So I FINALLY got my car running yesterday after a year and a half, been sitting in my driveway half finished since last October. Still needs a lot of work but now that it's running I don't mind putting the effort in. The engine that's in it now hasn't been run since august 2009 when I crashed the red car.

Anyway, I went through the whole engine and replaced all of the gaskets and seals and timing chain parts. I left all the internals alone because it only had ~80-90k miles on it. Now I haven't in the past, but I want to start running synthetic oil in it. I know the potential for leaks when running synthetic in a 31 year old engine, but I figured with all of the new gaskets it won't leak. A little while ago I was talking to a friend about it and he said something about not being able to use royal purple in an engine that old because it's got something in it (or is missing something, I forget exactly) that would actually cause it to be bad for my cam and main bearings... Anyone know anything about this? That's the first I've ever heard of this issue and it seems pretty strange to me but then again what do I know.

Anyone run synthetic in their car or have ever had a problem doing so?

 

As you stated, the common problem is gasket leaks. As for the moving parts, I've never heard any problems w/ converting to synthetic. There are about 50billion ( ) discussions about this all over the internet car forums. First google result:

http://www.hotrodders.com/forum/synt...rs-154917.html

 

The issue with synthetic leaking isn't a problem with synthetic oil but that the seals are old and need to be replaced. You've replaced yours so you should be fine. I run synthetic in all my Z cars - Pennzoil Platinum 5w30 and Wix filters. That way I stock all the same oil.

People believe that a high ZDDP content will increase the life of your cams/rockers. Redline has a high ZDDP content (which is hard on catalytic converters btw...)

 

Okay thanks guys, that's what I was thinking too. I wasn't worried about the seals because they are new, but I've just never heard anything about it being bad for the internals. I don't see why, you'd think it'd be better if anything. Dude must be breathing too many exhaust fumes or something.

 

Royal purple is suspected of being incompatible with "yellow metals". The fluid is not meant to be used in the manual transmissions with sycronizers made with the brass alloys. Maybe that was the bit you forgot?

 

Are you talking about royal purple gear oil or the actual motor oil it self? I was planning on putting in my manual transmission royal purple. It has over 170,000 miles on it. Would switching my transmission oil to synthetic transmission oil a good idea?

 

Yeah. the thread is on motor oil, but my post was on RP gear oil. Switchtr3 said he forgot something about RP, and I was just sayin'...Sorry for the confusion

 

I was referring to your post. I didn't mean to high jack the thread. Thought it was Beyer asking then posting a new one. Would it be safe to switch to a synthetic gear oil with 170,xxx miles?

 

Im running Royal Purple gear Oil in my 84 nA z31 trans, so far so good. After the change I drove her up to Glacier National Park (Whitefish Montana), got the best mileage on that trip, about 28 mpg, and I drove as fast as possible when ever conditions allowed. Seems to go into gear a little smoother, but it wasnt ever really a problem b4.

 

Redline MT90 (GL4) for the tranny
Redline Shock Proof (GL5) for the diff

DON'T USE GL5 in your yellow metal transmission! GL5 usually has a sulfur additive that will eat yellow metal - bye bye syncros!