Hi, before I turbocharged my 4G94 engine I was using Mobil1 10W-40 fully synthetic motor oil with extremely positively results; then I fully forged my engine with wiseco pistons and forged connecting rods etc. so, then I do first 500miles break in period with Havoline 10W-30 mineral motor oil (of course I change oil right at 50miles, then again at 250, and now that I reach the 500miles I will change it again.

But may I already switch to the Mobil 1 Fully Synthetic??? And what number should you recommend to me to use on a forged built engine 10W-30 or 10W-40???

Feel free to comment, and to ask me any question, about my engine.

Thanks a lot.

 

Neither. That stuff is too thin. Put Brad Penn 20w50 in it and don't look back. High zinc and phospherous content.

If you run that thin stuff and make any sort of horsepower worth talking about, you're going to spin a bearing.

 

Yea run a thicker oil you will spin a bearing that thin oil. Plus I think when you build a motor it will also depends how the motor was clearanced on the loose end or tighter end

 

Ok, all that about the bearings spining, gives me goosebumps; but the 20w-50 could not result too thick for the turbo bearings, and for the oil restrictor at the oil feed line flange?

 

In the summer I use a blend of 10-40 and 20-50 Amsoil AMO. 3# 10-40, 2# 20-50.

 

I run 20w50 amsoil z-rod in the summer and 10w40 amsoil in the winter in my built 2.3. Built motors do better on thicker oil.

 

Wow really? I have ran 10w30 in my car since I bought it. The power I make is worth talking about. You don't spin bearings being of to thin of oil. I mean I guess you could, but thats not what we are talking about. Forged internals don't mean you should run this or that for oil. What are your bearing clearences? Are they close to stock? Are they a little loose? That is what determines what oil you should run. I laugh at how many people use 20/50 in a stock motor had have nothing but problems with it. Oem motors aren't made for that thick of oil, but when you rebuild and use different type of bearings, or maybe have stuff done to the bearing sufraces, yeah use thicker oil.

 

Absolutely agree with you. Thanks for your reply.

 

+1 million

i saw the OP question and then i immediately see all this crazy talk about how he will spin a bearing if he uses 10W-40.these are guys that have no clue who built his motor or how it was built or what the clearances are.

i guess i saw a guy here not long ago that had a brand new Bushcur motor blow and he was using 10W-30 and i guess they told him that is why the motor blew.now it's like 20W-50 is always recommended no matter what.

honestly i think you could use 10W-40 no matter what,stock or loose motor.but i would stick to 10W-30 if i had a stick motor and if i had a built motor,i would ask the builder what he recommended.

like cursed said,forged really doesn't mean anything,it's the clearances.my buddy has a Roush SC mustang that puts out 600+whp and he runs 5W-20 even on race day.

all that said,yes you are ready to change to a synthetic and i would advise a good fully synthetic race oil if you plan on racing it.i like the ester base Group V oils such as Motul 300V,Redline,Silkolene,etc.they are the best for lubricity and heat resistance,but they do cost a little more.

Mobil 1 make s a race oil too that i believe comes in 0W-50,that way you'll be covered in the simmer and winter.it's a group IV like Amsoil is,and not quite as good as the ester base group V oils,but still a great oil.

i didn't look at your build specs,but i guess will an all forged internal build you will be looking for high hp;definitely stick to group IV or V for high horsepower and race engines and make frequent oil changes.

 

[QUOTE=masonh;10374417i guess i saw a guy here not long ago that had a brand new Bushcur motor blow and he was using 10W-30 and i guess they told him that is why the motor blew.now it's like 20W-50 is always recommended no matter what.[/QUOTE]
Its kinda funny you say that being everyone knows David's motors use loose bearing clearences. With that said a thicker oil is recommended.

 

You will not spin a bearing nor will you harm your engine by running a 10W30 nedless to say a
10W40 !

find out how your motor has been built from a clearance stand point, was it tight or loose ? the looser the engine the thicker the oil you can get away with and the less blow by i.e. less oil consumption. this is why i like motors built to stock clearances because i can get away with running a thin oil without burning it, thinner oil faster i spin the engine. i use a heavy duty oil synthetic and get away with a lot.

 

+1

 

[QUOTE=apagan01;10375173]You will not spin a bearing nor will you harm your engine by running a 10W30 nedless to say a
10W40 !

find out how your motor has been built from a clearance stand point, was it tight or loose ?...QUOTE]

My engine was built with same stock specs clearances. Do that make it tight or loose?

Thanks.

 

that makes it tight.go with a good fully synthetic 10W-30

 

i just picked up 4G64 and was wondering the same, guy i got it from said 20w50, but was wondering if i should run 10w40 in winter