Blow by / Exhaust smoke
#1
Hi this is my first post here,
I have a 69 mach 1 351w, I have just started the car up for the first time in 1 year and the motor only had 500 miles on it from the previous owner.

Problem is there is smoke comming from both banks (light grey) the car and puffing out the breather, it runs clear for about a minute then it starts.
Had run for a while with not much let up with the smoke/ steam. The only thing I had done to the car was replace the pushrods with correct sizes as the ones they used were way to long for the roller set up this engine has, the motor sounds fine, though there is condensation which wont let up.

All head bolts have been checked for tension along with manifold just in case this had not been done by the previous ownners motor guy.
Besides the mechanical issues the car didnt blow smoke prior to its storage a year ago. I could conclude pcv, head gasket at a bit of a loss.SCo_hmmthink

Hope some of you pros can throw some sugestions

Thanks in advance
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#2
Hi...I am not clear on whether or not you are running a PCV valve. Are you? Also, is the smoke coming out of the tailpipe or just the breather cap or both? If you are not running a PCV it is not that uncommon to see some blow by through the breather cap. Since you did not notice it last time and you had stored the car for a year, you may just want to run the car a bit and see if it continues
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#3
(04-06-2014, 06:10 AM)Mustangmike Wrote: Hi...I am not clear on whether or not you are running a PCV valve. Are you? Also, is the smoke coming out of the tailpipe or just the breather cap or both? If you are not running a PCV it is not that uncommon to see some blow by through the breather cap. Since you did not notice it last time and you had stored the car for a year, you may just want to run the car a bit and see if it continues

Hi Mike.
Its coming from both the breather and pipes and I am running a std pcv set up. I lifted the valve covers off and they look fine inside same with the sump. checked all valve are moving up and down as they should no hang ups, and rollers are riding nice on the center of the valve tip. I did notice a distinct fuel smell in the oil, the plugs were powdery black sooted which did not ryme with a head gasket, but you never no. I have not changed carb or settings
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#4
Sounds like a real puzzle.

Are you running an automatic?

The transmission modulator valve could stick and suck transmission fluid into the vacuum system of the motor which would cause a light gray smoke.
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#5
(04-06-2014, 02:00 PM)Steven Harris Wrote: Sounds like a real puzzle.

Are you running an automatic?

The transmission modulator valve could stick and suck transmission fluid into the vacuum system of the motor which would cause a light gray smoke.

Good point Steve...
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#6
(04-06-2014, 02:00 PM)Steven Harris Wrote: Sounds like a real puzzle.

Are you running an automatic?

The transmission modulator valve could stick and suck transmission fluid into the vacuum system of the motor which would cause a light gray smoke.

Good tip, but shes a 4 speed..Regardless Ill drain the oil to prevent further mech damage, go with maybe some 30wt ? change out the pcv, check for further vac leaks, Oh did I mention its running a 4bb holley, maybe float is sticking leading to improper vac / crank case press, etc etc.:
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#7
Typical for a long-term stored engine. Fresh oil and just drive it. Very likely will stop within 50 miles.
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#8
Reading your post I noticed the comment of strong fuel smell in the oil. If you are still using a Mechanical fuel pump, it very likely could be a cracked diaphragm in the pump causing fuel to be pumped directly into the crankcase. The float could be sticking on the Holley or miss adjusted as this is a common condition for them. But your start ability would be compromised as well as you Idle quality both of which you had not mentioned having any trouble with. So I would probably suspect the fuel pump first. The smoke is very likely, as Kit mentioned a nuisance and will clear up after, repairing the cause of fuel in the oil, an oil change and some miles. Most likely cause is the diluted oil, dry cylinders, and from sitting for a year. Give us a few more details and maybe we can hone in a little closer on the diagnosis. JTS 71 Mach1
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#9
In your post, you mentioned driving 500 miles since the last owner.. Is that since the engine was rebuilt? If that is the case, the rings have or were not seated properly and it will have blow by. Perform a compression test on all cylinders after making the fuel issue repairs..
Hope this helps..
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#10
(04-08-2014, 10:24 AM)piper62j Wrote: In your post, you mentioned driving 500 miles since the last owner.. Is that since the engine was rebuilt? If that is the case, the rings have or were not seated properly and it will have blow by. Perform a compression test on all cylinders after making the fuel issue repairs..
Hope this helps..

This has been on my mind a bit too, though I dont recall it blowing smoke before storage, I will run a compression test as soon as ive finished with this other stuff.
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