compression of 700kPa (101psi)

[yarikoptic]

While changing plugs decided to do compression testing of my cylinders (on 2.2L 1995 Legacy). 1,3,4 came up to be 900-950kPa, but 2 came out just slightly more than 700kPa :-/ By manual specs it has to be >155psi= 1068kPa.

I think that gives a hint to relatively low mpg (getting 18/21).

 

Is that too bad or tollerable. I passed emissions 2 years ago... not sure if it would do it now..

Is there anything I could do non-invasively (ie like swapping engine, rebuilding it) to seal the cylinders a bit...? May be some additives? (sounds like a silly question but what a heck)

[Legacy777]

What procedure did you use to check the compression? Was the engine hot? Did you have all the plugs out, and the throttle open all the way? Those things need to be done when doing a compression test.

[porcupine73]

Are you sure the timing belt marks are all aligned properly and/or it didn't jump teeth (like due to faulty tensioner and/or if MT the guide plate thingy over the crank sprocket)? If you want to try an additive schaeffer's #132 moly e.p. would be what I'd use (can get online from speedpartz).

[nipper]

While changing plugs decided to do compression testing of my cylinders (on 2.2L 1995 Legacy). 1,3,4 came up to be 900-950kPa, but 2 came out just slightly more than 700kPa :-/ By manual specs it has to be >155psi= 1068kPa.

I think that gives a hint to relatively low mpg (getting 18/21).

 

Is that too bad or tollerable. I passed emissions 2 years ago... not sure if it would do it now..

Is there anything I could do non-invasively (ie like swapping engine, rebuilding it) to seal the cylinders a bit...? May be some additives? (sounds like a silly question but what a heck)

 

Ok people lets review, we need to know mileage on these posts to help.

 

Also you need to do a wet and dry compression test before we can tell you if its rings or valves. Rings we can try an additve, valves we cant.

 

nipper

[yarikoptic]

What procedure did you use to check the compression? Was the engine hot? Did you have all the plugs out, and the throttle open all the way? Those things need to be done when doing a compression test.

First of all, I want to thank everyone who answered my posting

And I am sorry that I was too explusive and missed providing proper details

 

My Subi has 161kmiles on it and it is of 1995.

I tried to perform the procedure as it was written in Haynes but probably not 100% correctly:

 

Engine was warm but not hot... I could touch it easily and take the spark plugs by hands -- they were warm but not hot

removed all spart plugs,

 

opened throttle (not fully though but I think enough for air to suck in freely -- is it really crucial to have it 100% open?... may be that was my mistake...)

 

friend of mine was standing outside with manometer and telling me when to stop cranking (whenever it reached stable max)

 

 

I have done testing only on dry, ie I didn't add any oil into any cylinder.

BTW - Haynes said that if 1 cylinder is approx 20% lower than the others, and I experience rough idling (which I think I do... rpms stay around 600 but fluctuate so you can easily feel that and some times drop 50 or 100 for part of a sec) -- then it is probably worn camshaft ... (crap - forgotten the word) -- the thing on camshaft which pushes the valves to open.

Indeed - I should come back to the testing, do wet testing to figure out if that rings or not and if that is rings then add suggested additive, is that the right logic?

[yarikoptic]

Are you sure the timing belt marks are all aligned properly and/or it didn't jump teeth (like due to faulty tensioner and/or if MT the guide plate thingy over the crank sprocket)? If you want to try an additive schaeffer's #132 moly e.p. would be what I'd use (can get online from speedpartz).

 

Is it this one http://speedpartz.com/schaeffer_moly_treatment.htm ? I just don't see any number 132 thus want to confirm ;-)

 

As for marks on timing belt -- dunno actually - it was previous owner who changed it and I never got there but since the other cylinder has higher (almost normal) pressure can't I assume that it should be ok?

[porcupine73]

Yep that's the stuff, I guess they don't show the schaeffer part #. Not sure how much one tooth off would drop compression; EndWrench article says 'A properly timed car will typically crank out 175 psi. Two teeth off will drop it to around 110 and the engine won’t start'

[yarikoptic]

Yep that's the stuff, I guess they don't show the schaeffer part #.

Do you know if it is available in any (local to NJ) retailer chain (just eager to add it... though probably I would better first change oil ;-))

Do you think it is worth adding this stuff to any elderly engine?

[yarikoptic]

A properly timed car will typically crank out 175 psi. Two teeth off will drop it to around 110 and the engine won’t start'

Hm - this is something to worry about since I am closer to that point than to 175 ;-/

[porcupine73]

I don't know about NJ dealers, you could check at schaefferoil.com. You pretty much would have to find a dealer that specifically carries the #132; schaeffer themselves have like a $300 minimum order so you can't really order it direct from them.