Smoke coming from driver side pipe - Good and bad news

[Fman]

Hi all, hope everyone is doing well...

Looking for some insight on what this problem could be, I am just a weekend hack mechanic on my best day so any guidance or input would be appreciated!

My car was completed back in April 2021, has 6500 miles on a dart block 427, EFI. Oil has been changed approx every 1000-1500 miles (annually). Car has always run great, no overheating issues, good oil pressure, etc... Recently over the past couple weeks I have noticed smoke out the drivers side pipe when accelerating and decelerating at higher rpms. The passenger side pipe is completely clear. If the car sits over night I will also get a brief puff of smoke upon a cold start out only the drivers side pipe. Once engine is running when idling there seems to be no smoke at all. The color of the smoke is blue-ish, definitely contains oil (see troubleshooting below). Passenger side pipe is always clean in all driving circumstances.

Ok, so here is what I have done so far.

Pulled all the plugs - The drivers side were in terrible condition, black, gummed with oil residue (see pics below). Infact I was shocked the car was actually even able to run. The passenger side also looked like it has heavy carbon on them definitely on the rich side. I am assuming these plug conditions indicate oil getting into the cylinders and burning off.

Replaced all the plugs with Autolite 3924's (what was installed by my engine builder)

Compression test - All cylinders came back at 210-220 psi

Intake manifold - Checked all bolts, they were definitely loose (under 10 ft lbs). Re torqued to 22 ft lbs.

PCV - Eliminated it, now just running two breather caps and plugged off the intake port where PCV was previously hooked up.

Went for a test drive this morning and same results, nothing has changed with the above tweaks. Car runs fine just smokes out drivers side pipe as described above.

My next move is to do a leak down test this week, have the tool on order.

I am hopeful it is not bad rings but my gut is telling me this might be the problem seeing as it happens under hard accelleration and deceleration. My other take is could it be the intake manifold (seeing as bolts were loose) is somehow allowing oil to enter into the valves/cylinder, and then there is also valve guide stem seals. What is really odd to me is how its only happening on one side of the car. If anyone has any constructive input/recommendations they could give me I am all ears. At this point I feel like the leak down test will give me some more information.

Thanks for reading.... Travis

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[Mike.Bray]

Bad intake valve seal?

[cc2Arider]

Hey Travis,

Sorry to hear about your engine woes

You wrote that all the cylinders seemed about the same for compression pressure. I'm with Mike on this one -- valve guide seals. One simple test you can perform before you get your leakdown kit is to inject a small amount of lightweight oil (equal amount) into each combustion chamber before performing another compression test. I've got a glass syringe for this kind of thing (also to prep motorcycle engines for seasonal storage)...

The theory is that the additional oil will help the rings seal (better) temporarily, and if your compression goes up, then it is an indication of worn rings...

You pictures seemed to show # 8 as worse than the others (hard to see for sure). Is that what you observed?

Craig C

[Fman]

Bad intake valve seal?

Mike, if this was the case and the seals were bad can they be changed without pulling off the head?

Hey Travis,

Sorry to hear about your engine woes

You wrote that all the cylinders seemed about the same for compression pressure. I'm with Mike on this one -- valve guide seals. One simple test you can perform before you get your leakdown kit is to inject a small amount of lightweight oil (equal amount) into each combustion chamber before performing another compression test. I've got a glass syringe for this kind of thing (also to prep motorcycle engines for seasonal storage)...

The theory is that the additional oil will help the rings seal (better) temporarily, and if your compression goes up, then it is an indication of worn rings...

You pictures seemed to show # 8 as worse than the others (hard to see for sure). Is that what you observed?

Craig C

Hi Craig, I feel like 210-220 is a good solid consistent pressure for compression. Question(s) for you... if I had a bad ring would it be pretty evident on the compression check? all the readings are pretty close to each other. If I do add oil to see if this changes any of the readings should I wait until after the leak down test is performed? Not sure if the oil would affect the leak down test? Yes, cylinder 8 was definitely the worse of all of them. As you can see in the pics the drivers side is much worse than the passenger side.

[Jeff Kleiner]

It could most definitely be pulling oil into the intake ports on one or more cylinders due to a failed manifold gasket. Got a boroscope? If so pull the carb (throttle body in the case of your PF4) and snake it through the manifold to look at the intake ports…if you see evidence of oil upstream of the valve it eliminates rings, guides or calve seals as the culprit and points to the intake manifold gasket.

Jeff

[Fman]

It could most definitely be pulling oil into the intake ports on one or more cylinders due to a failed manifold gasket. Got a boroscope? If so pull the carb (throttle body in the case of your PF4) and snake it through the manifold to look at the intake ports…if you see evidence of oil upstream of the valve it eliminates rings, guides or calve seals as the culprit and points to the intake manifold gasket.

Jeff

Jeff, that is a great idea! Yes I have a cheap Amazon boroscope that should do the job. I think I will try the leak down test first then if all goes well give your idea a try. I have been in contact with my engine builder and he thinks this might be the problem (intake). He said he has never had rings or valve guide seals fail at 6500 miles. I guess anything is possible... fingers crossed.

[bobl]

I have to agree with Jeff. It's very likely the intake gasket allowing oil to be sucked in from the valley. I also suspect the oiling problem is causing incorrect A/F readings, the ECU is trying to correct it resulting in the plugs fouling.

Bob

[CraigS]

You had intake bolts that were super loose. I'd drain the coolant and pull the intake. Have new gaskets and a stud kit ready to go. If you had bolts and change to studs and nuts you will be surprised at the difference. Once reinstalled warm the engine fully and let it cool and retorque the nuts. Now you can drive it but kind of gently and retorque cold until the nuts don't move any more. This can take 5-6 cycles.

[narly1]

If you had bolts and change to studs and nuts you will be surprised at the difference.

From personal experience I can tell you that manifold studs are a superior solution to bolts. Especially if the bolts are too short and not engaging with enough threads in the cylinder head so as to allow for sufficient tightening torque. Details of my experience with this issue are in my engine build thread.

Plus a side benefit is that the exposed studs on the top of the manifold make clean anchor points for the PF4 wiring harness using P-clamps and an additional nut.

Also my $.02, using a borescope to look down the intake runners & cylinder head ports for oil is minimally invasive and thus a great first step.

Earl

[rich grsc]

Like Jeff, I think intake manifold gaskets

[Fman]

Really appreciate all the replies back, plan is to perform the leak down test, assuming all goes well with this I will then borescope the intake manifold. If I do end up replacing the intake manifold gasket is there any recommendations on what gasket set/sealer to purchase? I have never done this before.

[MB750]

Have you ever had the EFI system tuned? And by that I mean do you know your AFR levels at various RPM's and loads?

Color me skeptical, but I've got heartburn over intake gaskets or valve seals being the problem on all 8 cylinders. I'm not saying it's not, but I put that in the statistical camp of improbable.

Do you lose any oil over 1500 miles?

[egchewy79]

Really appreciate all the replies back, plan is to perform the leak down test, assuming all goes well with this I will then borescope the intake manifold. If I do end up replacing the intake manifold gasket is there any recommendations on what gasket set/sealer to purchase? I have never done this before.

I used felpro gaskets and “right stuff” black RTV on the front and rear of the block. You want to put a nice 1/4” thick bead on the “China walls”. The intake studs let you line up the intake without smearing the RYV everywhere. Loosely hand tighten the nuts, let the RTV cure for the prescribed time, then torque to spec from the center out as instructed. Retighten several times after heat/cool cycles.

[Jeff Kleiner]

Really appreciate all the replies back, plan is to perform the leak down test, assuming all goes well with this I will then borescope the intake manifold. If I do end up replacing the intake manifold gasket is there any recommendations on what gasket set/sealer to purchase? I have never done this before.

Any time you replace an intake on a Ford Windsor ALWAYS use the gaskets with a steel core such as Victor Reintz Nitro Seal or Fel-Pro number 1250S3. Stay away from the non laminated "Print-O-Seal" Fel-Pro. When you go back together run around the torque sequence 5,6,7 times then let it sit and come back the next day and do it again 2 or 3 more times. It’s a Windsor thing Yes, a fat bead of Great Stuff or another good silicone at the front and back China walls.

MB 750, he’ not showing oil on all 8, only some on one side.

Jeff

[Mike.Bray]

Mike, if this was the case and the seals were bad can they be changed without pulling off the head?

Yes they can. I ended up upgrading my valve springs with the heads installed. You need one of these to put compressed air into the cylinder to hold the valves in position. I used one of these to compress the valve spring.

Concerning the intake manifold, I agree completely that studs are far superior to bolts especially if you're going into aluminum heads. For one studs insure you have the proper amount of thread engagement. And second when torquing you're not stressing the threads in the aluminum heads like you would be with bolts. I used these on my build.

[egchewy79]

Yes they can. I ended up upgrading my valve springs with the heads installed. You need one of these to put compressed air into the cylinder to hold the valves in position. I used one of these to compress the valve spring.

Concerning the intake manifold, I agree completely that studs are far superior to bolts especially if you're going into aluminum heads. For one studs insure you have the proper amount of thread engagement. And second when torquing you're not stressing the threads in the aluminum heads like you would be with bolts. I used these on my build.

If it’s a humid day and your compressor has been running a while, make sure you have a water separator or your compressor will spray a bunch of water in your cylinder. Ask me how I know.
Look up the string method too for replacing valve seals. You basically run a bunch of string into the spark plug hole to hold up the valves.

[Fman]

Have you ever had the EFI system tuned? And by that I mean do you know your AFR levels at various RPM's and loads?

Color me skeptical, but I've got heartburn over intake gaskets or valve seals being the problem on all 8 cylinders. I'm not saying it's not, but I put that in the statistical camp of improbable.

Do you lose any oil over 1500 miles?

The smoke is only on the drivers side exhaust, passenger side pipe runs clean. I think the consensus is there is definitely excess oil on the plugs on the drivers side. To answer your question about the EFI tune, have never had it tuned. The Pro Flo 4 has a learning mode for the first 500 miles, this is all I have done with the system. The car has always run good, never felt like the EFI was not performing well. And yes the engine does consume oil, I would say a quart every 1k miles.

[ProfessorB]

Just a couple of things to keep in mind: If it's only smoking on the driver's side, that doesn't mean all four cylinders have a problem...it could be only ONE cylinder (example: ONE intake valve seal on ONE of the cylinders on the driver's side). The plugs should give you some indication of which cylinders. The fact that you said ALL drivers side plugs were fouled supports the intake manifold leak theory. Also remember that, as a rule, bad rings make a cylinder smoke CONSTANTLY while bad valve seals smoke more on deceleration. I doubt it's the rings. I would agree with the general concensus that's it's a manifold gasket....seems to me it would suck more oil during deceleration due to engine vacuum. And if it was valve seals, what's the chances all four intake seals on the driver's side would go bad (since all four drivers side plugs are fouled) but all four passenger side seals are NOT bad?

[rich grsc]

A quart per 1000 miles on a new engine isn't normal.

[CraigS]

When reassembling, before using any sealer, drop the intake gaskets on the studs, and then gently sit the intake manifold on the studs. Look at the clearance intake to china walls. I did this on mine and was surprised to find only a 1/16" gap. This tells you how thick a bead of sealer will be needed. I discovered this when I first took my intake off and found a ton of extra sealer installed by the original builder had oozed inside the china walls.
china walls.jpg

[Erik W. Treves]

"Intake manifold - Checked all bolts, they were definitely loose (under 10 ft lbs). Re torqued to 22 ft lbs."

I am in the "Jeff camp" on this one - leak down is probably a waste of time IMO. You can change the valves seals on the engine with the correct tools and an air compressor.

[narly1]

"Intake manifold - Checked all bolts, they were definitely loose (under 10 ft lbs). Re torqued to 22 ft lbs."

I don't recall seeing this in the initial post. Definitely a must fix first action in the troubleshooting process.

Earl

[David Williamson]

If the intake is not the cause of the oil getting into the cylinders. Valve guide seals don't wear out on an engine unless it is old and has many miles on it. This is what happened with my engine. It started smoking very noticeably after about 5,000 miles. In my case I had the same issue as you smoke from one side and plugs that looked just like yours. I did the intake manifold gasket change, still smoking. i took the heads off to get them checked at a machine shop and they found the valve guides seals were worn but it was because the heads were poorly made, the valve guides were machined oval. They put new guides in and that solved the problem. In case you have the same as me, I have RHS heads on a Dart 363 engine.
David W

[steno]

If the intake is not the cause of the oil getting into the cylinders. Valve guide seals don't wear out on an engine unless it is old and has many miles on it. This is what happened with my engine. It started smoking very noticeably after about 5,000 miles. In my case I had the same issue as you smoke from one side and plugs that looked just like yours. I did the intake manifold gasket change, still smoking. i took the heads off to get them checked at a machine shop and they found the valve guides seals were worn but it was because the heads were poorly made, the valve guides were machined oval. They put new guides in and that solved the problem. In case you have the same as me, I have RHS heads on a Dart 363 engine.
David W

I saw exactly the same issue with valve guides. Wrong length pushrods were deflecting the valves and wore the guides. Used quarts of oil and killed every mosquito for miles around.

[Tuftster]

I had very similar symptoms and agree it's worth checking the intake gasket. Here is what I found.

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[Railroad]

Cannot tell by the pic, but the results look like Fel Pro print o seal gaskets. They literally dissolve with any exposure to moisture.
Follow Jeff's advise and get the steel laminate ones.

[BRRT]

I had very similar symptoms and agree it's worth checking the intake gasket. Here is what I found.

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Wow, that's ugly

[Fman]

Spent some time today troubleshooting, I think I have found the problem. Had a friend over helping me and we first pulled the throttle body and looked inside the manifold and discovered all kinds of issues. It was pretty evident oil is leaking into the heads from the manifold, and the gasket is sticking out all over the place in different ports. So we decided to pull the intake and discovered a mangled up gasket that looked to be installed incorrectly. Or at least it has moved quite a bit and caused separation in different areas and was also oil soaked. Was able to spend some time and get the heads and intake cleaned up. I have parts coming Thursday and will replace the intake gasket, install studs and get everything back together. I snapped a few pics of the gasket looking into the manifold with borescope. Hopefully this is the problem, regardless it needed to be re-done. Did not perform a leak down test.

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[Fman]

I had very similar symptoms and agree it's worth checking the intake gasket. Here is what I found.

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That is similar to what mine looked like, interesting enough it was also the Edelbrock gasket... so my consensus is stay away from Edelbrock intake gaskets! Apparently they are junk.

[CraigS]

Excellent news. Even though this is a pain in the butt, the intake gasket is the easiest fix of any of the possible ones. Don't forget a thin wipe of sealer around the water passages front and rear of intake on both heads and intake.

[rich grsc]

Like Craig suggests, a THIN wipe of sealant. No need for a large bead of it.

[steno]

Glad it turned out to be an easy fix!

[Tuftster]

That is similar to what mine looked like, interesting enough it was also the Edelbrock gasket... so my consensus is stay away from Edelbrock intake gaskets! Apparently they are junk.

Don't forget to check the manifold bot torque multiple times after heat cycles. I did after letting it sit without a heat cycle a couple of times as well as after every drive and cool down for a while. I was shocked how long it took to finally stay torqued.

[CraigS]

Don't forget to check the manifold bot torque multiple times after heat cycles. I did after letting it sit without a heat cycle a couple of times as well as after every drive and cool down for a while. I was shocked how long it took to finally stay torqued.

My experience too. 'Shocked' is exactly the right description. This is where the studs/nuts really shine. The stiction is so high w/ bolt into aluminum that the TQ would probably stabilize after 2-3 cycles. A lightly oiled stud/nut is so much more free moving that a 5# TQ difference will be obvious.

[Fman]

I am going with the ARP stud kit recommended by Mike.Bray and the Fel-Pro gasket number 1250S3 Jeff Kleiner recommended. Hoping to have it all back together today, will let it set up overnight and try and to fire it off tomorrow.

Thanks again for all the replies back, huge help.

Travis

[Mike.Bray]

Just be sure and check the timing.

[Fman]

Good and bad news today. The new intake gaskets have definitely seemed to resolve the smoking after a 20 mile test drive it has really cleaned up. Unfortunately I have an oil leak from the front china wall right under where the water neck is located, ugh! I obviously did not use enough silicone on the wall, I was concerned about too much would drip into the valley. The back is fine and not leaking. So I guess I will be doing this again. Should take me half the time now, but still what a bummer.... live and learn.

[Blitzboy54]

Good and bad news today. The new intake gaskets have definitely seemed to resolve the smoking, after a 20 mile test drive it has really cleaned up. Unfortunately I have an oil leak from the front china wall right under where the water neck is located, ugh! I obviously did not use enough silicone on the wall, I was concerned about too much would drip into the valley. The back is fine and not leaking. So I guess I will be doing this again. Should take me half the time now, but still what a bummer.... live and learn.

If it makes you feel any better I had a coolant leak on my intake manifold gasket on my first car. I replaced the gasket and that fixed my issue but I also did not put enough sealant on the china wall (back wall in my case). I lived with it for a couple weeks while I pouted then fixed it.

Really glad to hear you fixed your burning oil problem. That would have put me in a bad mood for sure.

[weendoggy]

Good and bad news today. The new intake gaskets have definitely seemed to resolve the smoking after a 20 mile test drive it has really cleaned up. Unfortunately I have an oil leak from the front china wall right under where the water neck is located, ugh! I obviously did not use enough silicone on the wall, I was concerned about too much would drip into the valley. The back is fine and not leaking. So I guess I will be doing this again. Should take me half the time now, but still what a bummer.... live and learn.

My advice is to lay a good 1/4" or more bead along the walls and a dab extra in the corners after the intake gasket is down, then let it sit for a few minutes before laying the manifold down. I even put a nice finger swipe on the bottom of the intake as well. Take your time and make sure to not move it much when installing. Then torque as needed and walk away for the day. Let the stuff seal overnight.

[Fman]

If it makes you feel any better I had a coolant leak on my intake manifold gasket on my first car. I replaced the gasket and that fixed my issue but I also did not put enough sealant on the china wall (back wall in my case). I lived with it for a couple weeks while I pouted then fixed it.

Really glad to hear you fixed your burning oil problem. That would have put me in a bad mood for sure.

Yea not my first time having to do something twice nor will it be the last... At least this time I will be twice as fast, always easier second time around

My advice is to lay a good 1/4" or more bead along the walls and a dab extra in the corners after the intake gasket is down, then let it sit for a few minutes before laying the manifold down. I even put a nice finger swipe on the bottom of the intake as well. Take your time and make sure to not move it much when installing. Then torque as needed and walk away for the day. Let the stuff seal overnight.

Great advice, and I also did not let it set up for 1 hr before I set the manifold in place... guess I should have read the directions maybe this has something to do with why it is leaking.

I am using Permatex Ultra Black, this is what my engine builder recommended. Assuming this is adequate for this task?