean the head and block surfaces of gasket residue with a plastic or brass scraper, without scratching the aluminum. Do not let debris get into the cylinders and oil passages. Plug them with a rag before cleaning.
8. Check the head surface: lay a straightedge on the mating surface lengthwise and along the diagonals, and measure the gap with a feeler gauge. The allowable warpage for aluminum heads of this type is usually about 0.05 mm. The exact value is in the manufacturer's service manual. If the gap is within the limit, resurfacing is not needed and replacing the gasket is enough. Also check the flatness of the block.
9. Before resurfacing, have the head inspected: check for cracks (pressure test), the condition of the valve seats and valve guides, and the camshaft bearing journals. There is no point in resurfacing a cracked head or one with worn camshaft journals.
10. Have the resurfacing done on a machine that mills or grinds aluminum. Remove the minimum amount of metal needed to eliminate the warpage, usually no more than 0.2 mm in total. The machinist should measure the head height before and after and tell you how much was removed. Heavy removal changes the compression ratio and shifts the valve timing because the distance to the crankshaft changes. It can also cause valves to hit the pistons if the timing belt jumps a tooth.
11. After resurfacing, the head must be washed and all passages blown out. The valves should be lapped or replaced, with new valve stem seals. Check the valve clearances (adjusted with shims or lifters, per the service manual).
12. Install a new head gasket dry, without sealant, in the correct orientation ("TOP" facing up, if marked). Set the head onto the dowels. Lubricate the bolt threads with engine oil.
13. Tighten the head bolts strictly in the sequence from the center outward in a spiral, in 2-3 passes (as a guide, about 30 N·m (22 lb-ft) on the first pass, then an additional 90° turn on the second and third passes; exact values are in the service manual). If the bolts are stretch-type, check their length against the specification and replace any that are stretched.
14. Install the camshafts and the bearing caps in the order of their marks, and tighten the caps evenly with low torque (about 12-20 N·m (9-15 lb-ft); exact value is in the service manual). Install new seals.
15. Install the timing belt according to the marks: the crankshaft mark and both camshaft marks must line up. It is best to replace the tensioner and rollers along with the belt. Turn the crankshaft by hand 2 full revolutions and recheck that the marks line up.
16. Reassemble the manifolds with new gaskets and tighten the fasteners evenly (as a guide, 15-30 N·m (11-22 lb-ft); confirm in the service manual). Reconnect the connectors, hoses and cables. Fill with fresh coolant and oil.
17. Start the engine, let it warm up, and bleed the air from the cooling system. Check for oil and coolant leaks, error codes and smoke from the exhaust. After 500-1000 km of driving, check the coolant and oil levels if necessary.

• Resurfacing an aluminum head is a job for a specialized machine shop
• Do not try to do it yourself on a sanding plate, because it is easy to end up with an uneven surface
• Do not exceed the allowable amount of metal removal, or you risk changing the compression ratio and having the valves hit the pistons if the timing belt breaks
• The 4S-Fi timing belt is on engines with a risk of bent valves, so always recheck the marks after assembly
• If you have no experience disassembling engines, leave the job to a repair shop