I did a comp. test today (located 660 ft above sea level). Started dry, without oil and got:

Cylinder 1: 130 psi
Cylinder 2: 137 psi
Cylinder 3: 135 psi
Cylinder 4: 137 psi

Then I added a capful of oil to each cylinder and got:

Cylinder 1: 169 psi
Cylinder 2: 165 psi
Cylinder 3: 163 psi
Cylinder 4: 162 psi

This is on a 2010 LNF, fully bolted at 75k miles. Tuned with trifecta.

How's the general health of my motor? Cylinder 1 has me a bit concerned. It had the lowest compression while dry, but the highest when oiled. What gives?

The plugs look like they're in good shape. Thoughts?

 

Did u do it when the engine was warm or cold? Cause I made the mistake of doing it when engine was cold first time and got shitty numbers like that to. Ur supposed to do it with engine at running temps

 

I drove the car for a good while right before doing this test. Coolant was up around 83 celcius.

Could a weak battery have anything to do with it?

 

yes, u have to put a charger in boost mode onto the batt before u do it so the test is with full batt power across all cylinders. boost mode gets u the 14 volts as if ur car is running. how long do u crank for? I did 7 times to make sure, if u have another person, crank till the needle stops moving

 

if after that u still get those numbers. then id do a leak down test. its more likely that ur valves need blasting cause they don't close all the way due to gunk than all ur rings being bad.

 

I would of kept driving around a bit, 83C is warm but these engines like closer to 88-90C for the normal operating range.

Also the difference in cylinder 1 isn't that different than the rest, just above 5% difference. What oil have you been running on your change intervals?

 

I don't have a charger, but the voltage dropped from like 11.X volts to 10 ish when cranking. Each cylinder was cranked until the starter cut out on its own, so about 15 seconds.

What is disconcerting is the 30 PSI from adding a cap of oil. I'm not sure if this is normal, or indicative of bad rings.

 

About every 6200 miles, pennzoil full synthetic.

 

Well if get a charger and try again. But don't let it go so long, no need. Also do leak down test, that will tell u more. I just find it unlikely ur having issues with every cylinder

 

It could be a bum gauge too. It was a loaner from crappy tire.

Diagnosis is fun when you don't have any equipment.

 

that's why u buy it. I had a crappy ebay one and it worked. check if it works with air compressor gun. put it to 100 psi and blow into the gauge and see what it reads.

 

I bought one from princess auto cheap enough and it works wonderfully. Have used it on a few different cars now.

 

Redid the comp test with a gauge from Princess auto and hooked up the battery to a running car. Came back 170# across the board dry, 200# with oil.

I think I'm good. Time to get rid of Shitfecta.

 

haha there u go. shitty leaky gauge and proper battery power. 170 is tons.

 

Like the gauge is outta spec tons, that puts his compression ratio above 11.

OP the important part of a compression test is consistency between cylinders which you have. Drop the trifecta and you'll be happy again, although I recommend a good valve cleaning prior to new tune

 

Whats the easiest way that doesnt involve a sand blaster? Does that CRC aerosol work?

 

blasting is super easy. prep just takes a while

 

Dont have a compressor4 nor a gun

 

Gun is cheap, compressors can be rented. If you have the space or a friend's place it's well worth it.

 

I got a compressor for my bday, 20 gal 175 psi. need the gun and I plan to do this to my valves. I am certain they are nasty looking.

Might be a timing chain and valve cleaning party.

 

Ill look into it. Do you just set the cylinder at TDC and blast away in the port?

How effective is it without being able to clean the valve seat? What if the walnut media gets into the chamber?

 

Just check to make sure the valves are closed before you start blasting, and block off the other ports you're not currently working on. Then it's blast and vacuum, blast and vacuum, and on and on and on. Just make sure you use walnut shells, so if any gets into the cylinder it wont do damage.

 

Once you're done, pull the plugs, hold the gas pedal wot and crank it over. This will help blow out any remaining media in the cylinders. Like ECaulk said, the walnut media won't hurt anything anyways, but if you're worried this will aid in getting any unseen excess out.