AZP Installs Posted August 27, 2011 Share Posted August 27, 2011 Mike, I'm thinking of going Stage 2+. At over 173k, I did compression check, spec, are 141psi to 171psi, at 350 RPM's with no greater then 7 psi between cylinders. Starter must be getting weak. With Battery fully charged & a charger set on 225A "Start", the motor only turn 286rpm, 1) 145psi, 2)150psi, 3)145psi, 4)147psi. How much will only turning 286 rpm, instead of 350 rpm effect my compression test. Mike Well, 171psi is pretty darn high! I've never seen that on any subies. Generally you want to look at the delta of the PSI that you are testing. I believe subaru specifies 3-5% delta across them. So if you are seeing more than about 4-7psi you probably have a bad cylinder. Generally if you have a bad one it will be like 50psi v. 120-150psi for all the others. -mike http://www.pbase.com/paisan/image/91072632.jpg http://www.pbase.com/paisan/image/133406601.jpg http://upload.pbase.com/image/137566671.jpg Call directly for your best Whiteline Price! | We also carry almost every manufacturer now, so before you buy parts call us. AIM: AZP Installs | E-mail: paisan@azpinstalls.com | 725 Fairfield Ave | Kenilworth, NJ 07033 | 908.248.AZP1 (2971) | T-1 Certified Amsoil Direct Jobber "Race Tested, Enthusiast Approved!" Link to comment Share on other sites More sharing options...
HAMMER DOWN Posted August 27, 2011 Share Posted August 27, 2011 The spec. came from ALLDATA, http://www.alldatadiy.com/includes/img/header/alldata.gif Leading source of Online Diagnostic & Repair Information Your Vehicle: 2005 Subaru Legacy F4-2.5L DOHC Turbo Specifications Compression Pressure Compression pressure (350 rpm and Throttle fully open): Standard 981 - 1,177 kPa (10 - 12 kg/cm2, 142 - 171 psi) Difference between cylinders 49 kPa (0.5 kgf/cm2, 7 psi) or less © 2011 ALLDATA, LLC. All Rights Reserved. The motor turning only 286 rpm, instead of 350 rpm. Would that make a big difference in my compression test data? Mike Mileage:331487 Retired/Sold Link to comment Share on other sites More sharing options...
ehsnils Posted August 29, 2011 Share Posted August 29, 2011 The difference in RPM isn't a big deal as long as you compare the difference between cylinders. Most compression tools are actually not very precise so don't trust the scale - just the difference between cylinders. Link to comment Share on other sites More sharing options...
HAMMER DOWN Posted August 29, 2011 Share Posted August 29, 2011 OK, thanks, Mike Mileage:331487 Retired/Sold Link to comment Share on other sites More sharing options...
authenticamd Posted August 29, 2011 Share Posted August 29, 2011 The difference in RPM isn't a big deal as long as you compare the difference between cylinders. Most compression tools are actually not very precise so don't trust the scale - just the difference between cylinders. I think you mean the compression tools aren't very accurate. But I'd hope they are precise from what you are talking about. Optimally, it would be precise and accurate. Link to comment Share on other sites More sharing options...
music.to.kill.yourself.by Posted September 6, 2011 Share Posted September 6, 2011 Not necessarily. I didn't have any misfires on my #4 ringland failure. I don't even know how long it had been that way. I had low compression and consumed 1Q every 700 miles, yet it dynoed fine and had no misfire or other CEL codes... This is where I am right now. 153k miles, using a quart every 750 miles. Black, sooty exhaust pipes, but no smoke on acceleration or overrun, no leaks, plenty of power, original clutch -- so no rear seal leaks, etc... I never thought to check the inside of the intercooler for signs of an oil leak from the turbo. But either way, whatever the problem, I'm going to have it fixed. Link to comment Share on other sites More sharing options...
ehsnils Posted September 6, 2011 Share Posted September 6, 2011 I think you mean the compression tools aren't very accurate. But I'd hope they are precise from what you are talking about. Optimally, it would be precise and accurate. They are usually not very well-calibrated but at least they are usually not varying much between tests. So if it says 9 on the scale it can well be a pressure of 9 hens instead of 9 lbs or 9 bars. So don't pay much attention to anything else than the difference between the cylinders. That's the most telling part. Link to comment Share on other sites More sharing options...
CHENTEC Posted September 8, 2011 Share Posted September 8, 2011 Ok, Did compression test. Result: 120, 90, 90, 110. Also, even though I told the mechanic it did not smoke. He got it to smoke by revving it past 5000 rpm in the morning. So the verdict is that I need to rebuild a 90k mile engine. even though this looks bad, I still love my car. Since I will be pulling down the engine. Can anyone recommend upgrade to the internals? Cosworth maybe .... Link to comment Share on other sites More sharing options...
nm Posted September 9, 2011 Share Posted September 9, 2011 Ok, Did compression test. Result: 120, 90, 90, 110. Also, even though I told the mechanic it did not smoke. He got it to smoke by revving it past 5000 rpm in the morning. So the verdict is that I need to rebuild a 90k mile engine. even though this looks bad, I still love my car. Since I will be pulling down the engine. Can anyone recommend upgrade to the internals? Cosworth maybe .... What do you want from your car? Cossie stuff is way too expensive if you're not talking huge turbos. Link to comment Share on other sites More sharing options...
frank_ster Posted September 9, 2011 Share Posted September 9, 2011 but the low compression could mean many things. . could be simply the valves and valve seals. Now that's thinking out of the boxer! fyi all 05 + legacy's have built in code reader Link to comment Share on other sites More sharing options...
HAMMER DOWN Posted September 9, 2011 Share Posted September 9, 2011 If you go a little further, once you did the compression check. You can put some oil in the low cylinders. I like to crank the motor over to spread the oil around & retest. If compression goes up a lot, your problem is in the rings & pistons. If it don't the problem in your heads, valve, seats & steam seals. Mike Mileage:331487 Retired/Sold Link to comment Share on other sites More sharing options...
ehsnils Posted September 10, 2011 Share Posted September 10, 2011 At least the valve seats, the stem seals won't make any difference on the compression in the cylinder. Link to comment Share on other sites More sharing options...
nightspeed98 Posted October 12, 2011 Author Share Posted October 12, 2011 Back to square one... Still low. Link to comment Share on other sites More sharing options...
PuffKevinFizzle Posted October 13, 2011 Share Posted October 13, 2011 After reading this I'm a bit worried... Looks like I'm doing a compression leakdown test. Link to comment Share on other sites More sharing options...
nightspeed98 Posted November 29, 2011 Author Share Posted November 29, 2011 They just did yet another oil consumption/leak down test. I lost track which number this is. Gotta go back in another 1k. The cashier knows my first name already. No answers yet. Well, I got one. I need a clutch... I just put in all I had into a condo we bought and close in 2 weeks god willing. Last thing I need is to replace a 1 year old clutch. Link to comment Share on other sites More sharing options...
nightspeed98 Posted January 9, 2012 Author Share Posted January 9, 2012 Update: once again, the subaru field technician found "nothing out of the ordinary" so there is "nothing wrong with the car save for noisy wheel bearing and clutch... Subaru offered me to upgrade the warranty to the gold plus package (7yr/100k)... includes the bearing but not the clutch... Gonna get in touch with mike to see about that clutch work... Link to comment Share on other sites More sharing options...
nightspeed98 Posted January 23, 2012 Author Share Posted January 23, 2012 ....AND now the engine went... dealer is going to replace the engine and the turbo... spun bearing i think then seized. Link to comment Share on other sites More sharing options...
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