engine lost power at track..car cut off
I apologize for my short sided answer, I was just leaving work and was in a little bit of a hurry. You are correct, the oil test is not as beneficial on dished pistons as normal dome style piston tops. However, if you put oil in the chamber to do a "wet test" on the first compression stroke that the cylinder takes it usually displaces a good amount of this oil out of the dishes (or valve bowls on the piston) and around the rest of the piston head. Eventually this oil will settle down into the rings and ring landing, raising compression on a cylinder that has ring seal issues. You may have to crank it a few more cycles to get it to displace this oil, but it will.
I have used this technique to diagnose at least a half dozen issues with rings on the 4G63 and on other import motors. It works at least 90% of the time to diagnose a bad ring seal. Cheap, easy and effective. Just because you say these motors use "dished" pistons is not a reason for the OP to ignore a tried and true technique.
I have used this technique to diagnose at least a half dozen issues with rings on the 4G63 and on other import motors. It works at least 90% of the time to diagnose a bad ring seal. Cheap, easy and effective. Just because you say these motors use "dished" pistons is not a reason for the OP to ignore a tried and true technique.
While plausibly effective, I believe there are better and more accurate options to check ring seal then pouring in oil and risking a false diagnosis.
Nothing like dumping time and money into a car not to fix it.
Nothing like dumping time and money into a car not to fix it.
Like what, a leakdown test? That will be effective to diagnose an issue also, but why do you say running a compression test is dumping time and money into a car and not fixing it?
Last time I checked a cheap compression tester cost maybe 20-30 dollars new? Search for it on Google: http://lmgtfy.com/?q=compression+tester
A cap of oil is pretty cheap, too. It would take 5 minutes. If the compression doesn't go up then try a different test or method, like you said. If it does go up then you have diagnosed an issue with the rings for certain.
To me less than 30 dollars to have a confirmed diagnosis of an engine issue is cheap... Wouldn't you say?
Last time I checked a cheap compression tester cost maybe 20-30 dollars new? Search for it on Google: http://lmgtfy.com/?q=compression+tester
A cap of oil is pretty cheap, too. It would take 5 minutes. If the compression doesn't go up then try a different test or method, like you said. If it does go up then you have diagnosed an issue with the rings for certain.
To me less than 30 dollars to have a confirmed diagnosis of an engine issue is cheap... Wouldn't you say?
Just off the wall have you looked inside your intake filter. I only ask because I had the same thing happen to me at the track. It ended up that the car sucked the honeycomb out of the MAF and spit it out in the intake filter. The car would idle fine but as soon as I hit the throttle the wad of honeycomb would suck up and block all of the airflow going to the turbo at the MAF.
Like what, a leakdown test? That will be effective to diagnose an issue also, but why do you say running a compression test is dumping time and money into a car and not fixing it?
Last time I checked a cheap compression tester cost maybe 20-30 dollars new? Search for it on Google: http://lmgtfy.com/?q=compression+tester
A cap of oil is pretty cheap, too. It would take 5 minutes. If the compression doesn't go up then try a different test or method, like you said. If it does go up then you have diagnosed an issue with the rings for certain.
To me less than 30 dollars to have a confirmed diagnosis of an engine issue is cheap... Wouldn't you say?
Last time I checked a cheap compression tester cost maybe 20-30 dollars new? Search for it on Google: http://lmgtfy.com/?q=compression+tester
A cap of oil is pretty cheap, too. It would take 5 minutes. If the compression doesn't go up then try a different test or method, like you said. If it does go up then you have diagnosed an issue with the rings for certain.
To me less than 30 dollars to have a confirmed diagnosis of an engine issue is cheap... Wouldn't you say?
He puts a cap full of oil in his cylinder the compression raises he thinks his rings are bad rips the motor apart and spends money on parts.. just do discover that's not really his issue.
See where I'm going now? I'd rather be more then "fairly certain" before digging into anything.
I understand what you are saying, but if a cap of oil raises the compression in the cylinder it is always the rings. The rings or piston top cracked. Always. If it doesn't rise then it's the valves or timing issue. Either way, the head has to come off. Boroscope the motor if you have a device or a shop who has a video feed to double check before anything, but I just thought that writing off the wet test because of dished piston tops was a rash decision.
Okay. Lets not pollute the tread, OP I apologize for going into it here.
Okay. Lets not pollute the tread, OP I apologize for going into it here.
Just off the wall have you looked inside your intake filter. I only ask because I had the same thing happen to me at the track. It ended up that the car sucked the honeycomb out of the MAF and spit it out in the intake filter. The car would idle fine but as soon as I hit the throttle the wad of honeycomb would suck up and block all of the airflow going to the turbo at the MAF.
but did one of your plugs gap close as well?
PM me if you need anything.
