HI, TOP GASKET WAS CHANGED BY SOMEONE, ENGINE AFTERWHICH IS NOT STARTING, ASSUMING THEY DIDNT SET Z TIMING CORRECT, WE NEED HELP HOW 2 CHECK Z TIMING,THKS,,,,2007supercharged

Exactly which gasket did you change? There is a gasket on the valve cover and a gasket between the cylinder head and the engine block, the Head Gasket. It's the Head gasket you need to change. Then you need to flush the Oil system and the coolant system to clean them out.
Changing a head gasket is a Big job where you remove the top half of the engine exposing the piston tops. If the gasket has been changed 'several' times your probably looking at a cracked cylinder head or engine block, a VERY expensive repair. If this is the case it's usually easier to replace the whole engine.

First, DO NOT start the engine if the mechanical timing is wrong! My next obvious suggestion is to get it to a good mechanic and get them to sort it out for you.
I'm assuming your refering to the Mechanical Timing? Mazda use an 'Interference' engine so read this all the way through BEFORE doing any work. An interference engine means the valves will hit the piston face if the mechanical timing is even slightly out. That is why you don't start your engine with the timing set wrong. It's a VERY expensive repair.
Start from scratch. Remove the chain from the CAMs and cable tie it to something on the top of the engine to stop it disappearing out of sight.
Turn the Crank to about 10 to 15 degrees past Top Dead Centre (TDC). This is to move the pistons away from the valves so you can set the Cam timing marks. Set the Cam marks first then turn the Crank BACK to TDC. As long as the chain marker on the crank sprocket is lined up correctly the Cam chain markers should be correct.
Once you have timed everything into place use a socket and ratchet to turn the Crank pulley bolt Clockwise 2 full rotations. The timing marks should return to the correct positions.

I am assuming this is when the spark plugs are still in place and the oil isn't from a spill when someone has missed the hole filling the oil.
If it is a leak the most obvious place the oil is leaking from will be the rocker cover gasket. Make sure you clean the plug and it's mounting hole before removing it to reduce any oil getting into the cylinder.
Take a good look at the top of the engine, there is a bolt on, full length cover right on top of the engine. A lot of engines have the oil filler cap mounted into it. There should a be a seal between this and the top of the cylinder head.
Changing this gasket is fairly easy and won't affect anything important like mechanical timing. If you can, clean the engine as best you can with a degreaser as this will help hunt the leak if it isn't the gasket.
*Note* When you remove the old gasket make sure both the surfaces that squeeze together are completely clean before refitting the new one. Also make sure the gasket is lined up correctly to avoid leaks. A TINY amount of gasket sealant can be used to hold the gasket in place when fitting the cover.
The cover bolts are NOT in too tight. You should wind them until you hit resistance then turn it a small amount more, Then Stop.

Recheck valve timing and initial ignition timing for correct settings.

Hi
firstly, do you have the equipment to change the head gasket.
ie: a suitable torque wrench for the head bolts?
do you know how to re-time the engine having removed and refitted the timing belt(which you should renew)
I`mj looking at the worshop manual now and I presume you know how to strip an engine
The important part is when you replace the head (having made sure it`s not warped or cracked) and having cleaned all mating surfaces, you should have ten cylinder head bolts the tightening sequence is ____________________________
8 6 2 4 10


9 3 1 5 7
_____________________________

the torque settings are assuming you`rs is a M.40 engine is stage1 30 n/m stage 2: angle tighten 90 degrees stage 3 angle tighten 90 degrees.

Good Luck

Doug

2 blocks is fast to reach boiling.Take the cap off the overflow tank and fill it right to the very top with coolant.Start the car and watch for a steady stream of bubbles.If you see a steady stream you do need a head gasket or have a crack somewhere in a combustion camber.

The 2.2 is known to "strip" the timing gear. The cam gear is made of a synthetic material. But...you could possibly have an injector bad on #1.

your mechanic does not know what he is doing. you need to find someone with training and experience to fix it correctly.

hi from uk i assume you have done all the above work correctly? and the leads from coils are correct firing order 1 3 4 2 ? CAMBELTtiming set correctly etc as you say this has happened since cyl head renewed and miss fire is on Nos 1+2 cyl's this normally suggest now after all work u have done and assume compressions are ok ? i had such a fault on a customers mini some years ago who had done exact type of job as you described this fault turned out to be the inlet manifold gasket had split between cyls inlet ports and resulted in missfire on 2 cyls adjoining on removal of manifold the gasket had been damaged whilst reassembling new gasket cured missfire which had caused weak mixtur on both cyls ie on induction more air being drawn via cracked gasket on each cyl and as your engine if injection same problem?? might be worth checking?? hope this throws some light on the problem?

No. 4 to Top Dead Center is Correct.