My current car is a 64 valiant with a 225 that was rebuilt about 25,000 miles ago. The engine has performed flawlessly. I changed oil and filter recently. I have noticed that on two cold start-ups it has taken the engine about 5 seconds for the oil pressure to pick up. I noticed it because of the sound of the engine. Otherwise it has excellent oil pressure, about 50 lbs. warmed up and at highway speed.
Thanks for any comments about what could be causing this slow pick-up of oil.

A cheap oil filter with a substandard anti-drainback valve is the most likely. Orange oil filters are very dangerous in this regard. We've discussed this very issue at length so there is much to learn using the search function.

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Joshua

Yes, please do your new engine a favor and install a WIX 1806 for silent start ups!

Been there and done that..... Mine has about 60,000 miles since the rebuild 3 years ago. I hated that sound first thing in the morning especially on a new engine. Now running 0-30W Mobil 1 and the WIX 1806 and get 50 lbs. immediately on start up with no noise except from the starter.

Use the search function to read all about it.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Thanks for the responses. I changed over to the Wix 1806 oil filter. This did not stop the oil from draining back into the oil pan after the car has set long enough. I searched this site and as usual found lots of good information and learned more about my slantsix. One of the things I came across where the references to the oil pressure relief valve. I was not familiar with it and have never serviced the valve. I could not determine whether a non functioning valve could cause the leak down from reading the posts. I went ahead and pulled out the valve and inspected it. I found a tiny nick on the upper side of the notch in the valve. The valve looked good otherwise, so I cleaned it up with crocus cloth and re-installed it. This did not solve the problem. I went to my junk pile and got another valve. It did have some visible striations that I could not feel. I went ahead and cleaned it up and installed it in place of the original nicked valve. This did not solve the problem.
So I am back here requesting more advice about which way to proceed. Should I replace the pressure relief valve again? The oil pump? Try another filter?
I am and have been running Kendall GT1 10w-30 oil synthetic blend.
I am assuming that oil drainback to the pan is the problem. I've noticed that if I check the oil level at 30 mins. after cut off that the oil level is on the full mark. If I check it the next day the oil level is about a 1/2 qt. above the full mark.
Also, when I went to replace the oil filter I found it to be overtightened. It required all my strength to remove it. I found this very unusual as I installed the oil filter and I am sure I did not overtighten it. I feel like I had a defective oil filter and it has somehow damaged the oil pump.
Any advice will be greatly appreciated.

Does your pump have the stand pipe with the check valve inside?
If not, you may want to try one.
DD

If you're using the #1806 filter, it won't make much of any difference if your pump has the standpipe because the #1806 filter has its own standpipe built in. What grade (weight) of engine oil are you using?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

64 slantsix,

I use 0-30W Mobile 1 and have zero drain back problems or any noise on start up. The WIX 1806 filter stays full all the time and can not drain back because of the built in standpipe. In fact when you take the filter off it is hard to spill any oil, maybe two spoons full at most that collects at the base of the standpipe on the pump.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

I am using Kendall GT1 10w-30 synthetic blend oil. My pump does not have the built in stand pipe. I have no problem changing oil brands, so I will try the Mobil oil and see if this helps. From what I am hearing from you all it seems to me like drain back from the filter is not the problem because the Wix 1806 filter should prevent this from happening. Is it possible that a defect or damage inside the oil pump itself is allowing the pump to drain down? I am assuming that the "head" of the pump stays full of oil at all times.
My slantsix is a 225 with a stock 1964 block and a later model head. It has the original oil pump.

When air enters into the pump / filter, the oil drains back into the pan.
The standpipe, anti-drain back check valve, other gaskets, seals and o-rings all work to keep the air from entering so the oil stays put, inside the filter and pump.

Most of the time, the air comes-in from the oil gallery side. The stand pipe is on the gallery (exit) side so it is designed to prevent the oil from draining out thru the bearing clearances. The stand pipe alone will not prevent air from entering and oil from leaving the filter thru the pump's impeller. It is the filter's anti-drain back valve that does this job.

The pick-up side of the system is pretty simple but a loose pick-up tube, cracked p-up tube thread or a gasket leak at the pump to block pocket can let air in.

If this is a recent problem that came-up after a oil / filter change, I would replace the filter (again) to see if that helps.
DD

Doc,

Thank you very much for the info on the operation of the pump and filter. Now I know what to look for and where to start looking. I will start at the oil filter and work my way down through the oil pump and into the pan.

A worn oil pump can contribute to faster drain back but again, air has to get into the system for the oil to drain back.
This diagram and photo may also help: