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So I Did A Compression Test Right ...

Featured Replies

hey guys

 

I did a search trying to find standard compression rates for a 4k (in PSI) but had no luck ...

 

i did a test on my 4k - 125 was about average, highest 127 lowest 121.

 

Is this low? I noticed someone on here had a 5K with 10.1 compression and managed 225 average ... :P

 

Cheers, Dyzza

  • Author

hey

 

actually it might have had one done ...

 

the last bloke, on carsales, just put like 'headwork, camshaft...' like that ... i didn't ask any questions ...

 

Cheers

Did you do a wet compression test or a dry one.

  • Author

ah ...

 

well never heard of that terminology before, but this is what i did do ..

 

screwed thread into cylinder 1 (screw in guage type), took lead of dizzy cap, pumped accelerator a bit as i turned the motor over. ..

 

stopped, read guage, reset it, put spark plug back in cylinder 1, went onto cylinder 2...

 

Dyzza

you should have the throttle fully open when you do a compression test.

 

a dry compression test is what you have done.

 

if you get low readings from a dry test you do a wet test. a wet compression test is when you put a teaspoon or so of oil down the plug hole. if the compression increases on a wet test, it means your ring seal is suspect. no improvement means the valves or headgasket is the culprit.

  • Author
if you get low readings from a dry test you do a wet test. a

 

yeah ... but i don't know my readings are low ... thats what i really wanna know

 

I'll give that a shot too :P

I tested my 4k(carb) n the result r 140,135,130,150(psi)...

I just overhaul the engine last month....

All stock,just the exhaust is diff...

Is the test result good..??

I found this a long time ago....

 

 

Engine

Engine Displacement (cc): 1290

Firing Order: 1342

Spark Plugs

Type: Denso W16EP

Gap (mm): .80

Compression Pressure (psi): 127-156

Distributor

Make: Bosch

DWELL: 50±2

Point Gap (mm): .40-.50

Ignition Timing Initial/Static: 8@Idle C/S

Fuel System

Make/Type: Aisan

Float Level (mm): 7.5

Idle Speed (rpm): 750N

Emission CO%: 0.3-2.0

Fuel Pump Pressure (psi): 2.8-4.3

Fuel Capacity (cc/min@rpm): 900@5800

Oil Pressure (psi): >45@3000

Valve Clearances

Inlet Hot/Cold (mm): .20

Exhaust Hot/Cold (mm): .30

Torque Specification

Cylinder Head (ft.lbs): 39-47

Main Bearings (ft.lbs): 47-49

Con Rods (ft.lbs): 29-37

i got

1 - 160

2 - 160

3 - 145

4 - 160

but i think my gauge is old and overreads....

anywho, expect around 160 from a good, stock engine

if you have had a cam grind you will get less because there is a bigger overlap of intake and exhaust (is it only me that this makes two thirds of bugger all sense to?)

  • Author
anywho, expect around 160 from a good, stock engine

if you have had a cam grind you will get less because there is a bigger overlap of intake and exhaust (is it only me that this makes two thirds of bugger all sense to?)

 

yeah man i hear ya ... doesn't make the most sense to me either ... hmm ... sounds as though the inlet is still open while compression is occurring ... wouldn't that be detrimental performance-wise ?

 

Dyzza

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