bonz

I bought an 89 gta about 5 months ago. Not to long after I bought it, it started having a start up smoke issue. I believe it is a valve guide seal use due to that fact that I only bought it with 20,000 miles on it, since it has no smoke at all under load ever "hoping its not a ring ussue. I figured since I will be takin off the heads to replace seals anyways I might as well just put on new heads, intake, cam, headers and a few other things on since I have all winter to work on it and hopefully a nice bonus to fund it. The question is, since my first oil change i started running Castrol syntec in it, now Ive heard the running synthetic oils on a break in is bad since the parts will not seat right. So I figured I should go back to a standered oil just a standard castrol for maybe 3000 miles before I run syntec oil in it again. From what I have heard synthetic oil will not allow the valves to seat right, but I have also heard that once you run synthetic your shouldnt change back. I have only put 3000 miles on the car since I bought it but I plan on giving it a good break in before I start beatin on it, since thats what these cars are made for. Any break in suggestoins would be great. Since Im on the subject though, at first I was thinking of keeping low miles on the car, but then I figure the amount of money I have and will be sticking into it, it will be very hard not to drive it a lot and I have figured out low mile cars arent all they are cracked out to be. Would you guys say scew it drive it all the time and forget about it. I am think this car will be in my name a long time so miles are not as important. THANKS for all the help guys.

8Mike9

Valve seating and oil used have nothing in common. You may be confused with ring seating and oil used.

You don't need to pull the heads to replace the seals (or cam either), all can be done with the heads in place.

Regarding trying to keep the miles low...why save it for someone else, go enjoy it

So to answer your question, there really is no breakin needed with the parts you're going to fix or replace, since you have a roller cam and wil be replacing with the same.

bonz

Thanks for the help. I know I dont need to pull the heads to change seal but I figured I might as will go to town on it since I have all winter. The faster the better.

THANKS AGAIN

bonz

Thanks for the help. I know I dont need to pull the heads to change seal but I figured I might as will go to town on it since I have all winter. The faster the better.

THANKS AGAIN

8Mike9

Okay

8Mike9

O kay

bonz

Another question, after came break in do I need to take it easy on it for a certain amount of miles before I start beatin on it or does will it require a good break in.

THANKS

Mkos1980

iTrader: (8)

I started my new 383 and it idles for about 10 minutes while I made sure there were no leaks, adjusted valves with motor running, and redid the timing. After that I drove a few times around the block to make sure it was ok then hit the highway for a 20-30 mile drive (with cell phone of course lol) After that, the computer relearned its idled and it was good. I drove it normal till about 500 miles. Changed oil and drove normal again to about 1500 and then drove it kinda hard. I switched to syn at 2000 and its been perfect. No oil burning and always on full. After that I considered it broken in. I also took it to where I know hills would be since It was nice going down them with the backpressure to seat the rings better.

Doug Gulley

I'm by no means an expert, but I will share a few things I've heard about synthetic oil and the break in period.

When I built my 383 I used conventional oil for about 2000 miles before switching over to Mobil 1 syn.

Todays good moly rings with the correct honing procedure being done, the rings will seat in a very short time. No more are the "500 mile break-in" required. No flames, thats just what I've been told my mechanics and machinist both.

I've also been told that GM runs the syn oil (Mobil 1) when they do the break ins in the LS1's and the new LS2's. If so, that kills the myth that you can't run syn from the start. I personally wouldn't due to the fact that I change oil after the initial start up, 500 miles and then after another 500 miles, and then usually after the next 1000. Then I switch to the syn stuff. That'd be a bunch of syn oil to be dumping.