i just swapped out a blow '88 305 with a rebuilt 305 , started it for the first time yesterday and the thing puffed a giant cloud of smoke directly out of the engine ... the hood is still off the car but there was so much smoke i couldnt see where it was coming from... the engine was sitting outside for about 3 1/2 weeks before i did the swap and the place i got it from said it was just rebuilt ... everything looked new .. any suggestions on what could be causing the smoke .... i only let it run for a few seconds, it was dark out so i'm gonna try it again today ..

 

Do you have proof it was rebuilt? Chances are it was all of the pre-lube burning off.

Which transmission do you have? The older vaccum modulated tramsmissions would allow trans fluid to be sucked into the engine when the modulation diaphram ruptured. However, I doubt you will have this problem.

 

a few seconds and it generated a huge amount of smoke? Do you by any chance have nice new headers that still have the paint on them? Or maybe you've spilled a buncha crap on the headers (or manifolds) while putting the motor in? That can cause a crap load of smoke but it'd probably take the motor like 30 seconds to get hot enough to start really burning it off.

 

YOU BLEW IT, MAN

 

I got the engine from the used car dealer i bought the car from.. they showed me the receipt from the rebuild, but it didnt specify parts ... the first time i started it a huge puff of smoke came up .. the engine was still running, i shut it off .... and it started afterwards with no smoke .... when the engine warmed up it burned the oil off the exhaust manifold. i don't have headers. now the timing wont adjust properly. i can turn the distributor to the left or the right until the engine stalls, there is no timing plate on the crankcase cover, just a mark on the balancer. i've been trying to time it by ear ... but can't get it right. i started from the furthest point clockwise i can get without stalling and went counterclockwise in increments until it stalls and the car is only barely driveable at the furthest counterclockwise point. but there is no power and the injectors are spraying so much that i can hear them inside the car with the hood closed. i had to drive it into work tuesday this week cuz i didnt have a ride, and when i left work i was having stalling problems when the car was on idle and the exhaust was blowing tons of smoke when i accelerate. also the oil pressure gauge is pinned when the cars running ... i wonder if whoever built it put in a high volume pump and it blew the valve seals ? im ready to just take the whole car back to the dealer and shove it in their ****.

 

Personally, I think all your problems are self-induced from hurrying and not taking time to check things and do it right.

Put a timing strip on the damper and do it right. Same with the fuel system. Are you using a pressure regulator? Do you know your fuel pressure? You likely haven't done any serious damage yet but you are well on your way. Wash the cylinder walls with fuel and the engine is done. You probably need to change spark plugs already.

 

Was it a longblock or a shortblock 305's are known to have bad valve seals if it's blue I'd venture that guess. If it's black you're burning oil. You said oil on the exhaust WTF something is wrong and oil should be no where near your exhaust unless you had the vc's loose and it dripped out.

Get a timing mark as someone said disconnect the brown wire at the blower box and set it up then diagnose, it's the only way.

Good luck!

 

That doesnt make any sense. What would make a 305 "known to have bad valve seals" compared to any other SBC? All the heads are the same design and use the same parts. Also what would it be burning if it had bad valve seals to make it specifically blue, when you say oil burning is black? Its very easy to get all kinds of grease, oil, and other fluids on headers/manifolds when you're installing a motor. You fire it up, it burns off, creates a ton of smoke, and then goes away.

 

Actually no! the castings are different between some of the 305 and 350 heads for one. Two when blue smoke appears it usually is from a mixture of oil and gasoline for example bad valve seals letting fuel and oil slip into the combustion chamber or rings letting fuel and oil slip into the combustion process.

Just an example and makes quite a few cents


When oil burns it burns with a black consistency. Try it you'd be suprised. Also add a little gas to oil then light it see what tint you get! Add on top of that that I've never seen in my 15 years as a hobbyist with these cars(all I've ever had) the valve seals lasting longer than 100K at the most usually around 60K when you get the smoke on start up.

I would do a compression test and a leakdown on all the cylinders to rule out the rings.

If you are getting that much grease and oil on your engine during a reinstall on a rebuilt motor you're doing something wrong or you're not very clean. I clean everything thoroughly before asembling it. Then again I may be a perfectionist. As well I usually do not install any exhaust components until the engine is together on its mounts in the car. Makes life easier I feel!

again! HTH

 

Well, sorry pete, but every time I've seen oil burn, it burned blue. If you are blowing black smoke, youve got too much fuel. I think you may have them a little turned around. As for different heads being different, THEY ARE NOT. Sure they may be styled a little different from casting to casting, but they work the same. Chevys are notorious for the valve seals. Happens all the time, but it has nothing to do with what head specificaly.

 

Maybe it's just my experiences then. I blew an engine after ingesting a lot of water into the tb. It lasted a little while but then the piston cracked in half and when I pulled it apart there was a tremendous amount of oil above the cracked piston, but before it blew there were tons of black smoke coming from it. Yes I do know the heads generally are the same but some seem to last a lot longer. The non tpi heads, I think they came on the LG4 seem to last quite a long time without having the vlave seal trouble. That's what I'm referring to.

But If it was a rebuild from unknown origins who could have anything slapped together which is why I was inquiring about the rebuilt motor.

 

Have you timed the car?

 

okay , i haven't posted in a while cuz i couldn't pay my internet bill and it got shut off. been dumping too much damn money into that car and it was killing me. anyway, i've had enough ... there have been nothing but problems with the car since i got it ... the electric fan died, the stereo blew, burning oil , blown engine , etc .. the list goes on. the rebuilt engine they gave me was fully assembled but with no carb and no pulleys .. the old engine had TBI and i didnt have a carb on hand, so i modified the TBI intake to fit onto the older heads. i don't know why it made the initial puff of smoke when i first started the car with the new engine but it hasnt done it since. and the oil burning off the exhaust was because when i first started it i did it with the VC's off so i could adjust the rockers if needed. believe me , i took my time to try to do everything right. i think i may have discovered the problem, but now its too late because the dealer already came and got it and now i'm arguing with them to get my money back. the intake had to be drilled out at an angle to fit the older heads ... and *** knows why i didn't think of this before ... but maybe one or more of the holes didnt seal right when i sealed them and i was just getting a bad vac leak? anyway ... the car was a big hack job to begin with ... someone changed the wiring harness and then hacked it to s*** before i got it anyway and it gave me nothin but problems from day one. the dealer also seemed a little shady to me so maybe it was just a bad engine from the get go. and to top it all off ... after looking up all the RPO's i found that it wasnt even a true IROC ... it was a sport coupe with trim and iroc badges. in any case ... the car is gone so i wont have anymore problems with it. i found and bought a nice '85 Z28 in near factory condition to replace the fake IROC, and it runs and looks much better than the other one ever did. i appreciate all of the input from everyone, even though the car ended up going back to the dealer. until next time i guess ...

 

Ok, you do know that whenever you do work on the engine, you get oil and grease from your hands all over it. You start the engine and you'll see smoke coming from the engine, that is perfectly normal. That is just the oils from your hands burning off. Everytime I work on my engine, it always scares me at first but it goes away after a few minutes. With regards to your timing, are you disconnecting that one wire on your harness before you try and set it? You aren't going to do anything to your timing until you do that, you'll just be fighting against your ecm. It tries to adjust timing by itself.

 

When I got my rebuilt 305 put in, it DID smoke a little from under the hood vents for about a minute or so, but nothing serious.
It was just the oil and crap burning off.
-G

 

Just something I didn't hear anyone say after I read about him trying to adjust the timing...

If it is a CC distributor, and is working properly, it will appear VERY advanced at idle, and rotating the distributor while the engine is running with the CC dissy plugged in will not appear to change the timing at all.

To set the timing properly with that distributor, you have to unplug its connection to the computer (4 connection plug behind the cap), THEN you can set the timing properly. After that, then you plug it back in. The timing will still appear way different than you just set it at, but thats normal.

Also, if it was rebuilt, was it run and broken in before you got it? Or was it just put together and never fired before you got it?

Just my $.02

 

wow .. i unsubscribed from here after my last post, because i no longer had the car .... i didn't think anyone was going to post anymore since said i got rid of it.

however, just to answer your question, yes, it was a cc dist. and yes, i did unplug the isc connector when i was setting the timing. i highly doubt that it was fired, let alone broken in before i got it. actually i know it was never fired before i got it (after it was *rebuilt* that is). there was no carb, the intake, valve covers, and oil pan were not sealed (no gaskets, bolts not tightened etc.) now that i think of it, there could have been gaskets missing anywhere, the head gaskets come to mind.

i think the major mistake i made was with modding the later style intake to the older style heads, but i was flat broke and getting into debt because of that car, it was my only car and i needed it. my ride to work at the time said he wasn't going to be able to pick me up anymore. there was a lot going on. i dumped every penny i had into that car, including some rent and bill money!

it was my first truly involved engine experience, and i learned a lot from it. i didn't pull the heads off and check the gaskets, i should have. it was a stupid thing. i should have ripped the whole thing apart and verified everything to be sure it was done right. oh well, the car is gone now. my gratitude to everyone who posted to try and help me out, thank you. hopefully i'll be able to return the favor in the future!