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post #1 of 21 (permalink) Old 08-09-2013, 01:44 PM Thread Starter
 
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Oil Pressure

I just changed the oil and now at idle its reading 60-65 psi, before the change it was 40. And this is almost a quart low, I left it low on purpose to be sure I didn't over fill it. I'm just afraid to blow the filter out into the engine. I bought the ACDelco filter.

Pressure guage is the manual auto meter with copper wire. Used Valvoline VR1 20w-50.

What would cause the increase in pressure from only an oil change? Could there be air trapped in the pressure line?

Thanks
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post #2 of 21 (permalink) Old 08-09-2013, 02:10 PM
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Your oil. It's too thick. Factory fill is 10w-30. I never run anything thicker than 15/40. 20-50 has its place in worn engines and race engines with loose clearances, but not in a close tolerance engine. I would replace the oil with an appropriate grade, like 10w-30.
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post #3 of 21 (permalink) Old 08-09-2013, 02:14 PM
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I run the VR1 20w-50, have for years, no issues, and no pressure gauge either.
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post #4 of 21 (permalink) Old 08-09-2013, 02:19 PM Thread Starter
 
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I used it because the PO said that is what they used as well. Only difference is they used Castro 20w-50.
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post #5 of 21 (permalink) Old 08-09-2013, 02:30 PM
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I used to use Kendall GT 20-50 myself, before I knew better. 20-50 is very poor at flowing cold, especially at start-up, where most engine wear occurs. It's an 'old school' viscosity, meant to be used with loose tolerance engines, like air cooled motorcycles and race engines. Not the best choice for a stock-clearanced Pontiac engine, IMHO.
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post #6 of 21 (permalink) Old 08-09-2013, 02:43 PM Thread Starter
 
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Unfortunately I don't know the clearnace of my 455, but nothing about it is stock. I went with 20w-50 since its what I could find with higher levels of zinc for my flat tappet cam.

I didn't see a 10w-30 version of VR1. What else has high zinc in a lower weight I can get off the shelf?

I forgot to mention I also added break-in lube. Could it be the cause? I wouldn't think that little bit would change the total viscosity that much. But I've been wrong about everything else. I just don't want my cam to go flat.
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post #7 of 21 (permalink) Old 08-09-2013, 03:44 PM
 
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Quote:
Originally Posted by geeteeohguy View Post
I used to use Kendall GT 20-50 myself, before I knew better. 20-50 is very poor at flowing cold, especially at start-up, where most engine wear occurs. It's an 'old school' viscosity, meant to be used with loose tolerance engines, like air cooled motorcycles and race engines. Not the best choice for a stock-clearanced Pontiac engine, IMHO.
I agree. I used to use 20w/50 exclusively in all my hotrods, thinking that I was providing better protection. The reality is that I wasn't racing them and I was probably doing more harm than good. I now use 10w/30 because I now have a better understanding of flow characteristics and the need for protection while cold.

When these engines were produced, they were more than likely spec'd with straight 30 wt. Today's oils are better formulated and a 10w/30 is perfectly appropriate unless your engine has a bunch of miles on it, then a 15w/40 is probably appropriate.

My $.02 worth.

Chuck

When the only tool in your toolbox is a hammer, you tend to see every problem as a nail.
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post #8 of 21 (permalink) Old 08-09-2013, 05:45 PM
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Batman, Brad Penn has a 10w-30 with the ZDDP you need. You can run any 10w-30 oil as long as you add the correct amount of ZDDP additive. Too much can be a bad thing. Some cam break in lube is too thick and can gum things up, like oil galleys. (I've seen it happen). I've been running Diesel spec Rotella 15/40 in my '67 (it's hot here in Fresno) with no issues, although I understand even that is getting too low on zinc/phosphrus. I've also used 10w-30 with the GM additive with no issues. I've been running both my GTO's with the same engines and cams for decades now. Chucka, these engines were indeed originally spec'd for multi-vis 10w-30. It says so in my owner's manuals!
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post #9 of 21 (permalink) Old 08-09-2013, 08:00 PM Thread Starter
 
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I'm not sure where to find brad Penn. Got a jegs link to the exact kind I need? If I use brad Penn will I need addative? Also what is the correct addative I need? I thought break in lube was what I needed. Again a jegs link please :-)

I decided to drive it anyway, I idled entil I left the side roads. Wasn't min more than a mile and the Paul droped to 40 at idle. Cruise was 60 and under acceleration went up to 75. Once I was happy with the pressure I did a few runs up to 4k rpm and pressure never went past 75. Shut it off for 20 min and idle was 60 when I started it back up.
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post #10 of 21 (permalink) Old 08-09-2013, 09:16 PM Thread Starter
 
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Rather than creating a new thread, I'll add to this one.

I believe I am allot closer to finding where my oil leak is coming from. Here is a picture where you can see the oil coming from inside that black cover. The odd thing is it only seems to be happening under heavy acceleration. I was up to 4K RPM and no signs of new oil leaking, just the old. When I cleaned it up I could push on that black piece and old oil would ooze out. I'll do a 20 mile low rpm run tomorrow and check it. If all is good I'll then do a short run up to 5K, then if its still good I'll red line it and see if that will cause it.

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