Draining the Oil

fundytides

fundytides

Well-known member
Did my first oil change today on my Model A that I put back on the road last year. Motor was partially reguilt in the 60's and before I put it on the road, I removed the oil pan to make sure that it was clean and everything looked ok. Today I decided that with fall coming and even though I have only put 145 miles on it I would change the oil. After running the car for 20 min, to warm it up, I unscrewed the oil pan drain plug and was surprised that oil drained very slowly instead of coming out in a gush. Used a small screwdiver up through the drain plug hole to see if there was any crud blocking it. No crud in the oil. I poked around with the screwdriver a bit and all I could feel was the bottom of the oil pump assembly. Is slow draining normal or do I have a potential problem? The oild drained after about 15 min so I put the drain plug back in and filled the engine with 4 qt's of oil. Just brought it to the fill mark so obviously all of the oil drained. Do I have any reson for concern?
 
When you removed the pan, did you also knock the dipper tray out? If not, the bottom of the pan may be coated with 1/2" deep congealed oil crud that will hinder a free flow of oil when draining the pan. You can't see the bottom of the pan with the dipper tray still in place. To remove it, turn the pan upside down and drop it from your waist onto a hard surface. That will jar the dipper tray loose and it will fall out. Be prepared for a mess. Place a large plastic garbage bag on the floor where you intend to drop the pan. You'll be glad afterward that you did that. Scrub out the bottom of the pan and replace the dipper tray, making certain the ribs enter the channels along the sides of the oil pan. Check that the tray is level and seated. Guys have done this, put the pan back up and started the engine, only to hear the connecting rod dippers striking the tray because it wasn't seated properly. DOUBLE CHECK the dipper tray's seating unless you want to drain the oil and drop the pan again afterwards. :)
Marshall
 
Marshall V. Daut said:
When you removed the pan, did you also knock the dipper tray out? If not, the bottom of the pan may be coated with 1/2" deep congealed oil crud that will hinder a free flow of oil when draining the pan. You can't see the bottom of the pan with the dipper tray still in place. To remove it, turn the pan upside down and drop it from your waist onto a hard surface. That will jar the dipper tray loose and it will fall out. Be prepared for a mess. Place a large plastic garbage bag on the floor where you intend to drop the pan. You'll be glad afterward that you did that. Scrub out the bottom of the pan and replace the dipper tray, making certain the ribs enter the channels along the sides of the oil pan. Check that the tray is level and seated. Guys have done this, put the pan back up and started the engine, only to hear the connecting rod dippers striking the tray because it wasn't seated properly. DOUBLE CHECK the dipper tray's seating unless you want to drain the oil and drop the pan again afterwards. :)
Marshall
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Thanks for the suggestion. Yes I removed the dipper tray and made sure that there was no crud in the pan and did make sure that the tray snapped back into place. At that time the motor had not been run since the "rebuild" so everything was clean.
 
That's good news, but it's still troubling that the oil (even heated) didn't come gushing out of the drain hole when the plug was removed. The only times it didn't gush out for me was when there was a build-up of crud on the bottom of the pan. Once in an unknown to me engine, the oil just laid on top of the crud and only trickled out. I had to drop the pan, remaining oil and all, rather than wait until Judgement Day for it to all drain out. 'Gotta be a reason the oil didn't willingly come out of your pan like a gusher...
Marshall
 
It could be that the spring that holds up the oil pump is compressed to the point where the coils are almost solid bound so that they are restricting the oil flow. This is a little concerning as it could be that the oil pump is not inserted all the way into the hole in the bottom of the block. I advise to use a bore scope in the hole in the block that normally has the oil fill tube in it to see if the oil pump is all the way inserted. Or drop the pan.
 
nkaminar said:
It could be that the spring that holds up the oil pump is compressed to the point where the coils are almost solid bound so that they are restricting the oil flow. This is a little concerning as it could be that the oil pump is not inserted all the way into the hole in the bottom of the block. I advise to use a bore scope in the hole in the block that normally has the oil fill tube in it to see if the oil pump is all the way inserted. Or drop the pan.
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Could I tell by looking the hole in the side of the block that the bolt is in that holds the oil pump up. Or maybe I should remove the valve cover on the side to see if the distributor lower shaft is engaged on both ends. If I can tell.
 
Not a happy thought, but say a chunk of material, like a piece of broken out babbit is loose in the bottom of the pan. It moves over partially blocking the drain hole but too large to pass through. Probing up would not detect such an object.
I hope not the case for you ..

Joe B
 
It would seem that there is nothing foreign restricting the flow or you would have found it when you poked the screw driver up there. If you take the drain plug out again you could view the oil pump retaining spring and see if that is the culprit.

Many years ago I left a rag in an engine and it clogged up things. I now count the rags I use when working on an engine.
 
Did you have difficulty in pouring the new oil down the fill tube? If so the baffle in the fill tube might be plugged which could possibly affect the flow when you drained it.
 
CT Jack said:
Did you have difficulty in pouring the new oil down the fill tube? If so the baffle in the fill tube might be plugged which could possibly affect the flow when you drained it.
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No problem pouring oil in. From what I have done so far, I suspect that the oil pump support spring has broken/collapsed forming a bit of a dam arouind the drain. I will take the bolt out in the side of the block to see if I am getting any oil flow/pressure there. If so, I will just leave it alone until next oil change and in the meantime get a new spring to have on hand.
 
Wouldn't you have noticed a broken oil pump spring when you first removed and re-installed the oil pan to clean it out? I doubt whether a broken pump spring is the cause of your slow drainage problem. Even if the spring is lying at the bottom of the pan, the gaps between coils will allow oil to flow past and out the drain hole.
Actually, there should be a plug in that side hole, not a bolt. If the bolt is too long or screwed in too far, it will lock against the oil pump and cancel out the purpose of the spring at the bottom of the pump, i.e., to absorb the shocks from bumps in the road. A bolt holding the pump in place inside the block will lead to a broken pump housing, which is only cast iron and easily broken under stress. When you remove that bolt, if you hear the oil pump drop to the bottom of the pan, that will tell you if the spring is broken. Replace the incorrect bolt with the correct plug available from any parts vendor.
Marshall
 
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OK. Here's an update. I removed the bolt in the side of the block. (A previous owner had stripped the original hole and retapped it for a standard bolt. I now use a slotted stud and a lock nut and don't tighten it against the pump. Just put it far enough in to put a lock nut and gasket on it. Doesn't leak and doesn't put any stress on the pump). Started the car up and had good flow of oil coming out the hole. Will order new spring just in case and drop the pan after I get the spring. Thanks everyone for the suggestions. This forum is the best!
 
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