I've been sitting on a '69 396 for about 10 years now. I drove my buddies car it came out of and it had plenty of power, although it seemed undercarbed to me off the line. I bought it from him for $500 because he ordered a crate motor and didn't want to have to store the motor and he knew I wanted it. Anyway, the dang thing blew white smoke, which I've always interpreted as one of a few things: 1) piston rings are no longer sealing, 2) crankcase breather has failed. Like I said, the engine had plenty of power and I figured I could just install new rings, hone the cylinders, install a new engine seal kit...you know, essentially refresh the motor and maybe do a head job or install new heads, and maybe not. A friend keeps telling me I need to rebuild it because when so and so was running it he remembers it blowing white smoke and running poorly. He's also telling me 396's are touchy and I need to make sure the engine is top notch, but I keep hearing nothing bu b&ll $hm!&t every time he opens his mouth. He also happens to be an engine builder who wants to do the work for me. Any opinions?
I always heard blue smoke was oil burning (rings,valve seals) White smoke was water (head gasket,block,heads) After 10 years sitting, I would do a full rebuild after checking for cracks,leaks etc
So, if it had really good power when it was taken out of the car, it's likely just a head gasket? Weird, it must have happened just prior to it being removed, because I didn't see any water or light brown sludge when I took the valve covers off or when I drained the oil and refilled it to pickle it. Could a headgasket hole be so small that there is so little water that it's becoming steam and being burnt before contaminating the oil? Now I'm worried that there may be rust accumulating in the block, although I did fill it/piclkle it to the brim just in case.
You can just do a "slight" freshen up like you posted,get it back installed,and find a problem and have to do all the work and expense all over. I find a lot of times it's cheaper to do it the more expensive proper way the first time rather than gambling.
Well, now I'm thinking I'll tear it down and do a full inspection... probably line bore, new bearings, the whole ball of wax. Damn...
You won't know until you take it apart. Maybe all it needs is rings, bearings, gaskets, and a valve job. The only way to make sure is take it apart and start measuring and inspecting.
Back around '76, I got a 396 that was abandoned in a dirt field. Drug it home and disassembled it. The motor was frozen so I pounded out the old pistons. Micro polished the cast crank, honed the cylinders, re-ringed and added new bearings. Did a 3 angle valve job on the oval port heads and installed Sig Hy-Flo II cam. Even though it had oval port heads, used a rectangular port dual plane manifold with a Holley 800 double pumper. Stuck that motor in a '65 Malibu SS with a 4 speed and 4:88 gears. It was one of the fastest motors I ever had. Total junk but it ran good. I suppose it was like having a new 100,000 mile motor since the clearances were so loose. My roommate had a 435 hp 427 Vette with a 4 speed and 4:56's. The Malibu was faster. I even ran nitrous through that motor. My roommate could never believe it was a lo-po 396 until I spun a bearing. I took the motor to his shop to install a new crank. He pulled the crank and saw the gouge marks on the pistons where I pounded them out. Who knows, the motor was a freak.....
BBCs have to be one of the easiest motors in the world to rebuild. Whatever you do it's bound to have more grunt than you need. The only bad part about the blocks is you occasionally find core shift bad enough to make cyls 6 and 8 a little sketchy. There's another plan laying right in front of you for the price of a smogger 454. Slap a 427 together. The 396 crank and rods are the same. You'll need pistons and little else. The heads are probably closed chamber too. Might be able to finance the whole 427 project selling the leftovers, like the block to serious restoration guy, and the 454 crank to one of many would be race types. Just thinkin out loud...
I would not let him do the work, simply.... he wont do his own work? Seems strange... White smoke can happen during warm up, and moisture from sitting burns off. You really don't know what you got unless you do a compression check, and or take the oil pan off, and inspect a few bearings, and cylinders from underneath....
I have one of those, now sitting under the bench but the thing was an animal. Thought it was a 454 based on the block casting number but then found the 396 crank inside. If you go that way get the lower end balanced, 427 pistons are heavier and the counterweights are not the same between the 396/427 cranks from what I have read. Mine was already built when I bought it in a car so I didnt have to go through it. Bigger engines make more power but I love the 396s, last one in my 70 chevelle would spin over 6500 easily with a steel crank and solid cam, I beat that thing mercilessly and it never gave up.
Touchy? no one told the last one I had. It was from a car that burned to the ground in a garage fire. Disassembled - cleaned - gasket set - reassembled - ran daily for 8 years
I still say the BBC is the easiest of all motors to build/rebuild. If this guy that's pissin in your ear about it comes up the old wives tails, I'd run away and never look back. The only "touchy" thing about BBCs that I found is they like high limit bearing clearances. Seems like .002 lasts for ever. That's a lot of metal in there that gets big n little so it moves farther than your average 350. I know that's like the least technical description about that facet of the build, but I think you get my meaning. Also, when it comes up that the journals are too small for std, they still make .001 under rod n main bearings for em. I spun a set of those at 7800 in the traps over 400 times without fail. I also mentioned the 6 n 8 core shift, and while grinding away on something I remembered the ones with the issue. The high nickel Mercury Marine blocks had that problem, as did some of the other late 4 bolt main 454s. It's not all BBCs so sorry for the input on the one you have. Even as a 396 it'll scream in the right car.
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