Compression Test

[Deutscher]

(not commodore related (toyota mr2))

My engine smokes on start up, the longer it sits without being driven the more it smokes. Smoke can still be seen when reving the engine 3000rpm+. I had done a compression test on the weekend and my results are:

1st Cylinder: 200, 2nd Cylinder 190, 3rd Cylinder 185, 4th Cylinder 200.

According to the manual, 192psi is the standard. So my dry testing fits in the recommendations. But the smoke is still a problem. So I did a wet test on the 3rd Cylinder and got a reading of 225psi which is really high. I had put 1-2 tablespoons of oil into the cylinder. Although I did not have full throttle while doing the testings (only realised half way through but because of the readings thought it didn't matter). Also, the battery had drained recently, so after charging it probably half full I began the tests - this wouldn't affect the results would it. Also the temperature of the engine was around 1/4... normal operating probably 1/2.

Edit: I had thought that i'd get a lower reading than I did with not having the throttle open etc.
Edit2: "Note: If your battery is weak, the engine will turn over slower and give you lower readings." - so the battery must of been fine.

[Tsunamix]

Your valve guides are worn, oil is leaking down the valve guides and pooling in the combustion chamber when the engine isn't running.

Common problem in older design engines - cars like hemi powered valiants / centuras, Magna's and what have you.

Smoke will be grey blue, dissappearing after a few seconds, quite a pungent oil smell.

Smoking at higher revs is usually a sign of the oil control rings being worn. These don't affect compression, just bvasically scrape the oil off the cylinder walls.

Your engine is tired.

[Deutscher]

Your valve guides are worn, oil is leaking down the valve guides and pooling in the combustion chamber when the engine isn't running.

Common problem in older design engines - cars like hemi powered valiants / centuras, Magna's and what have you.

Smoke will be grey blue, dissappearing after a few seconds, quite a pungent oil smell.

Smoking at higher revs is usually a sign of the oil control rings being worn. These don't affect compression, just bvasically scrape the oil off the cylinder walls.

Your engine is tired.

Wouldn't the compression test show the valve guides being worn, it shouldn't have as much pressure because it's got cracks or whatnot? or maybe the oil seeps through when the engine is cold because the oil hasn't expanded? cause when the engine is hot the oil expands and fills the cracks better so I don't get smoke during driving (apart from the higher revs area).

On start up it's more of a white smoke than a grey/blue.

and the oil control rings wouldn't cost much to fix/replace/clean would it? nothing to really worry about.

See the issue I have is that, when I brought it I took it to Toyota and said it's smoking on start up, and they said it's most likely the valve stems, but they couldn't be certain until the opened the head up. I was going to get AutoMasters to do my timing belt/valve stems/brakes, the guy there said It's not just the stems - I'll need a new engine. Neither Toyota nor AutoMasters had done a compression test or adviced to do one.

[Deutscher]

I've been reading different amounts of oil to use for the wet test. Ranging from 5ml to 30ml (2 tablespoons). Can anyone clarfy which is correct? it's a 4cyl MR2 3S-GE. The manual just says a small amount of oil.

[Deutscher]

After driving home from work, engine temperature is 50% (normal operating temperature). I did test as soon as I got home.

Compression Test Procedure Used:

Dry Test:

1. Take out Fuel Pump fuse, turn ignition to make sure all fuel is out.
2. Take out Ignition Fuse,
3. Disconnect spark leads from distributor
4. Take out all 4 spark plugs
5. Fit compression gauge
6. Put full throttle, turn ignition for 6 revolutions.
7. Read and record for each cylinder

1st Cylinder: 185 PSI
2nd Cylinder: 190 PSI
3rd Cylinder: 192 PSI
4th Cylinder: 192 PSI

Wet Test:

1. Squirt 15ml of Castrol Magnetic 10W-40 into Cylinder
2. Wait ~30 seconds for oil to coat pistons
3. Full Throttle, turn ignition for 6 revolutions
4. Read and record for each Cylinder

1st Cylinder: 230 PSI
2nd Cylinder: 260 PSI
3rd Cylinder: 240 PSI
4th Cylinder: 250 PSI

What do you think about this test? Standard PSI is 192 PSI

[strgas]

valve stem seals and worn guides your compression readings are good , also check your engines breather/s and PCV for correct operation blocked breathers can induce excessive amounts of oil back into the intake manifold and also cause blue smoke out exhaust , long periods of idling with worn stem seals will produce lots of smoke out the exhaust and when cruising less visible smoke . compression readings within 15 PSI of each other are considered normal wet or dry , The 192 PSI reading is the factory spec for a new engine .

[Blown355cca]

stats are pretty good..... The norm is a 10% difference between cylinders on a dry test & 20% difference on a wet test.

Valve stem seals will not show up on a compression test as they are outside the combustion chamber. Smokey start ups that clear after a short time shows stem seals, as the oil has a chance to seap past while collected in the head. Another test is to idle down a hill and get back on the throttle at the bottom, looking behind for a cloud of smoke. While coasting in an idle state there is high vacuum in the manifold and this causes the oil to be sucked thru the valve guides into the inlet manifold, when you get back onto the throttle temp increases and the oil is burned in the combustion chamber causing the smoke screen you have no doubt seen behind older cars & newer one's that have not be serviced regularly.

[Blown355cca]

LOL the post above mine wasn't there when I was writing...... damn slow typing speeds LOL

[Deutscher]

valve stem seals and worn guides your compression readings are good , also check your engines breather/s and PCV for correct operation blocked breathers can induce excessive amounts of oil back into the intake manifold and also cause blue smoke out exhaust , long periods of idling with worn stem seals will produce lots of smoke out the exhaust and when cruising less visible smoke . compression readings within 15 PSI of each other are considered normal wet or dry , The 192 PSI reading is the factory spec for a new engine .

Thanks for the reply mate. I've read up on compression tests and know that my dry test is fine. My concern is the wet test. the readings I got aren't normal right? There shouldn't be more pressure than the factory standard right?

[strgas]

wet testing will always show a higher reading coz it seals the rings better hence the extra compression . as long as the readings are close to each other and not varying to much the readings are normal if one cylinder didnt change then you have a problem

[Deutscher]

wet testing will always show a higher reading coz it seals the rings better hence the extra compression . as long as the readings are close to each other and not varying to much the readings are normal if one cylinder didnt change then you have a problem

I explained what you said to my dad. He says from the back while driving it's a black/grey smoke when revs over 3000rpm. What could that mean?
The wet test results differ by 30psi between cylinder 1 and 2.
Edit: Spoke to AutoMasters mechanic today, explained my readings (from 1st test), he said the oil rings or piston rings.

[Deutscher]

The concern I have is the start-up smoke (which looked white to me) coming out of the exhaust - after sitting a few days it was a HUGE cloud, regular driving only had a small cloud of smoke. The smoke coming out while revving over 3000rpms (black/grey smoke according to my father). I don't want to be pulled over by the cops and get yellow stickered. Also the high oil consumption (1L in 1week).

Is there any other tests I could perform to give a clearer answer? Automasters mechanic still recons to fit a second hand engine ($1000 labour, $500 parts and I supply the engine ($900 + $250 shipping (not sure on the kms or compression (from a shop))). I want to be more certain on what is actually wrong before replacing the engine. But I don't want to through money into it and then realise it was cheaper getting a different engine or reconditioning this one.

Edit: Since the 1st and 2nd test. I got a Optima D34 battery and put on a Apexi 160mm OD Air Filter. Plus the operating temperature was at 50% instead of 25% and I had Full Throttle on all my testings. (I don't know if any of these things could of affected the difference in readings (thought I'd point it all out ).

[Deutscher]

Can anyone confirm that I did the Compression Test right.
I used adequate weight and amount of oil for the wet test?

[VK_3800]

Your compression is fine, if you want to determine whether its a top or bottom end issue you need to do a leakdown test. I agree with all the comments here that it just needs new valve stem seals, common Toyota thing.

[Tsunamix]

Wouldn't the compression test show the valve guides being worn, it shouldn't have as much pressure because it's got cracks or whatnot? or maybe the oil seeps through when the engine is cold because the oil hasn't expanded? cause when the engine is hot the oil expands and fills the cracks better so I don't get smoke during driving (apart from the higher revs area).

On start up it's more of a white smoke than a grey/blue.

and the oil control rings wouldn't cost much to fix/replace/clean would it? nothing to really worry about.

See the issue I have is that, when I brought it I took it to Toyota and said it's smoking on start up, and they said it's most likely the valve stems, but they couldn't be certain until the opened the head up. I was going to get AutoMasters to do my timing belt/valve stems/brakes, the guy there said It's not just the stems - I'll need a new engine. Neither Toyota nor AutoMasters had done a compression test or adviced to do one.

Valve guides are not in the combustion chamber so know they wont show on a compression test. Neither are the oil control rings, they are below the Compression rings.

[V8Silverfox]

I go with value steam seals ... I had a Mitsi that had a similar issue. Test it by coasting down a long hill. Make sure the car is still in gear so that you're using engine braking.
Stop at the end of the hill for a few seconds then take off like normal. Should give you a cloud of smoke. You could also see smoke pouring out the back during the engine brake.

[MasterOfReality]

I'll go with valve stem seals.

When I rebuilt my old Kawasaki kl250, I lightly lubed the valves with oil before I dropped them into the head.

My jaw hit the floor with the amount of smoke that was pumped out when I fired it for the first time after the rebuild. I initially thought it was the seals until I remembered that I had lubed the valves and they had to burn off.

Of course a mechanic is going to try and talk you into a new engine.

[Deutscher]

Just rang a couple reconditioning places.

Engine Exchange: AUD$3190 + $1590 Labour + $400 to $1500 parts. The guy didn't really want to talk to me. Just gave straight answers. and is overpriced. They had 3S-GE engines in stock but only for the Celicas.

Hiflow: Recondition (sounded like everything, he went through a list of things, I didn't know if it was everything but it sounded like it), they'd change the timing belt and water pump and all that aswell. Quoted me $3000-4000 for everything. He asked me why I thought I needed a recon, so I told him my compression test results (dry and then wet), he said the dry sounds fine and the wet is normally high. I told him smokes whitish after it's been sitting for few days (recons it's probably blown gasket), and the grey/black smoke on high revs could be all sorts of things ie. fuel mixture, sensors, etc etc. Asked if it could be the Pistons, he said most likely not because of the compression results. He said he wanted to do a "TK" test to confirm the Gasket, it's only $35, and if I wanted them to do the compression it'd be $90-100 (depending on how long it takes). All in all he said he doesn't think it needs a recon.

Hi Flow Engine Recondition seems pretty decent. He didn't recon it'd need a recon, and he seemed friendly enough on the phone and let me explain everything and then he gave his answers. I'll try to book it in there and get this TK test done and see what else he recons. I'll have a chat to him and see what he thinks I should do. Atleast he didn't go right away I'll need a recon.

[Deutscher]

Just got my car back from Hi Flow Engine Reconditioning. Got a CO2 test done and a Compression test.

My compression dry test was: 150, 150, 150, 145 and wet test: 160, 165, 160, 160. Says 15ml was too much. Says the piston rings are fine, because it's not blue smoke on higher revs. Says it's just the fuel or something rather.

According to the CO2 test, my head is blown.

Anyone know a place in Perth that is rather cheap but still does a good job?
I've just rung RAC Balcatta about getting a rebuild, they quoted me $2500-$3000. I'm not sure if that is a full rebuild or if it's just the top half & radiator. I was speaking to Reception lady and she was asking questions to a technician, I'll go in on Sat and speak to em directly. If I have to recon the cylinder head I may aswell get em to check the rest of it aswell (pistons, rings etc).

I'm currently not a member of RAC, but as a member: "To help keep our members' cars happy and safe on the road, all RAC members receive 10% off all labour on vehicle servicing and repairs." wonder if that covers the rebuild labour it's part of repairs... my car needs repairing cause it's not driveable atm.