225 Cylinder Misfire Help

TBh if your doing it on a budget and need it quick your best bet is a second hand engine in good condition.

Without tearing the engine down/ doing a leakdown test/ looking with a boroscope your just guessing its the rings. If its ringland failure you will need a new piston plus rings.
New rings are around the £100 mark alone. I'm unsure how much a new piston would be i've picked a seconf hand one up before for £50 - you will need to check the numbers on the top of the piston as they are graded my old engine had 3 B labbelled pistons and one C labelled, ideally you'd want to hone the cylinder with the new piston too(price dependant on machine shop). plus timing belt kit(£80ish quid), new gaskets(50-150) etc etc
Without looking at the piston you wont tell if its just a simple crack of the ringland or if something has come off and scratched the cylinder walls/ damaged the combustion chamber etc.

With your dipstick being blown out it does sound like bad blow by though so probably bottom end.

Are you able to fit a new engine yourself or tear down an engine and inspect?
As cost wise it will be probably be similar in parts/ new engine but i'd imagine the labour would be more for repairing the engine rather than replacement. (depending on damage)

 

Cant see a great deal from those pics - any chance of getting a few more with some better light/ less oil on the pistons? I'd also drop the suspect cylinder to the bottom and inspect the walls for any scratches.

I know what you mean about a second hand engine can be a bit of a gamble.

It is an odd one though as your compression was a good 155psi across all 4 cylinders to start, now you have no compression on cylinder 2 and low compression on cylinder 3. Was the compression tests both done with the same kit?

Your car didn't overheat while you were stuck in the jam? Just wondering if it could be a cracked head/ buggered head gasket?

 

It is a struggle to get the head off with the engine in the car, it took me about 3 half days, i only wanted to replace the valve stem seals, once the head was off i pulled the engine out in a couple of hours, put the engine back together on the floor and then you can get at all the nuts and bolts that were such a pain to get to when it was in the car, to refit the head, turbo, and all the other bits took just over 3 hours, then refitted the engine, it is so much easier to pull the engine out i would almost consider it when the cambelt needs replacing.

 

In removing the engine ????

 

This i would say this a good option,
http://www.rsmegane.com/threads/225-r26-engine-for-sale.13490/
then you can sort your engine out at leisure, forge it or what ever, then resell this one when you are good and ready.

 

Jack up the car, make sure its solid on axle stands and high enough to get in under the car.

Disconnect the battery
Remove
front wheels
inner front arch liners
front bumper and under tray
drain engine oil, gearbox oil and coolant
remove head lights
the crash bar
intercooler, air con rad and radiator
you need to loosen the hub nuts, so get someone to put foot on the brake, or use a chisel
calipers and discs off
undo lower suspension mounts, track rod ends, anti twist links (only one end needed) hub clamp bolt, then remove the hub
passengers side, pull out drive shaft
drivers side, undo the bearing retainer plate and pull the complete shaft out
remove battery, battery box and ecu bracket, after unplugging the plugs on the ecu, air box if you have one
disconnect the engine wiring loom from the fuse box
gear cables
pipes on the air con pump
fuel and vacuum pipes
top rear and bottom rear stabiliser mounts
exhaust
take the weight of the engine with engine hoist
undo gearbox mount nut, you might have to give it a good clout to release it
drivers side mount from chassis and engine
there are two hoses at the rear for cabin heater easier to pull the engine forward to get at
and then the clutch pipe, this will empty your master cylinder so lift it up or cap it off

lift the engine out of the hole, that is about it, might be a few odd bits i have missed but that the gist of it.

 

I have done a couple now, last time was for me about 3 1/2 hrs if you have not done this before i would say a days work, there are all the rusty bolts to over come, going back would be quicker

 

No problem, by the time you spend out on gaskets, pistons etc it would be just as well to put another engine in it, the engine i took out of mine for the 250 upgrade had done 117k miles and in the last 2 years has basically been used only on track days, there is nothing wrong with it, i suppose there are good ones and not so good ones