hello i have just had a motor rebuilt lt1 355 and whas thinking about going with synthetic motor oil ut i just dont know which weight to use can anybody give me help
chevyboi22:THATS A GREAT QUESTION? DON'T USE THE SYNTHETIC OIL UNTIL YOUR ENGINE IS COMPLETLY BROKEN IN...I would say 3,000 to 5,000 miles. On a complete new build. I'm sure other guys will say 1,000. I would want my piston rings broken in and sealing. There is nothing written in stone or any time limit to when you can change over to the synthetic. With that said. On your initial start up!Just some advice fill the engine and radiator with water only. Just in case you have a leak you won't lose your coolant. Then when your engine is running, and you've taken it down the street and you comfortable with the way it runs then dump it...I've been there and done that. 1.I'm sure your engine builder used Moly Lube on the CAM and LIFTERS. Follow the cam manufacturers procedure for cam break-in. I can't stress that enough. You could use Joe Gibbs oil at $8.00 a quart then dump $40.00. (I wrote my method below).2.Make sure your engine is primed with an oil priming tool or an old distributor, that has been modified. You can turn the engine by hand 1/4 turn while priming it every so often. It will help the oil to pump through the push rods up to the rocker arms.. Once that is done...WHEN PRIMING THE ENGINE USE A 3/8HP to 1/2HP DRILL OR HIGHER.You will burn up a 1/4" drill motor in a heart beat....3.Make sure the carb is full of fuel, and your timing is set so the engine fires up on the first attempt. If it doesn't start right away stop.... START THE PROCEDURE OVER AGAIN. RECHECK ALL YOUR SETTINGS. Then when it starts follow the procedure below.4.Once it fires up bring the RPM up to 2,500 and hold it there for 10 minutes.(you can turn the curb idle screw in to hold the RPM) Then cycle it from 2,000 RPM to 3,000RPM for atleast 30 minutes. DON'T LET THE RPM DROP BELOW 2,00RPM. This may seem like a lot of work. BUT LOOK AT THE TIME AND MONEY YOU HAVE SPENT GETTING IT TO THIS POINT...You don't want to lose the cam and/or lifters.JUST SOME FYI: The reason your cycleing the RPM the cam and lifters are splash lubed by the crank whipping around and the more RPM the higher the flow of oil onto the cam and lifters...You want the CAM and LIFTERS to mate. The lifter is spinning on the cam making its pattern. That helps the break-in.Bob
chevyboi22If you want more info on cam and lifter break-in procedures go to the following.Lunati, Crane Cams, and Comp cams. They have the procedures on their web-sites.
I have never really been a fan of synthetic oil for a street car with a carb for induction. Do like it for turbo applications.Some time back I was searching several sites for parts and happened upon an article regarding such a question. After reading said article took alot of knowledge from it, consider source; Master Engine builder David Reher.http://dragraceresults.com/article.cfm?id=3202&type=2.I have since started using synthetic oil in my personal race motors and have seen perfomance and longevity improvments.I merely have suggestions; but as the article details, the street engine is not stressed like a race/performance engine. Thus I continue to use non-synthetic oil in street engines and observe a "true" break-in period for them as opposed to hardly any for my personal performance engines.Hope this info helps.