Compression Check

[Akfahad]

Well, my car has been in the shop for the past week as they tried to fix the AC. Since it was in there, I figured I'd have them do a compression check on the front three cylinders.

I read a post from JoeB that they should be ruffly around 190psi. I just got off the phone with the shop and all three read around 150psi. For those of you who don't know, I've been running the 6lb. pulley for about a month now, since doing my dyno run.

Driving wise, I won't really push it during the day since it's so freaking hot here plus the humidity, which just kills you. At night it cools down, then I'll open it up a little bit, but nothing major unless I find someone to race. Plain and simple, I just don't race during the day when it's so damn hot.

Didn't mean to make this long, just wanted it to be informative.

Josh

[SC V6]

sounds like you need a new motor due to broken ring lands ( 150 psi compression check basically)

[Fletch]

I thought the acceptable range went down to 145 psi?

[Alex(AUS)]

Hi Josh,

Did you read my post? I originally did a comp check on my front 3 cylinders and the mechanic got a reading of 160odd. Initially I wasn’t too worried because I have a high mileage engine (and 145 is acceptable). I eventually got my own compression gauge and I did a readout on my own (I cycled the engine while the needle went up ... the mechanic stopped the process very early). I got 220+ on each of the 6 cylinders. I have been running 6psi for over a year now ...

Alex

[SC V6]

150 is low.. should be like 190.... I would check some old threads.. im pretty sure thats lower than speck

[Akfahad]

150 is low.. should be like 190.... I would check some old threads.. im pretty sure thats lower than speck

Yeah, I remember reading JoeB had said it should be around 190psi, but now that I think about it, reading Alex's post, the mechanic did stop early and only took the reading a certain way. He told me, but I can't remember exactly how he did it.

[SC V6]

Im pretty sure that the leak down test should be done w\ the engine off... anyway... I would get a second opinion on this and get a hold of JoeB because I know w\ it at 150 thats not good.. check the hose that comes off the front valve cover.. it should have a suction to it.. check and see that its sucking air in and not pushing air out..

if air is being pushed out then it has blow by which would mean you have a cracked piston land

[Fletch]

The compression check is done by cranking the motor several times so that it is able to go to TDC and build the max pressure. It's not going to start.

[Alex(AUS)]

150 is definately on the low side SC V6 but it is within the Toyota "still ok" spec (being 145-210 or more). Normally, members get around 190.

Josh's power figures suggests that the 150 reading may be a little off the actual.

Alex

[SC V6]

they did a leak down test of my car when I was having issues and mine was somewhere around there... and I had cracked piston lands... Get in touch w\ joeb

[DatSRBoi]

How do you test for these things? Where is it located on the car? Is that why they have them valcum gauges? Im learning