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Discussion Starter #41
Have you measured hot oil pressure of some other renault k4m engine with correctly working dephaser? I'm wondering how much difference there might be.

I upgraded the oil pressure sensor and gauge to more accurate one and current hot engine readings with mobil 5w50 oil are(after 30km driving ~100km/h): idle 0.49 to 0.6bar, 3000rpm 2.14 to 2.35bar and 4000rpm ~3.1bar.
Cold engine max is ~4.1bar whitch is the release valve opening pressure.
 

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Yeah the timing of this little exercise is really bad .................... I do have my own K4M with only 30K km on it for reference but with the current Covid lock-down in operation for another hopefully only 3 weeks, the comparison thing will have to wait :eek:

Question ............... I don't have a solenoid ready to be made an offering to the engine gods yet (the spares I have is known to be still ok) ................. since you have one in pieces, would you say the drain holes on that plunger bottom is sending oil going back to the sump directly (iow the cam's nose is getting lubed by the advance and retard channels' excess only)
 

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Cold engine max is ~4.1bar whitch is the release valve opening pressure.
Yeah interesting that for comparison :geek:

First time since I own it I actually hung an oil pressure meter off my own engine this morning (K4M with only 30K km and imo "good working condition" dephaser)............... to my surprise cold startup (18C) with relatively fresh 10W40 HX7 oil and new filter (1500km) ................ startup oil pressure "only" about 3.75 Bar (idle to 2000rpm) ..........

Looking at my Renault reference manual (77 11 318 022) they reckon at 80C oil temp idle press should be 1 Bar min and at 3000 rpm 3 Bar min

................gut feeling? ...........if I were to spec a pump for this engine I would think a higher volume pump is required, but let me get readings for you when my engine hot again for reference :unsure:
 

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Discussion Starter #44
About the solenoid: I haven't taken the cylinder head appart yet and google didn't gave me a good pictures of that so I'm not sure where the oil return cannel is going. It is a deep hole in the cylinder head.
Yes, the cam nose gets oil only from retard and advance channels. This can cause the pressure drop if aluminium surfaces around cam nose are worn out. If the pulley have a oil leak between advance and retard chambers then the cam nose can have a weaker oil pressure.
Solenoid itself can send some oil from pressure input to drain when the ECU sets the solenoid piston to some middle position where pressure and drain holes are both little bit open.
It looks like the oil pump is a little piece of sh** and can't handle the oil demand.
It is also possible that there is some errors in the ECU control software. If it is not sending a sharp short pressure spike (100% advance) to force the locking pin to release at correct time and something is a little bit worn then the camshaft back force can be enough to not let the locking pin to release.
If you have CLIP then you maybe can check how the ECU is controlling the solenoid.

I have some pdf manual "MR364MEGANE1.pdf" There are different minimum oil pressure numbers (engine temp: 80C or first cooling fan start) (picture below).
183035
 

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I know that just after I got my vehicle I was looking at the ECU's control of the dephaser while reading up and getting familiar with the thing ................. I did discover that my ECU at that stage was running an obviously ancient and "stepped" control strategy based on particular engine speeds only ............... I then updated the ECU to the latest firmware available (and it has not been updated again since in the Reprogram facility in Clip) and I could immediately see a more progressive control strategy getting applied.

I'm not saying they solved/addressed all the problems they intended to, but do suspect that there may still be some tweaking that could further optimize the dephaser's operation.

Having thought about this a lot the last few days (and before) I am however not sure the oil pump's delivery rate is adequate for the control system's hydraulic requirements/abilities once the engine approaches its mid-life stages ...............

I am trying to see if its not perhaps possible to simply restrict/block the solenoid's return drain hole and via that prevent the unnecessary oil flow and thus pressure loss

I do agree the oil pump looks ridiculous/puny ................. I cannot figure if the lack of absolute pressure is simply due to pathetic design of the pump itself or if the (imo) unnecessary oil flow/release back to sump with the solenoid around mid-range is actually causing the problem

I have Clip, Autel, etc etc etc and they all show the same dephaser demand signal when monitored - without hydraulic engineering info I cannot say its "wrong" ito solenoid movements - I do however see the measured position getting lethargic as engine/oil temp goes up.



IMO both our reference manuals may actually be totally useless ito what is now deemed "normal" oil pressure specs with the application of ECU firmware updates that via the funky dephaser solenoid design, is obviously screwing the oil pressure control pooch royally
 

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Discussion Starter #46
LvR, Did you find the cause or a solution to that low oil pressure and incorrectly working dephaser problem?
 

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Unfortunately not - Covid struck and guy lost job - he either didn't want to wait or didn't want to spend for me to chase the oil pressure problem so he collected his vehicle.................

Turns out you cannot block the solenoid's drain holes - it results in an uncontrollable dephaser

Pity - because if it was up to me I would go modify the oil pump and see if a higher flow rate and thus pressure can be affected but no experimental motor to do this on atm.

If you solved it let us know - I will do the same soon as I have a K4M with "issues" to experiment on
 

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Discussion Starter #48
I also don't have the solution yet.

Is there any other oilpump with better flow rate which will fit to that engine without modifications?

I have fully blocked solenod, but I haven't tested it yet. It should keep the dephaser in locked retard position, but the cam nose is also without fresh oil, so the test will be really short(hot engine solenoid swap and less than 30 sec run)
 

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Should be a good reference point that test...............

Sorry no idea about alternative oil pump that will just bolt on
 

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Discussion Starter #50
I tried to search about different oil pumps but didn't get any good info and it looks like there is no aftermarket high flow pump available.
There are different part numbers for K4M but on the picture they all look the same.
Is there a different pump used for VVT engines and engines without it?
Newer Megane mk3 & others have some little bit bigger pump (maybe variable flow type?) Mounting holes look similar, but the oil pickup is shorter on the picture and i'm not sure about chain fitment.

I also saw that the pressure relief valve output is going directly back to the pump input not to the sump. Great chance to make cavitation at high RPM when the oil is hot and the valve is releasing some pressure. :(

Some Clio owners also talking about low oil pressure in their racing engines and bad pump design with loose tolerances.

I'm wondering what pump is used in Renault engines with turbo?

I would like to test oversized oil filter also but haven't found suitable part yet.
 

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Yeah I'm not moving in those circles where this knowledge/details on K4M oil pumps is available unfortunately.

Guess a possibility would be to fit an electric oil pump if the vehicle has some sentimental value? (ala the guys racing V8s) .................

See something like this



or if you are serious about the issue

 

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I have seen pumps advertised with 20 or 22 teeth sprockets so far ................. but I dont know if their bases and pickup arrangements are compatible ................. perhaps a change from 22 (if that is what you have currently) to a 20 sprocket may just be enough to solve the oil pressure/volume problem - I would look into that as a possibility?
 

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Discussion Starter #53
I'm not sure but based on the part number it should be with 22 teeth.

Pickup can be modified. This would be a problem if the pump have a wrong base. Do you have any part number for 20 teeth pump or which engine have it?

One williams clio owner said that new Renault oil filter (Mann W 75/3) will cause low oil pressure when engine is hot and some Champion one is better. Original filter for that engine was Mann W 75/2 (it is obsolete).

I found oversized filter(79mm height) Mann W 714/4 which should fit, but it have 1.2bar bypass valve and there is no data about filter flow rate. Also I don't have the flow rate data for Renault original filter.
 

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One of my spares suppliers just threw this part number 8200783526 for a 20 tooth Renault oil pump at me .................. guess if the pump base doesn't work one can just adapt a 20 tooth sprocket to an original pump?

Given the obviously inadequate pump capacity (imo anyway) I doubt if the pump's own regulating valve ever gets a workout except when really really cold ................

Filter bypass spec should therefore not really be a huge concern but I guess a higher than OEM spec bypass implies possibly more restrictive (thus more efficient?) filter material

Sorry - no oil filter reference specs from a reputable source here so cannot help with that
 

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Discussion Starter #55
8200783526 is from F9Q 1.9 diesel engine. The base looks similar, maybe the mounting bolt guide sleeves need to be removed. There are full kit with chain and crank sprocket available. I'm not sure if the crank sprocket will fit. Do you know how many teeth the K4M crank sprocket have?
This engine have min idle pressure 0.9 or 1.0 bar, min pressure at 3000 rpm 4.5 bar and max pressure at 3000 rpm 5.8 or 5.9 bar.
I'm wondering what will happen to K4M engine seals and that weak plastic thermostat housing at cold winter?
Maybe the pressure release valve or it's spring from K4M pump need to be used to reduce the max pressure?
 

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From your earlier pic of oil specs K4M is 22.

Diesels run slower avg engine speed so that explains the 20 teeth I suppose .................

Since you are down on it atm, a 20 tooth sprocket will probably get you right back to where you should be pressure wise


Problem with all these references is that there are a horde of them ito oil pressures ............... and I have absolutely no idea who/what to be believed anymore - I would slap a 20 tooth pump assembly on there with no problem at all and just monitor to see if the oil pressure gets to 6 Bar ............. if its under that I would not think its going to be a problem for the plastic thermostat housing at all
 
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