I am installing a new oil pressure gauge into a 66 dart with a built slant 6 and am wondering what pressure i should expect with my engine so that my gauge will read it. Any ideas?

Wow...oil pressure lotto, I'll play!

I guess 30 psi hot idle and 52 psi at speed. (over 2000 RPM)
DD

Twenty five at hot idle, 50 at driving speeds. (OK, so those are my readings...)

Awsome! Thanks for the help guys. My gauge reads up to 100 so i should be all set. Thanks again.

I used to race my Duster with "0" at idle and 40 revved up.

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Official Cookie and Mater Tormentor.

i have 60lbs at idle 75-80 under a load............when its been run on the freeway it dips to about 40. It also depends what kinda oil you run. straight or mixed weights.
I Run castrol 20w50.

On my 440 with 10.5:1 and race clearances I run straight 60 Valvoline and im lucky if I get 60lbs

castrol 20W50 is the only oil I will use in any of my machines. I talked toa friend of mine who was a crew chief for drag bikes and street racing sport bikes (he worked for Vance and Hines if any of you know that company). He would use only 20W50 castrol in anything, said in his opinion nothing is better than thick dino oil. I asked "what about racers that swear by synthetcics and crap like that?"

well they are sponsored and besides, "you could piss in a race engine, you are going to tear it apart when race is over anyway"

remember that quote from racing mechanic next time someone tries to sell you something because some racing team uses it. I thought that visual I got from that quite was funny.

and oil pressures might vary slightly depending on oil viscocity. And yes I know thin oil for cold weather, but I live in southern california, we dont get cold weather.

Caesar

Well, I guess if you are going to tear the engine down every time you drive it you COULD use piss for oil..... Personally I like to DRIVE my car not work on it.... Run dino until 5K break in, then Mobile One FULL Synthetic..... whatever weight works for you.
I deliver pizza for a living... I drive 800 miles a week... I run 15K on a change with a filter swap halfway... No troubles.. oils stays CLEAR for 2-3K... I am driving a 97 Miata. with 107K on it.. Miata's have a built in "Time to check/change the oil" indicator... the hydraulic lifters will tap a bit in ANY 1.6 or 1.8 90-98 if the engine is in need of a flush, or if you get 1 quart low, or if the oil viscosity has broken down... running dino I got 3-5K before the tapping arrived... With the miles I drive I do not have the time to change the oil every 4 weeks... that was the main reason for switching to sythetic.... I beat the hell out of the car every day... bumping the limiter regularly..... There is PLENTY of statistical data verifying better flow at cold, better viscosity at high temps, and better lubricity than dino.... I am NOT a ricer type. I use what works best for me. In my 75 Duster I use dino oil. But in my hi reving 4 banger I use Synthetic, because it lasts longer under the conditions I put the car in. if the Duster had a fresh rebuild I would probably run Synth after break in just for the extra protection at cold start... Mobile One 15W50 Synth will pour at -49F, and has a flash point of 446F.
Just my opinion.

Forgot to Login before posting... previous message is from me.

I've run 20-50 back to back against straight 30W in a couple of my race cars. The main thing 20-50 does is rob horsepower. With straight 30 the car would pick up a tenth to a tenth and a half.

I have not tried synthetic yet, but I might in the new motor. I think it may help with consistency.

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Official Cookie and Mater Tormentor.

I run Quaker State 10-30, in all my cars. In 1974 I did a test, on my Z/SA 65 Valiant, with a 170. Ran 3 runs with 10-30, Replaced with same brand straight 30, made 3 runs, went back to 10-30, and made 3 more runs. Average was .15 quicker in the 1/4 mile with 10-30.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Hey... Slantzilla.. if you want to try Synth just remember to break the engine in on dino. for 3-5K The synth will prevent proper ring seating, and main,rod,cam bearing break in.

I am aware that thicker oil will rob power. But the 15-50 synth pours much easier than dino 20-50 at room temp. However it also will not thin out much more when it is hot.... very important when you are running at 6000 RPM for half the day. A good test.. is to put a quart of your choice in a frying pan.. OUTSIDE of course. And turn the heat up. Easy enough to find out at what temp the oil turns to black crud.

I am not really concerned with saving a tenth in the 1/4... I am concerned with protection under extreme conditions, and extended oil changes. Synth gives me this... It costs me $35 for the oil and filter vs $12 for dino. But I can go 3-4 times longer, and I simply don't' have the time to do it every 3 weeks. I do all my own work, because I don't trust anyone to work on it.

Oil is sort of like religion... Difficult to convince others of your opinion.. And in the end you should use what works for your needs. There are SO MANY variables involved... thats probably why there are so many oil choices.... Use what you like, and what works.

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Stock 75 Duster 109K. Working on Turbo setup.

Me too. 52 psi at idle, 54 psi revved up, no change hot or cold. 10W-30 dinosaur oil. 78k miles, 1964 motor.

At 70psi cranking compression, the rings are pretty weak... but I'd say the bearings are probably fine.

- Erik

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Lots of early Valiants and Barracudas have crossed my path.
Also a handful of other toys for variety now and then.

Hey.. I am kinda suprised the cranking compression would show that low with only 78K on it.... what's the comp ration on the 225? I have never check my Duster to see what it is. Make sure you remove all the spark plugs when testing. The engine can turn a lot faster without the dead compression load of the other 5 cylinders. It would not really matter if you are just looking for the realtive difference between cylinders, but the overall # might show low if you don't remove them.

My Miata has a comp ratio of between 8.5 and 9.0 to 1 and with 112 K on it I still get between 195-210 PSI.

The 225 has a very long stroke for it's displacement, my 1.8L Miata has a short stroke. So mabye the 225 block ends up with significantly more side loading on the cyl walls, that would definitely make it lose commpression sooner... Just a thought.

Ken

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Stock 75 Duster 109K. Working on Turbo setup.

I'm banking that the walls were not wiped clean enough during overhaul, the air filter was ripped or there's a gap letting dusty air in, or the valves are set incorrectly. A wet/dry test and an oil analysis will narrow the causes down. Driving for extended periods (months) with a lean mixture will cause overheating of the valves, too.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.