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Discussion Starter #1
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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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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Discussion Starter #4
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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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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Discussion Starter #6
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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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
 

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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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Discussion Starter #9
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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Discussion Starter #10
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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asunderful

It doesn't seem you'll be successful with that approach, as the oil is "all up anunder" that cover, and will be leaking whenever, and wherever it leaks, (more than likely the rear main seal-but pray not) and just collecting all "up in there" in unobvious spots due to spinning components and air velocity, then oozing out at its' own leisure, pooling and collecting, then eventually spewing out at the lowest point, and you'll never know at exactly what point in time this is happening . Have you pulled the cover and cleaned the inside out as best as you can, and shined a light "all up in there"? Probably won't help, but for piece of mind, perhaps, won't hurt. You ARE running a pcv system, YES??? :willy:
 

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Discussion Starter #12
There is a PCV in the top of the engine going to the back of the carb. There is a number 40 stamped inside. That is all I have.

Also 2 breathers, but the stud girdle is blocking 99% of the hole.
 

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polyvinylcrankcaseventilation

Sometimes if the pcv is blocked or disconnected, it'll push oil out the rear main, due to excess pressure in the crankcase.
 

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Back on the oil discussion. Check out Shell Rotella-T 15w-40. It has good zinc levels and also isn't so thick.

The 50 weight oil IS the cause of your pressure increase. 60 psi "cold" and also at rpm after warm-up isn't anything to be concerned about, but I also agree with the other opinions that it's more than likely too thick to be safe in your engine. The reason xw-50 oil is referred to as a racing oil is because RACING engines, i.e. those that have been built with intentionally "loose" clearances need the extra viscosity in order to maintain integrity of the oil film --- because of the loose clearances. In a "street" engine, one that hasn't been intentionally built "loose", all having that extra viscosity does is to ramp up the stress and strain on the oil pump, oil pump drive, distributor cam gear, cam gear, and timing chain making them wear quicker and be more likely to fail --- for no real benefit.

Bear
 

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Discussion Starter #16
I did some more testing today. PSI in neutral is about 27, with normal throttle 60 and heavy throttle it tops out at 75. So I think this oil will be OK. I'll order up some Brad Penn and try that next. I don't want to make a change until I know whats needs to be done to fix this.

I did a 10 mile run driving like a granny never touched 4k RPM and seen no signs of leaking. Then I did a 4 mile run where I got on it a little, maybe 75% throttle taking it to 5K. It was leaking after that.

Before I drove it I removed the inspection plate. It wasn't anything like I had expected. Wasn't much oil in there at all. I am completely stumped where this oil is coming from. It dumped 1.5 quarts from the previous day and I don't see much evidence under this plate. I expected the flywheel to be soaked in oil, it looks dry. So how is oil spraying all over? Its sprayed all over the headers as well. You can't see in the picture, but I can see oil way up as far as I can see, not sure what is up there or if its getting sprayed up there.

To make matters worse, I got the number of an engine guy and his recommendation was to put in a chevy. Said all my problems would go away. lol. So that wasn't all that helpful. I assume this problem was probably always there since I bought the car, but I had never really run it hard until recently.



 

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Suicide makes all of your problems go away, too. The Chevy guy is mis-informed to the point suicide wouldn't help even him. Back to your isue, I think you are building up pressure at the rear pan/rear main area at high rpms and it is weeping a bit. I can't tell if it's the pan seal/gasket or the rear main. My advice would be: 1. thinner oil 2. don't rev it to 5 grand. 3. pull engine and reseal it. In that order. Me, I'd change the oil and drive it.
 

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Discussion Starter #19 (Edited)
OK, but which Oil? I thought the SAE meant it was no good for my engine. I see Brad Penn is SAE. You have a jegs or summit link to the one I need? Also it says its partial synthetic.

And option #2 is no fun, lol. My rev limiter is 6500. In 2nd and 3rd its still pulling strong at 5K. In 1st 4500 seems to be where it falls off.
 

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SAE is Society of Automotive Engineers. The Brad Penn stuff is fine. No need to add ZDDP to it, either. You probably have a slight rear main/pan seal leak, but it may not be so bad with less oil pressure. I think 5,000 rpm with the thick oil you are now running may be adding to the oil leakage, but I've been wrong before. In either case, switch to thinner oil and go from there. You may be looking at eventually pulling the engine and resealing it. I did that with my '67 2 years ago and am glad I did, after 20 years of leaking. It's not that big a deal after it's all said and done.
 
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