Compression

Q

qball

Sunday Drivers
Hi lads has anyone got the numbers on the compression of the ej20k engine from a version3 sti just did a test wanna compare to one thats running well. Much Appreciated.
 
Compression ratio for a stock ej20k 8.0. Hope that helps.

Googling a few different web sites, and any that listed the ratio said 8.0.

Steve.
 
to be honest i couldnt tell you i dont know a lot about the car and the guy that had it previously was just as informed as me, i presume there is no way of telling with the head on. I also read around saying if there is more than 10% difference in compression there is something wrong could you confirm that.
 
Also maybe some useful information 3 plugs are covered in carbon changed them out a while back just before i parked the car up but one plug seems to be as clean as the day i put it in would this be no fuel going to that cylinder?
 
if no fuel weas going in i would say it would be misfiring??i thought if it was cleaner than the rest it was a sign of head gasket gone as the water getting into the cylinder was "cleaning " the plug???could be way off though
 
If the injector is gone or blocked would this have the same effect, all plugs are firing and there's no smoke from the car at all to suggest a head gas kit gone.
 
High compression ratio can be caused be loads of things but mainly carbon build up on the piston or a thin head gasket.

I wouldn't worry about high compression, but I would worry about low compression. Carbon build up on the pistons or plugs is normal and is just caused from normal running, less carbon on 1 may be a sign of running lean but it could be grand. It is unlikely the injector is blocked especially if the car runs ok. Have you got a compression test done to say what psi each cylinder is?
 
Thats the problem the engine isnt running ok its running at very low power all the time, with the exception of sometimes where full power will come back then it will drop again in a matter of seconds.
 
silverbullitt said:
shocking scurrillous remark outta you :naughty: :hand:
Click to expand...

out of me? what do you mean? Legacy engines run higher compression that why he could be getting the higer readins coupled with a wrx ecu and turbo this would cause problems, this happend to my mate. Could be a cause of his problems was trying to help the guy,I own a legacy btw.
 
Ok did compression test again think engine may have been too cold last time and all cylinders are running at 9.5bar 138psi, checeked injectors and spark plugs they all seem to be fine, what could be the next step, maybe maf? Any help would be great. Oh and car is running an impreza sti engine.
 
qball said:
Ok did compression test again think engine may have been too cold last time and all cylinders are running at 9.5bar 138psi, checeked injectors and spark plugs they all seem to be fine, what could be the next step, maybe maf? Any help would be great. Oh and car is running an impreza sti engine.
Click to expand...


if all are running equal 138psi then wouldn't worry.....

issue is somewhere else.
 
Scoobymaniac said:
High compression ratio can be caused be loads of things but mainly carbon build up on the piston or a thin head gasket.

I wouldn't worry about high compression, but I would worry about low compression. Carbon build up on the pistons or plugs is normal and is just caused from normal running, less carbon on 1 may be a sign of running lean but it could be grand. It is unlikely the injector is blocked especially if the car runs ok. Have you got a compression test done to say what psi each cylinder is?
Click to expand...


High compression across the board is caused by a high compression engine.

And high compression i would worry about more so then low compression so reallly do not understand your point as would lead to more disaster on a turbo engine..



I.E. dish volume and cc and head gasket thickness...
 
davelegacy said:
qball said:
Ok did compression test again think engine may have been too cold last time and all cylinders are running at 9.5bar 138psi, checeked injectors and spark plugs they all seem to be fine, what could be the next step, maybe maf? Any help would be great. Oh and car is running an impreza sti engine.
Click to expand...


if all are running equal 138psi then wouldn't worry.....

issue is somewhere else.
Click to expand...

Had a look around intake on the turbo end of things and there seems to be a rip around where it is cliped on to the turbo housing i reckon that was caused when i changed the turbo out a few months back, im sure this would have some issue as there is air leaking with the result of the poor performance and unsteady revs and bad responce on the throttle, i think anything else is beyound me for the moment. All my thinking is probably wrong and im open to correction.

Was trying to get in touch with ya today Dave to see did you have an intake hose, ended up getting an ebay job cause i couldnt find them anywhere else.

Also if its possible to tell me how high compression is reached on this engine, if there is anything physical i can see in plain view. Also if the results i am getting from the compression test are similar to a high compression sti engine and if its safe to run it at this amount of compression.

I will soon have to bring this car up to ya Dave to get this mystery machine the once over when i can drive her on.

Cheers for all the help lads.
 
You must log in or register to reply here.
Back
Top