What pressure should be in the cylinders after a compression test?

MarcoGTTurbo

Member +
Hey all,

I recently purchased my new GT 1992 EP 82. I am just wonder what the psi was in the cylinders when these cars first rolled out the factory.

When I got my car it had no service history at all, nothing.

So I've done a full service (2x oil changes, coolant flush, plugs, leads, filters, belts etc etc). Now I'm trying to get a better picture of the engine health.

It's done 207000km and seems in good condition, but would like for my own piece of mind to do a compression test at some point today.

So just wondering what factory psi was and roughly what it should be at now with that many Kms on the engine.

Thanks

Mark
 
Just because it has no history doesn't mean anythin,i had one glanza from 103,000 to around 250,000 kilometres i never documented servicing it..i did it every 7-8k,it had good compression about 165 on all 4

if yours makes anythin above 150 its grand
let us know what you get
 

MarcoGTTurbo

Member +
Firstly :( :( :'( :'(

Just finished my compression test and not good results :(

207000km on clock

Cyl 1 - 100psi
Cyl 2 - 120psi
Cyl 3 - 115psi
Cyl 4 - 95psi

Did the test with engine warmed up and left the plugs in whilst I tested each cylinder,also my foot down to the floor on the accelerator and cranked for about 10secs each.

I recently did an oil change and have put about 500km on the car since and the oil is still clear.
There's no smoke on start up and doesn't miss a beat.
Also all the spark plugs are perfect.....no sooting etc

How long would you say until I need a rebuild?

Cheers :(
 

rage

Lifer
Most starlet engines i rebuild or strip for parts have the piston rings seized up. Could account for the lower pressure. Could be an easy rebuild as there might not be real notable damage to any parts. But that is just my best guess at the moment
 

MarcoGTTurbo

Member +
Thing is though, it's not using any oil, not one drop. The spark plugs are mint. It's running better than any other I've driven before and the engine is so quiet and stock.

I'm wondering if my compression tester is playing up :s

If the compression was really that low what would I need to look out for/notice different?

Cheers
 
It might be worth a check as am not sure how starlets react to being a tooth out on the cambelt, but may be out of timing, this would cause low compression results as valves are out slightly? Just a thought
 

dac69er

Super Moderator
you want all your spark plugs out for a start.

try it again and see what you get. after trying it, drop a bit of engine oil down each cylinder and retest. if it improves the compression then you have wear.
 
you want all your spark plugs out for a start.

try it again and see what you get. after trying it, drop a bit of engine oil down each cylinder and retest. if it improves the compression then you have wear.

ye you need the plugs all out the engine needs to pick up enough speed cranking to give a good reading
 

MarcoGTTurbo

Member +
No worries guys. I'll give it another try in the morning cuz it's 10pm here in Aus :)

I'm going to buy another comp tester in the morning cuz I have a sneaky feeling this one is duff. Those readings would mean a substantially worn engine but likeive said earlier it feels so tight and responsive. It's weird.
 

MarcoGTTurbo

Member +
Ok new results in :)

Bit happier this morning

Seems I had the an extra fitting attached to the tester which isn't used in this application (silly me)

Ok did 2 tests

Cold engine, all plugs out using correct tester

Cyl 1 - 140psi
Cyl 2 - 140psi
Cyl 3 - 140psi
Cyl 4 - 140psi

Warmed up engine, all plugs out using correct tester

Cyl 1 - 152psi
Cyl 2 - 149psi
Cyl 3 - 150psi
Cyl 4 - 151psi

Bit happier with these results.

With these results what sort of condition is the engine currently in?

Cheers all
 

dac69er

Super Moderator
try it with a drop of engine oil in each cylinder and see if you get a better reading?

its towards the lower end of the Scale, but nothing to worry about.
 

rage

Lifer
true it's on the low side but with 200k on the clock and pressure equal over all cyl. it's quite good :)
 
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