Zeke1953 Posted September 27, 2009 Report Share Posted September 27, 2009 Changed the oil and filter in the Zekemobile today. Bought one of the sock type filters and was able to get it into the canister after I spread oil on the sides - but stilll a tight fit. The filter element I put in last time was the metal type and it was not correct for the model I have. Here's my question: The oil pressure used to be about 25 while at idle and normal engine temp and about 40-50 while driving. With the new filter, the pressure is 40 at idle and about 50 at fast idle. (Didn't have time for a drive today). Used 10W-40 both times. Is this okay or do I have a problem? Zeke 1 Quote Link to comment Share on other sites More sharing options...
bkahler Posted September 27, 2009 Report Share Posted September 27, 2009 I'm betting the filter you had previously was not sealing properly and you were bypassing oil back to the crankcase. The new filter sounds like it's working as it should. You might hook in a temporary mechanical gauge to verify pressure. Keep us posted what you find out. Brad Quote Link to comment Share on other sites More sharing options...
Reg Evans Posted September 27, 2009 Report Share Posted September 27, 2009 Was your radio on or off when you noticed the difference ? Sorry....it's just 610T envy. Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted September 27, 2009 Report Share Posted September 27, 2009 It sounds about right to me now. Having the wrong filter element in place probably caused too much oil flow through the filter reducing how much was available to the rest of the engine causing the lower oil pressure. You're in good shape now. Merle Quote Link to comment Share on other sites More sharing options...
Zeke1953 Posted September 27, 2009 Author Report Share Posted September 27, 2009 Thanks for the help, guys. I will double check that the oil pressure reading is accurate and it looks like I'm good to go. On a side note, the gasket that came with the Wix sock filter was just a little too big and there was a gap in the seal when I tightened it down. Oil flowing out the top of the filter and all over my engine at 40 psi is not a pretty sight! I had to use my old gasket as a template and make a new one myself. Zeke Quote Link to comment Share on other sites More sharing options...
Mike@DRH Posted October 2, 2009 Report Share Posted October 2, 2009 Correct oil pressure is created with the proper bearing clearance. If oil pressure is low, to much clearance on bearings or crankshaft or just plain worn out and not the result of an improper oil filter. Oil pressure to high could be bearing clearance to tight, or in your case, sounds like a restriction in the oil filter. To high of an oil pressure reading can be a way bigger problem than to low. If your oil pressure is high because of a restriction in the oil filter (the key word is "restriction") can you be absolutely positive that the rest of your engine is getting all the oil it needs? Maybe not. If your oil pressure is to high because of bearing clearances being to tight (key word would be "tight") that would mean the oil film on which the crankshaft rides is to thin. Either way if all you did was change the filter you can be pretty sure that your increase in oil pressure is due to a restriction. Your oil pressure numbers sound very good but not if they are a result of a restriction. We have found these engines to be very forgiving as far as running them with low oil pressure but I'm not sure about the restrictions. Quote Link to comment Share on other sites More sharing options...
TodFitch Posted October 2, 2009 Report Share Posted October 2, 2009 Correct oil pressure is created with the proper bearing clearance....snip... And by other things too. One of those things is how much oil is being bypassed from the engine back into the crankcase. In the case of most years of the Plymouth/Dodge L-6 engine with a bypass oil filter, the amount of bypass is a function of two things: 1) Restriction of oil going through the media. 2) The pressure relief valve which closes off the return from the filter if the pressure drops too low. So if installing a new filter element raises the pressure then I'd guess that the old filter was doing little or nothing to restrict oil passage and the pressure relief valve was kicking in to keep the pressure from falling too far. Putting a new filter element in was probably a good thing. (The pressure relief valve mechanism went through several iterations in Plymouth in 1933 with the final form only showing up late in the model year. So item 2) above does not apply to early/mid-year 1933 Plymouths. I assume Dodge would be the same.) Quote Link to comment Share on other sites More sharing options...
Mike@DRH Posted October 2, 2009 Report Share Posted October 2, 2009 Maybe I don't understand these systems very well. I'll try your idea and let you know how I come out. The oil pressure in my truck is very low at idle and if I can fix it by installing a restrictive oil filter consider me "all in". Thanx Mike Quote Link to comment Share on other sites More sharing options...
TodFitch Posted October 2, 2009 Report Share Posted October 2, 2009 Maybe I don't understand these systems very well. I'll try your idea and let you know how I come out.The oil pressure in my truck is very low at idle and if I can fix it by installing a restrictive oil filter consider me "all in". Thanx Mike I'd suggest getting a manual and looking carefully at the oil pressure regulating system on the engine. It is different than those I've see on any other engine in that it has the standard over pressure relief but it also controls the bypass flow of oil through the oil filter. If you pressure is "very low at idle" then you may have a different issue than the oil filter (malfunctioning pressure relief, too much bearing clearance, etc.). But if the pressure is at the low end of the specification then there is a chance that the pressure is being maintained by the pressure relief system by restricting flow through the filter. Quote Link to comment Share on other sites More sharing options...
grey beard Posted October 3, 2009 Report Share Posted October 3, 2009 Gentlemen, gentlemen: Somehow we're sorta' throwing the baby out with the bathwater here. Oil filters do not make, nor do they subtract oil pressure from the engine. Saying a plugged filter makes engine oil pressure higher is to ignore logic. Many of these MoPar engines ran just fine with NO oil filter. The thing was a dealer - or field - installed option, at best. It was not standard equipment, by a long shot. Furthermore, if you study the oiling diagram, as Mr. Fitch suggests, you will notice that when pressure does indeed drop, the nature of the relief valve is that it shuts the filter off, thus keeping it out of the loop - in other words, it no longer has any part of engine oil pressure. My son in Montana has five B series Dodge trucks of 1 1/2 tons or larger. All have bypass filters. No two are connected the same. One has oil from the main galley - not the pressure relief port - going into the filter on a full-time basis, with the other line returning filtered oil back to the crankcase. This is a full-time bypass filter. I sorta' like that idea, and may make mine that way, so that it filters more of the oil, more of the time. It's almost - but not quite hardly - a full flow filter. Mebby we could call it a full-flow/bypass fillter. I believe in the final analysis, that it is not the oil pump that produces pressure, but the restriction offered within the total engine oiling circuit. When that resistance drops, hot idle oil pressure drops with it. For that reason, worn engines lose pressure at idle. Plugged bypass filters will not raise or lower engine oil pressure. The presssure is simply the product of the engine's tolerance stackup at the low pressure end and the pressure releif valve on the high end. JMHO. Quote Link to comment Share on other sites More sharing options...
Young Ed Posted October 3, 2009 Report Share Posted October 3, 2009 Very well said Dave. And everything I've heard about Mopar flatheads is the cam bearings get worn first causing the pressure drop which then starts to effect the mains and rods Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted October 4, 2009 Report Share Posted October 4, 2009 1 Quote Link to comment Share on other sites More sharing options...
carl b51 Posted October 4, 2009 Report Share Posted October 4, 2009 Don, Thanks , Very informative, I like the pics. Carl Quote Link to comment Share on other sites More sharing options...
Zeke1953 Posted October 5, 2009 Author Report Share Posted October 5, 2009 Now I'm confused. If the filter has no effect on oil pressure, why did the pressure increase by 10 psi when I put the correct filter element in? Zeke Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted October 5, 2009 Report Share Posted October 5, 2009 Zeke, I stand by my original statement. If your engine has a bypass filter than the filter needs to have a certain amount of restriction otherwise it acts like an major internal leak in the lube circuit. As mentioned, by some of the guys in this thread, the oil pressure regulator will shut off the flow of oil to the filter if the pressure is too low, but if it's still above that point and is open to the filter than the oil will flow through the unrestricted filter and back to the sump and act like a major leak in the circuit. By getting the correct filter element in the canister you created the proper restriction and in a sense plugged, or slowed down, the "major leak" that was caused by having the wrong element in place. Fluid under pressure is lazy and will take the path of least resistance. If there is no resistance through the filter the oil would rather go that way than go through the restricted passages through the crankshaft and etc, and the pressure will drop some because there is an overall lower amount of restriction in the circuit. I would be willing to bet that if you were to connect the pressure and return lines together, bypassing the filter, you would see the pressure drop again like you had with the wrong filter. And if you plugged off the pressure line, like if there were no filter, the pressure would come back up. Remember, a pump does NOT create pressure, it only creates flow. The resistance to the flow is what creates the pressure. The resistance to flow happens when the oil is forced through the small passages in the engine block, crankshaft, connecting rods, bypass oil filter, and etc. When there is a lower amount of resistance the pressure will be lower. By getting the correct filter in place the overall resistance was higher which makes the pressure higher. You may also notice that your oil pressure drops slightly when the engine is hot. This is because when the oil warms up it flows easier. The pump is still pumping the same volume of oil, and it's pumping it through the same small passages, but because it's thinner and it flows easier there is less resistance and the pressure is lower. It's all simple fluid dynamics laws on place here. Merle Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted October 5, 2009 Report Share Posted October 5, 2009 Merle; As has been mentioned what happens if there is not a filter in a by-pass filtering system? Oil pressure should not drop IF the pressure relief valve is functioning correctly. Quote Link to comment Share on other sites More sharing options...
TodFitch Posted October 5, 2009 Report Share Posted October 5, 2009 Merle;As has been mentioned what happens if there is not a filter in a by-pass filtering system? Oil pressure should not drop IF the pressure relief valve is functioning correctly. I'd rephrase that to "oil pressure should not drop to zero IF the pressure relief valve is functioning correctly". I agree with Merle. Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted October 6, 2009 Report Share Posted October 6, 2009 Thanks Tod. Merle Quote Link to comment Share on other sites More sharing options...
Zeke1953 Posted October 6, 2009 Author Report Share Posted October 6, 2009 O.K. I think I've got it now. Thanks to all who responded, especially Merle for taking the time to post detailed explanations. I'll keep an eye on my oil pressure gauge and report any unexpected readings. Zeke Quote Link to comment Share on other sites More sharing options...
Kels Posted July 10 Report Share Posted July 10 HI Guys ...... I know this is a very old thread , but it seems to have the knowledge in it. I have a 1941 218 Flat Head engine that is in my show car (car is '37). It was completely rebuilt 11 years ago and installed. It has been ran VERY little since then (show car thing etc) NOW, I have decide to start driving it vs showing it. The issue I am having is oil dripping out of the crankcase over-flow tube AND high oil pressure. This car's (original) oil pressure gauge shows 80 PSI pressure at idle and driving (could be the gauge).. After it warms up a bit, the pressure drops minimally. Question#1: Is this too high? and is there another oil pressure port plug (at the block) I could plumb in a new gauge to verify pressure? Question #2: I , suspect (asking here), if this dripping from my vent tube could be related to the high pressure? I KNOW the cap is venting. It is hard to verify, but I do NOT really see signs of oil spewing out the vent tube while running. It seems to happen after you stop and the car sits. It will drip out a decent amount onto the floor. I have changed the oil (Lucas high zinc 10-30W oil) and it is VERY clean. I should also note.. I have leaks out the timing cover and rear main.. This is odd because all these were replaced and, IMO, should not leaking. Wondering if the pressure is just too high for the seals/gaskets? Long shot, I know, but, this engine was completely rebuilt and I do not think it should be leaking anywhere. Anyway.. this vent tube leak is something I want to get under control since it makes a mess on the floor and just should not be happening IMO. Looking for some answers/advice from the experts on here.. Tanks in advance! Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted July 10 Report Share Posted July 10 Yes, that oil pressure is too high. It's possible that your oil pressure regulator spool is stuck closed. If you want to verify with another gauge look at the left side of your engine, where the current gauge connects, and you'll see a raised ridge that runs the length of the block. This is the main oil galley and it will have 4 ports (1/8" NPT) along the length. One is where your dash gauge connects. Any of the other 3 can be used with a manual gauge to verify the pressure. Quote Link to comment Share on other sites More sharing options...
Kels Posted July 10 Report Share Posted July 10 1 hour ago, Merle Coggins said: Yes, that oil pressure is too high. It's possible that your oil pressure regulator spool is stuck closed. If you want to verify with another gauge look at the left side of your engine, where the current gauge connects, and you'll see a raised ridge that runs the length of the block. This is the main oil galley and it will have 4 ports (1/8" NPT) along the length. One is where your dash gauge connects. Any of the other 3 can be used with a manual gauge to verify the pressure. Thanks for the reply.. So where is this regulator spool located so I can check it out? Do you think this higher pressure will cause the vent tube to drip after running? I pulled the oil filter out to look at it (WIX 51080 cartridge) and by the looks of the design.. the filter can (housing) should not remain full of oil? Correct? It looks like it would always drain out after the engine sits? I will attach a pic of the oil level Quote Link to comment Share on other sites More sharing options...
Dave72dt Posted July 10 Report Share Posted July 10 I'm not surprised at the front and rear seal leaks. It's somewhat common on engines that get run infrequently. Gaskets and seals dry out, shrink a bit and leak and the rear seal is especially prone to leak. It's a common complaint and it's not limited to Mopar. Sometimes they heal themselves with running and sometimes not. On your rebuild invoices did you happen to see a speedi sleeve for the front hub? NOS parts to rebuild? Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted July 11 Report Share Posted July 11 Just below where your oil filter lines connect you'll find a plug. Behind that plug is a spring and plunger for the oil pressure relief. When the valve is closed it also blocks the return flow from the filter to prioritize oil pressure to the engine. When proper pressure is achieved the valve should open to relieve the excess pressure, and at the same time open the return path for the filter so that oil can flow through it. Quote Link to comment Share on other sites More sharing options...
Kels Posted August 12 Report Share Posted August 12 UPDATE: Installed a modern oil pressure gauge at the engine..Pressure is around 55-60 PSI.. So, I think I am in spec on the pressure.. The old Gauge must just read high. Havn't been driving it much to see it anything else changed.. Thx for all the advice on my car! Quote Link to comment Share on other sites More sharing options...
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