Oil pressure drop/ hesitation

[Rck68]

hi All,

Been wondering why this happens in my 440 magnum 73 charger.

why does the oil pressure drop from the normal 45-50 down to 30ish when going from park to drive? Is this normal? Any adjustment I can make somewhere?

There’s a hesitation right after when I hit the gas to bring the pressure back up and be able to go. Rarely, when I hit the gas too hard, engine dies.

 

[jamie]

Rpms drop when going into gear......may need an accelerator pump

 

[RM23M9A]

Momentary RPM drop when shifting, may cause the oil psi to drop. 45-50 seems prettty high,(IMO). MY 6 Pack 443 c.i. usually hold 35/40 in D.. Guess it could vary on Camshaft/bearing clearance

 

[moparedtn]

What are your RPM's in Park and in Drive?

 

[beanhead]

Drop in psi is due to spinning the pump slower when going into gear, some drop going into gear is normal. I don't like to see more than about 150 RPM. Timing and fuel mixture, and the balance between the two will change/correct that, unless there is a mismatch like a very tight converter and big camshaft, etc. As for the other carb issues--sounds like it just needs adjusting and good tune-up. Based on the very limited info given your hesitation issues could be from going too rich or too lean. Start by pulling some spark plugs and check it out..if you aren't comfortable reading them take some good clear pictures and post them up.
What does your year service manual spec for oil pressure? For mine ('68) the factory pressure spec is 20 psi minimum at 500 RPM, 45-65 psi at 1000 RPM...for a stock 440. Some go by the 'rule of thumb' of 10 psi for every 1000 RPM, may be fine for some builds but not what the factory spec'd. Your pressure doesn't bother me a bit.. Better a little high than a little low.

 

[Mick56]

Is it an electric gauge? They are not real accurate.

 

[Rck68]

Thank you guys for the responses. So it just seems to be a carb issue, makes sense, I’ve been running a bit rich with my Holley 750 dp. The plugs look nice and dark and they’re fairly new autolites.
It is a stock 440 so the pressure on is not higher than 45–50 in park. In drive drops to 45.
The gauge is electric yes

 

[beanhead]

Thanks for following up...sounds like you've got some tuning to do!
If I can offer one piece of basic advice--hook up a vacuum gauge with a long enough hose to have it in the cabin with you. Note the readings at all different throttle/driving conditions and how vacuum changes with the RPM and engine demand. It saves time and takes some of the 'trial and error' guesswork out of getting the carb dialed in. It's also useful for tuning your distributor's vacuum advance, if equipped.

 

[Rck68]

Thanks for following up...sounds like you've got some tuning to do!
If I can offer one piece of basic advice--hook up a vacuum gauge with a long enough hose to have it in the cabin with you. Note the readings at all different throttle/driving conditions and how vacuum changes with the RPM and engine demand. It saves time and takes some of the 'trial and error' guesswork out of getting the carb dialed in. It's also useful for tuning your distributor's vacuum advance, if equipped.

Ok thank you, I do have a nice vacuum gauge!