ms85er Posted July 10, 2015 Report Share Posted July 10, 2015 (edited) Hi all, I'm bit of a foreigner here as I don't own any corolla but I have a 1978 ms85 Toyota crown that I just put a 5mge in to. Everything has been working great since I put the 5mge in until I hooked up the oil pressure light and a gauge. The car has a Brand New (old stock) Aisin 4m oil pump (to suit my old 4m mid sump) which I installed to the 5mge and a large capacity K&N oil filter. I put 10w30 oil in it, I would start the car and it would be about 25psi at idle, then as the temperature of the car increases it would drop slowly down, then at about operating temp it drops down to 3-5 psi and after a while of driving the oil pressure light comes on. I then proceeded to install a mechanical oil pressure gauge as I just thought the sender was stuffed, turns out the readings are correct....CRAP. I fortunately was able to borrow a Olympus borroscope from work so I drained the oil, chucked the borroscope up into the sump and had a look around, looks great, perfect nothing stuck in the pickup. I also had a look at the oil, perfect!. So I have now changed the oil filter to a genuine Toyota filter and upgraded the oil to 15w40. Started great was 60 psi cold in the morning (11 degrees here) and then as it warmed up it did the exact same thing dropped really low, then at operating temp it was slightly better but was dropping down to about 5 psi at idle and then the oil pressure light started to come on. Now its getting real bad, there are brief moments where the idle rapidly increases and it is temporary starved of oil for a about 1.5 seconds so I shut it off immediately BUT its only when warmed up, never when its cold, runs great cold. sump has 5.6 litres of oil in it as stated by an old crown brochure the 4m mid sump is 5.6 litres. I am prepared to drop the sump if I have to but it makes no sense. Any help is greatly appreciated. Edited July 10, 2015 by ms85er Quote Link to comment Share on other sites More sharing options...
styler Posted July 10, 2015 Report Share Posted July 10, 2015 Maybe the motor is worn out and the clearances are too big, when the oil heats up it thins out and seeps out too quickly losing pressure. Quote Link to comment Share on other sites More sharing options...
ms85er Posted July 10, 2015 Author Report Share Posted July 10, 2015 Yah I was thinking that maybe the bottom end is worn, the head has been reconditioned. It was hard to look at the bearings with the borroscope and a light through the sump plug hole it's still real dark in there, I'll try again later. So if the engine were mega worn would the oil pressure still be reasonable cold? Cos the pressure is great at idle from cold to 30 degrees coolant temp then the closer it gets to operating temp it's goes rapidly low. Quote Link to comment Share on other sites More sharing options...
oh what a nissan feeling! Posted July 10, 2015 Report Share Posted July 10, 2015 Sounds like a broken seal in the oil system. Usually where the sump pickup bolts on, or the o ring seal between the front case and the block. I know nothing of 5m but someone who does should be able to tell you where to look. I guess in theory a heavily worn oil pump could cause this also, but I have never heard of it. Quote Link to comment Share on other sites More sharing options...
ms85er Posted July 10, 2015 Author Report Share Posted July 10, 2015 (edited) hhhmmmm the plot thickens.... or thins :P I'll have a thorough look for leaks tomorrow but the sump and block seems to be holding pretty well from what I've seen so far. I'm thinking of trying some Shell Helix HX7 High Mileage 15W-50 tomorrow and seeing what pressure I get. Edited July 10, 2015 by ms85er Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted July 10, 2015 Report Share Posted July 10, 2015 Is the 4M pump the same (vane) size as the 5M? You only get oil pressure when its cold as the oil is thick, so you see pressure but you won't get much flow as it is hard to pump through the oilways. Once its warmed up it flows much easier and hence the pressure drops and the flow increases, so a low pressure when warm is to be expected. So either the pump isn't pumping enough volume to give pressure when warm, or the oil is leaking out too fast to get the pressure to build up as Styler said. I assume the new pump had a new oil pressure relief valve on it?? No chance of shit under the ball? Quote Link to comment Share on other sites More sharing options...
ms85er Posted July 11, 2015 Author Report Share Posted July 11, 2015 (edited) I had checked on old toyomods threads before I fitted it and there should be no problems with pressure with the 4m pump, I'm not sure about vane size, I don't have a great deal of knowledge about the oil pumps and pressure relief valves so that's why I just fitted a brand new pump correctly (or so I thought). I'm starting to think there is a leak from the pickup tube maybe. I guess the sumps coming off. If I can't find the culprit maybe I'll fit a 7mge or 7mgte mid sump pump from a mk3 supra and shim it with 7mm worth of washers for more pressure. Edited July 11, 2015 by ms85er Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted July 11, 2015 Report Share Posted July 11, 2015 In this picture, the easiest way to make an oil pump 'bigger' is to lengthen the star gear and the ring called a rotor set, and fit the same length steel spacer around the outside of them. http://www.japan-parts.eu/EU/4/MA0427H.png So at the same revs the oil pump pushes more oil, and Toyota did this with some pumps. The pressure release valve is built in, as you can see, and on a new pump it should be dead clean. Its an odd problem.. maybe it is sucking air in, or maybe the oil is leaking out somewhere, but it obviously gets worse when the oil can flow more easiiy. If it was something like worn bearings I'm sure you'd hear them knocking. Can you get it so you can see if oil is flying around in the cams?? Take off the oil filler cap? I wondered if you are still getting flow up there when the pressure is on the red light. We had an 18RG motor where the cam grinder left the plugs out of the back of the cams, so as oil went in it just flowed straight out the back and didn't build up enough pressure to push it out of the lobes. Odd things happen. Quote Link to comment Share on other sites More sharing options...
ms85er Posted July 12, 2015 Author Report Share Posted July 12, 2015 (edited) In this picture, the easiest way to make an oil pump 'bigger' is to lengthen the star gear and the ring called a rotor set, and fit the same length steel spacer around the outside of them. http://www.japan-par...U/4/MA0427H.png So at the same revs the oil pump pushes more oil, and Toyota did this with some pumps. The pressure release valve is built in, as you can see, and on a new pump it should be dead clean. Its an odd problem.. maybe it is sucking air in, or maybe the oil is leaking out somewhere, but it obviously gets worse when the oil can flow more easiiy. If it was something like worn bearings I'm sure you'd hear them knocking. Can you get it so you can see if oil is flying around in the cams?? Take off the oil filler cap? I wondered if you are still getting flow up there when the pressure is on the red light. We had an 18RG motor where the cam grinder left the plugs out of the back of the cams, so as oil went in it just flowed straight out the back and didn't build up enough pressure to push it out of the lobes. Odd things happen. Hmmm Thanks for the info, for simplicity if I have a spare $400 lying around I noticed drift motion also make a upgraded pump, I would probably have to modify it to fit my sump though. http://www.driftmoti...mp-p/dm1072.htm Today I put 4.4 litres of 15W60 and barely any difference, the 5.6 dry sump figure was way too much as the car used to have an oil cooler. I had a look around all the main seals, front main is not leaking, rear main has been replaced during transplant and no leaks near the gearbox, back of cam towers are dry and the oil level is solid, other than some leaks from the cam seals which don't seem to be that bad I don't think its a seal. After doing hours of research on the net I'm starting to think it's got something to do with the top end as the bottom end has roughly 200,000 on it from the donor car and it ran beautifully, it isn't knocking currently and it hasn't been touched in the conversion. I'm thinking cam bearings (5mge's don't actually have individual bearings as such they are built into the cam towers). I took off one of the cam covers and the cams are pretty beat up, I stupidly didn't put assembly lube on the cams when I installed them I just lathered them in oil additive, with the small oil leak near the cam area and the condition of the cams I'm wondering whether the oil pressure is dropping rapidly when warm as the clearances on the top end have drastically increased. Top end oil starvation on vy-vz commodores and a some newer euro cars seems to be a common thing - all for slightly different top end problems but all seem to throw the oil light. video of issue, probably skip to about half way where the audio kicks in. Edited July 12, 2015 by ms85er Quote Link to comment Share on other sites More sharing options...
oh what a nissan feeling! Posted July 12, 2015 Report Share Posted July 12, 2015 (edited) hhhmmmm the plot thickens.... or thins :P I'll have a thorough look for leaks tomorrow but the sump and block seems to be holding pretty well from what I've seen so far. I'm thinking of trying some Shell Helix HX7 High Mileage 15W-50 tomorrow and seeing what pressure I get. Not external leaks, internal! It would be extremely unlikely that is cam bearings, or even bottom end bearings, if it is either of these the engine would have to be so stuffed that you would hear other noises. it would be unlikely that the problem is directly related to how many ks the engine has on it. The oil pump does not need shims to the relief valve or anything similar as that would only be a band aid fix, and wouldnt work. 1. as above check the pressure release valve, and that it functions correctly, that it is still bolted together properly. 2. check the seal between the oil pickup and the block/ oil pump. 3. check the seal between the oil pump and the feed out to the engine. It is very likely one of these 3 items. Edited July 12, 2015 by oh what a nissan feeling! Quote Link to comment Share on other sites More sharing options...
ms85er Posted July 14, 2015 Author Report Share Posted July 14, 2015 (edited) Thanks for all the responses Pretty sure I've solved it without removing the sump yet, I have searched the internet for over 6 hours I recon I finally found something. There's a thread on oldschool.co.nz and a guy has the exact same problem. Turns out there are inconsistencies in the whole: "Yah all M series pumps will work in any M engine, although 2m pump in 5m and later blocks will be hit by counterweight". I got all this info from toymods threads it is only partially correct. The drive gears on the pumps are ever so different and it sounds like people have had to make their own hybrid pump. There is also information to suggest there is 2 types of 4m mid sump pumps. I ordered a new Aisin 4M pump to suite a 1978 4M Corona (I think) as I knew it would fit my sump perfectly. Turns out I would of been better off using a ms123 crown as my donor car instead of a mx73 cressida, then none of this sump swapping would of been required. So I need to source a 08.1984 - 08.1987 MS123 crown oil pump. Edited July 14, 2015 by ms85er Quote Link to comment Share on other sites More sharing options...
ms85er Posted August 8, 2015 Author Report Share Posted August 8, 2015 (edited) So I managed to get the sump off but what a PAIN IN THE A**. There was a drag link bar or whatever it was in my way just to the rear of the sump bulge managed to get 1 of 4 ball joints separated after applying heat, hammer and swearing, was just able to remove the sump after 2 whole days of screwing around. so anyway nothing much to see in the sump, there didn't appear to be any leaks from the pickup tube, although its pretty had to tell. Here is a comparison of the two different sumps top is 4m mid sump bottom is 5mge mid sump from a crown, pretty much same-same here is a comparison of all the different 4m mid sump pumps: left is a mid sump 5mge from ms123, centre is from 4m ms85 crown, right is from 1976 mid sump corona here is the new 4m corona pump that came out, looks pretty clean and not much to see Here is the 5mge mid sump pump I'm going to fit from a 5mge ms123 crown, I noticed it has a hole drilled where the bolt is for the pressure regulator, the other pumps don't have this. from this photo you can see the 5mge pump actually has a larger pickup tube although you would think the previous pump with a smaller pickup tube would give a higher pressure rather than a lower pressure if the tube was smaller. If anyone can explain the hole in the head of the bolt of the ms123 pump would be great. Edited August 8, 2015 by ms85er Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted August 8, 2015 Report Share Posted August 8, 2015 you would think the previous pump with a smaller pickup tube would give a higher pressure nope- only within the tube, then the pressure would drop more as soon as the oil flowed around the engine. The bigger tube would allow more flow, which would turn into pressure when contrained in the bearings. Anyway, are the gears the same height in all the pumps? The gear housing on the mid sump 5mge from ms123 in the left of the photo seems to be higher than the others. Are the gears larger? Pop the three pumps apart and check inside for wear anyway, and measure the lobes against one another. Quote Link to comment Share on other sites More sharing options...
ms85er Posted August 9, 2015 Author Report Share Posted August 9, 2015 nope- only within the tube, then the pressure would drop more as soon as the oil flowed around the engine. The bigger tube would allow more flow, which would turn into pressure when contrained in the bearings. Anyway, are the gears the same height in all the pumps? The gear housing on the mid sump 5mge from ms123 in the left of the photo seems to be higher than the others. Are the gears larger? Pop the three pumps apart and check inside for wear anyway, and measure the lobes against one another. ahh I see, All pumps have exact same gears, the height of the gears are the same, the height of all the pumps is identical. I'm not too familiar with the insides of the pumps but ill pop 2 of them off and have a look. The 5mge one I don't want to stuff with too much, I'll fit anyway and hope for the best :P Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted August 9, 2015 Report Share Posted August 9, 2015 Fair enough- Don't be afraid to strip and clean them then reassemble them, they are every simple inside. Look for wear and grooves on the tips of the vanes, you can google a measurement for feeler gauges between the vane tips and the rotor itself, and between the rotor side and the housing. The other area that wears and lets oil slip backwards is between the end plate and the rotating parts. There will be a measurement for this endplay as well, but you can easily see worn pump parts from high mileage or from dirty oil. Quote Link to comment Share on other sites More sharing options...
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