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Exhaust road draft tube and oil filler smokes


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Hello All,

 

After searching around the forum for awhile I found a few things that could potentially be causing my smoking problems but I wanted to put it to the forum to get more of an idea of what I’ll be looking at in terms of what might need to be fixed and if it’d just be better to just tear down the engine completely or not. I’ll attach some video links to my YouTube so you can see what I’m seeing:

 

oil filler tube smoking (possibly bad rings?)

 

Smoke coming out of road draft tube while running

 

Overall view and some light revving to see smoke out of the exhaust

 

I was also curious about the state of my main pulley that wobbles all over the place. I’ve never really rebuilt too much of an engine, mostly carb work and minor tuning but not a full tear down so I just want to see what I’m probably going to get into to get the truck running correctly.
 

Here’s the wonky main pulley.

 

Thank you all for your expertise with the flathead and I look forward to your suggestions and help to get this 2-ton back on the road!

 

 

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The consistent smoke out of the fill pipe + blue smoke out of the exhaust tells me that ya have blowby + oil consumption, which puts that flathead on the parh to a rebuild.  Might be leaky valves from worn guides, might be worn rings from use or stuck rings from disuse.  Inspection of the internals is warranted...

 

The crank pulley might not be too bad, as long as the hub is true...might just be that the sheave got bent a little somewhere along the way, maybe somebody tried removing with a prybar instead of the proper puller.

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12 hours ago, JBNeal said:

The consistent smoke out of the fill pipe + blue smoke out of the exhaust tells me that ya have blowby + oil consumption, which puts that flathead on the parh to a rebuild.  Might be leaky valves from worn guides, might be worn rings from use or stuck rings from disuse.  Inspection of the internals is warranted...

 

The crank pulley might not be too bad, as long as the hub is true...might just be that the sheave got bent a little somewhere along the way, maybe somebody tried removing with a prybar instead of the proper puller.


JBNeal,

 

thank you! I likely figured that with that much smoke out of every end it wasn’t going to be good haha. It is an old farm truck from Idaho so it was likely used and abused for most of its life. I’ll get myself prepared for a rebuild. Thank you again for your input!

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I would change the oil and put in a quart of Marvel Mystery Oil with the fresh oil, it's pretty good at unsticking stuck rings and might help here.  I know it helped on my 218.  Letting these old engine set for years/decades has a tendency to cause things like this. 

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9 hours ago, Sniper said:

I would change the oil and put in a quart of Marvel Mystery Oil with the fresh oil, it's pretty good at unsticking stuck rings and might help here.  I know it helped on my 218.  Letting these old engine set for years/decades has a tendency to cause things like this. 


Would you also try to put some in the top of the cylinders or just let everything run through the oiling system? I’ll go buy some MMO tomorrow and some new oil. Any recommendations on oil since these engines are older? Like Delo or something with a higher zinc content?

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Is it smoke or water vapor??  If the engine doesn't get hot and stay hot for a good long period water from condensation can be the culprit rather than oil blow by.  Have you done a compression test lately??? That will give you a good indication of  ring and cylinder condition.

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On 3/8/2021 at 3:14 PM, greg g said:

Is it smoke or water vapor??  If the engine doesn't get hot and stay hot for a good long period water from condensation can be the culprit rather than oil blow by.  Have you done a compression test lately??? That will give you a good indication of  ring and cylinder condition.


it is definitely smoke, we’ve run it until it gets up to temperature and it smokes the whole way. I did a compression test and all cylinders were in the 90s or close to 100 at least. I’m going to do another compression test and see if it’s one cylinder or if all of them are similar. If they’re similar it could just be that the engine is just fairly worn out and needs a rebuild anyways. If you get a chance to look at the YouTube links it looks like blow by as the filler tube has lots of air moving out of it.

 

I will try an oil change and some MMO to try and see if that helps anything and then if that doesn’t work and the compression test doesn’t turn anything up then I’ll need to tear things down I’m afraid.

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On 3/7/2021 at 8:57 PM, Haydenh said:


Would you also try to put some in the top of the cylinders or just let everything run through the oiling system? I’ll go buy some MMO tomorrow and some new oil. Any recommendations on oil since these engines are older? Like Delo or something with a higher zinc content?

 

You could put some MMO in the top, let it set awhile.  As for zinc, that's a function more of valve spring pressure than anything else and we have virtually no valve spring pressure to speak of.  My research has led me to decide that for me regular oil is just fine.  More zinc won't hurt though,

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Has any one come up with a date that zddp was first added to motor oils.  In looking on several sites regarding this I have found no information as to when it became common.  I believe the issue came up fairly recently where folks who were swapping to high performance after market cams (read offshore roducts with iffy metalurgy) started complaining about rounding off their cams after just a couple months of installation.  In 46 oil was basically oil with some anti foaming stuff, not a blend of viscosity stabilizers, friction modifiers, rust inhibitors, anti foaming, enhanced surface tension enhancers,etc.  

 

Withour original cams, 35# springs and occasional operation, I am also in the camp where the amount of zinc isn't much not an issue.  If you are worried and have installed a new cam, then half a can of STP with your oil change is probably all you need.

Edited by greg g
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Do a good solid compression test on each cyl. Above I read you checked a couple?

 

Mine smokes almost like yours does. It sat for a long time. My compression test showed a few cyl 100-115 couple @90+  then one was 60 another 75.

I used the mmo in the cylinders to soak the rings. Let it sit for a week or 2 while doing other projects. Run the engine awhile then compression check again.

Now all cyl are 100-115 except the worse one, is now 85 or 95 ... need to check again. Still smokes some like your.

 

I am told the smoke from the road draft tube, breather cap is blow by. Usually caused by worn or stuck rings.

Rings need to spin on the piston in the grooves when working properly. After sitting long periods, they get stuck and no longer spin, work properly.

mmo in the cyl will help loosen them. I also am told, the engine likes to be driven in it's power band ...nice long drive 35-40 mph to get everything loosened up. Not just sit and idle in the driveway. Thats what I am waiting for as a final attempt for it to clear itself up.

 

If your compression test shows all the cyl within 15# of each other, good chance you need a ring job. Just worn out.

Back in the day, could drop your truck off at the local gas station and get a ring job done in 1 day.

Pull the head, drop the pan, remove pistons/rods. hone the cylinders, install new rings ... over sized rings if needed, new bearings inspect the valves.

May take 2 days if valve job was needed.

Was just common maintenance back then to do rings/valves. Poor materials, rings wore quickly.  Still need to inspect the wear on the cylinders.

 

 

 

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5 hours ago, greg g said:

Has any one come up with a date that zddp was first added to motor oils.  In looking on several sites regarding this I have found no information as to when it became common.  I believe the issue came up fairly recently where folks who were swapping to high performance after market cams (read offshore roducts with iffy metalurgy) started complaining about rounding off their cams after just a couple months of installation.  In 46 oil was basically oil with some anti foaming stuff, not a blend of viscosity stabilizers, friction modifiers, rust inhibitors, anti foaming, enhanced surface tension enhancers,etc.  Without original cams, 35# springs and occasional operation, I am also in the camp where the amount of zinc isn't much not an issue.  If you are worried and have installed a new cam, then half a can of STP with your oil change is probably all you need.

 

First response to an internet search:

ZDP (Zinc dithiophosphate) in the range of 0.03 percent was first added to engine oil more than 60 years ago to control bearing corrosion. In the mid 1950s, Chrysler and Oldsmobile engaged in a horsepower race using high-lift camshafts, and both experienced camshaft scuffing and wear problems

So, yes spring pressure, cam profile and RPM created the need.  But it wasn't hot rodders or imported parts that caused it.  Well, not exactly, it was factory hot rodders.

 

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  • 2 weeks later...

Well folks,

 

I finally got around to doing a compression test and added some MMO afterwards and I’ll do a compression test for the next couple weekends and see if the numbers change. 
 

             1.       2.       3.      4.       5.       6.   
 

Dry.     85    110     100     90     90     90

 

 

Wet.   100    130    155   125    140   145

 

 

 

i guess let me know if you have some insight from the numbers and whether or not I’ll need to pull things apart and do a rebuild. I’m still figuring things out with this engine since it’s not the original to the truck. Thank you in advance and for your help so

681C72BA-F93C-4B65-828A-348BFC93A516.jpeg

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That motor seems OK to fire up with those compression #'s.

 

Change oil before and filter if one, check for spark, fix as needed plugs out, add fuel from container line to fuel pump intake line ,  check flow to carb Crank again-plugs out to check oil pressure with cranking only -also fuel flow to carb. disconnected from carb from line. to a catch container. reconnect if good.

15+ psi oil psi. and put it all together- prime carb with gas from  can/squirt bottle/ start fluid (small amount only) - -good luck! Hope she starts up after new plugs installed.

 

Enjoy!

 

Do not worry about smoke for a while after starting. Watch temperatures.

 

DJ

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5 hours ago, DJ194950 said:

That motor seems OK to fire up with those compression #'s.

 

Change oil before and filter if one, check for spark, fix as needed plugs out, add fuel from container line to fuel pump intake line ,  check flow to carb Crank again-plugs out to check oil pressure with cranking only -also fuel flow to carb. disconnected from carb from line. to a catch container. reconnect if good.

15+ psi oil psi. and put it all together- prime carb with gas from  can/squirt bottle/ start fluid (small amount only) - -good luck! Hope she starts up after new plugs installed.

 

Enjoy!

 

Do not worry about smoke for a while after starting. Watch temperatures.

 

DJ


hey Dj,

 

so curiously enough the engine runs already  but it just stumbles a bit even after I rebuilt the carb. The original post I had at the top has links to the short clips on YouTube so you can see the blow by I’m getting out the draft tube and the oil filler neck. That was my original concern was that it would run just fine but that it seemed like a lot of blow by was happening.

 

that being said, that’s great to know the compression numbers aren’t too bad. I don’t know if that means that the rings are just seized on the piston or not or if there’s some other cause for the blow by. Thank you for your help and information!

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Sorry Hayden, I am no help. it looks like a fuel mixture issue to me. Guess I see a little blow by at the idle.... but nothing I’d worry about.

if it were me, I’d make sure the valves were set, the fuel mixture is correct, vacuum time it and work on the brakes. 😊

 

but, I am not a mechanic and I’m going blind, so ignore what I just said,  LOL

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Posted (edited)
22 hours ago, Brent B3B said:

Sorry Hayden, I am no help. it looks like a fuel mixture issue to me. Guess I see a little blow by at the idle.... but nothing I’d worry about.

if it were me, I’d make sure the valves were set, the fuel mixture is correct, vacuum time it and work on the brakes. 😊

 

but, I am not a mechanic and I’m going blind, so ignore what I just said,  LOL


Brent,

 

thank you, any idea on how to adjust the fuel mixture with non-adjustable main jets? I read somewhere that someone said to braze the main jet in and drill a new one smaller. I don’t know if that’s the correct path to go or if there are some different jets for these old b & b carbs. I did reach out to Holley to inquire about their Sniper EFI stuff since where I currently live is about 2,900’ but I regularly drive up to the mountains up around the 10,000’ elevation and was thinking it’d be great to take the old truck up there sometime so the adjustability would be fantastic. The price tag is just a little high for that.

 

I’ll have to look up vacuum timing as I’m learning a lot of “new” old skills! I’ll have to get some feeler gauges to do the valve adjustments.

 

brakes will be slowly coming along and then some tires and some minor electrical work to get the signals working before setting off into traffic haha

 

 

 

Edited by Haydenh
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21 hours ago, JBNeal said:

Those compression numbers look good, so I repeat my original assessment that oil may be getting through worn valve guides.


JB,

 

Any idea on how to pinpoint a worn valve guide? Just get into the valves and wiggle things around to see what’s loose?

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There is probably a specification somewhere in the shop manual but with the valve spring removed, I would rock the valve back and forth, and if it rattled around, it was too worn...usually there are several worn at a time, so I just do them all to keep them matched...the last time I replaced valve guides, the valves were also visibly worn, so those were replaced too.  I had new valve + guide combos sitting on the shelf, so the new vs old comparison was striking on my last rebuild.  Cannot remember where I read it, but found that if valve spring surfaces are not smooth, such as having rust spots from extended period of disuse, then the springs are weakened and need replacing.

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The idle mixture screw 
33D51E54-1F3F-4778-9315-36A3D0D306C8.jpeg.a5383d846c89223ba44a6ef6e7f77c5c.jpeg

 

I replaced the valves and guides on my 1ton 

Using the air hammer is always soooo satisfying. 😊

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50 minutes ago, JBNeal said:

There is probably a specification somewhere in the shop manual but with the valve spring removed, I would rock the valve back and forth, and if it rattled around, it was too worn...usually there are several worn at a time, so I just do them all to keep them matched...the last time I replaced valve guides, the valves were also visibly worn, so those were replaced too.  I had new valve + guide combos sitting on the shelf, so the new vs old comparison was striking on my last rebuild.  Cannot remember where I read it, but found that if valve spring surfaces are not smooth, such as having rust spots from extended period of disuse, then the springs are weakened and need replacing.


i keep forgetting about the shop manual sitting on my shelf! I need to whip that out and go for it! I’ll give the guides a check sometime here in the next couple weeks and see if they’re in spec and also if the guides are worn or not. I’ll likely need to jack up the truck and remove the front wheel to get at the valves easily since the bigger trucks fender is very high off the ground! Not an easy way in there behind that huge tire! Thank you for your help! 😁

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12 minutes ago, Brent B3B said:

The idle mixture screw 
33D51E54-1F3F-4778-9315-36A3D0D306C8.jpeg.a5383d846c89223ba44a6ef6e7f77c5c.jpeg

 

I replaced the valves and guides on my 1ton 

Using the air hammer is always soooo satisfying. 😊


thank you for the photo/info. I’ll have to break out my manual to make sure I turn the screw I’m thinking of but I think it’s definitely very rich so leaning it out substantially will probably be a good idea. I’ll have to go pickup a vacuum gauge and figure out where to plug it in to get the best reading and then have at it!

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