Compression test

[supra_jms]

So yesterday i did a compression test on my supra. I know its not as accurate as a leakdown test but someone Who is interested in the car asked me to do one.

 

The car is a 2000 vvti with 67k on the clock.

Results were as follows on a dry run:

Cylinder 1 140

Cylinder 2 143

Cylinder 3 155

Cylinder 4 148

Cylinder 5 155

Cylinder 6 140

 

My question is are the scores ok and the difference between the clyinders ok?

Cheers

[and1c]

So yesterday i did a compression test on my supra. I know its not as accurate as a leakdown test but someone Who is interested in the car asked me to do one.

 

The car is a 2000 vvti with 67k on the clock.

Results were as follows on a dry run:

Cylinder 1 140

Cylinder 2 143

Cylinder 3 155

Cylinder 4 148

Cylinder 5 155

Cylinder 6 140

 

My question is are the scores ok and the difference between the clyinders ok?

Cheers

 

They look a little on the low side to be honest . My motor was around the 180psi mark and within 8psi of that on all cylinders

 

See here for Toyotas TSRM info on it

 

Standard pressure:

2JZ–GE

1,275 kPa (13.0 kgf/cm2, 185 psi) or more

2JZ–GTE

1,079 kPa (11.0 kgf/cm2, 156 psi) or more

Minimum pressure:

2JZ–GE

1,079 kPa (11.0 kgf/cm2, 156 psi)

2JZ–GTE

883 kPa (9.0 kgf/cm2, 128 psi)

Difference between each cylinder:

98 kPa (1.0 kgf/cm2, 14 psi) or less

d) If the cylinder compression in 1 or more cylinders is low, pour

a small amount of engine oil into the cylinder through the

spark plug hole and repeat steps (a) through (b) for the

cylinder with low compression.

• If adding oil helps the compression, it is likely that the

piston rings and/or cylinder bore are probably worn or

[and1c]

What do you mean a dry run? Did you do it like this?

COMPRESSION CHECK From the 1995 TRSM EG–9 and EG-10

 

HINT: If there is lack of power, excessive oil consumption or

poor fuel economy, measure the compression pressure.

1. WARM UP AND STOP ENGINE

Allow the engine to warm up to normal operating temperature.

2. 2JZ–GE:

DISCONNECT DISTRIBUTOR CONNECTOR

3. 2JZ–GTE:

DISCONNECT CAMSHAFT POSITION SENSOR CONNECTORS

4. 2JZ–GE:

DISCONNECT HIGH–TENSION CORDS FROM SPARK

PLUGS

(See high–tension cords and cord clamps removal in

Ignition System)

5. 2JZ–GTE:

REMOVE IGNITION COILS ASSEMBLIES

(See ignition coils removal in Ignition System)

6. REMOVE SPARK PLUGS

7. CHECK CYLINDER COMPRESSION

(a) Insert a compression tester into the spark plug hole.

(b) While cranking the engine, measure the compression

pressure.

HINT: Always use a fully charged battery to obtain engine revolutions

of 250 rpm or more.

© Repeat steps (a) through (b) for each cylinder.

NOTICE: This measurement must be done in as short a time as

possible.

Standard pressure:

2JZ–GE

1,275 kPa (13.0 kgf/cm2, 185 psi) or more

2JZ–GTE

1,079 kPa (11.0 kgf/cm2, 156 psi) or more

Minimum pressure:

2JZ–GE

1,079 kPa (11.0 kgf/cm2, 156 psi)

2JZ–GTE

883 kPa (9.0 kgf/cm2, 128 psi)

Difference between each cylinder:

98 kPa (1.0 kgf/cm2, 14 psi) or less

d) If the cylinder compression in 1 or more cylinders is low, pour

a small amount of engine oil into the cylinder through the

spark plug hole and repeat steps (a) through (b) for the

cylinder with low compression.

• If adding oil helps the compression, it is likely that the

piston rings and/or cylinder bore are probably worn or

damaged.

• If pressure stays low, a valve may be sticking or seating

improper, or there may be leakage past the gasket.

8. REINSTALL SPARK PLUGS

9. 2JZ–GE:

RECONNECT HIGH–TENSION CORDS TO SPARK

PLUGS

(See high–tension cords and cord clamps installation in

Ignition System)

10. 2JZ–GTE:

REINSTALL IGNITION COILS ASSEMBLIES

(See ignition coils installation in Ignition System)

11. 2JZ–GE:

RECONNECT DISTRIBUTOR CONNECTOR

12. 2JZ–GTE:

RECONNECT CAMSHAFT POSITION SENSOR CONNECTORS

[Mike2JZ]

You are just exceeding the limit of the acceptable range of differences between cylinder compression as specified by toyota.

 

Might be worth doing a wet test to see what the numbers are then.

[Luxluc]

Toyota says 12 psi is the max delta allowed between maximum and minimum.

 

I would have a check.

[supra_jms]

Please bare in mind guys this was done with a £30 gauge so is not going to be 100% accurate.

[Burna]

Please bare in mind guys this was done with a £30 gauge so is not going to be 100% accurate.

 

Should be ok, depends how you did the test. How many cranks on each cylinder?

[Tricky-Ricky]

The figures are a little low and the difference between cylinders is over the limit...just, for the mileage I would say the car has had a harsh life, however, I would run a leak down test, as this will give a better idea of where the low compression is caused IE ring seal or valve seal, could be either.

[Nic]

http://www.mkivsupra.net/vbb/content.php?66-Engine-Mechanical-(2JZ-GTE)

[Frank Bullitt]

So yesterday i did a compression test on my supra. I know its not as accurate as a leakdown test but someone Who is interested in the car asked me to do one.

 

The car is a 2000 vvti with 67k on the clock.

Results were as follows on a dry run:

Cylinder 1 140

Cylinder 2 143

Cylinder 3 155

Cylinder 4 148

Cylinder 5 155

Cylinder 6 140

 

My question is are the scores ok and the difference between the clyinders ok?

Cheers

 

Far from great results to be honest.

 

Please bare in mind guys this was done with a £30 gauge so is not going to be 100% accurate.

 

If someone is interested in buying the car why not just take it to a garage and pay to get the compression & leak down done professionally rather than risk damaging any potential sale doing it yourself with a cheap gauge that is not 100% accurate?

 

That is akin to shooting yourself in the foot IMO.

[chrispot]

They look a little on the low side to be honest . My motor was around the 180psi mark and within 8psi of that on all cylinders

 

i assume your car is a NA having 180psi super jms's car is a TT.

 

going by the data supplied from the workshop manual super jms's engine is just out of spec on cyl difference. I would suspect gauge or the way it's being done is more than likely why the readings are low/difference

Edited June 30, 2016 by chrispot (see edit history)

[T2 MSW]

yeah are those figures with the engine cold. If so they are not that bad

[Frank Bullitt]

yeah are those figures with the engine cold. If so they are not that bad

 

Oops missed that bit

[supra_jms]

The car had not been driven for a few days and then only did 5 mins before it was then tested.

Sorry should state my car is a TT not an NA

[Mike2JZ]

The car had not been driven for a few days and then only did 5 mins before it was then tested.

Sorry should state my car is a TT not an NA

 

Not much point doing a compression check if engine is not at proper running temperature. I would do it again and do a dry, followed by wet test, depending on results you wouldn't need to bother with a leak down test.

[supra_jms]

I thought as long as it had come off choke it was warm enough to do the test?

[Mike2JZ]

I thought as long as it had come off choke it was warm enough to do the test?

 

Well if you are confident that the engine was warm enough then the results you got show the engine could be in better condition. Edit: I would still do a wet test however, given the differences you are seeing across cylinders

[Tricky-Ricky]

Not much point doing a compression check if engine is not at proper running temperature. I would do it again and do a dry, followed by wet test, depending on results you wouldn't need to bother with a leak down test.

 

I would disagree, i often do a cold compression test followed by a hot test, it gives a better idea of ring/bore condition, even cold those figures are low for a good TT engine, a wet test will always result in a slightly better reading, and is not a definitive sign of badly sealing valves.

[Mike2JZ]

I would disagree, i often do a cold compression test followed by a hot test, it gives a better idea of ring/bore condition, even cold those figures are low for a good TT engine, a wet test will always result in a slightly better reading, and is not a definitive sign of badly sealing valves.

 

The Significance of running a wet test following the dry test is to see what compression can be reached and what cylinders are still low and if the same symptoms are present or disappear with the addition of oil. No point did g wet test by itself with no dry sample to compare with. Cheap, quick and rough way of getting an idea of cylinder sealing if a leak down test kit is not present

[Tricky-Ricky]

I do know all the reasons fella, but i think you missed my point.

[Mike2JZ]

I do know all the reasons fella, but i think you missed my point.

 

"a wet test will always result in a slightly better reading, and is not a definitive sign of badly sealing valves"

 

That's the point I was referring to

[T2 MSW]

For the OP, do a test again when the engine has been running and is fully up to temp. Then post the results.

[Tricky-Ricky]

"a wet test will always result in a slightly better reading, and is not a definitive sign of badly sealing valves"

 

That's the point I was referring to

 

Not quite sure how to re explain it to you, if you add oil to a cylinder it will (unless damage is server) increase the compression reading, however you can still have a badly seating valve that's dropping compression, even if the added oil increases the reading, therefore the adding of oil does not rule out using a leak down test in order to correctly diagnose whether the problem lies with the valve seal or not.

[Mike2JZ]

Not quite sure how to re explain it to you, if you add oil to a cylinder it will (unless damage is server) increase the compression reading, however you can still have a badly seating valve that's dropping compression, even if the added oil increases the reading, therefore the adding of oil does not rule out using a leak down test in order to correctly diagnose whether the problem lies with the valve seal or not.

 

Adding oil tests out piston rings unless they are completely gone. If compression is still low then that's your queue for a leak down test as it's most likely valve related. If you don't have a leak down test kit to hand, then wet testing is the closet thing you can do to get a rough idea of what's going on inside. That's all I'm trying to say. Obviously you can have a situation where rings and valves are in a poor state, but the next best thing after doing a leak down and is easy for most DIY'ers to do is a wet test. The results from dry vs wet are going to say a lot more than cold/warm dry tests.

[Chris Wilson]

I wouldn't worry about those figures. If you *are* worried have a leak down test done, they are far more informative.