Engine disassembly

Started off by finding the new classroom, not too bad since it was near my last one.
Got myself introduced to the new Teach and away i went.

I paired up and picked out an engine, we were told to disassemble a 4 cylinder mazda engine. it wasnt too bad, more commen sense really, unbolt the corresponding bolts to the part that needed to come off, like the Cylinder head for example (that came off aswell) onthe the head came off we had to decide between each other Who's doing what, i chose the engine block to disassemble while my partner got the cylinder head.

i had to take out the pistons first then take out the crankshaft, funny enough those were pretty much all i had to remove from the block other than the water and oil pumps, hehe. the other bits was just a cambelt tensioner and cam gears.
afterwards came the semi-boring to boring part...Measuring the parts, crankshaft journals, piston diameter, cylinder bore etc.

i re-learned how to use the micrometer for measuring and learned how to use some new measuring equipment like the dial gauge.

I still have a bit of measuring to do.
-crankshaft journels
-conrod big ends
-conrod straightness
-piston ovality
-cylinder bore ovality
-etc

After all my measuring bizzo was done (which took a very long time because precision isnt really a fast task) i was to put back together the short block again.

For the reassembly i cleaned the parts then oiled them.
i started by placing the crank bearings back into place then placed the crank into place put the caps on and torqued to spec.


i got the pistons (numbered from the cylinders they were taken out of) compressed the rings with a ring compresser tool and placed them carefully into the cylinders, minding that the cap bolts dont score the crank journels. i placed the caps back onto the pistons from numbered order and torqued to spec.

lastly for the short block i placed the oil strainer, oil sump, water and oil pumps onto the block and torqued to spec, no real challenge here, its all pretty self explained.

Note: i did not have a camera for my own pictures of my work but ive placed pictures relating to what i have done.

robs questionaire

How does a four stroke engine work? Name the cycles I want to now what the piston is doing and the valves on each stroke :
 -A four stroke engine has four cycles, thus the name four stroke (stroke being the cycle).
 -First comes Intake Stroke, the piston pulls down in the cylinder distorting the air inside it creating a vacuum (inlet valve open while the exhaust is closed) sucking in an air/fuel mixture.
-Next comes the compression stroke where the piston moves up the cylinder to TDC (top dead centre) compressing the air/fuel mixture into the combustion chamber ready for combustion. (Both valves closed)
-Afterwards comes the Power Stroke, the compressed air/fuel is then ignited via spark plug creating a high pressure explosion within the small space that is the combustion chamber "Power"fully pushing the piston downwards. (valves are closed)
-Last Stroke is the Exhaust Stroke, the piston comes back up after the Power stroke pushing the waste gas out of the engine via the exhaust valve. (inlet closed, exhaust open).

Who and what year was the  four stroke engine invented:
-Nicolaus August Otto invented the Four Stroke engine in 1876.

What is the purpose of the crankshaft,camshaft,valves collects(keepers),valve sterm seals,head gasket,pistons,piston rings name them all, cambelt,flywheel?
-Crankshaft is has the pistons connected to it and keep them moving in a motion.

-Camshaft is like the brains of the engine as it controls the timing of when the inlet and exhaust valves open and close.

-Valves are the seals and gateways in a combustion chamber, inlet opens letting in a air/fuel mixture to be combusted when ready and the exhaust opens when its time to rid of the combustion bi-product, or exhaust gases.

-Valve seals stop oil from getting into the combustion chamber or anywhere near that general area but still lets oil circulate the valve guides and valves.

-Head gasket is used to tightly seal the very fine opening between the cylinder head and the block preventing compression from escaping.

-pistons are used to compress, suck , push, power and run the engine, compress by compressing the air/fuel mixture when in the cylinder, suck by creating a vacuum to intake, push to rid the exhaust gases, power by pushing downward help turn the crank and keep the rest of the engine running etc.

-piston rings are used to tightly seal the very very fine space around the piston when in the cylinder ensuring no compression escaping around it.

-Cambelt to run the camshaft/s off the crank and keep them in perfect timing.


-Flywheel to keep the turning momentum up on the engine when turning and something the starter motor can engage to tun the engine in the first place.

What is the bore and stroke.
The bore is the diameter of the engine block's cylinder, the stroke is the pathway the piston takes (eventhough its just a straight line) the lenth or distance it moves AKA the stroke. Stroke is from TDC (top dead centre) to BDC (Bottem dead centre) TDC being the top of the piston stopping just at the lip of the combustion chamber and BDC Stopping near the bottem on the cylinder.


What i am looking for is a good explaination about each component, use you-tube for videos...
http://www.youtube.com/watch?v=60QX5RY_ohQ&feature=related