My '90 RS 305TBI smokes on start up. Seems GM issued a Technical Service Bulletin 914496A "smoke on start-up" on nov '91; but I haven't been able to actually read it, and see what is it all about.

Anyone has this TSB handy? or has fixed the same problem? I checked my engine's compression, and it is ok, so it seems that there's a bit of oil seepage only after the engine has been parked for a while. If there's a quick fix, rather than replacing all the valve seals, I would like to know, because that's the only thing that occurs to me that could be causing it.

Thanks for your help.

Thunderboy

 

It's the valve seals.

 

Everybody that's ever had a SBC engine since 1955 has had the same thing happen to them. I'm glad GM finally wised up and noticed what all the rest of us have been dealing with all these years. It's about time.

Like ME said, it's the valve seals. Wait until the search function becomes available again, it has been posted about exhaustively over and over again, with pictures, part numbers, techniques, and advice.

But for the meantime, take comfort in the fact that it's easy, cheap, and relatively painless to fix. It takes a couple of hours, but other than that, it's a piece of cake.

 

And you can take further comfort in the fact that the quantity of oil you are burning is not really harmful to either teh spark plugs, the oygen sensor, or the cat converter. It also provides a little etra upper cylinder lubrication on startup, but that really isn't necessary. Once you have the time and will, repair it. In the interim, don't lose any sleep over it. Personally, I'd wait until the heads need other service or upgrade, such as valve grind, new springs/seat machining, replacement studs, etc. At that juncture, machining the valve guide bosses for positive Teflon seals would probably be the most effective upgrade. By then, you may have decided to install aftermarket heads anyway, so the issue would be moot.

 

....but if you decide to do it anyways, let me know. I just wrote up a description of the job and some tips for somebody who hadn't done it before. Oh yeah, new seals can end up selling for only thirty bucks.

 

I smell a Tech Article....

 

No, no, that's just some oil burning

With some rearrangement though, I'm sure it could turn into one. No pictures though

 

How long does it normally take to change the valve seals on a normal 8 hour day basis? I can get the whole TPI and manifold off it 1.5 - 2 hours. Thats cleaning evreything and stopping for na occasional cigarette.