Which is best?

[keith m 131]

Hi All,

I use 15W/40 oil in my 2 ltr twin cam, but which of the following is best?

1)   Mineral

2)   Part Synthetic

3)   Fully Synthetic.

Regards

Keith

[mirafiori76]

Hi Keith,

If i were you i would go for half synth. This is always the oil i have used and it's the cheapest.
There are no bad oils nowadays.

[Sev131]

Would advise semi syn too.

[jasonh131]

mineral for new - rebuilt engines for bedding in
 semi for nomal use doesn't degrade as quick as miineral ...
 fully for new clean engine after bedding in ..

[keith m 131]

Thanks Guys,

I have been using mineral since rebuild 2000 miles ago and was wondering what grade to start using now. Very helpful info.

Regards

Keith

[miro-1980]

Hi Keith



I would go mineral for brake in and depending how hard REV the engine  : easy( max 5000  to medium ( max 6000 RPM ) -  semi ; hard to very hard (7000  plus  RPM) -  fully synthetic (one of Motul 300V range (i.e  for summer 20w60 and 10W40 for winter). Expensive but absolutely unbeatable.    

Miro

[keith m 131]

Thanks MIRO,

I rarely go over 5000 rpm. So semi it is then.

Regards

Keith

[miro-1980]

Keith,

Remember that all modern engine oils are really very high quality perfectly fitting standard modern cars and most old timers - like ours. The differences are really negligible for standard use !!!!.

What is key is change your oil frequently , make sure you use different one for winter and different for summer.
Make sure you change your oil filter when changing oil, and that the filler has sufficient flow capacity (is really for your model - not just fits the mounting) . Always use a filter with internal pressure valve ! 

Make sure you do not rev the car before it is really warm ( Note : DOHC engines are considered fully warm when the fan has switched on and off twice.  keep the temperature of your oil low and coolant temperature at max 85 deg centigrade.

Otherwise synthetic. mineral or semi is not really not as important as some think. and all major international rands offer exceedingly good quality . with easy driving - semi. synthetic and or mineral oils is not really  that important .

Miro   

[keith m 131]

You make a lot of sense MIRO,

My engine is fitted in a Morris traveller. You have me thinking about the filter now because it is one that just fits the mount. The original oil filter would hit the chassis so I fitted a filter housing from an Alfa (cant remember exactly from model) but the filter now sits horizontal not vertical.  Hmmmm

Some photo's of the filter I have been using. How can I determine if it is suitable?

Might this affect oil pressure readings? My oil readings, idle is 15psi, 2000 rpm is 55psi and 3000 rpm is 70psi.  In the manual it says that oil pressure should be. 49 - 71 psi at 100c, is this at idle or what rpm?      

UPDATE: I have spoken to Motaquip and they have confirmed that the filter I am using is for Fiat and Alfa but only upto 1.4 ltr engines. This is the filter I was given by a motor factor so big cock up. As you can see in photo I am restricted for space and the original filter spec is larger in both width and length. So I will need to go with a remote filter set up to accommodate the correct filter size. I asked if this would affect the oil pressure and the guy told me that because the filter is undersize it would increase oil pressure. So that means when I change to the correct size filter that my readings will drop again, is that OK?

It is amazing what one can learn on this forum by just posting what appeared to be a simple question, so pleased I did ask now.

Thanks again MIRO for highlighting this.

Keith

[Thotos]

coolant temperature at max 85 deg centigrade.

Strange how all the Fiat designers got that wrong then 

[mirafiori76]

Theo, where did you get that quote from? Water or oil temperature?

[keith m 131]

Got what wrong Theo?

Keith

[Thotos]

Theo, where did you get that quote from? Water or oil temperature?

The quote was from Miro's post and he claimed coolant (water) temperature should not exceed 85 degrees.

Got what wrong Theo?

Keith

The coolant temperature. The thermostats fitted by the Fiat engineers/designers will not ensure the coolant temperature stays below 85 degrees but will allow the coolant to reach much higher temperature without considering it to be wrong.

[mirafiori76]

When i was a Fiat mechanic long ago    i learned that the temperature should be around 89 degrees celcius. The thermostat should open around 83-87 degrees. At plus/minus 93 degrees the fan should fall in.

The thermostat in my Abarth however, opens at 75 degrees celcius. Fan hits at around 88/89 degrees.

[Thotos]

When i was a Fiat mechanic long ago    i learned that the temperature should be around 89 degrees celcius. The thermostat should open around 83-87 degrees. At plus/minus 93 degrees the fan should fall in.

The thermostat in my Abarth however, opens at 75 degrees celcius. Fan hits at around 88/89 degrees.

QED  Fiat designers allow the engine coolant temperature to exceed 85 degrees