Re: 1930 7th Series- 320 engine- low compression issue- help sought...

Posted by TxGoat On 2024/4/11 20:44:09

I'd look into the cold start issue first. I seriously doubt it is a serious problem, or any internal engine problem. I'd suspect a fuel delivery issue or an ignition issue, or both. The low(?) compression may be related to rings not fully seated, or perhaps stuck rings. The readings being so even is a good sign, as is the fact that the engine runs well once started. The compression may improve with some run time, if it is actually deficient. I'd expect it to. Compression readings up around 60 PSI are more than sufficient for the engine to start and run normally, especially when all 8 cylinders show similar readings. I've run worn out engines that used a lot of oil, yet still started very easily in any weather. Model T Fords start easily with compression ratios down around 4:1. In fact, a T will often start simply by turning on the ignition, with no cranking at all.

Weak ignition could cause the starting issue you are experiencing. You should have a hot spark at all cylinders with the starter motor engaged and cranking the engine. Pushing the car to start it allows higher electrical system voltage which might overcome an ignition system issue such as oxidized points. a weak coil, or a bad condenser.