Oil smoke on new rebuild of 223

[Adriatic Machine]

I’m no expert on jetting though I’ve been reading up on it quite a bit lately. First thing I learned is to change jet size no more than one or two sizes between test runs, and know which direction you should be headed. Don’t forget the jets are mostly for cruising speed, not idle. They are used during acceleration but are enhanced by the accelerator pump.

All my carbs and spares have had a #62 jet. Quite the coincidence. I plan on buying an air -fuel meter and using it to fine tune the jets in my 2X1 setup.

 

[DON]

You will be pleased with an o2 meter. Well worth the money for tuning. Tons more accurate than ear or seat of your pants. When adjusting Holley 2300, I can see an 1/8 of a turn on one screw at idle. If you have heard of a lean surge, you can see it on the meter

 

[alwill923]

The PCV connection must be added at the carburetor or a carb spacer to distribute the air to mix with the carb flow and be equal to all cylinders.
Did you put the valves in without the plastic sock over the end of the valves?

 

[philford]

heres my suggestion pull pout the plugs, disconnect the coil.
take a spark plug knock the porcelain out.
pop a tubeless tire valve out of an old rim grind it so you can press it into the spark plug.. Or of you like buy the thing..

turn engine normal direction till #1 ehausts out spark plug hole continue to TDC check the crank marks or use a drinking straw as a feeler tool. you want piston 1 at TDC

hook your compressor up to charge up cyl 1 wiht compressed air. in theory all is good it will seal but some leaks, domt worry, if it wont retain pressure then its not looking so good .. carful ! pressurizeng the cylinder can cause engine to try to turn to BDC suddenly..


if rings leak youll get air going in the tcrankcase and likely out of your road tube. if valves leak it may leak out the exhasut or possibly up through carb. you seemed to say compression is ok so this may help or perhaps it will steer you down the wrong path ,

If compression is weak it can help determine wheather the pressure loss is through the valve not sealing or leaking past rings.

Q for others , any chance he has a head gasket leak from oil passage through the head gasket and into a bore? often it is water leaking intothe bore and a bad head gaslket but I beleieve oil does flow through so it seems possible.

also if you looked in around timing gears is there a "sprayer" that screws in , on other engines forgetting to re-install that nozzle thing results in low oil pressure but ford might be different.

how is the oil pressure? can you connect a guage?

black crap? is the oil clean ? why the black? buring the oil in the cylinders maybe? do the plugs look similar to one another?

i have an odd litle tune up item at home , it is called a "colortune," what it is , is a spark plug but iit has glass rather than porcelain. its purpose is to tune a carb engine by the color of the flame.

heres a picture of it, if you want one, shop around, it can be used on dual or triple carb engine to help synchronise carbs. it might be outdated and now replaced by somethign youd stick in the exaust to measure 02 . but perhaps useful to tell if an engine is running rich or lean. the idea is that you can synchronixe dual carbs by watchign the air fuel mix at each plug , to even up the fuel distribution from boith carbs so one carb isnt;l supplying more fuel than the other carb. you are actually seeing the flame of combustion that way.. and its color. the color changes if its too lean or too rich , thats the idea.

Colortune 500 Lean/Rich Tool

Colortune 500 Lean/Rich Tool

mossmotors.com

in general blue smoke is burning oil black smoke is too rich , it smells different. a good mechanic may be able to sense that better than those with less experience. often youll get a whiff of too rich if you are following a hot rod thats tuned to waste gas ;-) if its valve guides I've seen a blue mist behind me in a severe case..

often at near dusk if you floor a car to the mat get the revs up near redline and and look behind, youll see that smoke behind yourself, maybe get a sense if its blue oil mist or maybe black smoke. from excess fuel. if you see no smoke thats a good sign. if its using oil the dipstick will obviously also go lower.

in this ford, would you re torque the head hasket after it has gone through its initial warmup? some cars may call for that others maybe not , i suspect its not a ford proceddure, I cant; see it being practical at all if you have EFI like my van , as thats a lot of work to remove the manifold to get there.

id keep an eye on the underside of the filler cap maybe it's on the rocker cover in my van its just a tube .. anyway
look for any white foam, if so that might mean a head gasket issue. retorquing a head gasket might seal it if you put it together and it leaks..

when you install a head its important to clean the bolts make sure all the threads are clean and they screwin quite efforlessly all the way down.. Ill often chase the threads with a tap.
what can happen is rust throws off the torque or oil or water gets in the hole and then you have a hydraulic lock so when installing head bolts it pays to make sure that can;t happen by being sure its very clean in there. otherwise any oil that did come up as, the bolt goes in, could possibly corrupt the head gasket seal. you wnat the mating surfaces to be clean and not oily.



watch the water bottle (or rad) if it does strange things like fill or empty, it could be blowing exhaust into the combustion chamber. pressurizing the water jacket and forcing water from the head into the rad or water bottle.. and also emptying..
look for any water out the tailpipe, or antifreeze smell.

if you extract valves from the head were you careful to deburr them? that can perhaps scrape out the inside of the valve guide, like if there is a burr near the valve stem keeper groove. some may just try to tap them on through basically reaming out their own valve guide in the process.

if the valves aren't bad you can then lap them in the old school way or send it for a proper 3 angle grind if its worse.

if you do need to go there, a shop may be able to knurl your existing guides and then ream them to fit. the knurling process reduces the ID and also traps oil where it helps so you may not choose to go the route of replacing guides with new, I'd speak to a shop that is capable of reaming guides first. before ordering new ones if you go down that road.
if you do that it stands to reason you might also need to at least check the fit of valves to their seats in case they move any, You can check that fit to the seats yourself with prussian blue or some may just say "bluing"

I think plugs can change quite fast on different operating types so maybe if you floor it down the highway shut it off roll to a stop, and pull a plug you'd see some difference from doing that after its been idling.. to be sure sometimes I'd just instal a new plug(s) just so I know my ( visiual) reading isn't from historic use.

I wonder if the needle valve (the one your float presses on ) that prevents the carb from overfilling could be not working ( not sealing ) and allowing the float bowl to fill too much, and flooding possibly.. there is probably a correct ford procedure to check that. Any fuel leaks near the carb? if it overfills it might leak gas. ?

Maybe the float level is too high and you are just getting way to much fuel. Im hoping for that as it would be much easier to fix than engine disassembly.

ask the others how to check the float level properly they know it better.. maybe you take the top off and look for a mark or there may be some other procedure to verify the float is adjusted at the correct level. you might want a new gasket or possibly a new float or needle valve or a kit.
it can happen because the needle and seat are worn or dirty. so then it wont shut off the gas when the float floats up to press on the needle.

maybe if you took the carb off and turned it about when removed,, something could fall in some awkward way? dislodge the float somehow maybe?

oversize jets probably would not improve performance unless the engine is modified to actually need more fuel.

in my van I found a hose leading to the carbon cannister leaked, you might try plugging any hoses like that off and see , In my case I believe it was making it run lean because air had a way in and since it only wen tot the vapor cannister and many would think that unimportant it went unnoticed. a broken or rotted hose might really affect things. mine goes ot a hard tube under the passenger tire well near there, in a pickup Im not sure but I'd check that hose you could plug it off short term to see if there is any difference. if your trick has it it may need it to suck vapors from the tank ,, plugging it off may cause fuel starvation as the air needs to get into the tank somehow as fuel is used. older cars might do it differently , your tank wont starve for air if the fill cap is loose. it can display if you remove the fill cap and hear a rush of air, it might mean the tank has a "vacuum" or negative pressure it the right way to say that. ive heard of the opposite happening where pressure builds up the tank and the cap tries to blow off as your relaese it but thats probably rare. the tank can expand and pressurize the fuel with expansion from warming. normally that pressure goes intothe charcoal cannister and then gets sucked up into the engine so it can burn its own fumes up rather than just expelling them ot the air. any leak may ammount to basically a vacuum leak maybe upsetting idle.


could it possibly be sucking crap up a hose like that and trying to burn it? I once accidentlly filled a charcoal cannister in a VW with water because I comfused a small hose with a windshield wiper hose and yes it sucked it into the carb, and then it didn't run great on water lol ; -) if there is a draincock or a plug maybe you can let the gas out of the carb see if any rusty crap follows. or just run it for a bit gravity fed from a small tank like from a lawnmower to be sure its not just fuel starvation. that way you can supply some fresh clean gas. just to prove its not bad fuel or a plugged fuel filter. you can check gas flow into a can from the fuel pump into a gas can if you like, to see if theres any rust or water coming. or maybe a torn fuel pump diaphram or bad electric pump.or bad relay or blown fuse.

in a volvo those PCV fumes go through a little plastic =screen, it can plug and that can cause the crankcase pressure to build excessively, I do not think ford ever did put one in, I guess its supposed to catch any chunks ..
that can cause the vapor pressure int he crankcase to build then it can bliw seals like the rear main or cam seals. ive seen it blow the dipstick out of its tube before but thats not in a ford.. if you have a road draft tiube then it should be open but you could check that thats not actually somehow blocked. the fules from blow by need to be able to leave somehow.

often a quick check is that an idling engine really should be trying to suck intot he oil filler cap and when there is blow by it may be blowing out. it might not be definitive but somehing easy you can do if examining a car, maybe thinking of buying it.

if its barfing out oily fumes at idle with the filler cap removed, then maybe it means bad rings ? it might mean the PCV system can't; keep up with the amount of blow by., or a plugged PCV hose or similar? if underside of filler cap has white froth, suspect head gasket issues.

lets hope you just have a really rich mix becaue the carb is screwed up and needs attention because thats not so bad. It's not fun to assemble a whole engine to then take it apart again. but sometimesits just a matter of course and if so you just have to move ahead and accept that the job got extended..

 

[philford]

The PCV connection must be added at the carburetor or a carb spacer to distribute the air to mix with the carb flow and be equal to all cylinders.
Did you put the valves in without the plastic sock over the end of the valves?

I have heard of people who pressurize a cylinder (or all the cylinders ? ) and do it with both valves up. the theory there is that if the valves are held up into their seats by air pressure you can then compress the springs, replace the valve seals without taking off the cylindrer head. otherwise they may want to drop right down into the bores. it might fix a bad seal or similar,, change them all and see ? of course it wont fix worn valve guides.

 

[jminor]

The PCV connection must be added at the carburetor or a carb spacer to distribute the air to mix with the carb flow and be equal to all cylinders.
Did you put the valves in without the plastic sock over the end of the valves?

The valves have the correct seals in place. That was actually the first thing I checked, thinking I might have forgotten them.

 

[jminor]

heres my suggestion pull pout the plugs, disconnect the coil.
take a spark plug knock the porcelain out.
pop a tubeless tire valve out of an old rim grind it so you can press it into the spark plug.. Or of you like buy the thing..

turn engine normal direction till #1 ehausts out spark plug hole continue to TDC check the crank marks or use a drinking straw as a feeler tool. you want piston 1 at TDC

hook your compressor up to charge up cyl 1 wiht compressed air. in theory all is good it will seal but some leaks, domt worry, if it wont retain pressure then its not looking so good .. carful ! pressurizeng the cylinder can cause engine to try to turn to BDC suddenly..


if rings leak youll get air going in the tcrankcase and likely out of your road tube. if valves leak it may leak out the exhasut or possibly up through carb. you seemed to say compression is ok so this may help or perhaps it will steer you down the wrong path ,

If compression is weak it can help determine wheather the pressure loss is through the valve not sealing or leaking past rings.

Q for others , any chance he has a head gasket leak from oil passage through the head gasket and into a bore? often it is water leaking intothe bore and a bad head gaslket but I beleieve oil does flow through so it seems possible.

also if you looked in around timing gears is there a "sprayer" that screws in , on other engines forgetting to re-install that nozzle thing results in low oil pressure but ford might be different.

how is the oil pressure? can you connect a guage?

black crap? is the oil clean ? why the black? buring the oil in the cylinders maybe? do the plugs look similar to one another?

i have an odd litle tune up item at home , it is called a "colortune," what it is , is a spark plug but iit has glass rather than porcelain. its purpose is to tune a carb engine by the color of the flame.

heres a picture of it, if you want one, shop around, it can be used on dual or triple carb engine to help synchronise carbs. it might be outdated and now replaced by somethign youd stick in the exaust to measure 02 . but perhaps useful to tell if an engine is running rich or lean. the idea is that you can synchronixe dual carbs by watchign the air fuel mix at each plug , to even up the fuel distribution from boith carbs so one carb isnt;l supplying more fuel than the other carb. you are actually seeing the flame of combustion that way.. and its color. the color changes if its too lean or too rich , thats the idea.

Colortune 500 Lean/Rich Tool

Colortune 500 Lean/Rich Tool

mossmotors.com

in general blue smoke is burning oil black smoke is too rich , it smells different. a good mechanic may be able to sense that better than those with less experience. often youll get a whiff of too rich if you are following a hot rod thats tuned to waste gas ;-) if its valve guides I've seen a blue mist behind me in a severe case..

often at near dusk if you floor a car to the mat get the revs up near redline and and look behind, youll see that smoke behind yourself, maybe get a sense if its blue oil mist or maybe black smoke. from excess fuel. if you see no smoke thats a good sign. if its using oil the dipstick will obviously also go lower.

in this ford, would you re torque the head hasket after it has gone through its initial warmup? some cars may call for that others maybe not , i suspect its not a ford proceddure, I cant; see it being practical at all if you have EFI like my van , as thats a lot of work to remove the manifold to get there.

id keep an eye on the underside of the filler cap maybe it's on the rocker cover in my van its just a tube .. anyway
look for any white foam, if so that might mean a head gasket issue. retorquing a head gasket might seal it if you put it together and it leaks..

when you install a head its important to clean the bolts make sure all the threads are clean and they screwin quite efforlessly all the way down.. Ill often chase the threads with a tap.
what can happen is rust throws off the torque or oil or water gets in the hole and then you have a hydraulic lock so when installing head bolts it pays to make sure that can;t happen by being sure its very clean in there. otherwise any oil that did come up as, the bolt goes in, could possibly corrupt the head gasket seal. you wnat the mating surfaces to be clean and not oily.



watch the water bottle (or rad) if it does strange things like fill or empty, it could be blowing exhaust into the combustion chamber. pressurizing the water jacket and forcing water from the head into the rad or water bottle.. and also emptying..
look for any water out the tailpipe, or antifreeze smell.

if you extract valves from the head were you careful to deburr them? that can perhaps scrape out the inside of the valve guide, like if there is a burr near the valve stem keeper groove. some may just try to tap them on through basically reaming out their own valve guide in the process.

if the valves aren't bad you can then lap them in the old school way or send it for a proper 3 angle grind if its worse.

if you do need to go there, a shop may be able to knurl your existing guides and then ream them to fit. the knurling process reduces the ID and also traps oil where it helps so you may not choose to go the route of replacing guides with new, I'd speak to a shop that is capable of reaming guides first. before ordering new ones if you go down that road.
if you do that it stands to reason you might also need to at least check the fit of valves to their seats in case they move any, You can check that fit to the seats yourself with prussian blue or some may just say "bluing"

I think plugs can change quite fast on different operating types so maybe if you floor it down the highway shut it off roll to a stop, and pull a plug you'd see some difference from doing that after its been idling.. to be sure sometimes I'd just instal a new plug(s) just so I know my ( visiual) reading isn't from historic use.

I wonder if the needle valve (the one your float presses on ) that prevents the carb from overfilling could be not working ( not sealing ) and allowing the float bowl to fill too much, and flooding possibly.. there is probably a correct ford procedure to check that. Any fuel leaks near the carb? if it overfills it might leak gas. ?

Maybe the float level is too high and you are just getting way to much fuel. Im hoping for that as it would be much easier to fix than engine disassembly.

ask the others how to check the float level properly they know it better.. maybe you take the top off and look for a mark or there may be some other procedure to verify the float is adjusted at the correct level. you might want a new gasket or possibly a new float or needle valve or a kit.
it can happen because the needle and seat are worn or dirty. so then it wont shut off the gas when the float floats up to press on the needle.

maybe if you took the carb off and turned it about when removed,, something could fall in some awkward way? dislodge the float somehow maybe?

oversize jets probably would not improve performance unless the engine is modified to actually need more fuel.

in my van I found a hose leading to the carbon cannister leaked, you might try plugging any hoses like that off and see , In my case I believe it was making it run lean because air had a way in and since it only wen tot the vapor cannister and many would think that unimportant it went unnoticed. a broken or rotted hose might really affect things. mine goes ot a hard tube under the passenger tire well near there, in a pickup Im not sure but I'd check that hose you could plug it off short term to see if there is any difference. if your trick has it it may need it to suck vapors from the tank ,, plugging it off may cause fuel starvation as the air needs to get into the tank somehow as fuel is used. older cars might do it differently , your tank wont starve for air if the fill cap is loose. it can display if you remove the fill cap and hear a rush of air, it might mean the tank has a "vacuum" or negative pressure it the right way to say that. ive heard of the opposite happening where pressure builds up the tank and the cap tries to blow off as your relaese it but thats probably rare. the tank can expand and pressurize the fuel with expansion from warming. normally that pressure goes intothe charcoal cannister and then gets sucked up into the engine so it can burn its own fumes up rather than just expelling them ot the air. any leak may ammount to basically a vacuum leak maybe upsetting idle.


could it possibly be sucking crap up a hose like that and trying to burn it? I once accidentlly filled a charcoal cannister in a VW with water because I comfused a small hose with a windshield wiper hose and yes it sucked it into the carb, and then it didn't run great on water lol ; -) if there is a draincock or a plug maybe you can let the gas out of the carb see if any rusty crap follows. or just run it for a bit gravity fed from a small tank like from a lawnmower to be sure its not just fuel starvation. that way you can supply some fresh clean gas. just to prove its not bad fuel or a plugged fuel filter. you can check gas flow into a can from the fuel pump into a gas can if you like, to see if theres any rust or water coming. or maybe a torn fuel pump diaphram or bad electric pump.or bad relay or blown fuse.

in a volvo those PCV fumes go through a little plastic =screen, it can plug and that can cause the crankcase pressure to build excessively, I do not think ford ever did put one in, I guess its supposed to catch any chunks ..
that can cause the vapor pressure int he crankcase to build then it can bliw seals like the rear main or cam seals. ive seen it blow the dipstick out of its tube before but thats not in a ford.. if you have a road draft tiube then it should be open but you could check that thats not actually somehow blocked. the fules from blow by need to be able to leave somehow.

often a quick check is that an idling engine really should be trying to suck intot he oil filler cap and when there is blow by it may be blowing out. it might not be definitive but somehing easy you can do if examining a car, maybe thinking of buying it.

if its barfing out oily fumes at idle with the filler cap removed, then maybe it means bad rings ? it might mean the PCV system can't; keep up with the amount of blow by., or a plugged PCV hose or similar? if underside of filler cap has white froth, suspect head gasket issues.

lets hope you just have a really rich mix becaue the carb is screwed up and needs attention because thats not so bad. It's not fun to assemble a whole engine to then take it apart again. but sometimesits just a matter of course and if so you just have to move ahead and accept that the job got extended..

Thanks Phil. a HUGE help. After getting everyone's advice from this forum, I am going to run the car for the summer to get at least 1000 to 1500 miles on it and see how that might effect it.
Your list of checks and process's is invaluable! I will come back to it as I get more miles on.
I truly appreciate all of the time and effort.

 

[sixtseventwo4d]

pull the plugs; if they are black sooty and can be brushed clean easily with a toothbrush then it is too much fuel. this is also indicated by black smoke with heavy fuel smell. The engine oil will also turn dark, almost black in short time.
If the plugs are filmy/greasy and require a spray cleaner to restore them you know it's consuming oil; also indicated by light grey smoke from the exhaust.
A mostly white smoke from the exhaust could be engine coolant. A 12 to 24 hour pressure test on the coolant system can help reveal this.

Could you possibly make a short exhaust video showing the smoke at various acceleration/deceleration rpms? up to 3k and back down two or three times if you can

 

[jminor]

pull the plugs; if they are black sooty and can be brushed clean easily with a toothbrush then it is too much fuel. this is also indicated by black smoke with heavy fuel smell. The engine oil will also turn dark, almost black in short time.
If the plugs are filmy/greasy and require a spray cleaner to restore them you know it's consuming oil; also indicated by light grey smoke from the exhaust.
A mostly white smoke from the exhaust could be engine coolant. A 12 to 24 hour pressure test on the coolant system can help reveal this.

Could you possibly make a short exhaust video showing the smoke at various acceleration/deceleration rpms? up to 3k and back down two or three times if you can

Clear, simple direction. Thankyou. The plugs are WET and BLACK,,,,,,all of them look the same. The exhaust is light grey.
Oil color remains light brown and clean.
What does ALL of the plugs having the same wet / black condition tell you?
See photo of the smoke attached. Sorry, was not able to get a video.

 

[sixtseventwo4d]

This is sounding more like an oil-control ring problem. The second compression ring is also the scraper ring, managing oil consumption. Possibly the second ring has not sealed yet but after 300 hundred miles 95% of ring seating has been accomplished.

In saying you have done many rebuilds, are you confident this second ring has been installed in the right direction? There is a top and bottom side like the top ring has.

Is there anything noticeable coming from the road draft tube? How good is the engine power? Have you set your ignition timing?
Are you using conventional oil for the break-in? Synthetics aren't good to use during this time

 

[Bill1958]

No down side….. till you talk to a motorcycle rider

Yep.

 

[jminor]

This is sounding more like an oil-control ring problem. The second compression ring is also the scraper ring, managing oil consumption. Possibly the second ring has not sealed yet but after 300 hundred miles 95% of ring seating has been accomplished.

In saying you have done many rebuilds, are you confident this second ring has been installed in the right direction? There is a top and bottom side like the top ring has.

Is there anything noticeable coming from the road draft tube? How good is the engine power? Have you set your ignition timing?
Are you using conventional oil for the break-in? Synthetics aren't good to use during this time

I was very careful, laying them all out in order with the correct faces up.
Nothing noticeable coming from the draft tube.
The valve cover breather does have quite a bit of "smoke" coming out of it.

 

[Frank]

I was very careful, laying them all out in order with the correct faces up.
Nothing noticeable coming from the draft tube.
The valve cover breather does have quite a bit of "smoke" coming out of it.

Interesting that you have a valve cover breather AND a draft tube. With the tube the VC can (should) have a non vented cap. The smoke is blow by, indicating rings are not sealing well. It's coming out of the VC breather and not the D tube because the VC is higher, an easier chimney for it to escape.

 

[philford]

do the plugs smell like gasoline when you foirst take them out?
it does sound like blow by , the smoke coming out of the valve cover area won't be caused by the carb causing it to run rich.

there might be some tips on breaking in the rings and Im nto sure Im the best to make those statements , but Id ry to accellerate at medium throttle and every minute or two take your foot off the gas and decellerate. the theory Ive been told is when you step on it, you are seating the rings and when decellerating you are allowing some oil on the bores..

its beter to ask others here about the subject, I am not an expert on that so take what others say into account.

I rememeber talking to an officiial volvo mechanic and I said my dads car is often hard to start, it was a 5 clinder engine. he figured that engine had an issue with the rings or glaze on the cylinders. and to partially cover the rad and then drive it up a steep hill , drive it hard, The idea was to try to break in the rings in again although it was not a new engine.
i
was one plug DIFFERENT than the others?

sometimes people try to rebuild engines and they hone the cylinders but fail to use a ridge reamer.. and they replace the rings. so another theory is that that top comporession ring will not be worn in and they cylinder hone wont remove the ridge. the old ridge is rounded offf somewhat. the new ring is square, so although its only a minor amount , its basically a "collision"
the ridge can catch the edge , breaking the top compression ring. you can look up "ridge reamer"
was this a machine shop bored engine or was it a honed bore with new rings?

there may be some assorted theories on the best way to break in and angine and be successful at getting the rings to seal properly. please ask others before reacting to any of this or reading it as gospel.

if you do have broken rings I think it may not be easy to identify that. taking it apart for a look is obviously a lot of work. maybe yu could see obvious scratches in the bore or similar , I dont want to cause you to do stuff liek disassemble your engine only based upon my own , possibly questionable info.

I once broike a compressio ring by not using a proper tool and thinking I could just use a hose clamp rather than the proper ring compressor tool. It has been done.

When I did that I learned, No, one cannot buy only one piston ring.. I paid a hundred dollars for that little lesson, in the form of a new set of rings. ;-)

 

[jminor]

Interesting that you have a valve cover breather AND a draft tube. With the tube the VC can (should) have a non vented cap. The smoke is blow by, indicating rings are not sealing well. It's coming out of the VC breather and not the D tube because the VC is higher, an easier chimney for it to escape.

The valve cover breather was on the car when I bought it. Never occurred to me that it should NOT be there.

 

[sixtseventwo4d]

A cylinder leak-down test will help with a course of action.

When is the heaviest smoke produced? during warm-up? after warm-up? on acceleration or deceleration? Is it detectable at 30mph? at 50mph?
One of the worst things to do to an engine during break-in is idle it excessively with no load.
What temperature thermostat are you running?

 

[jminor]

do the plugs smell like gasoline when you foirst take them out?
it does sound like blow by , the smoke coming out of the valve cover area won't be caused by the carb causing it to run rich.

there might be some tips on breaking in the rings and Im nto sure Im the best to make those statements , but Id ry to accellerate at medium throttle and every minute or two take your foot off the gas and decellerate. the theory Ive been told is when you step on it, you are seating the rings and when decellerating you are allowing some oil on the bores..

its beter to ask others here about the subject, I am not an expert on that so take what others say into account.

I rememeber talking to an officiial volvo mechanic and I said my dads car is often hard to start, it was a 5 clinder engine. he figured that engine had an issue with the rings or glaze on the cylinders. and to partially cover the rad and then drive it up a steep hill , drive it hard, The idea was to try to break in the rings in again although it was not a new engine.
i
was one plug DIFFERENT than the others?

sometimes people try to rebuild engines and they hone the cylinders but fail to use a ridge reamer.. and they replace the rings. so another theory is that that top comporession ring will not be worn in and they cylinder hone wont remove the ridge. the old ridge is rounded offf somewhat. the new ring is square, so although its only a minor amount , its basically a "collision"
the ridge can catch the edge , breaking the top compression ring. you can look up "ridge reamer"
was this a machine shop bored engine or was it a honed bore with new rings?

there may be some assorted theories on the best way to break in and angine and be successful at getting the rings to seal properly. please ask others before reacting to any of this or reading it as gospel.

if you do have broken rings I think it may not be easy to identify that. taking it apart for a look is obviously a lot of work. maybe yu could see obvious scratches in the bore or similar , I dont want to cause you to do stuff liek disassemble your engine only based upon my own , possibly questionable info.

I once broike a compressio ring by not using a proper tool and thinking I could just use a hose clamp rather than the proper ring compressor tool. It has been done.

When I did that I learned, No, one cannot buy only one piston ring.. I paid a hundred dollars for that little lesson, in the form of a new set of rings. ;-)

The plugs do NOT smell like gas.
All of the plugs have same look and coatings. Wet and black.
The block / cylinders where all machined by my go to machine shop. Decked, bored out 20 over, new pistons made for it, new rings.
My next course of action is to put some miles on it. A lot of clear advice from the forum for process on the break in.
Again, a huge thank you for all of your time and advice.
I have learned a lot and will keep this thread up-dated on the progress.

 

[jminor]

A cylinder leak-down test will help with a course of action.

When is the heaviest smoke produced? during warm-up? after warm-up? on acceleration or deceleration? Is it detectable at 30mph? at 50mph?
One of the worst things to do to an engine during break-in is idle it excessively with no load.
What temperature thermostat are you running?

I just bought a new leak down tester and will go through the process after a few more miles on it.
The smoke is worst AFTER warm-up.
Speed does not seem to matter.
If I take my foot off the gas, the smoke gets worse,,,,,,If I then take it out of gear (three on the tree) the smoke goes away.
Thermostat temp = 180 degrees. The car idles and cruises at about 160 degrees.

 

[sixtseventwo4d]

It is running to cool. A fresh engine runs hotter during break-in, there is a lot more added friction with new rings and from the cylinders being honed. Many people are concerned about the rise in temp but it is temporary. A hotter thermostat should be used also. I would want the engine to be running a minimum of 180.

 

[Frank]

The valve cover breather was on the car when I bought it. Never occurred to me that it should NOT be there.

Understandable for sure. However, I would recommend a flat-cap non vented in place of the vented. It's possible the natural chimney-effect of the hot vapors rising and exiting the VC could cause the draft tube to become a source of air being drawn into the engine, not good since it's unfiltered. Also it keeps the oily mess off the top of the engine, and from smelling it in the vehicle.
This change won't solve the problem unfortunately, but will cause the system to operate as designed.

Last comment: run the engine hard to break it in. Somehow I grew up with the common notion to baby a new engine. I learned different when I got involved in commercial diesel overhaul. First fire-up after rebuild: One to two minutes idle to verify vitals, then the engine is "floored" to max governor speed in neutral for 20 minutes. Yikes! Then put directly back into normal service, moving a semi or heavy boat. I like your plan to just run it a while- be sure to include frequent WOT pulls- daily. No over-revving, just hard loading. My 240 full overhaul last year, with less than 2 hours on the engine I went to a rural country road and did repeated WOT take offs to 4500 rpm thru every gear and just general romping the gas in high gear winding it up from slow speed- for about 45 minutes. Normal driving since. To date the engine has used no oil-none- since initial start. There is a legit chance that hard running of your engine could clear and seat the rings.

Thanks for keeping us posted, best of luck with a resolution.
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