JL...20-50 is not straight weight, straight weight is SAE 40, (no 10-, or 0- etc).

Also, personally I think your doing more harm than good changing oil with so little time on it. Petroleum products are designed to operate in certain environments, and changing oil every 500 miles is something I would do with the cheapest $.78/qt STRAIGHT 30w or something for break-in. I have been running loads of nitrous in this built engine and the stocker. When I tore my stocker down it looked almost new inside, that was with 50,000+ miles and more than a fair share of nitrous thru it, I used M 10-40 or 0-40, depending on availability.
In my new engine, which is built for 300shots, and I do spin it up and over the 7k mark, I broke it in with the cheapest non-syn oil, and then switched to M1 again. I spoke with Patman, and find it beneficial to run the Redline, or Amsoil synthetic 10-40. Yes my bearings are set for nitrous, and I gapped the rings for nitrous as well. Yes I go thru almost 1qt/1500miles or so, but still, thats due to the rings etc, which you should be told about during your build...a looser engine will consume oil.

Its your engine, your builders recommendation etc.. just talk to him about it.

Charlie

 

We had an oil pump pickup come off in an older motor we had in our race car and we had just switched to the valvoline 10w30 sythetc. It was a 427 BBC running 8.6's and the low oil light(15psi) was coming on the entire way down the track and my dad stayed in it just to see if the oil was any good. When he pulled the pan, all the bearings still looked perfect, he just put a new pump and pickup back on it and ran it for the remainder of the season. Besides that, the car picked up about 5 hundreths and 1-2 MPH over 20w50 Castrol that he was running before.

 

I know it's not a "strait" weight oil, it's a term, nothign other then 20-50. The wholt thing will be built/gapped/clearanced for alot fo abuse and nitrous, and my plan is to tear the motor down probably every 3 to 4 years and rering and rebearing the thing to keep it fresh, with the use I put on it that will keep it runnign like new pretty much all the time.

I find it almost impossible for any damage to occur by changing the oil too often other then putting wear on the drain plug bolts. All that is gonna happen is the life blood fo the engine is gonna be cleaner.


I'll be going with my builders reccomendation, regardless what I find on here, I almost wish I hadn't even asked at this point.

 

I have a built motor head/cam setup diamond pistons, eagle rods, etc. I started using Royal Purple 20w50 as the engine builder recommended. But I needed an oil change and couldn't find anywhere with 20w50 RP and got some Mobile 1 15w50 and the oil pressure seemed to go up so that's what I have been running lately.

 

I'm gonna run castrol 20-50 in the motor per my builder, and change it on a very regular basis, probably every other month (about 500 miles with my use during the summer).

I will have an oil analysis done after the initial break in is done, and will keep an eye on it.

Thank you for the feedback everyone.

 

How long do you need to seat the rings good?

LME told me to run regular dino oil (castrol 10w40 is in mine) and not worry about break ins because the motor was ready to go as soon as i was willing to go WOT. I'm wanting to switch to a 10w30 or 40 synthetic to pick up more power and better protection.

 

I agree with your builder... If the motor is built right (i.e. cylinders honed with a tq plate and the mains torqued, line honed, and everything is true and round) there is no need to "break it in". You may want to heat cycle the springs a few times, and change the oil enough to be sure you have gotten any dust, dirt, debris that may have found its way into the motor while it was being built but other than that it should be good to go. It is not uncommon for builders to build a brand new motor, stick it on a dyno, make a few light pulls just to make sure everything is right and get the tuning dialed in, then shut it off, change the oil, refill it, and then let it rip.

 

I wouldn't have a motor built that has to use 20w/50 to start with.The clearances just keep opening up till it's bearing time very quickly.Our race engine builder keeps them tight,even in the 1800rwhp cars.They just run 0w/30.Our shop car was spinning 8000rpm/24psi of boost today on the dyno with a motor built last winter -10w30 synthetic.

Now,synthetic is worth it even if you change your oil every 500 miles due to the heat it can take.

PurEvl car runs 800rwhp all the time,probly 5-6k miles this year with a Turbo and runs 0w/40(synthetic) with oil pressure at 40-50psi at idle.This is more strain on bearing's than a sometimes sprayed nitrous setup.

 

If you knew how this was built, then you'd understsnd. I will be switching to a synthetic 20-50 once the break in is done, dont' really see any reason not to, probably no real reason to do it either as I know it will be changed 4 times more often then it needs to be, not that it helped the motor it's replacing.

 

why do you change the oil so often?? I run amsoil in mine.I believe its 0w-40...I was running the mobil 1 10-30 but it doesnt have the viscosity of 30 weight oil and is just too damn thin..

 

I'd rather change it very often, then not often enough. Have you ever heard of someone damaging their engine from changing it too much? I haven't. Plus, if something were to go wrong, it might be a good indicator. When you put a big cammed big CI motor together, it tends to make alot more noise, so a small problem may not be heard, but if you're taking the oil out at intervals that keep it a dark gold color, you may notice something that you normally wouldn't. I personally run all my oil out thru a funnel and onto a coffee filter before letting it get into the oil collection can.. if there's something going on, I see it on the coffee filter. When I had my sotck shortblock, head/cam setup develop a problem, the oil was a very good indicator. The heads were put on, fresh oil put in with that, ran the car for probably 10 minutes, changed it again, drove it home. Probably started it a 1/2 dozen times over the winter, and drove the car from my parents to my house, so about 100 miles and a few startup's on that oil. When I changed it, I noticed alot of what looked like metal dust on the coffee filter, within 100 miles, it went. Oil analysis is the only real way to see what's going on in there, but the way I do it it will tell you if there's a problem starting. With the $ I put into the new motor, I'll be changing it on a very regular basis, and doing an oil analysis after it gets a few thousland miles on it to be safe.

IMO, keeping an eye on the oil like I do, can only warn me ahead of time if somethign is starting to go south, and I can catch it and get the motor torn down hopefully in time before any major parts have to be replaced. By sticking to the castrol that my builder reccommends, I can do oil changed for about 16 bucks. Cheap insurance for an expensive motor for the start of it's life. I'll switch to a synthetic of the same viscosity once it's broken in, but that constant changing it will see initially will just give me a way of keeping an eye on things.

 

I run 10w30 Valvoline racing

Only run thick enough oil to give you good oil psi You only need 10 psi for every 1000 rpm your turning

The last ls motor I built and use 10w30 idles @ 45 psi @190 degrees after driving in 100 degree heat and maintains well over the 10 psi rule and this is a n/a car that runs rock bottom 10's.
Remember too much oil psi is just wasted horsepower robbed by the oil pump.

If you need 20w50 in an ls style motor you have some serious bleeding taking place. If your motor was built loose for a helper of some kind, that is fine but it does not have anything to do with bearing clearances, it is usually piston clearances.

Keep this in mind since you do not build your own motors, who's *** is it when the motor comes apart? I think he is the one you should ask for advice!!! If your builder will not stand behind his work, I would find a more compentent engine builder.

Good luck

 

Well said..

my 2 pennies

Well I have just recently started running Castrol GTX 20w50 (two oil changes now) as well I change my oil every 1500 miles. but I am only putting down 499.4rwhp so I don't think I meet your requirements j/k .

 

actually snapps, you're about where I expect to be power wise... thru a th400, moser 12 bolt, and a 5000 converter


Biggs I suspect that I'll be well over the 10 lbs/1000 rpm rule, I am gonna run the thicker oil for one reason, that's why my builder reccommends. The motor's got alot of stuff in it that's not your normal everyday build, with the results that he's had with stuff in the past, and the fact that he's had not a single engine fail due to the way it's built, or any issues with any premature wear, I'm gonna trust him. He's built some of the fastest ls1's in the country, he knows what he's doing.