Smoke troubles

[Elmomo]

Hello everyone I bought my 79 bronco two months ago and since then have added a few new parts and everything works fine, except for after running it for a little bit, the oil pressure begins to drop and after a certain point bluish smoke starts to come out the exhaust when idling not so much when driving but oil pressure continues to be low I can’t seem to figure it out Would really appreciate some help on this. it has a 351M and everything else seems to run in normal order plus old owner claims it has 83,000 miles original so I’m just hoping it’s nothing too bad! Thanks again for the approval and looking forward to being part of the community

 

[L\Bronco]

Hey Elmomo!
Welcome to the zone!
That is a nice looking Bronco!
Best year ever!
That mileage is insanely low!
Good find!(If its real)
a couple questions first:
Did it sit in storage for a long time?
What oil is currently in it?
When the oil pressure is low, are there any ticking or knocking noises from the engine at idle?

Cheers

 

[Elmomo]

Hey Elmomo!
Welcome to the zone!
That is a nice looking Bronco!
Best year ever!
That mileage is insanely low!
Good find!(If its real)
a couple questions first:
Did it sit in storage for a long time?
What oil is currently in it?
When the oil pressure is low, are there any ticking or knocking noises from the engine at idle?

Cheers

Hey and no I’ll post a picture of the condition I found it in and 10w 40? Is what was recommended at the store and was wondering myself if I should switch it out again to something thicker? Also it was not smoking before only till after tuneup was done And no there is absolutely no knocking or ticking noise engine sounds nice and strong oh and before the 10w40 they gave me 10w30 so now it has 10w 40 and an additive they recommend I rebuilt the carburetor did spark plugs, water pump, power steering pump, spark, plug cables, oil filter carburetor was rebuilt after it was already smoking

 

[L\Bronco]

Very cool find!
10w40 should be fine. (They originally had 10w30)
It might have stuck oil control rings from sitting.
You could try adding a bit of either Marvel mystery oil or sea foam to the crankcase (with the oil) plus some in the gas (for a couple tank fulls) It occasionally frees up stuck rings.

Theres no chance it has stale gas in the tank is there?

Could be a lot of things.
One step at a time
Cheers

 

[johnnyreb]

Welcome to the club Elmono. Nice looking bronco. You might want to check the hos that comes out of your LEFT valve cover. Pull it out ans check for moisture and smoke. . Check the PVC VALVE . The PVC valve might be stopped up and they will cause on to smoke. They are good about it . I change them every once in awhile.

 

[lynchsg]

Good project. I like Marvel Mystery oil in the oil and squirt some in each cylinder through the spark plug holes. You'll need to clean or change the plugs after you run the engine after the cylinder oil treatment (hold the revs high and squirt some more Marvel Mystery oil down the carburetor).
You also mentioned you rebuilt the carburetor. Is the choke working properly and not sticking partially closed?
Low oil pressure; if no ticking or knocking:
Are you basing your PSI reading on the stock dash gauge and sending unit? If so, try a mechanical gauge setup to verify the PSI reading.
If any ticking or knocking at idle or even if you do verify low oil pressure without ticking or knocking, you could have a partially plugged oil pump pick up screen in the oil pan. This can be verified without dropping the pan using a bore scope through the oil drain plug with the oil drained. Just some suggestions.
Ultimately some of the symptoms you mentioned sound like an engine in need of a refresh. Valve job (including valve stem seals and maybe guides), cylinder hone, rings, and gasket set.

 

[Elmomo]

Good project. I like Marvel Mystery oil in the oil and squirt some in each cylinder through the spark plug holes. You'll need to clean or change the plugs after you run the engine after the cylinder oil treatment (hold the revs high and squirt some more Marvel Mystery oil down the carburetor).
You also mentioned you rebuilt the carburetor. Is the choke working properly and not sticking partially closed?
Low oil pressure; if no ticking or knocking:
Are you basing your PSI reading on the stock dash gauge and sending unit? If so, try a mechanical gauge setup to verify the PSI reading.
If any ticking or knocking at idle or even if you do verify low oil pressure without ticking or knocking, you could have a partially plugged oil pump pick up screen in the oil pan. This can be verified without dropping the pan using a bore scope through the oil drain plug with the oil drained. Just some suggestions.
Ultimately some of the symptoms you mentioned sound like an engine in need of a refresh. Valve job (including valve stem seals and maybe guides), cylinder hone, rings, and gasket set.

Hello and thank you for replying to my thread. I have been pretty busy and hadn’t had a chance to get back on here appreciate all the tips! so I ended up taking the valve cover off because I had a suspicion. It was one of the cylinders on the right hand side of the motor Because cylinder number five was sweating a little oil so once opened up, I realized that cylinder had a bent push rod so bad it came out of place, therefore no more working valve so ended up replacing all the push rods and rocker arms on both sides of engine and now engine runs perfectly fine no more smoke no more misfires an engine sounds beautiful at high speeds like it should appreciate everybody’s help in the process! next up heater core leak

 

[lynchsg]

Good find and good luck with the process...

 

[L\Bronco]

Hello and thank you for replying to my thread. I have been pretty busy and hadn’t had a chance to get back on here appreciate all the tips! so I ended up taking the valve cover off because I had a suspicion. It was one of the cylinders on the right hand side of the motor Because cylinder number five was sweating a little oil so once opened up, I realized that cylinder had a bent push rod so bad it came out of place, therefore no more working valve so ended up replacing all the push rods and rocker arms on both sides of engine and now engine runs perfectly fine no more smoke no more misfires an engine sounds beautiful at high speeds like it should appreciate everybody’s help in the process! next up heater core leak

Good find! Glad it worked out for you!
Cheers