Fresh Rebuild Problems
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Fresh Rebuild Problems
Hello everybody Im new to the forum and am looking for some advice. First a little background on the truck. I am rebuilding a 66 f100 with a 352 bored 30 over. Had a valve job done, put Comp Cams 268h camshaft new timing chain hydraulic lifters and new push rods. The crank was turned and all new bearnings put in for cam and crank. New oil pump new fuel pump. I added a edelbrock performer intake and 600 carb. Also headers and dual exhaust. Now ive got the truck running but have white smoke coming from drivers side exhaust and plugs are getting black and wet. I have about 125 to 130 compression on all cylinders. Vacuum is running at idle about 11inches and wants to go up and down about an inch or so. If I advance timing way advanced to 30 or so btdc smoke seems to go away and plugs dry out???!!! Also vacuum hovers at about 16 or 17. Am I doing something wrong? This is my first rebuild so Im not sure what to do from here. Any help would be greatly appreciated. Thanks
Laughing Gas
Joined: Dec 2010
Posts: 1,091
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From: Tucson, Arizona
I consulted my FE engine diagnostic book, and two possibilities show up - blowby caused by a clogged or malfunctioning PCV system - or a blown or incorrectly installed cylinder head gasket. Even though your engine is newly rebuilt, mistakes in the process have been known to happen. Head gasket installation is a particularly notorious one. Good luck.
Elder User
Joined: Feb 2014
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From: Florida
White smoke (steady, like a crop duster) is typically a sign of anti-freeze burning in the exhaust. Smell the exhaust (carefully). Does it have sort of a sweet smell? Check your levels...coolant and oil, and also the color of both. I hate to say it but it does sound like head gasket. Why the smoke clears when you advance timing is a bit odd....
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Tuned
Joined: Feb 2014
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When the valve job was done was the head pressure checked for cracks ? if they were then I would lean towards a head gasket problem on that bank . Pressure check the cooling system on the engine after it has warmed up to operating temp ..... Just be very careful removing the radiator cap . if you lose pressure .... pull that head .
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Thanks for the input. I had no idea a pcv valve could make such a difference. I just picked one off the shelf that looked right. I'll switch that out first to see if it helps. Also as far as a head gasket wouldn't that show up in a compression test?
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well I replaced pcv valve. and it made no change. tested pressure of cooling system and it seems to have a slow leak. driver side exhaust blows smoke and is moist. black residue when I put my finger inside exhaust also what looked to be like oil??? Next I pulled the header and all cylinders are clear on that side accept #7 which was wet black and sticky. I guess I have to tear the top end and replace the head gasket. Looks like I'll have a good Friday afternoon. Gotta order gaskets
Elder User
Joined: Feb 2014
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From: Florida
well I replaced pcv valve. and it made no change. tested pressure of cooling system and it seems to have a slow leak. driver side exhaust blows smoke and is moist. black residue when I put my finger inside exhaust also what looked to be like oil??? Next I pulled the header and all cylinders are clear on that side accept #7 which was wet black and sticky. I guess I have to tear the top end and replace the head gasket. Looks like I'll have a good Friday afternoon. Gotta order gaskets
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Joined: Jan 2012
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From: Andale,KS
"Black Residue" -- not sure but this could just be a rich mixture. You said cooling system "seems" to have a slow leak. If it does and you don't see anti-freeze leaking externally, sure sounds like issue with head gasket or head at cyl #7. When you had the valve job done, did they mill or deck the head at all? Did they check for hairline cracks between valves? There are valve jobs and then there are valve jobs...just saying.
Did they replace the valve guides? If so they might not have gotten the fit correct and water could be leaking around them? or cracked the head. Have the head pressure checked or mag checked for cracks before you put it back on. Good luck
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I don't know if the head was checked for hairlines. I was lind of ignorant to the whole process as this is my first build. I guess I will have to call and find out. Here is the list of what he says was done.
1. Disassemble and qualify parts 2. Glass bead and clean
3. Valve job- competion 4. New valve seals
4. Surface heads
5. Assemble and blueprint springs
So I guessing no it was not checked????
Also as far as a rich mixture I have tried to set the mixture a number of times to see if it would make any difference with no results. That had entered my mind could there be an issue with my carb?
1. Disassemble and qualify parts 2. Glass bead and clean
3. Valve job- competion 4. New valve seals
4. Surface heads
5. Assemble and blueprint springs
So I guessing no it was not checked????
Also as far as a rich mixture I have tried to set the mixture a number of times to see if it would make any difference with no results. That had entered my mind could there be an issue with my carb?
Elder User
Joined: Feb 2014
Posts: 713
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From: Florida
I don't know if the head was checked for hairlines. I was lind of ignorant to the whole process as this is my first build. I guess I will have to call and find out. Here is the list of what he says was done.
1. Disassemble and qualify parts 2. Glass bead and clean
3. Valve job- competion 4. New valve seals
4. Surface heads
5. Assemble and blueprint springs
So I guessing no it was not checked????
Also as far as a rich mixture I have tried to set the mixture a number of times to see if it would make any difference with no results. That had entered my mind could there be an issue with my carb?
1. Disassemble and qualify parts 2. Glass bead and clean
3. Valve job- competion 4. New valve seals
4. Surface heads
5. Assemble and blueprint springs
So I guessing no it was not checked????
Also as far as a rich mixture I have tried to set the mixture a number of times to see if it would make any difference with no results. That had entered my mind could there be an issue with my carb?