Compression

[TROOPER88]

Hi
0.?
I have just about completed a nut and bolt restoration on a Ford Fiesta RS Turbo.
I purchased a second hand engine that I was told had very recently been fully rebuilt and I was given a copy of all receipts for the work.

Last week I started the engine for the first time and the good news is that it runs ok. The engine had not been started for 2 years (maybe a little more).

All seems to be ok but I thought (and still do) that it is a little bit noisy. When cold the auto choke kicks in meaning it idles at 12-1300 rpm and then settles at around 1000rpm.

It does 'hunt' a bit which I will look into in time.

For the time being I purchased an engine compression tester on my way home from work. Having never used one before I warmed the engine to operating temperature whilst reading the instructions in the manual.

The reading I obtained are:

Piston 1: 168 psi
Piston 2: 169 psi
Piston 3: 172 psi
Piston 4: 160 psi

My question is: Are these good values? Do they indicate any issues?

Thank you

[HustleRussell]

A good rule of thumb is you're looking for less than 10% variation between cylinders. Your readings are normal.
Was the throttle wide open and is your battery good and strong?

[TROOPER88]

HustleRussell said:

A good rule of thumb is you're looking for less than 10% variation between cylinders. Your readings are normal.
Was the throttle wide open and is your battery good and strong?

Hi
Thanks for taking the time to reply.

I had the throttle pedal on the floor for all tests and the battery is new.

Cheers Paul

[davepoth]

Probably worth checking the head bolt torque if it's recently rebuilt - those numbers are will in tolerance as above, but the head may be not quite fully nipped down.