I have just completed my first rebuild of a 302 and put it in the truck 77 longbed cranked it a few times and let it run a little. I didn't want to run it too much because it still only has open long tube headers on it and i didn't want to hurt anything. well the other day i went to crank it up and it smoked some not a giant cloud of smoke but some smoke as it was idleing. when i had cranked it up in the few days before there was no smoke but it is now. I have done a search about smoking after a rebuild and the same thing kept coming up (the rings have not seated) is what nearly every post had in it. And the resposnes always asked did you use synthetic oil or additives. Well i didn't use sythetic and didn't add any additives to the oil but, There was still a VERY SMALL amount of gas in the gas tank (that is two years old) that i could not get out so i poured in a little gas treatment and a little mavel mystery oil (like an idiot i guess now) and it says to lubricate cylinders and i was wondering if this could be my problem and it is going to work itself out or did i mess up REALLY BAD!!!!! I was so happy at first when it cranked and didn't smoke now i'm worried about it! Thanks for all the help!!

thanks

jason

 

I would'nt worry right now as you found out the rings have'nt seated yet. What you added should'nt be a problem just make sure you have plenty of gas to mix with whats in there. Take it easy and allow the engine to break in and you should be fine.

 

I hope so, and i did only put like 3 gallons of gas in to start with the other day before i started it the first time,and i didn't put the whole bottle of gas treatment and even less of the MMO i think i will go get about 10 more gallons to put in it. The new mufflers from summit will be in tomorrow and i already got my "S Bent collector extensions" from headman to get around the crossmember so hopefully when i put more gas in it and with the mufflers on i will drive it around the block a few times and hope i don't get caught! I have to wait to get tags and insurance on it before i can run it up and down the highway cause i surely don't want to do that with out insurance! thanks for the reply!!

jason

 

well u wouldnt hurt anything with no exaust other then headers, and ur lookin at like 200-500 miles till they seat completly, so just lettin it run for a few min isnt gonna do it much good, and ur supposed to vary the idle and drive sparaticly...ie like go from hammerd to idle to half to 1/3 etc for the first 400, to break the cam in if thats also what u did. but ur just not supposed to hold a certian rpm for to long..sry if u already knew all that

 

I didn't know about holding the same rpm for too long, but I didn't replace the cam or the lifters they are the same ones that came in the short block from an 83 grand marquis but i plan on driving it tomorrow. hopefully i can get the mufflers on tonight so i don't make any neighbors mad. like i said in another post it sounds like a race car when i crank it up the way it is. Thanks and i am gonna drive it and hopefully it will stop smoking! i am also going to go ahead and change the oil while i have it up on the drive way.

jason

 

u'll prolly wanna change it every 500 miles like 3 times to be safe to. would be more but since u didnt do all that much to it, and as long as u have an appointment with a shop to do ur muff's the cops can pull u over but they cant do anything...unless u dont getem fixed on ur app date lol. ima be doin goin on open headers for like a month lol, people round here are gonna love me

 

Jsutton- You went through the trouble to rebuild the bottom end and didn't replace the cam and bearings or lifters? If you went to all that trouble you could a went a few steps more and completely rebuilt it.
Did you hone the cylinder walls and use ridge reamer before you put new piston rings on? If not, and if the cylinder walls were glazed or even tapered your gonna get smoke and it probably isn't gonna go away.

 

The engine had already been rebuilt when i got it out of the grand marquis, i don't know how long ago since it came from the U Auto Pull It.I wasn't going to do anything to it but put the 77 heads and intake on it and let it go. but i had it down to the short block so my friend that races dirt track said go ahead and put new rings and bearings in it since it is already down this far down. So he took the Block and crank to the guy who builds his race engines to have it all miked and everything and the guy said it was fine. no ridge or anything, crosshatch on the cylinder walls was fine, no problem with the crank just put the new stuff in and it would be fine! So i put new main and rod bearings and new rings (made sure to align them like the instructions said). And i have read many post on here that people state they didn't replace the cam bearings when doing a rebuild. Thanks for the reply though but i don't think that is it.

jason

 

Yeah you should be fine, if the ridge was removed and a good cross hatch was performed, it should seat just fine.

 

I hope so!!!! thanks i am going to retorque the head bolts and intake bolts. so hopefully i can get home from work and still have enough daylight left to do that. i didn't get home in time to put on the glasspacks but they did come in from summit. they feel pretty heavy too, even heavier than the purple hornies i sent back. but i have to make sure it runs right or the exhaust does me no good! HA HA

thanks
jason