Compression test results are here!!

[92ShoOff]

Hey everyone, if you haven't seen my other threads here's the low-down. I just put together a 3.2 motor, with each cylinder bored to 93mm. I used custom Diamond Racing forged aluminum pistons and Total Seal gapless piston rings. The engine has all new seals all the way around.... not a single old seal was left on the motor, heads, etc. The pistons, rings, cylinder walls, journals, bearings, cam lobes, shims, buckets, valve stems, etc. etc. were all lubed with engine assembly **** thoroughly.

Well the night I went to start the car for the first time it wouldn't start. My dad sprayed starting fluid into the throttle body (big mistake.... I know this now lol) and we got a backfire/explosion out the throttle body. Well minutes later I noticed oil dripping onto the garage floor from the oil pan. I jacked the car up and saw that the RTV sealant was blown from the sides of the oil pan. A few days later I pulled the pan, replaced the front and rear oil pan seals and redid the RTV and no more leaks. After cranking that motor over 30 times (which I'm not sure if this may have contributed to the burning oil problem) I replaced the fuel injectors and the motor fired right up.

I then continued to get puffs of gray smoke every time I started it up, and much of the time that I would start driving from a stop. After only 150-200 miles on the new motor I've burnt up somewhere near 2 quarts of oil!! So I've now finally gotten around to doing the compression test (yes the motor was warm when I did it ) here are the results:

Cyl 1 Cyl 2 Cyl 3
185 | 155 | 192 |
184 | 155 | 196 |
184 | 153 | 195 |
179 | 153 | 194 |
185 |

Cyl 4 Cyl 5 Cyl 6
153 | 170 | 192 |
168 | 175 | 192 |
173 | 167 | 193 |
168 | 170 | 190 |

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EDIT: After my first compression test today I read that the motor should make 4-5 revolutions, not just 3, when doing the test. So I went back and did the test again. Here are those results:

Cyl 1 Cyl 2 w/oil Cyl 3
192 | 165 - 196 | 209
200 | 174 - 210 | 223
197 | 166 - 204 | 208
195 | 168 - 200 | 220

Cyl 4 Cyl 5 Cyl 6
195 | 187 | 210 |
194 | 187 | 210 |

There is an extra column for Cyl #2, which was getting the lowest results. That extra column is another test on that cylinder with oil added.

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Each result is listed from top to bottom from the first result to the last result. I test each cylinder 4 times (except #1 which was done 5 times) just incase I did got any false readings. The motor cranked 3 revolutions each time to give me these results.

Upon removing the intake manifold I noticed a sligh coat of oil in the runners (which I had COMPLETELY cleaned the whole inside of the intake until there was nothing left), and oil coated on the intake ports of the heads. Upon looking down those ports just about every valve had a noticeable amount of oil in it except for the valves in Cylinder #2. All spark plugs were black and covered in oil except Cylinder #2 also, and obviously as you can tell by the readings that same cylinder gave me the lowest, most consistant results.

I guess while the motor is still warm I should read on how do to a leak-down test and see if I can't get that done too. But in the meantime, what can you guys tell me based off these results?? Thanks in advance!!!!!!

-Andrew

 

[egroce11]

The numbers aren't to bad, they show that you are breaking it in. Cyl. 2 is just taking more time. The oil test right now verifies that the rings aren't sealed yet. The oil in the intake is because you are still breaking in the rings and vapor is going through the tube in beteen the heads to the throttle body. Your oil usage is because you are running the engine hard for break-in and the oil is being used.

You have my numbers if you nhave questions.

Ernie

 

[yamahaSHO]

I would keep breaking it in. With only 200 miles on it, you haven't broken in the rings fully yet. As far as the oil, I see that too after cleaning the intake. You're going to get a little in there. There's nothing to worry about there.

Also, you can pretty much crank the motor until the compression tester stops moving.

 

[92ShoOff]

Hey thanks for your replies fellas. So you guys agree that 2 quarts burnt in 150-200 miles might be normal for this break-in? I HAVE been running the crap out of it, so maybe as Ernie suggested I might just need to calm that down. But I filled the oil up yesterday morning before I went to work-- filled it dead up to the top of the fill mark exactly. After just driving to work and back (maybe 30 miles round trip yesterday) I burnt maybe about 2-3 cross-hatches worth on the dipstick. I'll still take your guys' advice on continuing to drive it and see if it starts getting better before I go yanking the motor back out and tearing it all back down again.

But what I don't understand is why cylinder #2 is not showing signs of blowing oil (not really any on the spark plugs, nor on the tops of the two intake valves). So how is it being the one that's not seating yet? All of the other cylinders are the ones blowing the oil. I saw that all three of the front pistons (4, 5, and 6) are already black with a lot of carbon deposits on them. They were brand new aluminum, shiny pistons. Does this early build-up sound right?

When I took the intake off it didn't only seem to be vapors of the oil. Right where the manifold runners mate to the manifold-to-head gaskets there was a noticeable amount of oil just collected there. I can get pictures if you guys think it would help to show you.

Also, you can pretty much crank the motor until the compression tester stops moving.

Haha crap... I wish I knew that earlier. That's probably why I kept getting such different readings. It's been a pain in the butt trying to get exactly 4 cranks out of each cylinder several times. Well maybe I'll try that tomorrow on the engine even though it will be cold. Maybe the results within each cylinder will at least be more consistant.

Well thanks again guys and please post more if you have anything else to share. Ernie, I left you a voice-mail earlier this afternoon so just get back to me when you get a chance. And what's the progress on your motor swap Jason? I saw you got your hands on brand new heads! I'm jealous!!!

 

[93rev2sev]

yer on crak if you think 1 quart per hunded miles is even close to right.