I need advice as to a plan to address an engine smoking problem. Here is the background on this problem....

- Rebuilt engine totally. Heads have new guides, valves, springs etc.
- Block was bored .030", installed KB pistons with new rings
- Cam and all inerds etc.

When you run the engine and it is totally warm there is a trace of what appears to be blueish to white smoke. When you rev it hard, it is a cloud of smoke!

- I have used 3 different carbs ( 2 Q-Jets and an Edelbrock ) The only thing abnormal is the Q-Jets all drip from the boosters, one carb more than the other and that one seems to be one booster.

- I have removed and reinstalled the intake manifold 3-4 times using a stock one, a Torket II and a Performance Products dual plane. Still smokes. Used both Felpro and Mr. Gasket intake gaskets so with this I think I would have gotten lucky once and had good sealing.

- The engine idles well and smooth pulling 16-18" of vacuum.
- Timing is at 10-12 degrees so nothing radical.

- I replaced the PCV valve with 2 different ones - same smoke.

I need some advice on where to look for a problem before pulling the engine and tearing it down. Frankly I suspect the boring of the cylinders is not perfect and sucking oil. However, the oil level does not really go down much at all.

Oh this is a 454" in a 73.

Any and all ideas or questions are welcomed. Thanks Jim

 

How long have you driven it since the rebuild? Its not completely unusual to see some smoke in the first few hundred miles (or 3 or 4 hours of operation) from rings still seating, etc. Its likely it could just be some blow-by.

 

Did you do anything to seat the rings ?

 

could be leaking around the exhaust manifolds

 

Is it a auto trans? If so, check the modulator valve vacuum hose at the intake/carb for trans fluid in it. I made my brothers day big time with that one several years ago on a 65 Impala. Good luck

 

I'd have to agree with Motorhead. If you didn't use the proper oil for seating the rings it would smoke. If you used a synthetic type oil that didn't allow the rings to seat properly and take it easy for about 500 miles or so you may have to start over.

 

Yikes!!! A few hundred miles or 3-4 hours to seat the rings. If it took more than a matter of minutes to seat the rings well enough to eliminate all smoking, then the motor was built wrong. It should never take that long for the smoking to clear up. If it does, there is an issue or multiple issues with machining, part selection and/or assembly.

Jeez, I've seen them fire brand new Corvette's at the factory, and they don't even smoke when they first light off...........

 

Well, the question of whether or not to use syn oil right out of the gate is an issue that can be hotly debated. No matter what side you take on that, the fact is, many cars come right off the assembly line with factory filled full syn. One of my cars at home is a 400 hp '05 LS2 GTO, which came filled with full syn Mobil 1. Not one of my favorite oils, but none the less, the motor never smoked AT ALL, even driving it away from the Showroom Floor with only 5 to 10 miles on it. So, even if he did have full syn in it, its been proven thousands and thousands of times to be no issue regarding ring seating. Ring seating is really more about machining, parts and assembly, than it is about the oil being used. Sure there is nothing wrong with starting with dino, and switching to full syn later, but it just isn't mandatory.

 

Ive seen it both ways... car kicks over, spits out a little cloud and never smokes again.. Ive also seen it take a while before the rings to seat. You're right, It shouldn't take more than 10 - 15 min most the time if that long, but giving it a bit more time to seat is a lot easier than pull&replace trying to fix something that may not need fixing.

 

Did you get a good cross-hatched finish from honing the cylinders before you did the rebuild?

 

Maybe they jacked up an oil seal when assembling the heads.....Does it smoke when you rev it or when the engine decels back down to idle? I have had motors in the past that with a bad oil seal or two that would smoke at idle, smoke on decel and even smoke going down the freeway...I would slap in a new set of seals and it would be fine......at least until what ever damaged the seals, damaged them again...(ie. worn guides, improperly machined oil seal perches etc...)

 

Make sure your valve covers are baffled. No baffel in the valve cover will suck oil into the carb base through the PCV especially with a high volume oil pump.

 

Let me try to answer all and ask questions...
- The machine shop should have cross hatched the cylinders. I hope
- I used dino oil for breakin, changed it after a couple of hours
- It smokes at idle you can see a thin whisk from the pipes. If you rev it high several times it is a cloud of smoke.

- I think the first is new seals. It was put together with PC seals and I think I will try rubber umbrella.

- I have driven it about 4+ hours and let it idle long periods. I would think the rings were seated.

Is it the opinion that smoke at idle is from guides and/or sucking on the top end?

 

What do you mean baffled? I have aftermarket chrome covers now that look the same as the OEM steel. But i will look again tomorrow.

I think I changed the PCV one time. Do you have a number for a 454 or just go to the parts house and look one up?

I think you may be right on sucking it into the carb. Can I seal off the PCV hose line for a period of time without hurting anything?

Thanks.

 

jim:
First thought was leaking intake ... but seems you've probably eliminated that ... so assume you've checked off all the obvious stuff.

So ... sounds like upside down 2'nd ring(s) ... possibly upside down Top ... more likely inverted 2'nd. They've tapered face & will pump oil every time if upside down. It's an easy mistake to make.

 

I hate to ask but your coolant level isn't dropping is it? White smoke, bad head gasket? If it smokes right at start up that's probably the valve seals. Had an old camaro that did that.

 

"The machine shop should have cross hatched the cylinders. I hope"
Does that mean you didnt see because they also assembled the engine as well as the machine work? If so, I think I would be getting thier oppinion on whats going on.

 

To seat the rings properly you need to get it in second or third gear, and rev it to about 4500-5000RPM's and then let your foot off the gas and let the engine slow the car down.

You do this 3 or 4 times and your done. This should be done as soon as the motor is running and the first time you take it for a drive. Did the machine shop not mention doing anything like this ?

 

A lot of the aftermarket valve covers don't have proper baffles to keep to PCV from sucking oil in. Some come with the baffles not attached, you have to install them upon assembly. Sometimes they don't clear roller rockers so they get left out. Sometimes a high volume oil pump gets a lot of oil in the top end and it is flinging around in there so much it sucks into the PCV or a combination of crappy baffles and high volume pump. I swapped an engine out when I was a kid. It was smoking bad. Thought it was trashed. Dropped in a new motor and put my cool valve covers on it. Same problem. Ended up figuring out the VC baffles were the problem all along. To test you could pull the PCV valve out of the valve cover, just lay it next to the valve cover on the intake and put a breather in the hole. Drive it 15 minutes or so to get all the oil burned out. Park it and check for smoke idling and reving it up. If you haven't changed the PCV valve change it out too. A cheap push in breather is $5 a new PCV valve is $5. Money well spent if it isolates your problem. Either of these is a cheap fix compared to anything else it could be.

 

Seating the rings is not a science. Think about all the new cars that have no "break in period" like 20-40 years ago. Most of that was for the flat tappet cams. Think about a new car. How much it idles in the plant, on and off the carrier, moving around a dealers lot and so on. I have never had a new car in 35 years with a ring or smoking problem. Period. Good rings installed correctly will seat under almost any condition.
All that being said. I had my '72 350 rebuilt, and it evolved into a 383. It was professionally built, balanced and blue printed. Started smoking afer 500 miles. Bought another set of new aluminum heads, changed intakes, machined the intakes to be sure they sealed, differnt valve covers, carbs, etc.. Still smoked....bad.
Had to pull the engine out and go throught it again. Builder claims he could not find anything wrong. Rebuilt with Total Seal rings...intalled motor back in the car, fired, no more smoking....but still have oil leaks!!!
I read an article about 6 months after all the problerms I had about Hastings rings and their problems. Now they are made offshore and ARE NOT LAPPED or HONED. So they are not true....and most likely will never seal..
it's bad rings or improperly installed rings.
Best of luck....I know what you are going through...Mark