oil pressure help please

[lilrobo]

hey guys
i have a 1953 ford f100 with a SBC 350( dont know the age ) , i was have oil pressure issues, so i pulled the oil pan and installed a milling HV oil pump new shaft and new pickup , i followed the instructions by milling ,, i would of liked to pull a cap while the pan was off but didnt , anyway now on cold start i get about 45 to 50 PSI . after hot driving i get maybe 25 at 1500 to 2000 RPM ,, now at idle i get lower , its hard to tell by the new gauge i am down around the first and second line below the 25 and thats around 700 rpm ,, my question is should i pull a cap and check the bearings , and maybe change them ??? the pan is easy to pull , or through a can of additive, i am running 40w oil and a wix filter
thanks

 

[Russ300H]

Sounds like it's just worn out. You put a band-aid on (in) it by replacing the pump, but the bearings are most likely over clearanced. I would budget for a rebuild/replacement at some point

 

[uart]

Hi lilrobo, what was the hot idle oil pressure before you swapped out the pump?

 

[bullwinkle]

Don't be surprised if the issue is worn cam bearings, especially if there is no lower end noise. Think I would jump up a grade or 2, possibly even to 20W50, and live with it until I could do a complete rebuild or crate long block.

 

[uart]

Could it be that we've finally found a legitimate use for this product:

Penrite "10 tenths" 10W70 - http://www.penriteoil.com.au/products.php?id_categ=1&id_brand=4&id_products=282

 

[Eddie]

I might check the oil pressure Gage.

 

[GreeCguy]

If the pan is an easy drop, I'd give it a try. If you do go this route, you'll want to remove a bearing and figure out what size to buy before you purchase new bearings. It could be previous owner turned the crank so unless you already know, bearings could be standard, 0.10, 0.20 or even 0.30. Since you will not be turning the crank, you'll want to replace with same size bearings as are currently in the motor.

 

[demarpaint]

Originally Posted By: Eddie
I might check the oil pressure Gage.


I agree, I'd do that before I started changing out the bearings. If the gauge checks out OK, then I'd do the bearings.

 

[Shannow]

Originally Posted By: Eddie
I might check the oil pressure Gage.


Not sure what you are getting at...Gage is the kid's name in Pet Semetary....

 

[gregk24]

For now just jump up a grade at a time and see if that helps

 

[46Harry]

Putting a high volume, high pressure pump is a Band Aid for worn bearings. A small block with a stock pump and correct bearing clearance will hold around 45 psi at cruise and around 20 to 25 psi at idle with straight 30 or 10W-30 oil in the pan and with a warm engine. Just replacing the bearings without checking the bearing journals for the correct diameter, scoring and out of round will give you a less than acceptable repair as you could end up with the same problem in the near future.

 

[Chris142]

Those old engines disnt have much pressure @ idle anyway.25psi @ 2000 rpm is fine. Does the pressure go up the more you rev it?

 

[Zaedock]

I run a Melling HV pump in my Malibu drag car with a 355ci small block. It's been in for 20 years & 50K miles and I typically run 30-40psi at idle/off idle (depending on oil temp).

What part number Melling pump did you use?

BTW, not to be technical, but this thread is in the wrong forum.

 

[440Magnum]

Originally Posted By: Russ300H
Sounds like it's just worn out. You put a band-aid on (in) it by replacing the pump, but the bearings are most likely over clearanced. I would budget for a rebuild/replacement at some point


+1 If its not making unhappy noises, it can probably still go a long way like this, so you can save your pennies. But you're dealing with a pretty typical tired SBC from what you're telling me here. I'm tempted to agree with the comment that it could be the cam bearings since the HV Melling pump didn't provide even more improvement at speed with hot oil.

One other thing, you say you are running a "40w" oil- but what exactly? A high VI synthetic or semi-synthetic (like Rotella T5 10w30 or T6 5w40) might actually perform better if you're using an old-school single-grade 40.

 

[lilrobo]

no noise at all ,, i am using castrol 40w no syn, plain conventional, so you say it would be ok to jump up to 20w 50 ?? ,, i still might take a rod cap off and a main cap off to see whats going on ,, like i said no noise ,,, the gauge is new ,but hard to tell what you are running when that low

thanks for all the info

 

[uart]

Originally Posted By: lilrobo
the gauge is new ,but hard to tell what you are running when that low

Yeah, those gauges don't really give much resolution at the low end. You can however extrapolate reasonably well from the "25psi at about 1500 to 2000" to be pretty sure it will be in the 8 to 10 PSI range at 700 rpm. Not a lot, but should be enough to get the oil everywhere it needs to be.

If it's not making any noises then I'd just look at using a high viscosity index xw40, or even a 15W50.

 

[440Magnum]

I wouldn't necessarily up the SAE viscosity- I'd go with a high viscosity INDEX oil that is more temperature-stable first. I personally would try Rotella T6 5w40 first. If that didn't boost pressures a little (you're really not "out of spec" for an old American v8 as it is...), then and only then would I try something like M1 15w50.

 

[rrounds]

If your not burning a lot of oil and have 10 psi for every 1000 rpm you'll be fine. That engine might even go another 200k miles. My brother had a '72 SBC that had 35 psi@4000 rpm and he put over 150k miles on it. For oil I like Rotella T6 5/40 or the Rotella 15/40

ROD

 

[lilrobo]

what is xw40 ?? , i put a bottle of lucus treatment , and i'll see what it does,, i was thinking about do 20w50 ? maybe ,, anyway i am just going to drive it for now ,, i had a 58 biscayne with a 235 l6 it had bad oil pressure i ended up rebuilding it, i had 2k in the motor ,people thought i was crazy , but it was still all original when i sold it ,, i know a sbc 350 it cheaper to rebuild , i hate to have the truck down , i love driving it lol

thanks guys i'll keep you posted

 

[Errtt]

No engine history - could run up a grade.... the 20-50 as suggested.
If you have another gauge, might be worth a try. If the gauge is oil tube... be sure to bleed air out of the line while running, then see if the reading increases.
Even at idle, if it doesn't sound like its starving of oil - drive it like you stole it.