318 - High Oil Pressure

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74Dart318

74Dart318

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Thanks to all in advance.

I rebuilt the 318 in my dart and have driven it for about a year and put ~1,100 miles on it has been mostly good. 318, 30 over, KB flat tops, Comp XE268H, Eddy air gap, Eddy 650, tti headers.

I have done some reading lately that states high oil pressure is not good for the engine. Since the rebuild the oil pressure sits at 80 when warm at idle and maxes out the gauge when driving around easily.

I bought a new oil pump and oil pan gasket set. Before doing the work I figured I would just get some confirmations that high oil pressure is bad.

I have had troubles with oil leaking out of the dipstick tube and valve cover cap.
 
My 2 direct experiences with too high oil pressure (very similar numbers to yours) is in:
  1. blowing out the base gasket on the oil filter; the guy driving did not notice the smell and ) reading on the pressure gauge and toasted the main bearings big time (MY engine of course...)
  2. overpumping oil to the head and leaving the pan dry and seizing a crank... BUT that was not a SBM with its oil flow restrictions to the head, so that is not likely going to be an issue for you.
If you are not racing this thing at constant high RPM's, then I'd correct it just because of #1 above. I'll guess that the pressure relief piston in the original pump is inverted or stuck. Easy to rectify, but a new pump is cheap. And BTW, just so you will know, a high volume SBM pump won't put any higher pressure into the engine, but will maintain better oil pressure at low RPM's.

I would not suspect oil out of the dipstick tube from this. MAYBE high residual oil levels could build up more oil under the valve covers. But your 2 last symptoms sound like either having no PCV valve in the engine, or excessive ring blowby (poor piston ring seal).
 
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Try a new analog oil pressure gauge. The leaks could be just bad/improper sized grommets and a loose dipstick tube.
 
Oil leaks where you describe could be caused by a ventilation issue. Do you have a pcv system and a vented breather of some-kind?
Pressure, verify with a master gauge.
 
High oilpressure causes heat, possibly foaming, puts excessive force on the cam-gear and intermediate shaft.
80psi at hot idle in neutral is way too high. 30-50 psi is about normal, depending on oil and oilpump used.

What oil are you using?
Hope you're not running 20w50 molasses-oil in a rebuild engine.
10w30 should be good enough when engine clearances are correct.

PCV system installed and working properly?
Check for excessive crankcase blowby by temporary removing the pcv hose and watch what comes out.
It's possible the engine is creating more blowby than the pcv system can handle. Then it will pressurize the crankcase a bit and oil-vapour/drops comes out dipstick-tube and possibly front or rear crank seals.
 
Sorry for the late reply. Right after posting this I found out my Jeep was broken into last night. No damage and they stole some tools but I guess it could be worse. They tried to get the club off the steering wheel and failed.

Anyway, thanks for the input guys.

I do have a PCV and a breather, sorry I should have mentioned this because I found this during my research. When I disconnect the PCV, you can see the pressure coming out of the breather.

BigBlockMopar said:
High oilpressure causes heat, possibly foaming, puts excessive force on the cam-gear and intermediate shaft.
80psi at hot idle in neutral is way too high. 30-50 psi is about normal, depending on oil and oilpump used.

What oil are you using?
Hope you're not running 20w50 molasses-oil in a rebuild engine.
10w30 should be good enough when engine clearances are correct.

PCV system installed and working properly?
Check for excessive crankcase blowby by temporary removing the pcv hose and watch what comes out.
It's possible the engine is creating more blowby than the pcv system can handle. Then it will pressurize the crankcase a bit and oil-vapour/drops comes out dipstick-tube and possibly front or rear crank seals.
Click to expand...

I have been using Shell Rotella T6 5W-40 in the engine so far. Think this could be an issue?
 
Oil pressure is a function of the relief valve and relief spring. Standard spring is 45 psi and HP is 65 psi, using 20w50 or 10w30, your oil is not the issue. The rule of thumb is 1 psi per 100 rpm, and relates to keeping a wedge of oil on the rotating journals. I doubt you will make power to 8,000 rpm, so it is a waste. It can also balloon oil filters and crack blocks if it gets too high. When I had to "touch" everything, I broke the edges on the relief valve in the oil pump and it acted as you describe. I'd replace the oil pump or relief valve and spring at least. Pressure from the breather would be lack of ring seal.
 
Rotella T6 is a full synthetic. Any chance that it was used for break-in? Synthetics have been known to adversely effect ring seating and are not typically used for start-up of a rebuild. 10W40 synthetic won't cause this excess pressure.

As for the pressure coming out of the valve cover when the PCV is removed there will be a little, but this is a matter of: is it too much? Kinda hard to describe....but if it is coming out in a rapid stream, then that is excessive.

Sorry to hear about the break-in... that sucks.
 
Thanks guys. All part of the fun. This is my first time doing this.

I used comp cams break-in oil for the initial start up
 
74Dart318 said:
I used comp cams break-in oil for the initial start up
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Good. How long did you run it before changing to the synthetic?

And as for the 'acceptable' level of blowby with the PCV pulled out of the valve cover, a good amount would be for some vapors to just slowly drift out of the valve cover at idle. Again, it is hard to quantify, for me at least....you do enough engines and you get used to what is normal.
 
nm9stheham said:
Good. How long did you run it before changing to the synthetic?

And as for the 'acceptable' level of blowby with the PCV pulled out of the valve cover, a good amount would be for some vapors to just slowly drift out of the valve cover at idle. Again, it is hard to quantify, for me at least....you do enough engines and you get used to what is normal.
Click to expand...

I only used it to break-in the engine for 30 minutes plus maybe 15 more minutes here and there after break in with maybe 5-10 miles. I changed the oil after break in to look for metal shavings.

The gauge read the same high pressure with the break-in oil also.

I am not sure on the blowby. I would assume it was an acceptable amount. The breather just looked like 'steam' or a light mist was coming out of it.
 
I know some will disagree but I would never run a synthetic oil that soon after a rebuild 1200 miles at bare minimum .
jmo .
 
74Dart318 said:
I am not sure on the blowby. I would assume it was an acceptable amount. The breather just looked like 'steam' or a light mist was coming out of it.
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If it is just 'floating out' lazily at idle, then that is good. If it was coming out in a steady stream with some pressure behind it, that is not good.

I'd keep an eye on the PCV system; look for any dripping/leaking oil when cruising, and then again after romping on it.

Still not likely caused by the high oil pressure. BTW, the suggestions to re-check the oil pressure with another gauge are very wise.
 
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Thanks everyone for the help! Much appreciated. Didn't know people suggested against synthetic for a certain number of miles.

Well, should have the pan off tonight and will work on cleaning everything up, removing the old pump, and installing a new one. Probably take my time and not have it put together for a few days. No need to rush.

Hope I get the gasket to seal again!
 
74Dart318 said:
Thanks everyone for the help! Much appreciated. Didn't know people suggested against synthetic for a certain number of miles.

Well, should have the pan off tonight and will work on cleaning everything up, removing the old pump, and installing a new one. Probably take my time and not have it put together for a few days. No need to rush.

Hope I get the gasket to seal again!
Click to expand...


If the bores were prepped correctly, you can switch to synthetic as soon as the cam is broke in. If it takes X amount of miles to seat the rings, the bores weren't prepped correctly.

I left my break in oil in until I had 500 miles on it because it had a big zinc package and a bunch of detergent in it. Then I switched to synthetic. If the lobes on my cam weren't so aggressive, I'd have broke in the cam and the switched it over to synthetic.
 
Well quick update.

Replaced the pump and changed the oil. Glad no real leaks from the pan reinstall yet.

Gauge still read high. Got another gauge.

New gauge is reading 60psi when warm and in D. Still seems high. Didn't drive it yet, I have it up on Jack's still.

Was planning on installing my sniper efi first.

Thoughts?
 
74Dart318 said:
Well quick update.

Replaced the pump and changed the oil. Glad no real leaks from the pan reinstall yet.

Gauge still read high. Got another gauge.

New gauge is reading 60psi when warm and in D. Still seems high. Didn't drive it yet, I have it up on Jack's still.

Was planning on installing my sniper efi first.

Thoughts?
Click to expand...

I wouldn't worry about it one bit.
My old motor with unknown miles had 80 on startup and 50 at 200 degrees the entire time that motor was in the car with 10-40 Castrol GTX and never a single problem of any kind.
 
66fs said:
60 is good. Does it stay about there? How high does it go?
Click to expand...

I don't think it climbs nearly as quick as before. I haven't driven it yet though. I will check once I get it driving again.

Thanks guys
 
Sniper efi install is complete and I finally drove the car around.

Oil pressure looks great now. Runs around 60 when starting up. Fully warm it will drop to 35-45 at idle. High revs I have only seen it get up to about 70 or so.

Thanks again everyone
 
xw 40 is fine for Arizona
I use 0w40 eurospec (MB and BMW approved fully synthetic made from natural gas) Mobil 1, Penzoil Platinum and others
wallyworld has it for $mid 20 for 5 quarts
best synthetic base stocks require fewer additives
 
So lemmie get this straight. You did the work without verifying?
 
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