compression on a 1.0

[lancekilgore]

OK so I did a compression test on my 94 metro and received 120 on all three cylinders. that is good but what should the compression be on them. or is that just about right? I currently have another head in the machine shop that will be installed when it is done. just wondering if I should change it or not???? Egr ports are all open and not clogged, I am getting a pinging at times so maybe the timming is off just a bit. what you all think

[DOCTORBILL]

The Chilton Manual, page 3-21, right side of page numbers 1 thru 12 says
to use a screw-in gauge for accuracy.

No reading should be lower than 75% of the highest reading.

Was the value of 120 PSI (seems rather low) with or without OIL added to the cylinder?

Dry readings show valve condition.

If you add an ounce of new oil to a cylinder, spin the engine a bit, then take a
reading, the oil SEALS THE RINGS. If that reading goes up substantially, then the rings are worn and need replacing.

GOOD TEST !

Almost everyone advises that you drop the oil pan and remove the pistons
(without removing the engine!) and replace your RINGS and ROD BEARINGS
right now.

This is the best time to do it!

I did it and my 3 cylinder still gives 49 mpg with the 5 speed manual after
perhaps 25,000 miles on the new rings and valves some two years later.

94metroxfi just did it and he's had the same results - a "new" engine.
Look back at his 4-7-2008 Thread "Cylinder Valve Job." You might Private Message him for encouragement.

From what I have seen and read, new Rings and Valves should give you a
compression test value closer to 200 PSI or higher....

What follows is my normal and regular reply to anyone doing a "valve Job" only....

Read it if you wish......or not.....it is your choice.

I spent, if I remember right, the following:

Head rebuild at a local shop $240 after taxes. Included a complete gasket set.
I would not try to do that job myself, if I were you....

Rings were $50 from Schucks.

New Head Bolts were $35 from Schucks.

New Rod Bearings were $45 from Schucks.

New Pan Gasket was around $15 - can't remember that part well.....

Renting a Ridge Reamer from a local rental place $25.

Buying various things like a cylinder hone, tools, RTV Silicone etc which I
didn't have was maybe $40.....but then I went apeshit...(!) I love buying tools!

I also did a new Timing Belt for $30.

It came out about $450 all totaled.

Crvett69 says he can get the Japanese Engines for about $350 or so.

It is a philosophical difference. I like to know what is in the engine.
Crvett69 likes to replace it in toto.

So far, I have been lucky. My rings are sealing so tight that the oil hardly
looks used after 3,000 miles. I am getting 49.5 mpg now regularly.

I still keep wondering if the engine won't blow up for some dufus thing I may
have done while rebuilding it. I keep hoping the Rod Bearings were torqued
down w/o error. I try to imagine what I may have done wrong....

But after about 8,000 miles on my rebuild now, I guess it is OK (Knock on wood).

I screwed around and took my time. If one were to work on the engine in an
expeditious manner, I would imagine 3 or 4 days work would get it accomplished.

I did mine out in the dirt beside my driveway. Do it inside a nice garage if
you can pull that off.

Buy a Chilton or Haynes Manual if you don't have one.

If you have the patience to read thru my thread(s) on fixing my '93 Geo Metro
all with pictures taken as I did it, have a look at :

First Page of ..................."That's the end of my '93 Metro....."
http://www.automotiveforums.com/vbul...d.php?t=611713

First Page of..................."NOT the end of my '93 metro...Life after death! RINGS"
http://www.automotiveforums.com/vbulletin/t613410.html

First Page of ..............."The Flight of the PHOENIX !"
http://www.automotiveforums.com/vbul...d.php?t=645309

First Page of ..............”A way to Clean the Carbon out of the IM Passageways !”
http://www.automotiveforums.com/vbulletin/t622536.html

There are a lot of other nefarious threads that I interspersed in this Forum concerning
this and that....do a search of DoctorBill and they'll show up. Gas Tank replacement,
Front Wheel Bearing replacement, messing with the Throttle Body, the Injector, the Distributor,
door replacement after someone backed into me, etc etc.


DoctorBill

[Crvett69]

the price on the JDM engines has gone up so now it costs about the same to rebuild one as to buy one so its a toss up on what to do unless your pressed for time. you can usually get a complete rebuild kit on e-bay cheaper for all the parts instead of buying them seperatly

[DOCTORBILL]

Several points....

1. How many miles on the engine?

2. If you buy a JDM engine, you will have a second engine to rebuild out of the vehicle - on a bench.

3. If you drive many, many miles and if you don't wreck the body and if it doesn't
rust out, then you can swap the rebuilt with the worn out JDM in a few years!

4. Your Geo Metro will be immortal!

5. You can get 50 mpg into a future where gasoline may cost $10 a gallon!

6. A Geo Metro 3 cylinder is worth its weight in GOLD!

7. Consider this:

...If you drive 25,000 miles per year you buy 1,000 gallons of gasoline @ 25 mpg.
...If gasoline is $10 per gallon. (It could happen!)
...If normal vehicles get 25 mpg versus a Metro's 50 mpg, you save 500 gallons
...you save $5,000 per year on gasoline!

8. Keep the little bugger in good health - your's and it's....!

DoctorBill

[Woodie83]

120 is a disaster, but the fact that they're all the same leads me to believe that you didn't follow the test criteria correctly. Engine hot, all plugs out, and throttle wide open. Factory spec is 200#, 155# is minimum. Usually when compression is bad, one cylinder is much worse than the others. The fact that you're getting ping also makes me believe your compression is good. Ping comes from compression, when it's low, you can turn the timing anywhere without causing ping.

The only thing I can think of that would cause this is that someone replaced the valves, but the rings are evenly worn allowing oil into the cylinders, oil can cause ping. If you're not using oil, then that's not it.

[lancekilgore]

No I did the compression test as I always have with all plugs out and such. did not do a wet test but maybe I will. the last time I checked my gas milage it was around or between 46 and 53. Not bad at all. I usually check it every gas full up. I will do the test again tonight and do it wet as well.

[DOCTORBILL]

When you change your oil, does it turn black fairly quickly - say after a 1,000
miles?

I was getting 48 mpg several years ago right before my engine died and the oil
got jet black rather quickly after a change.

My rings were shot, but the mileage was good right up to when the number one
exhaust valve burned thru.

After the Head rebuild and ring change, the oil stayed clear and new looking even
after 4,000 miles. I change it and the filter anyway at 3 to 4,000 miles.

Only after about 20,000 miles now is it starting to darken by 3,000 miles.

DoctorBill

[lancekilgore]

ok redid the compression check this time engine hot, all 3 cylinders 130, added oil and all cylinders 145. I don't know if 15 psi points alot to rings some what you all think? Now here is something else new the head I am having rebiult had bocsh platnuim plugs so I installed them and ran for 200 miles, gas milage went down to 40 mpg and I had alot more power than with the oem plugs. is this normal?
the oil does not get black I am going on 1500 sence last oil chang and it still looks clean it does burn some though maybe 1/2 qt since oil change?????

[lancekilgore]

ok for those still watching the thread, I checked with the machine shop who has biult two other motores for me and they want 800 to short block the 1.0. but when I explained the situation said the engine did not need a rebiuld. at my altitude 7000 ft the best the engine could do is 160 where 200 was at ocean level. My 130 dry is totally exceptable. I also checked with the other shop rebiulding my head and they said the same thing. so when I get the head back from the shop on the shelf it will go untill it is needed, maybe I will get a bottom half of a engine at work and redue it then make a complete engine. Thnaks for all the replys

Lance