White smoke troubleshooting

[scenic760]

The hits keep on comin'!

Quick history is that the engine was rebuilt by someone I don't have a lot of faith in...I have basically broke in the cam and put about 5-10 miles on the truck and started having all kinds of other issues (the truck sat for 5 years)...

One issue from the beginning was white smoke coming from the exhaust about 20-30 secs after startup...I though I might be having ATF getting sucked into the intake but didn't see any in the modulator line..I pulled the radiator cap and I'm definitely losing coolant.. with that being said, I know I'm at least going to need to pull the exhaust manifold the check for leaking but is there any other tests/indicators I can perform without disassembling anything at this point?

I'm hoping I installed the intake gasket incorrectly rather than having a head gasket problem with 10 miles on the engine...but as mentioned previosly I don't have a lot of faith in the rebuild

 

[SirRobyn0]

Well, white smoke is moisture. A video of it smoking would be really helpful, for one thing guys like me that have seen this lots of times before can tell the difference between water vapor and coolant being burned by how the smoke bellows.

Sometimes if enough oil is sucked into the combustion under the right conditions it can look white. Smell wise oil smoke will smell oily and coolant will smell sweet.

Assuming it's coolant you really only have a few choices. head gasket, or crack in block or crack in head. Maybe... Possibly intake gasket, but really on a SBC I just don't see that being likely.

If you can get hold of a block tester you could find out if there are hydrocarbons in the radiator and that would confirm an internal issue.

 

[WP29P4A]

My son had his cooling system pressure tested at the radiator shop where he works, based on that test, they found a leaking intake gasket. They replaced it, redid the pressure test to verify no more leaks. Cheap easy test. This test might help narrow down the location of your problem, if its coolant related. Just a thought.

 

[scenic760]

Well, white smoke is moisture. A video of it smoking would be really helpful, for one thing guys like me that have seen this lots of times before can tell the difference between water vapor and coolant being burned by how the smoke bellows.

Sometimes if enough oil is sucked into the combustion under the right conditions it can look white. Smell wise oil smoke will smell oily and coolant will smell sweet.

Assuming it's coolant you really only have a few choices. head gasket, or crack in block or crack in head. Maybe... Possibly intake gasket, but really on a SBC I just don't see that being likely.

If you can get hold of a block tester you could find out if there are hydrocarbons in the radiator and that would confirm an internal issue.

Thanks Rob!

I will grab a video once the rain stops out here...at the risk of exposing my inexperience, I had never seen/used a block tester before. It looks like I can borrow one from the local Autozone and get some fluid for it.

Thanks again!

 

[scenic760]

Here is a video link...it seems as though the smoke starts at about 1 minute in...smells like it running rich BTW...also stepping back and listening to the video it almost sounds like a rod knocking (I though that was the smog pump noise)

PXL_20220329_020357966.mp4

drive.google.com

 

[scenic760]

My son had his cooling system pressure tested at the radiator shop where he works, based on that test, they found a leaking intake gasket. They replaced it, redid the pressure test to verify no more leaks. Cheap easy test. This test might help narrow down the location of your problem, if its coolant related. Just a thought.

If the block method comes up negative that is going to be my route...the block test is going to cost me $8 for the testing solution..

 

[SirRobyn0]

@scenic760 For just eye balling the smoke it doesn't really look like coolant or oil to me. It looks more like normal moisture in the exhaust being vaporized. This vapor can be more obvious on a older rig with an air pump and catalytic converter. Let me ask you some questions?

How much run time you have on the engine?
You did say it was just raining right?
Does it have a catalytic converter?
What happens if you run it for a bit say 20 or 30 minutes?

My gut instinct and I could be wrong (you'll need to do more testing), but my gut tells me that your not loosing coolant out the tailpipe, as in not burning it. You could have a coolant leak that is small, and just not making it to the ground. If you don't have much run time on the engine you might have had some trapped air that came out, which causes the coolant to drop. You'd add coolant and it would be fine after that if that is the case.

Since you mentioned you don't have a lot of repair experience, to things. Don't worry about looking in experienced we all started out that way. You can also likely borrow a pressure tester, when you are barrowing / renting the block tester. If you need how to's for using either tester let me know and I will do my best to help.

 

[scenic760]

Thanks Rob!

I did the block test and it was negative so I think your gut is on to something!

To answer your questions:
How much run time you have on the engine?
-I broke in the cam and have probably driven it for about 5-10 miles before the trans started slipping pretty bad
You did say it was just raining right?
-Yeah, the one day a year it rains in Socal...torrential downpour for these parts, I think we got an inch yesterday
Does it have a catalytic converter?
-Yes, and it looks original, haha
What happens if you run it for a bit say 20 or 30 minutes?
-The 20 or 30 minutes I have let it run seem to diminish the smoke.

I haven't had a chance to actually get out and run it because the transmission (which I rebuilt while everything else was out of the car) keeps slipping after about a minute or two of driving around...

I appreciate your patience and expertise!!

 

[SirRobyn0]

Thanks Rob!

I did the block test and it was negative so I think your gut is on to something!

To answer your questions:
How much run time you have on the engine?
-I broke in the cam and have probably driven it for about 5-10 miles before the trans started slipping pretty bad
You did say it was just raining right?
-Yeah, the one day a year it rains in Socal...torrential downpour for these parts, I think we got an inch yesterday
Does it have a catalytic converter?
-Yes, and it looks original, haha
What happens if you run it for a bit say 20 or 30 minutes?
-The 20 or 30 minutes I have let it run seem to diminish the smoke.

I haven't had a chance to actually get out and run it because the transmission (which I rebuilt while everything else was out of the car) keeps slipping after about a minute or two of driving around...

I appreciate your patience and expertise!!

Right sorry I forgot the bit about the transmission. My personal feeling is that what you are seeing is normal. Now it would help if I could stand there with you when you fire it up next but since that's not going to happen.

In general, if there is a head gasket leak or block problem causing coolant to get into the combustion chamber, usually the longer you run the engine the worse it will get, or it'll get worse to a point and then stay at that level, but not get better the longer you run it. And your smoke gets better with continued run time. Coolant burning smells sweet and the smoke is usually thick and bellowing and hangs in the air much longer than water vapor. I think what you are seeing is just normal water vapor. Any vehicle can have this happen, new or old. If moisture gets into the exhaust it will steam off, as the engine pumps hot exhaust gas though the pipe. BUT a vehicle with a carburetor and a catalytic converter and air pump maybe more prone to it. I say maybe because this is based on my observations not anything scientific, But during cold operation the choke is shut and the mixture rich, that rich mixture hits the cat and if the cat has warmed up enough to function it can cause some water vapor smoke, plus whatever maybe in the exhaust system already.

My vote is what you are seeing is normal, moisture being burned off.

 

[SquareRoot]

What transmission? Same thing recently happened to my mother. Had a new engine built, dad takes it out a few days later and "gets on it" and white smoke starts pouring out the pipes. The look on her face was she just s**t herself or she was going to die in disbelief. They thought they blew the new ol' girl up. Took it back to the shop that built the motor. An hour later they say the car is ready. Turns out the vacuum modulator on the trans went **** up and sucked ATF into the manifold. Just sayin..


UPDATE. Nevermind, I just reread your original post. I see you have already looked into that. Carry on

 

[SirRobyn0]

What transmission? Same thing recently happened to my mother. Had a new engine built, dad takes it out a few days later and "gets on it" and white smoke starts pouring out the pipes. The look on her face was she just s**t herself or she was going to die in disbelief. They thought they blew the new ol' girl up. Took it back to the shop that built the motor. An hour later they say the car is ready. Turns out the vacuum modulator on the trans went **** up and sucked ATF into the manifold. Just sayin..


UPDATE. Nevermind, I just reread your original post. I see you have already looked into that. Carry on

As I was reading your post I was trying to figure out how you were going to tie in a transmission problem on what is probably a TH400 to white smoke. You sure had me going, I was thinking what did I miss lol.

 

[scenic760]

What transmission? Same thing recently happened to my mother. Had a new engine built, dad takes it out a few days later and "gets on it" and white smoke starts pouring out the pipes. The look on her face was she just s**t herself or she was going to die in disbelief. They thought they blew the new ol' girl up. Took it back to the shop that built the motor. An hour later they say the car is ready. Turns out the vacuum modulator on the trans went **** up and sucked ATF into the manifold. Just sayin..


UPDATE. Nevermind, I just reread your original post. I see you have already looked into that. Carry on

I'll take any help I can get!!

So after thinking about this a little more...I did "modify" 3 things when I put the trans back together (1) hardened outer race (2) 5 clutch piston (and I did indeed put in the 5 clutches, haha) and (3) dual feed by leaving off seal on direct, ring off pump and plug reverse feed.. I remember checking the thickness on the piston and clearance on the clutches when I was putting it together and all was good...

One thing I'm not sure about, thinking back, is the separator plate. Is it possible that someone had previously installed a shift kit and in conjunction with my dual feed mods is causing the slipping? Honestly, I would have had no idea what I was looking at if the separator plate was or was not original...

 

[SirRobyn0]

I am not a transmission guy, but @Matt69olds is, he maybe able to answer your tranny questions.

 

[scenic760]

I am not a transmission guy, but @Matt69olds is, he maybe able to answer your tranny questions.

Received Sir! Thanks much for your direction!

I have another thread open that it would probably be more appropriate to send a shout out in.

 

[SirRobyn0]

Oh well, I just shouted him to this thread. I see Matt and several others have posted in your trans thread. Good luck!