54 replies to this topic

[PACINO]

Hi everyone! Engine rebuilt from zero and the time to start it is approaching. Yesterday I went to the workshop and the mechanic told me that the engine already has oil. He put 10w-40 semi-synthetic in it, when I've always put 20w50 mineral.
What do you think, do I leave it to start the engine it on and when I do 100 km I change it for the mineral, or do I change it now?

Thanks in advance!

Edited by PACINO, 20 April 2024 - 05:50 PM.

[cal844]

Change it now, even for a cheap and nasty 20w50,as 10w40 is for more modern engines with tighter tolerances

[PoolGuy]

Change it now, even for a cheap and nasty 20w50,as 10w40 is for more modern engines with tighter tolerances

What happens if the engine fails and he hasn’t followed the engine builders advice?  

[DeadSquare]

Way back in the 60s, people used 10w40 in winter and 20w50 in summer.

[ACDodd]

Use running in oil.

Educate yourselves;

https://youtu.be/8wE...3EsGWNH23RNH_Lr

Ac

Edited by ACDodd, 21 April 2024 - 05:22 PM.

[Cooperman]

If you can get it, a straight mineral 30 grade is good. There used to be Castrol XL, which was a straight 30 grade and that was ideal for initial start-up and the first few hundred miles.

Best not to use a synthetic. I normally use Halfords 20w50 for initial start-up and running in, then switch to Valvoline VR1. 

[timmy850]

Running in a new engine is different to normal running, as above a high zinc running in oil is perfect

 

It's interesting to note what the Mk1 workshop manual says:

Normal temps above -18C
10W30

10W40

 

Allowable oils above 12C

20W40

20W50

 

Cold temps below -18C

5W20

 

A freshly rebuilt engine should have tolerances on the tighter side compared to a worn out engine, so in some cases 10W40 is an appropriate choice. 

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[Rorf]

Do not use synthetic oils, the gearbox synchros will not like it

[PACINO]

Thank you very much everyone for the responses...especially Cooperman and Timmy.
I think tomorrow I will take a bottle of 20w50 mineral to the mechanic.

[PACINO]

I think this is the reason why the mechanic opted for 10w40. Seeing that the newly built engine was going so hard when turning it on the crankshaft pulley and everything was so tight, he put this thinner oil in it.

[whistler]

If you can get it, a straight mineral 30 grade is good. There used to be Castrol XL, which was a straight 30 grade and that was ideal for initial start-up and the first few hundred miles.

Best not to use a synthetic. I normally use Halfords 20w50 for initial start-up and running in, then switch to Valvoline VR1. 

Castrol XL was a 20w50 mineral oil which was replaced by GTX. Castrolite was a 10w40 mineral oil for cold climates or winter use.

Used to use XL for all my late 60's rallying. My navigator was the local Castrol Competitions Rep. Came in lovely 5 gallon containers with a tap.

[PACINO]

Used to use XL for all my late 60's rallying. My navigator was the local Castrol Competitions Rep. Came in lovely 5 gallon containers with a tap.

This one?

https://i.postimg.cc...descarga-3.webp

Edited by PACINO, 21 April 2024 - 01:44 PM.

[Shooter63]

Use running in oil.

Educate yourselves;

https://youtu.be/8wE...3EsGWNH23RNH_Lr

Ac

I expect this man has built more engines than most on here, so I would take his advice over others.

Shooter

[PACINO]

I wish I knew what Adrian meant. I suppose that for you it is a typical and easy to understand phrase, but I have put it four times through Google Translate, and what comes out of it makes no sense.

[stuart bowes]

are you talking about what 'running in oil' means

 

it's a type of oil which is for running in an engine.  i.e. in the early stages after a rebuild you use it to protect the cams, rings, cylinder bores and so on

 

(or something more technically accurate than that if you want to get all pedantic but the general idea is right)

Edited by stuart bowes, 21 April 2024 - 11:21 PM.