Jason Moussalli

I'm looking to buy a 1966 Mustang and had a compression test done. Bellow are the results:

CYL1 -105psi
CYL2 - 100psi
CYL3 - 90psi
CYL4 - 100psi
CYL5 - 130psi
CYL6 - 105psi
CYL7 - 95psi
CYL8 - 95psi

any feedback on this would be greatly appreciated... is it low? should i be concerned of the ratio from 130psi to 90psi??

Thanks

Gun Jam

Yeah it seems low.

Does it run okay?

Do you know how many miles are on the engine?

Does the engine have anything that resembles oil in it?

How long has the engine sat?

-Gun

Jason Moussalli

Thanks for the quick reply.

It seemed to run fine to be honest.

Mileage was around 50,000 if I remember correctly.

I'm guessing the car has only been taken out a few times in the last 3 months, it's mainly just been sitting in the forecourt.

Gun Jam

50k isnt much

If it runs okay maybe thats all that matters.

What do they want for it money wise and what do you plan to do with it?

Jason Moussalli

Around 28/30k, it needs new brakes front and back as well.

Just don't want there to be a bigger problem with the engine in the future as it will be first vintage car I'll have owned.

I'm gonna just drive it on weekends probably do max a 100 miles a weekend.

Jason Moussalli

what would your advice be?

barstowpo

Was the compression test done dry, meaning no oil squirted in the cylinders? I would be a little concerned with the 130 cylinder. It may just be some carbon buildup. If you throw out that high number, the remaining are all within 10%.

Chromeshadow

??
These are terrible numbers. All should be within 10% of 140 PSI!!. This car (depending on the engine) between 150 PSI and 170 PSI new. I've seen engines with the valves shot get over 90 PSI.

Jason Moussalli

150psi for 66' Mustang really?

Barstowpo - I'm not sure if it was a dry or wet test? I'll find out. Why and what would the difference be?

Chromeshadow

All of the '60 V8s were 9.0: 1 compression or higher, many were 10.5:1
9:1 gives you 150 PSI.