What PSI should my pistons be at when testing through the spark plug holes??

Cheers,

Dumpy

 

If I remember good all under 120 psi are OK , but best results are about 150 psi.
My car have about 10- 10.5 bar on all cylinders

dont forget to remove all spark plugs and disconnect (electric) plug from dizzy

 

That dont really make sense mate.

Under 120psi = Good

About 150psi = Best


Sure thats right?

 

Anything around 160psi is a good compression. The manual says it should be between 12-14 bar but that aint going to be the case for a 15+ year old car

 

the thing to check for is that all cylinders are the same

 

checked mine yesterday, 125 psi except numba 3 it had nothin!!

 

nothing as in 0 what have you done

 

thats the main point there well within 10% or so of eachother

 

u have proberbly cracked/holed no3 piston, does it smoke when u start it?

had exactly the same on my s1 a few months ago so i took the bottom end out had it stripped and checked and had cracked no3 piston on the side and the rings also

so i had all the other parts checke and all i ended up needin was one piston a set of rings and a set of bearings and now have 175psi across all four cylinders

 

Bugger, mine are running different PSI's across them all, and between 60-80!!

Looks like i'll be stripping her again, do you think its thr piston rings then??

Cheers,

Dumpy

 

could be valves not seating properly

 

i hope it aint pistons or rings,ive had the head off, no holes on top of piston didnt check side, there no scores in the pot, i was hopin it was a fcuked valve or faulty injector, as it idles at 400rpm an struggles to move

 

approx 170 to 200 psi on the 12 to 14 bar
hope thats not right as my nwely built 1600 only has 150/155 on each cylinder

 

Need an expert to give an anwser really

 

You cant give an exact figure with regards to cylinder pressures as each engine will vary even if standad. As said above you want to be seeing roughly the same compression on each of the 4 cylinders. Whats your reason for checking the compression's? Are you just checking the general condition of the engine of is there a misfire?

You want to....

1 - Disconnect black electrical plug from distributor

2 - Remove al 4 spark plugs

3 - Conect compression guage

3 - Either get someone to hold the throttle 100% open or wedge the throttle open.

4 - Crank the enge over and take not how many compression strokes it takes to read the highest figure. (Each time the cylinder is on its compression stroke the guage will rise).

5 - Repeat for the other 3 cylinders

As mentioned earlier the manual states around 12-14 bar but this figure will decrease with engine wear/mileage. You just want to be seeing good even figures across all 4 cylinders.

 

i normaly say anything from 150psi to 190 psi is good but anything under 100psi somthing is wrong