Run In Oil

[sean01]

iv seen alot of engines fail with synthetic oil...
doesnt necessarily mean it was from the oil but it is a bit of a coincidence. so i just stick to decent mineral oil

 

[daimojay]

+1 for castor.

Use it in all of my big build motors and never missed a beat.

 

[Cactus Jack]

Castrol Activ 4T ... is an excellent oil ... 15w50 and meets JASOMA2 ... You need the thicker viscosity to protect the gears AND the cam lobes where rocker arms and strong springs are used ...

40 weight is OK for engines only with separate tranny ... Those types of engines usually have multi valve overhead cams with buckets ... no rocker arms means they can run weaker valve springs ... so there's less shear/rubbing force which allows them to get away with using thin crap 40 weight oils ... They also usually have ceramic or nikasil coated bores ... NOT iron sleeves ...

Castrol Activ 4T Motorbike Oil - 15W-50, 1 Litre - Supercheap Auto

There's also Castrol Power1 4T ... 20W50 ...

Castrol Malaysia - Castrol Power1 4T

I've found the exact same thing as Sean01 says ... I ran an expensive Powroll 96 cc BBK equipped XR engine on Belray synthetic oil and the bore didn't last very long ... also the rod wore thru the case hardening pretty quickly too ... I haven't gone near synthetic ever since ... It might be OK in watercooled or road bike engines but it can't hack the high temperatures of racing air cooled motors ...

I had far better luck with plain old Valvoline XLD 20W50 car engine oil ... Minimal wear to the crank , cam , and tranny and a new bore was still in good shape after 4 years of thrashing ... XR engines can easily hit over 14,000 rpm ...

 

[sean01]

yeah that reminds of back when i had a fair bit to do with HQ race cars. we had a castrol rep come in and say they wanted us to try their new synthetic oil... castrol edge i think it was called..
it was fully synthetic zero weight oil.. Castrol Australia - Castrol EDGE 0W-40 i dont think thats the exact oil... this was about 10 years ago we used it
he said they had awesome results with F1 and alike race cars being quicker
straight away i had my doubts. but anyways we tried it...

yeah it was quicker at 2 things.... revving fast (not that they needed any help @ 13:1 comp) and destroying engines fast...
2 cars went to the track for testing. 1 come back dead (spun bearing) and other was really rattly.

if it was mineral based or semi syth then maybe the engines may of had a chance.

basically just because it is newer technology doesnt mean it is better oil...
i try and match an oil grade with the age of the engine.. and lets face it, china engines arnt exaclty new technology... there based on an engine that is just about prehistoric..