Hey guys,

 

Before l drive 5 hours to go and pick up this 4age, the seller has told me the engine has 140psi of compression on all 4 cylinders.

 

Is this good or bad as l am not a wizz with this stuff ?

 

Thanks

Assuming that the compression test has been performed correctly, for 1987 through to 1989 engines my manual tells me 1236kpa (179.26664psi) is normal whereas 863kpa (125.16756psi) is the minimum. I'm not so sure about later engines, hope this helps.

Impossible for all pots to show the same figure.

You want the figures for each individual - 1,2,3,4. cylinder.

Also was the test done wet or dry?

140psi seems a bit low.

 

i think the 4age manual specifies around the 170-180 mark for bigports and over 200 for smallports?

 

obatin a copy of the 4age manual and check these figures.

 

and agreed you want the compression on each cylinder. Low compression across all cylinders just means the engine is tired, but if one is alot lower than the rest it indicates a more localised problem, bad valve or headgasket failure.

 

also alot of compression guages are cheap and crap, so wont offer accurate or even repeatable results, so take any results obtained by someone else with unknown instruments.....with a grain of salt.

My big port has around 180 on all 4. 140 seems low.

also note. if the engine has aftermarket cam shafts with large overlap, the static compression will go down.