5w-50 in an xflow?

[techbod]

The car is an '89 1700cc xflow. When the previous owner had the car, the engine went bang (some kind of oil loss issue) some 5000 miles ago. The engine was rebuilt and upgraded by a known engine builder and has been going fine ever since. I have stuck with the oil the previous owner recommended, magnatec GTX 10w-40, as it is what the engine builder told him to use.

 

However once the engine is hot, the oil light tends to come on at idle and over the last few weeks, on the hot days its noticeable I don't have to be giving the car any stick before the oil light comes on at idle. The engine seems fine, no strange noises, smoke, rattles - it just seems once warm the oil pressure just dips below the warning point at idle. I'd like to track day it but I'm concerned that the current grade oil may not protect it since the engine is going to get hotter still.

 

I have read through the numerous thick, thin, fast, slow, oil posts in the archives and still haven't reached a firm conclusion about what I should do- so I'm posting.

 

Mobil 1 15w-50 seems to get a thumbs up, so that is a candidate, but sometimes I do have the odd cold starting issue so I don't know if going from 10w to 15w will make that worse.

 

As its seems to be on a BOGOF at the moment, what about the halfords 5w-50? is that just completely out for an xflow? Is there anyone happily running their xflow on this grade?

 

cheers.

 

 

Edited by - techbod on 9 Aug 2007 22:32:19

[I.Mupferit]

Do you have a mechanical gauge and a warning light switch tee'd into the capillary? The warning light switches are often set to a relatively high value; the idea being that if the light comes on whilst driving, you will hopefully have enough time to kill the engine before the oil pressure falls completely away and any damage occurrs.

 

What does the gauge read at idle when hot and at speed, say over 3000 rpm?

 

The X/Flow engine typically idles with very low oil pressure, even when healthy, so if the light comes on when hot, it isn't necessarily a sign of impending doom.

 

I believe Roger King used to recommend Mobil 1 15w-50 in his X/Flow engines. A very good friend (and 7er) has one of Roger Kings X/Flows (using Mobil 1) and his warning light is set to come on at a relatively high value so it is always on at idle when hot. He has done numerous trackdays with no problems at all and it is a cracking good engine.

 

Brent

 

2.3 DURATEC SV Reassuringly Expensive

R 417.39 😬

 

 

 

 

 

Edited by - Brent Chiswick on 10 Aug 2007 08:20:31

[Phil]

I will agree with Brent on this one.

 

Helping and encouraging others rather than putting them down.

 

[Drumster]

Techbod,

 

I am the person that Brent is referring too and his comments are spot on.

 

My oil pressure warning light is set to come on at 2 bar, so it's always on when idling. At full chat the pressure sits between 3.5 and 4 bar.

 

I've always used Mobil 1 15/50 and the engine has now done over 38,000 miles since the RK re-build.

 

Chris Alston

C7CAT 1800 Supersprint

R248.89 ....and then I jumped in

[Unclefester]

Might be useful to know what value the warning light switch is set at.

 

I know the OE bit on the Elise K engine is 5psi and it's replaced with one set at 13psi if you use the Eliseparts oil pressure and temp guages. Our crossflow always shows the warning light at tickover, it's normal on this engine AFAIK.

 

Lucy in the Sky with Diamonds..ooooh hooo hooo!!...

😬 😬Abbey Road Time-Machine *eek*

 

[Setok]

Just to add that my warning light is always coming on as well. Generally when idling but sometimes when driving too, if it feels like it. I haven't quite been able to work out the pattern, but definitely when it's idling. I was worried about this at first but after asking the experts around about it I was told not to worry and that the lights aren't often terribly helpful. Just as long as the dip stick shows there's oil and the oil pressure gauge is showing a nice figure (which it is).

 

Based on what I've heard you only really need to worry if the light comes on suddenly when going all-out hill climbing or whatever.

 

---

Kristoffer Lawson

[techbod]

Thanks for the replies.

 

Dangerous this measuring oil pressure stuff. I went out at about 9:30 this morning to find out what the gauge read when hot and cold. Its now 2 pm I've a sunburnt head and the petrol tank is mysteriously empty.

 

Anyway when the engine is cold and just turned on for a few seconds, I get just below 4 at idle and just above 4 at 3000 rpm. (with no load - just a press on the accelerator)

 

After the engine is warmed up to normal operating temperature it get about 3.5 at 3000 rpm (this isn't the max oil pressure it reaches) and just over 1 at idle.

 

After some enthusiastic testing I get just below 3.5 at 3000 rpm and just below 1 (red light on) at idle.

 

So - make the move to Mobile 1 or stay with the magnatec 10w-40 because it al looks ok?

 

cheers

 

 

 

[I.Mupferit]

Oil pressure sounds fine to me and it does sound as though your switch is sensibly set to more than 1 bar.

 

Mobil 1 is a fully synthetic oil where Magnatec is not. Mobil 1 also has very good wear resisting additives so personally I would use that but provided you are changing the oil regularly then you should be ok. Interestingly, it was a Castrol test engineer who told me that of all the competitors oils they test, Mobil 1 is significantly better than any other premium brand oils available, even Castrols own products, so you pays your money and takes your choices.

 

Brent

 

2.3 DURATEC SV Reassuringly Expensive

R 417.39 😬

[techbod]

 

Oil pressure light comes on at *just* over 1 bar - is it considered preferable to have it trip higher? Say 1.5.

 

I'll give mobile 1 a go and see how the car gets on.

 

cheers

[I.Mupferit]

If you can adjust it, I think it would be advisable to wind it up a bit in order to increase your safety margin but that would be just a personal preference of mine. No problem if you just want to leave well alone, however, and continue to enjoy the car as it is.

 

Brent

 

2.3 DURATEC SV Reassuringly Expensive

R 417.39 😬

 

Edited by - Brent Chiswick on 11 Aug 2007 09:17:58

[eric]

mine was 10w40 before hot idle was bad

 

now with 15w50 all is fine

 

eric

[ian.hoper]

Hi each .

Have my five penneth , Had my 1600 highly tuned X Flow now for many years and always used Mobile one but found at track days it chucked it out into the catch tank and was an expensive waste . Had it rolling roaded a couple of years ago and X Flow expert recomended 15 or 20 x 50 Valvoline Racing , Since then no probs but I have done the rocker box feed to front and back jobby and raised the catch tank as hiogh as poss .

 

[Phil]

A X/flow expert but not an oil expert offering an opinion, up to you if you act upon it or not.

 

Not aimed at anyone but please could anyone mentioning Mobil 1, state the grade they are referring to, thank you.

 

Helping and encouraging others rather than putting them down.

 

[Pezky]

Using Halfords Fully Synthetic 5-40 in my 1700 xflow. No problems so far.