How quickly should oil pressure come up?

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1973dust

1973dust

FABO Gold Member
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It seems like the oil pressure on my 318 "comes to life" later than it used too and I'm trying to decide if I should be concerned or am just worrying too much as usual. On a cold start or a warm start after sitting for an hour, it will take 2 - 3 seconds for the mechanical gage to come up with the lifters also rattling. The lifters quiet down and the gage comes up simultaneously as expected. It's a 74 318 with 46000 miles that I'm fairly sure has never had anyone in the bottom end. Pressure on a cold start at 1300 fast idle is 66 psi. Once warmed up to 180-190, the pressure at 750 is 22 with 58 going down the road at 2000 rpm. It tops out at 64psi at 3000rpm warm. I am using 10w-40 Lucas "Hot Rod Oil" and a Wix filter. A blip of the throttle at idle instantly increases the pressure. What do you guys think?
 
Another detail I forgot is that on a cold start, if I purposely don't set the choke until I've cranked about 3 seconds, the pressure will come up quickly with no lifter rattle.
 
I think the 40w is too thick. Whether it will help or not, I'd drop back to the 30w. That's what they were designed for. In fact, I've had great luck with Motorcraft 5w20 semi synthetic in mine. It gets oil pressure quicker. That's the whole purpose behind these modern oils with really low viscosity cold numbers. To get oil to the engine quickly on startup and help prevent cold engine oil starvation. IMO, it also helps to run the biggest oil filter you can physically fit. I run a 2qt Motorcraft FL299 on both my slant 6 in Vixen and on my Ford 400 in Gladys. Works well. IF you can fit one in, I recommend it. Paint it black and put Mopar stickers on it if it bothers you. lol
 
1973dust said:
Another detail I forgot is that on a cold start, if I purposely don't set the choke until I've cranked about 3 seconds, the pressure will come up quickly with no lifter rattle.
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If it pulls oil on the starter, I'd say the engine's in good shape still. I wonder of the filter drain back valve is bad?
 
I didn't think of that aspect of the oil weight. I ran 10w30 previously but tried the 10w40 for more idle oil pressure although it only gained me a couple of pounds. I also wondered about the filter drain back valve but I have had the "problem" with multiple filters. Maybe Wix filters aren't what they used to be like a lot of other brands. Honestly, I ran Fram on everything for years until people I assume know better told me they were no good. Never had any oil-related trouble.
 
I'm going with the heavier oil.. I have a 74 teen in my DS, it has 85000 on the clock and still kicks the pressure up to around 70 upon start up. I use 10w30
 
1973dust said:
Another detail I forgot is that on a cold start, if I purposely don't set the choke until I've cranked about 3 seconds, the pressure will come up quickly with no lifter rattle.
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It doesn't hurt to crank the engine over to get the oil flowing before you light the fire.
 
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toolmanmike said:
It doesn't hurt at all to crank the engine over to get the oil flowing before you light the fire.
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Cranking the motor does not spin the oil pump fast enough to build pressure. It’s not a good practice on a stock motor. If it was dry sump and had an external oil pump that’s one thing…..
 
Rusty got both things that you can do by changing oil and filter. Lighter oil when cold and a good anti drain back valve in the filter is what you can do easily and somewhat cheaply. A European spec 0W-30 and a filter with a silicone anti drain back valve would be my choice. There's plenty of anti-wear additive in the oil for the cam on a stock 318.
 
Scody21 said:
Cranking the motor does not spin the oil pump fast enough to build pressure. It’s not a good practice on a stock motor. If it was dry sump and had an external oil pump that’s one thing…..
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I'll think about that next time I spin mine over to fill the carb after all the gas has evaporated out from setting for a few weeks. In a perfect world we would all have fuel injection or at least a priming pump to help the engine start faster. I can't help but think that 300 or 400 cranking rpm wouldn't pick some oil up and send it through the crank.
 
toolmanmike said:
I'll think about that next time I spin mine over to fill the carb after all the gas has evaporated out from setting for a few weeks. In a perfect world we would all have fuel injection or at least a priming pump to help the engine start faster. I can't help but think that 300 or 400 cranking rpm wouldn't pick some oil up and send it through the crank.
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It does! Way back before I used oil primer bits & my drill, I used to prime new engines with just the starter. That is what I had at the time, and it worked fine to provide oil to the rocker shafts proving the engine was getting oil before the first startup.
 
One of the great "features" of a Mopar engine-

They will "tell you" via the lifters when you are low on oil (add oil and clatter goes away) or need to change the oil (add oil or dipstick shows full, but clatter doesn't go away).

10/40 shouldn't be a problem. I've run 20/50 without issue.

...but it sounds like your oil might be breaking down. How old is it by calendar age and by miles?

BTW- I don't subscribe to 3K mile oil changes. I've done 5K since the 1980's.
 
toolmanmike said:
I'll think about that next time I spin mine over to fill the carb after all the gas has evaporated out from setting for a few weeks. In a perfect world we would all have fuel injection or at least a priming pump to help the engine start faster. I can't help but think that 300 or 400 cranking rpm wouldn't pick some oil up and send it through the crank.
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Mike, do you have a vent you can open to fill your float bowl? On my Carter AVS, I open the vent, put in a little funnel, and pour in 2-3 ounces of gas. It starts instantly after sitting a week or more. Otherwise, it's crank for ten second or more until the pump fills the float bowls.
 
S'cuder said:
Mike, do you have a vent you can open to fill your float bowl? On my Carter AVS, I open the vent, put in a little funnel, and pour in 2-3 ounces of gas. It starts instantly after sitting a week or more. Otherwise, it's crank for ten second or more until the pump fills the float bowls.
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There is a bowl vent on every carb. I don't fill the carb before starting. I could and probably should but I don't.
 
toolmanmike said:
There is a bowl vent on every carb. I don't fill the carb before starting. I could and probably should but I don't.
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Me too. Too much hassle to open the hood, pull the air cleaner & squirt fuel... then reverse the process. Ugh. Maybe if I did not drive it for months at a time I might do it.
 
Scody21 said:
Cranking the motor does not spin the oil pump fast enough to build pressure. It’s not a good practice on a stock motor. If it was dry sump and had an external oil pump that’s one thing…..
Click to expand...

That's not true unless the oil pump has no prime in which case you should be priming with the drill method anyway. When I do an oil change on any of my vehicles I disconnect the ignition (or remove the fuel injector fuse) and crank it with the starter to finish filling the oil filter. Within about 30 seconds of cranking (not all in one go of course) I can see the oil pressure gauge come up. Heck I've had no-start issues on my Duster or D200 where I had to crank it a few times, just with the starter turning it a few hundred RPM the oil pressure came up to about 20 psi until I let off.

I figure it's better on the main and rod bearings to have it turning at lower speeds without the force of combustion pushing down on the rods until it gets oil pressure.
 
1973dust said:
It seems like the oil pressure on my 318 "comes to life" later than it used too and I'm trying to decide if I should be concerned or am just worrying too much as usual. On a cold start or a warm start after sitting for an hour, it will take 2 - 3 seconds for the mechanical gage to come up with the lifters also rattling. The lifters quiet down and the gage comes up simultaneously as expected. It's a 74 318 with 46000 miles that I'm fairly sure has never had anyone in the bottom end. Pressure on a cold start at 1300 fast idle is 66 psi. Once warmed up to 180-190, the pressure at 750 is 22 with 58 going down the road at 2000 rpm. It tops out at 64psi at 3000rpm warm. I am using 10w-40 Lucas "Hot Rod Oil" and a Wix filter. A blip of the throttle at idle instantly increases the pressure. What do you guys think?
Click to expand...
20/50W summer
10/30W when temperatures don't get above 45
That's my formula since the 70's. I use the high pressure spring with standard volume pumps both big and small blocks. Never had a problem
 
RustyRatRod said:
I think the 40w is too thick. Whether it will help or not, I'd drop back to the 30w. That's what they were designed for. In fact, I've had great luck with Motorcraft 5w20 semi synthetic in mine. It gets oil pressure quicker. That's the whole purpose behind these modern oils with really low viscosity cold numbers. To get oil to the engine quickly on startup and help prevent cold engine oil starvation. IMO, it also helps to run the biggest oil filter you can physically fit. I run a 2qt Motorcraft FL299 on both my slant 6 in Vixen and on my Ford 400 in Gladys. Works well. IF you can fit one in, I recommend it. Paint it black and put Mopar stickers on it if it bothers you. lol
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10w30 and 10w40 are both the same weight on cold start. That's what the 10 means.
 
Thanks for all the responses. I'll try to answer any questions raised in order. I'm using a mechanical gage so no sensor to change. The more I think about it, it was acting the same last year with 10w30 as it is now with 10w40. The oil and filter were changed in March and it's been driven about 1200 miles. It never gets started without being driven a minimum of 20 minutes so I would think the oil should last a long time although I change it yearly anyway. Not sure it matters, but it is not bone stock. I'm just fairly certain the bearings/oil pump have never been touched. I am running a cheap Summit cam and lifters so I've always used a higher-zinc oil to try to be safe. I'm really starting to wonder about the drain-back valve as the Wix filters I've been using were purchased on Amazon. Maybe old stock or "seconds"? I'll be sorry I ask this but what brand of filter are you guys using?
 
WIX has gone global now for about 7 or 8 years. You'll likely not get a WIX filter made in America anymore. That's why I run Motorcraft and recommend them.
 
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RustyRatRod said:
WIX had gone global now for about 7 or 8 years. You'll likely not get a WIX filter made in America anymore. That's why I run Motorcraft and recommend them.
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I should have known. Thanks for the info.
 
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