[Compression Standards for 1948 Pontiac 8 cyl]

Please advise what the compression readings for a 1948 Pontiac 8 cyl Streamliner  should be.

[Compression Standard for 1948 Pontiac Streamliner]

45 minutes ago, Bloo said:

I agree, but was hesitant to suggest setting them to spec unless they are too tight.

 

Too tight is always bad and could cause valves to burn. Too loose might just mean some crud or rust on the valves from sitting, and those valves would tighten up from driving.

 

I would make sure none are too tight and then break the engine in. Then, I would recheck all of them and set to factory spec.

Thanks, again

[Compression Standard for 1948 Pontiac Streamliner]

52 minutes ago, Robert G. Smits said:

Agree with Tinindian but would check the valve clearance first before I drove it several hundred miles

Thanks

[Compression Standard for 1948 Pontiac Streamliner]

12 hours ago, Pfeil said:

Specification  for 1949-51 at operating temp. 120 PSI and no more than 10 PSI variation

Thanks

[Compression Standard for 1948 Pontiac Streamliner]

Thanks

[Compression Standard for 1948 Pontiac Streamliner]

2 hours ago, Tinindian said:

Six hundred miles in five years on a newly rebuilt engine is not very many.  In fact not nearly enough.  If the valves were/are set right it needs to be run and run and run to break in the engine.  Don't drive it at a constant speed for a long time.  Drive it at 50 or 60 for a few hours, taking your foot off the gas and let the car push the engine down to about 30 and the accelerate again every 20 minutes or half hour.

Thanks

[Compression Standard for 1948 Pontiac Streamliner]

Just turned 52,000 which I know are original since my father bought it in 1950.  Also, the engine was rebuilt in 2014 at 49,399 miles.  Oil pressure is good.

[Compression Standard for 1948 Pontiac Streamliner]

2 cylinders are at 110, 5 are at 120, and 1 is at 95 & 100 wet.  Is that indicative of an issue?