Do forged pistons require different oil?

[Kristian_Wraae]

Do forged pistons require different oil?

I have read through the different posts here and I must say it's very informative.

However I do have a few questions:

I have recently had my 7MGTE engine rebuilt with forged JE pistons (and eagle rods). The engine has been built with close to normal specs regarding cylinder bore tolorances. The engine has all new bearings and the head has been fully rebuilt.

My engine builder told me that if I went with forged pistons I would have to use 20W-50 semisynthetic oil. He is a very good mechanic and I know he knows how to put together an engine. But after reading the different posts here about oils I'm not so sure that he knows all there is about oils.

So my question goes:

1. Do forged pistons require 20W-50 (I don't think so)

2. Will I have to use semisynthetic oil?

One additional question if the answer to #2 is a no:

3. Why is mineral oil a better choice for the break in periode. I read elsewhere that I'd have to wait 1500 miles before changing to fully synthetic oil. Why can't I use it straight away?

I have now done 500 miles with some 10W-40 (as my engine builder requested).

4. Which oil should I switch to now and for how long?

After reading the different posts about engine oil I plan on eventually use Castrol SLX 0W-30 as I was before the rebuild.

5. Would my engine be ok with that? Or what would be a better choice?

 

[jdub]

1) You've interpreted the info correctly...you do not want to run a 20W-50. Forged pistons have nothing to do with it...your mechanic is rationalizing a myth.

If you have not read this (all of it)...please do. It will tell you why your mechanic is wrong:
http://63.240.161.99/motoroil/

2) No you do not have to use a semisynthetic or a synthetic for that matter. Any good oil will do the job...the weight is what's important...your choice of a 0W-30 is dead on.

3) Read this thread:
http://www.supramania.com/forums/showthread.php?t=48993

4) Since you started with a 10W-40, I would change to that again. You can use a WalMart SuperTech filter for the next 1000 miles till you change again...at that change, go to the Wix or PureOne filter.

5) I would use Castrol European Formula 0W-30 (aka...German Castrol). Can't find anything on Castrol SLX 0W-30...sure it's not GTX you're thinking about? Here's a couple of threads on GC...the biggest thing will be finding it

http://www.supramania.com/forums/showthread.php?t=38768 (GC starts on post #4)

http://www.supramania.com/forums/showthread.php?t=55580 (where guys have been able to find it...depends if AutoZone has it in your area)

If you can't get GC, consider Pennzoil Platinum 5W-30. Of course you can't beat Red Line, but you're gonna pay for it

 

[Kristian_Wraae]

Thank you for your reply.

The oil I was using is this:

It's easily available here.

I can also get the GTX.

Would that be a better choice?

 

[jdub]

I apologize...I didn't realize you lived in Denmark

I could not find much on the SLX (at least I could read), but it does appear to be a true synthetic...likely Grp IV PAO based. Since you live in Europe, you might want to take a look at Castrol Edge 0W-30 or 5W-30. This line of oils is very good...can't get it or the SLX in the US though. I'm thinking either one will serve you well.


Edit: Kristian - did some more digging on Castrol SLX...it's the same as German Castrol sold here in the US.
An excellent oil...I use it and am very pleased with how it performs. I did also read some rumors it was being replaced by Castrol Edge in the UK. Don't know if that will apply in Denmark. Might want to get a case or two

Could you do me a favor...does the SLX you have look like the oil on the left or right in this pic?

 

[Kristian_Wraae]

The left.

 

[jdub]

Thanks Kristian - I was reading that the SLX was the old formula GC "Green" we used to get in the US...last seen here in early 2005. I found it hard to believe, and since you had some SLX in your hand, you confirmed what I thought. The SLX is the same as current production German Castrol we get here.