Compression test results - Advice?

[calaerial]

Hi again,

Just did a compression test to attempt to confirm whether or not the pre-cats are likely to have done any damage before they were removed (They were in a bad state by the end apparently). Ive completed the tests but i dont really know whether the numbers ive got are high, low or indifferent. The one thing that does concern me somewhat is that i would have expected all 4 cylinders to have been the same, unless there is a problem obviously.

Going left to right (Passenger side to drivers)

Cylinder 1: 220PSI
Cylinder 2: 219PSI
Cylinder 3: 210PSI
Cylinder 4: 210PSI

I have also taken pictures of the spark plugs since i hear this can be helpful in diagnosing problems of this sort.

Cylinder 1


Cylinder 2


Cylinder 3


For some reason i forgot the photo of cylinder 4, but it looked much the same as the others.

Anyone got any thoughts?

[E]

It looks to me like you got away with it, those pressures look fine to me. And I believe that upto a 15 psi differential is accceptable between the highest and lowest reading, but I do stand to be corrected on that.

[calaerial]

Beautiful, i can rest a little easier now  s:D s:D

Of course it couldnt be all positive news, because of working full time and being busy this is the first time ive actually seen the car in the daylight for a few days, and i find that someone has dinged the bloody thing! Big scuff over the passenger side rear wheel arch!

Bloody idots.

Before much longer its going to be more economical to re-spray the entire thing than try to touch up the little blemishes lol.

Oh well, at least my compression is right. Think i'll replace them plugs shortly as well, they look a little worse for wear to me.

It also does leave me with the question, if not the head, what is causing it to emit a large amount of white smoke when cold (Seems to go once up to temperature)

[mrzwei]

According to the MR-S quick reference guide (a group buy on here via sp I think, some long time ago) the compression pressure should be as follows:

1270kPa / 184psi (+/- 100kPa / 15psi)

You have good compression.

The plugs, goto  m http://www.triumphspitfire.nl/plugs.html m   for a pictorial guide.

[ChrisGB]

Numbers look a little higher than normal which could be a result of a little build up of deposits in the combustion chamber, but nothing to worry about. Plugs are right colour with a bit of residue, again nothing I would worry about. Only thing I would say is keep a close eye on oil consumption as it its possible to have good compression with poor oil control. Looks like you got lucky.

Chris

[Anonymous]

Last time mine was tested at Ding day they came back as 12.5bar (181 psi) across the 4.

 l viewtopic.php?f=11&t=31863&p=387081&hilit=compression#p387081 l

[calaerial]

Looks like theres a lot of variation really, but overall im pretty pleased.

Im also hoping i did it right, because the guide i got on the back of the box for the tester didnt match a guide i saw for testing the ZZ-FE specifically.

Though that guide was written by a celica owner.

The tester guide said unplug one of the sparks, connect the tester, floor the throttle and turn the ignition for about 10 seconds. Record, replace spark plug and coil, repeat on next cylinder.

The guide for the Celica seemed to suggest i needed to disconnect the injectors and the power steering electronics. Not sure why but i didnt do it anyway.

[Anonymous]

All of my spark plugs were removed and key turned for 4 "revolutions" if you know what I mean when mine was tested,IIRC custardavenger did the procedure so could possibly clarify method used.

[Anonymous]

According to this its saying you are looking for 189 psi approx.
 m http://madstyle1972.com/Repair/14/200f0c04/i740001.pdf m

[nathanMR2]

Can anyone recommend a compression tester? I would like to get one for my tool kit

[Anonymous]

I bought a cheap one like this   m http://cgi.ebay.co.uk/AUTOMOTIVE-COMPRE ... 3ef937829b m   but I havnt tried it yet,I will let you know what I think when I do.

[nathanMR2]

If you could do that would be great. Seems a good price but i dont want to bother if its no good

[michaelasaunders]

Seems like the place to ask the question, hope you dont mind calaerial.

This was my result

180 150 180 180 PSI

Is there anything I should be watching out for on cylinder 2 at 150 psi? Or anything I can do to bring it back up?

Thanks

[mrzwei]

I'm assuming you have double, tripple checked it.
There are three possibilities:
1. the rings on no.2 aren't sealing as well as the others.
2. the valve(s) on no.2 aren't sealing as well as the others.
3. a leaking head gasket seal around no.2

The classic test is to inject some engine oil via the spark plug hole and re-read. If no. 2 compression improves and there is little change in the others then that suggests a ring seal issue.
If there is no change then that suggests a valve seal problem on no.2. This could also be a badly adjusted tappet (unlikely unless someone has felt the need to adjust them).
If it's a head gasket issue, again unlikely, then this would normally be associated with water and/or oil loss and oilly deposits in the water.

Personally, I wouldn't worry too much unless you are experiencing fluid loss.

[Ilogik]

im pretty sure i got 220 on my engine when i had a compression test done, need to check figures. For N/A engines im pretty sure it should be over 200?

[Anonymous]

For N/A engines Im pretty sure it should be over 200?

Where did you get this figure from ilogik?

[mrzwei]

Read the bloody thread, it's supposed to be around 184psi +/- 15psi   s:lol: :lol: s:lol:  
I'd die for an zz1 with 220, you wouldn't have to bother about skimming the head to get more power   s:D s:D

[muffdan]

yes, 210 to 220 for a regular 1ZZ in an MR2 as far as I was aware is normal. I'm not sure why 189 is shown as normal in Bryan's link. Perhaps that is for a different variant of the engine. Also from that link, I don't agree that 150 is acceptable! My engine build with low compression pistons (8.8:1) is generating 175 across all 4. All cylinders within 15 PSI is good info though.

Three readings of 180 and a 150 isn't good. Are you using oil?

[michaelasaunders]

Personally, I wouldn't worry too much unless you are experiencing fluid loss.

This compression check was done by my garage.

The result is just within minimum spec I suppose based on  m http://madstyle1972.com/Repair/14/200f0c04/i740001.pdf m

My car does use oil, but not at an unmanageble level. I am currently monitoring consumption after my recent oil change.

[mrzwei]

yes, 210 to 220 for a regular 1ZZ in an MR2 as far as I was aware is normal. I'm not sure why 189 is shown as normal in Bryan's link. Perhaps that is for a different variant of the engine. Also from that link, I don't agree that 150 is acceptable! My engine build with low compression pistons (8.8:1) is generating 175 across all 4. All cylinders within 15 PSI is good info though.

Three readings of 180 and a 150 isn't good. Are you using oil?

With respect, I'd appreciate a source reference for that  200 to 210psi info.
Plus, everybody is probably using an uncalibrated device so it is the variation that is more important than the absolute figure.

[aaronjb]

yes, 210 to 220 for a regular 1ZZ in an MR2 as far as I was aware is normal. I'm not sure why 189 is shown as normal in Bryan's link. Perhaps that is for a different variant of the engine.

Toyota BGB states:

Compression pressure
STD 1,270 kPa (13.0 kgf/cm2, 184 psi) at 250 rpm
Minimum 1,000 kPa (10.2 kgf/cm2, 145 psi) at 250 rpm
Difference of pressure between each cylinder 100 kPa (1.0 kgf/cm2, 15 psi) or less

[Anonymous]

Toyota's official manual says it should be 184 psi.

Edit: Aaron beat me to it.

[michaelasaunders]

Ummm, I see a lot of new posts whilst I was typing to mrzwei.

I think I will duck out of this one until the dust settles......  s:lol: :lol: s:lol:

[calaerial]

Hmm, wondering if ive done this wrong and if im going to have to re-test the bloody thing. Which would be a colossal pain in the arse.

I did as the guide on the back of the tester seemed to instruct which was to remove 1 spark plug in turn, test the chamber and then reinstall and test the next.

So at the time of the chamber testing there were 3 chambers running as normal, with spark plugs and ignition coils inside. And 1 with the compression tester in.

Please tell me this wont have affected the figures because it took getting a bloody half day off work to get this done in the bloody first place!

[Anonymous]

The result is just within minimum spec I suppose based on  m http://madstyle1972.com/Repair/14/200f0c04/i740001.pdf m

Not really as they are not within 15 psi of each other.