Just had a mechanic friend of mine do a compression test on the front cylinders on the engine. He did a dry test where he disconnected one of the sensors, put the guage in one cyclinder at a time and cranked the engine with throttle full open. Engine doesnt actually turn over with the sensor off.
Anyway I got a rate of on average 155psi per cyclinder with no more a difference than 8psi per cylinder. I was told that the dry test would be lower than if the engine turned over etc but was wondering if any of you mechanically minded types knew wether this was low or high or acceptable etc. Car doesnt leek oil so Head Gasket seems fine, now does it feel slow but I dont have many otehr FTO's to compare it to here.
I recently had mine compression tested (major service with Unique), and they were pretty much all in the range of 175-185psi. So it does sound a bit low to me.
It is suppose to be 1226kPa (178PSI) with a min of 1030kPa (149PSI) and the cylinders should not vary by more than 98kPa (14PSI). These figures are at 250rpm and were found in the workshop manual
mrx wrote:I recently had mine compression tested (major service with Unique), and they were pretty much all in the range of 175-185psi. So it does sound a bit low to me.
High compression could mean you're leaking oil into the cylinders
Hi Guys thanks for all the replies. Forgot to mention is a GX so no mivec dont know if the compression would be different. He was going on about it being a dry test and that It would go up when the car started etc. but to be honest he lost me somewhere around there. I cant notice my oil level going down so I dont think it could be leaking a significant amount of oil etc.
Anyway so say its a bit low, what do ya think I can do about it without spending big $$$. Want to get 101% out of my engine like everyone else here Thanks again.
from what i understand, if your losing compression, it can be a number of things... Im losing about 30% on one cylinder, and because of that im suffering blow by.... "gases leak from the cylinder, and cause crank case pressure - because their is a pressure build up, your seals often go in the crank, cam and sump... then you start losing oil" or something like that.. to fix, they need to open up the engine normally and find out why you are losing compression - can be rings, pistons etc, but normally you are up fopr big bucks! the labour costs alone... if your only losing a little I wouldnt do much about it, wait till it gets worse.
Ok yeah he also mentioned the the engine should've been tested a little warmer. it wasnt quite operating temperature and that could've given slightly lower compression. We didnt do the back since that would've been a lot more work but one cyclinder was 160 and the other two were 150/152 IIRC. So I dont think its big enough issue to spend that much money on right now.
...pardon me... 