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Author Topic: Oil pressure on the circuit  (Read 8503 times)
michaltalbot
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« on: July 10, 2011, 09:31:33 pm »

 This will be the question to all who drive a Murena on circuit sometimes. Do you have problems with oil pressure in corners? I mean that when I go as fast as possible, after few corners the oil pressure gauge goes to 3 - especially in right ones. When I slow down, it's O.K. and it's still between 5 to 8 depending on rpm. No problem in normal traffic (for example on roundabout), no problem in one or two fast corners, no problem with temperature. 
 It seems to be that if the oil is shaking so much in crankcase, part of it become a "foam" (couldn't find better word in English language  Wink ).
 Is the solution in using a special oil or do you know about somebody who made some counters (Huh) inside to slow the oil down?
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GP
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« Reply #1 on: July 10, 2011, 10:20:30 pm »

I have done several trackdays at Brands Hatch and many Circuit Sprints and Hillclimbs and have not had any oil pressure problem myself. The last recent engine rebuild I had showed that all the big end shells were fine also.

I cannot reccomend enough though Millers Motor Oil CSS 20w60 for older classic engines.
http://www.millersoils.net/1_Millers_frame_MOTORSPORT.htm

I have no experience on fiiting plates with small holes in them (baffle plates) to reduce the oil surge on a Murena Sump, but am sure it is possible with some thought and design.

Failing that though you could always fit an "Accusump" that will definitely cure all your problems and prolong engine life.
PURPOSE OF THE ACCUSUMP™
Pre-oiling: supplying oil pressure to the engine before start up for the purpose of lubricating engine components.
Surge control: supplying oil to the moving components of the engine when there is an momentary interruption of the normal oil supply. (.i.e. fast cornering)
http://www.merlinmotorsport.co.uk/images/oilsystemsl/accusumpinstructions.pdf
Hope this helps.
GP
« Last Edit: July 10, 2011, 10:28:11 pm by GP » Logged
Anders Dinsen
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« Reply #2 on: July 10, 2011, 10:35:22 pm »

I have never had any problems either with the cornering I do in my Murena. I'm running synthetic 5w50 oil. I do find, however, that the oil pressure drops a bit as the engine warms up, but it remains stable.

/Anders
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1982 Talbot Matra Murena 2.2 prep 142
2017 BMW i3 "Charged Professional" 94Ah

Used to own:
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1997 Renault Matra Espace 2.0 8V
1987 Renault Matra Espace J11 2.2
michaltalbot
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« Reply #3 on: July 11, 2011, 02:22:23 pm »

I use 10W40 Shell Helix oil, but yes, my friend who works for Shell, told me so, that I have to go for 10W60 or something like that.

GP: I used my Murena for 4 years as it was - with wrong oil pump from P505 which is 1cm higher, the oil pressure went to 0 many times and it holds on for that long time, but it doesn't mean that it's fine. I'll try to change the oil  Wink

Thank you guys! Smiley
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Jon Weywadt
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« Reply #4 on: July 12, 2011, 08:24:34 am »

This will be the question to all who drive a Murena on circuit sometimes. Do you have problems with oil pressure in corners? I mean that when I go as fast as possible, after few corners the oil pressure gauge goes to 3 - especially in right ones. When I slow down, it's O.K. and it's still between 5 to 8 depending on rpm. No problem in normal traffic (for example on roundabout), no problem in one or two fast corners, no problem with temperature.  
 It seems to be that if the oil is shaking so much in crankcase, part of it become a "foam" (couldn't find better word in English language  Wink ).
 Is the solution in using a special oil or do you know about somebody who made some counters (Huh) inside to slow the oil down?

These old cars have often been modified with non-standard parts. Michael mentions his using a P505 pump. I would check that the oil return pipe in the sump is in the right location and not too high off the bottom. Also make sure you have an original dip-stick. If it is too long you may not put enough oil in.  Shocked Have you measured how much oil you put in to reach full on the dip stick? The engine should use 4,5 liters.

On this link they mention that the 2.2 had an oil starvation problem prior to its release. So some modification must have been made, perhaps to the oil return line position.
http://www.rootes-chrysler.co.uk/car-development/dev-murena.html

Incidentally, when I first got my Murena it had a valve knocking and only firing on 3 cylinders until engine was warm. I used some of this stuff:  http://www.rvs-tec.dk/00008/00014/ to clean it out. they claim that it also builds up a nanno ceramic surface on all friction surfaces, thus making them slicker. It at least got my valve loose again.  Grin
« Last Edit: July 12, 2011, 08:54:25 am by Jon Weywadt » Logged

Matranaut par excellence Cool
michaltalbot
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« Reply #5 on: July 12, 2011, 07:06:08 pm »

Jon: thank You, but, the 505 pump was there in years 2006 - 2010. It worked fine, but in all corners oil gauge went to 3 or 0, but without any problems, car worked fine. But in 2010, on the circuit, I finished the engine because of many reasons - high temperature with low level of oil due to huge leak through damaged 5th main bearing, which was damaged as a result of totaly unbalanced crankshaft and flywheel (as we've found later), low oil pressure due to 505 oil pump which is 1cm higher and in corners it was out of oil, and at least - my race with Impreza STI, where he wasn't able to overtake me for 3 laps, but I was watching my rewmeter at 7000 rpm sometimes Roll Eyes
Now it has original Talbot 2,2 oil pump, excelently balanced crankshaft + flywheel, new crankshaft + all bearings. Now there is no leaks, engine is much smoother, it fastly reacts on a small move of throttle pedal. There is no problem when using it normaly, just at the circuit. Tomorrow I'm going to change the oil to Shell 10W60 and than I will test it on circuit and will let you all know  Wink
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Jon Weywadt
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« Reply #6 on: July 13, 2011, 09:01:11 am »

Jon: thank You, but, the 505 pump was there in years 2006 - 2010. It worked fine, but in all corners oil gauge went to 3 or 0, but without any problems, car worked fine.
----
 low oil pressure due to 505 oil pump which is 1cm higher and in corners it was out of oil,
----

Michael: That was my point exactly.  Cheesy The 505 pump was probably used prior to the release of the 2.2 model. My guess is Matra discovered that it starved the engine for oil in fast, tight, corners. Normal driving would not be a problem with sufficient amount of oil in the sump. But, as you found, the 1 cm higher 505 pump can't reach the oil when cornering at speed.
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roy4matra
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« Reply #7 on: July 16, 2011, 12:53:59 am »

This will be the question to all who drive a Murena on circuit sometimes. Do you have problems with oil pressure in corners? I mean that when I go as fast as possible, after few corners the oil pressure gauge goes to 3 - especially in right ones.

The pressure has dropped slightly owing to oil surge during hard cornering taking the oil away from the pickup.  If you consider the engine was originally designed for a front engine rear drive and the oil pump was at the front and the pickup was just behind in the centre of the low portion of the sump.  Cornering either left or right meant the oil surge was only a small amount either way, so no trouble.

With the engine mounted transversely in the Murena and much harder cornering being possible, the oil will surge towards the oil pump end in left hand corners and away from the oil pump end in right hand corners.  They realised this would be more of a problem than with the 180/2-litre/Tagora so the alloy sump is designed with baffles in to surround the pick up and reduce the surge effect and keep a pool of oil around the pick up.  However, if the right hand corner is long, and the cornering hard, you will sometimes notice a drop in pressure but even 3 bar is roughly 45 psi and this is should not cause trouble for any engine.  In fact Ford engines never used to run at more than 45 psi their whole life!  The fact that this engine runs up to 8 bar (120 psi) is unheard of in most cars in the sixties and seventies - none ever ran more than 65 psi!  As long as there is say 1 bar the oil will get around - but it it the quantity that should be more of a concern.  You can have 3 bar pressure but if the flow is restricted then you can still damage bearings.

Since the drop in pressure is only for short periods whilst in the RH corners, as long as the oil quality is good, there should be no cause for concern.  I recommend 15W60 or 15W50 or possibly 15W40 or better (e.g. a 20W60 as Graham uses) but I would not use a really thin grade such as 5W30 or 10W40 which are generally made for the modern tight tolerance engines.  If you have just rebuilt your engine and know the tolerances are good and close then fine, but if the engine has been used for some time and the tolerances likely to be larger, then stick to the thicker grades.  More importantly though, use a good semi- or fully synthetic oil which is always more fluid than the older multigrades and can flow better around the engine.

Finally, I don't think you could improve the baffling that much if you were to try extra shielding, and you have to make sure that the oil can get in to the pickup fast enough to maintain good flow.  One problem is that if you slow the oil getting out as it surges away, it will also stop the oil flowing back in fast too!  So unless you design in some swinging plates to slow surge out but allow fast return, you could make it worse.

Roy
« Last Edit: July 27, 2011, 09:22:11 pm by roy4matra » Logged

michaltalbot
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« Reply #8 on: July 17, 2011, 08:49:22 pm »

Thank You very much Roy!  Wink On friday, I just bought Shell 10W60 Helix Ultra Racing, I allreday made cca 5000 kms from new brushed crankshaft with new all bearings, made the excellent alignment and balancing, so hope that all tolerances are as small as they have to be Smiley
I couldn't find any 15W60 or 20W60 here on the market and also in Murena User Manual is originaly writen 10W40, so I really hope that 10W60 couldn't be bad, what do You think Roy?
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roy4matra
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« Reply #9 on: July 27, 2011, 09:24:34 pm »

Thank You very much Roy!  Wink On friday, I just bought Shell 10W60 Helix Ultra Racing, I allreday made cca 5000 kms from new brushed crankshaft with new all bearings, made the excellent alignment and balancing, so hope that all tolerances are as small as they have to be Smiley
I couldn't find any 15W60 or 20W60 here on the market and also in Murena User Manual is originaly writen 10W40, so I really hope that 10W60 couldn't be bad, what do You think Roy?

I use Castrol RS fully synthetic 10W/60 and it is brilliant.  (Now replaced I think by Castrol Edge)  Castrol RS was the only oil recommended for the McLaren F1 so if it is good enough for that...

Roy
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