Replacement of cam and lifters.

I would check the oil pressue and ensure adequat pressure is on the hydraulic cam followers.
Could be just engine wear due to age/lack of maintainance etc.

buying any second hand car is a risk of loosing your money
check for rust in the body and subframes as if the shell is no good , then it will be a waste
take the car to someone that does car inspections and get a report on the condition and then decide on what you want to do
timing belts here cost around $900.00 aud to replace as a good mechanic will do the belt , replace idlers and adjusters and the crank and cam shaft seal/s
oil is very bad for a belt so if the seals are not done , expect about 1/2 the distance on a new belt
at that distance , it will be on the second belt and to make sure, all that I have referred to should be replaced

far too many things to list.
Worn cam lobes, bad lifters, valve seals, need full tune-up, wearing piston rings, O2 sensors, bad cat converter, etc, etc.

Hi there:
First I suggest to check this information about "engine noses"...
ENGINE CLICKING NOISES
A clicking or tapping noise that gets louder when you rev the engine is probably "tappet" or upper valvetrain noise caused by one of several things: low oil pressure, excessive valve lash, or worn or damaged parts.

First, check the engine dipstick to see if the oil level is low. If low, add oil to bring it back up to the full mark. Is the engine still noisy? Check your oil pressure. A low gauge reading (or oil warning light) would indicate a serious internal engine problem that is preventing normal oil pressure from reaching the upper valvetrain components. The cause might be a worn or damaged oil pump, a clogged oil pump pickup screen or a plugged up oil filter. Using too thick a viscosity of motor oil during cold weather can also slow down the flow of oil to the upper valvetrain, causing noise and wear.

COLLAPSED LIFTER NOISE
Worn, leaky or dirty lifters can also cause valvetrain noise. If oil delivery is restricted to the lifters (plugged oil galley or low oil pressure), the lifters won't "pump up" to take up the normal slack in the valvetrain. A "collapsed" lifter will then allow excessive valve lash and noise.

VALVE LASH NOISE
If you can rule out lubrication-related problems as a cause, the next step would be to remove the valve cover(s) and check valve lash. On older import engines, mechanical lifters require periodic valve lash adjustments (typically every 30,000 miles). Too much space between the tips of the rocker arms and valve stems can make the valvetrain noisy -- and possibly cause accelerated wear of both parts.

To measure (and adjust) valve lash, you need a feeler gauge. The gauge is slid between the tip of the valve stem and rocker arm (or the cam follower or the cam itself on overhead cam engines) when the piston is at top dead center (valve fully closed). Refer to a manual for the specified lash and adjustment procedure. Also, note whether the lash spec is for a hot or cold engine (this makes a big difference!).

On engines with hydraulic lifters, oil pressure pumps up the lifters when the engine is running to maintain zero lash in the valvetrain. This results in quiet operation. So if the rocker arms are clattering, it tells you something is amiss (bad lifter or worn or damaged parts) or the rocker arms need adjusting.

DAMAGED ENGINE PARTS NOISE
Inspect the valvetrain components. Excessive wear on the ends of the rocker arms, cam followers (overhead cam engines) and/or valve stems can open up the valve lash and cause noise. So too can a bent pushrod or a broken valve spring.

RAPPING OR DEEP KNOCKING ENGINE SOUND
Usually bad news. A deep rapping noise from the engine is usually "rod knock," a condition brought on by extreme bearing wear or damage. If the rod bearings are worn or loose enough to make a dull, hammering noise, you're driving on borrowed time. Sooner or later one of the bearings will fail, and when it does one of two things will happen: the bearing will seize and lock up the engine, or it will attempt to seize and break a rod. Either way your engine will suffer major damage and have to be rebuilt or replaced.

Bearing noise is not unusual in high mileage engines as well as those that have been neglected and have not had the oil and filter changed regularly. It can also be caused by low oil pressure, using too light a viscosity oil, oil breakdown, dirty oil or dirt in the crankcase, excessive blowby from worn rings and/or cylinders (gasoline dilutes and thins the oil), incorrect engine assembly (bearings too loose), loose or broken connecting rod bolts, or abusive driving.

Bearing wear can be checked by dropping the oil pan and inspecting the rod and main bearings. If the bearings are badly worn, damaged or loose, replacing the bearings may buy you some time. But if the bearings are badly worn or damaged, the crankshaft will probably have to be resurfaced - which means a complete engine overhaul or replacing the engine is the vehicle is worth the expense.

ENGINE PINGS OR KNOCKS WHEN ACCELERATING
The cause here may be Spark Knock (Detonation) caused by an inoperative EGR valve, overadvanced ignition timing, engine overheating, carbon buildup in the combustion chambers, or low octane fuel.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

The repair depends on the exact cause. Typically one of two things happens.

A lifter fails to "pump up" and looses pressure. Sometimes oil system cleaners can help this.

The other thing that happens is wear realted, called a collapsed lifter, this issue requires replacement of the camshaft and all lifters. I recommend against replacing only a collapsed lifter, as the cam lobe usually gets damaged, as the two parts are hardened and wear against one another (cam and lifter).

It is always possible to have a rocker arm come loose. The only way to know for sure is exploritory surgery.

Um, what does bad mean, exactly? If the lifter collapsed, the camshaft and lifters need to be replaced. If the lifter will not pump up, you could replace just the one lifter.

My L series throws grease up onto the exhaust pipes causing the smell, so you could have split boots on your CV joints. That could account for the smell. The noise could be coming from a rear brake, something in drum like an auto adjuster come adrift If you do have damaged CV joint boots, you will need to have them replaced immediately or you will wear these joints out very quickly.

If there are a lot of miles on the timing belt (over 60,000), the belt may have jumped several teeth due to wear causing the cam to be out of time. If the lifters go flat from oil lack, the engine will continue to run poorly, and very noisy. Check the timing marks on the cam and crankshaft to see if they are lining up properly.

At 21 years old it is important to look at the value of the vehicle and the ability to acquire used parts. If you are replacing the rear end you may be looking at big money if you had to tap the new market ..it could be terribly expensive. Look at things like body rust and engine health before diving into a major expense.