Which oil do you use

[karterdon]

Mobil-1 10-30, I spoke to the M-1 engineers regarding the Zinc thing and the "wear issues" They tell me that M-1 is fully compatible with the LT5 engine and the additive package will fully protect just as it did when it became factory fill in 92.

Again - this become a personnal thing to each car owner, his beliefs, what they read and who they trust!!!

Don Yoakem
91-#267 Dak Red Met.

[EuroPete]

Hi guys. I've read all you messages related to engine oil advice and I'd like to ask you a few questions.

I purchased my ZR-1 3 months ago and I had the oil immediately serviced, that is, engine oil and filter replaced. As I wasn't well read on this matter I put 10W60 Shell Helix on it and a Champ Oil Filter. I've made around 3,000 miles with the car (27,000 on the odometer when I bought) and I'm seriously thinking about servicing the oil and the filter again.

Do you think this 10W60 oil couldn't be suitable for very hot summer temperatures (over 100 ºF in my country)? As fair as I know 10W60 oils offer better protection in hot environments compared to 10W30 ones. But it's also true that the oil temperature in the LT5 is slightly over 100 ºF most of the time rolling.

Many thanks in advance.

[Jagdpanzer]

Originally Posted by EuroPete

Hi guys. I've read all you messages related to engine oil advice and I'd like to ask you a few questions.
I purchased my ZR-1 3 months ago and I had the oil immediately serviced, that is, engine oil and filter replaced. As I wasn't well read on this matter I put 10W60 Shell Helix on it and a Champ Oil Filter. I've made around 3,000 miles with the car (27,000 on the odometer when I bought) and I'm seriously thinking about servicing the oil and the filter again.

Do you think this 10W60 oil couldn't be suitable for very hot summer temperatures (over 100 ºF in my country)? As fair as I know 10W60 oils offer better protection in hot environments compared to 10W30 ones. But it's also true that the oil temperature in the LT5 is slightly over 100 ºF most of the time rolling.

Many thanks in advance.

SAE 5W-30 is the oil weight GM specifies for the ZR-1 LT5 engine. I know a lot of Zs out there in warmer climates running SAE 10W-30 weight oil with good results which is also acceptable according to the owner manual. However, the owner manual specifically states "Do not to use other viscosity oils such as SAE 20W-50". SAE 10W-60 weight oil is a lot heavier than specified for this engine and running it for long could cause you problems especially when weather conditions get colder. In plain terms the lubrication needs of the LT5 engine do not call for such a heavy oil to be used. The engine components are designed and optimized to work with lighter weight oils that are less viscous and easier to pump and filter. The use of heavier oils puts more load/stress on the oil pump and filtration system, causes higher viscous drag on the pistons rod and main bearings which reduces the net power produced at the flywheel.

[EuroPete]

Many thanks for your answer Jagdpanzer.

Definitely I'm changing the oil of my sooner the sooner I can. As it's not possible to get fully synthetic 10W-40 engine oil here, I'll ask a friend in the US to send me some gallon bottles of 10W-30 Mobil 1. I've already received a couple of Bosch oil filters, both PCV valves and a K&N air filter I'll have installed the day we replace the oil.

Using 10W-60 may be one of the reasons for the car not to run very fast until it reaches 2000-2500 RPM. I don't know how to explain, but if you hit the gas it doesn't accelerate progressively, it feels as if there were some kind of jamming or something. Maybe the ignition system is not working properly so I'm thinking about changing spark plugs, spark plug wires and even the distributor rotor.

[Aurora40]

Originally Posted by Jagdpanzer

SAE 5W-30 is the oil weight GM specifies for the ZR-1 LT5 engine.

FYI, only the later year cars. The '90 specified 10w-30. I think the change came when the LT1 came out, probably so they only had to keep one oil on hand. I could be mistaken about the transition year though.

[Paul Workman]

Originally Posted by EuroPete

Using 10W-60 may be one of the reasons for the car not to run very fast until it reaches 2000-2500 RPM. I don't know how to explain, but if you hit the gas it doesn't accelerate progressively, it feels as if there were some kind of jamming or something. Maybe the ignition system is not working properly so I'm thinking about changing spark plugs, spark plug wires and even the distributor rotor.

As far as torque below 2000 rpm goes, mine is "soft" there too. It builds quickly tho and as you noticed by 2500 rpm it starts pulling hard. Looking at torque curves for the LT5 seems to verify what I'm feeling in the seat of my pants too. I love the LT5, but it doesn't pull down low like my '95 LT1 did. (I noticed this right away as 6th gear below 2000 rpm is quite "doggy" for the LT5, whereas it was "OK" for the LT1.)

My point is, I don't think the oil has anything to do with the torque below 2000 or 2500 rpm for a couple reasons:
It has more to do with the design of the plenum, etc as to where the torque curve "kicks in".
The effects of high viscosity would be more prevalent at higher rpm than at the "off idle" speeds. So, way down low the effects would be much less severe.

As for changing the distributor cap and rotor on the LT5...it will be hard to do, as the ignition is 100% solid state. - A spark control module under the plenum handles most of the timing chores with inputs from crank position sensor.

As for Amsoil AMO (preferred by Marc Haibeck - one of the ZR-1 gurus), or Mobil 1, just say the word, and I or most others here would be happy to send ya a case, if your US contact can't be reached.

P.

[threestar40]

Originally Posted by ojb

Hi there,



I live in Munich, Germany. I use Castrol RS 10W-60. So far I do not

have any problems. I use it in my BMW and my Jag also.



Oli

so you can use that stuff in your motor and your tranny!?!?!?!?!?!

Rick

[threestar40]

Originally Posted by 11.72@119.26

M1 in 10-30 anybody tried 15-50 to see if oil consimption goes down?

I would like to report that I use Syntec 5W-50 in my LT5 and consumption is the same.

I race and drive the bejesus out of it...I mean I really punish the car.

It loves it.

Rick =)

[ZR-FUN]

RP best of the best

[lbszr]

Originally Posted by threestar40

so you can use that stuff in your motor and your tranny!?!?!?!?!?!

Rick

I've only heard of Castrol 10w60 in tranny which is what I've been using and then redline in engine if you want the best