Rebuilt Engine Smokes And Consumes Oil

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Oct 6, 2011
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Hey guys I posted about this in my progress thread, but didn't get any responses (I know my thread isn't as cool as others here) so I wanted to create a new one because I would appreciate some advice. I posted on the other forum too but wasn't that descriptive so to avoid follow up questions I will be as descriptive as possible.

The build: professionally built .40 over 306 forged internals brand new tfs 170s, stage 1 cam, Chinese cobra. Builder said it should make 10:1 compression

Initial start: Filled with 10 30 conventional and comp cams additive. Car started but would not stay running do to a chip previous owner installed. Had to keep revs over 2k to stay running. There was no smoke during this time, only unburned fuel.

Tuner: Car went to tuner on a flatbed They cleared the chip and set everything back to base until i get some miles on it. Told me to come back at 500 miles and they will dial it in.

First drive: Hard pulls to 4k and downshifting to slow down. No smoke, 10-15 miles. Pulled like a freight train.

15-50 miles: Smokes (oil) a little on cold start. Once warmed up smokes on decel and when returning to idle. Still pulls like a freight train. Changed oil with 10 30 conventional no additive.

50-250 miles: Same symptoms as before, but more intermittent. Consumes a quart of oil approximately every 75 miles.

The builder said he thinks the rings just have not seated and to come back after 500 miles. I just have really not had a great experience with this guy so I don't know what to think. Others have said it could be bad valve seals or faulty pcv system. I did not retorque lower intake bolts after first start up and I am not sure if tuner did too. I am going to check this later today. I did notice a little oil pooled behind the lower about a quarter sized. Maybe it is just a simple fix.

If you guys read all of that and reply, you rock!
 
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Definitely check and see if it's not leaking out of the intake area,valve covers,etc first. Then check the pvc system. It sounds like a leak but sure could be the rings. If you can't find a leak I rec a leak down test.
 
First things first would be starting with fixing your oil leak. No matter how small it may seem, this is step number 1.
Valve seals are not a likely culprit in this instance, Typically an engine that is very worn that has bad guides and seals will smoke a little on start up only. For what it's worth, I have the exhaust valve seals completely removed from my cylinder heads to try and help lubricate the exhaust valve stems and get zero smoke what so ever.
To check and see if an issue was in the pcv system you will just need to look in the throttle body/ intake for signs of oil. If you are missing the screen in the lower intake you could be sucking in an excess amount of oil and it will pool in the intake and could also lead towards a smoking/consuming issue.
Check this first as it will be easy to do while you fix the oil leak.. Report back after that is completed!
 
I'm curious why he wanted you to come back after 500 miles. Those rings should be well seated after a few full throttle pulls. I know a lot of people have different break-in theories, but heat cycling the engine a few times should do the job. Hell, I don't even remember how many 6k RPM pulls my tuner did. All the miles on my engine are from the dyno only. I'm actually dealing with a smoke on decel as well. Hoping thicker oil fixes my problem. I washed down my cylinder walls when I first started mine, so I may have ring issues.
 
Is the baffle missing off your Chinese lower intake? I have read some similar threads where there was no baffle on the Chinese cobra intakes and oil was being sucked through the PVC system.
Joe
 
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Is the baffle missing off your Chinese lower intake? I have read some similar threads where there was no baffle on the Chinese cobra intakes and oil was being sucked through the PVC system.
Joe

Don't remember if there was a baffle or not, but coincidentally the previous owner did not have vacuum hooked up to PCV. That vacuum line was hooked up to oil filler neck which I thought was weird.
 
What type of rings did the builder use? Different rings require a different hone on the cylinder walls or else they will never seat right. First thing I would do is check the PCV valve and hose, then check the plugs fors signs of oil, then I would do a quick leak down test. I would not be waiting 500 miles to bring the car back if you are losing that much oil.
 
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When you first ran it and you say there was no smoke only unburned fuel do you mean it was so rich it was smoking? If thats the case how long was this going on for? It's possible you washed the cylinders down. Does the oil have a strong fuel smell?
 
When you first ran it and you say there was no smoke only unburned fuel do you mean it was so rich it was smoking? If thats the case how long was this going on for? It's possible you washed the cylinders down. Does the oil have a strong fuel smell?

No the umburned fuel did not cause any smoke. Oil smells like oil
 
Pull the PVC and see if you can stick your finger very far in there. I think you should be able to tell if its there or not.

Joe

I pulled the valve and grommet out, the grommet came out very easily. There was some sort of baffle covering half of the hole under the pcv screen, but I could stick my finger around it and through. Oil was definitely being sucked through the pcv valve.

IMAG0251.jpg


When I pulled the upper intake oil poured out of it. It took me awhile to get everything out. I also pulled all of my plugs and they all looked like this.

IMAG0257.jpg
 
So this has to be the exact reason the previous owner had no pcv setup before. He had the pcv valve capped. The vacuum line that would normally go to the pcv valve routed to the oil filler neck and a breather cap on the oil filler. The throttle body was also capped. I am going to do this for now as well. Correct me if I am wrong, but this is not ideal to vent the crank case?

Am I also correct in saying I should be looking for a new intake manifold that was manufactured in Murica?
 
I think you definitely found your problem. Do a google search. I think some guys have made their own baffle. I would assume it is the baffle that's the issue, but it may be worth doing a compression test just to ensure that you are not pressurizing the crank case.

Joe
 
"Initial start: Car started but would not stay running… Had to keep revs over 2k to stay running. There was no smoke during this time, only unburned fuel.

Consumes a quart of oil approximately every 75 miles.

Pcv hoses and valve were full of oil. Just pulled the upper off and there is a ton of oil in it.

So this has to be the exact reason the previous owner had no pcv setup before. He had the pcv valve capped. The vacuum line that would normally go to the pcv valve routed to the oil filler neck and a breather cap on the oil filler. The throttle body was also capped. I am going to do this for now as well. Correct me if I am wrong, but this is not ideal to vent the crank case?

I also pulled all of my plugs and they all looked like this."


Your crank case should be vented thru the pcv and also a hose to the filler cap. If you remove the pcv temporarily for an oil consumption test and are worried that you do not have enough venting, you can buy a filter that will push into a new grommet or possibly your existing pcv one. Running without a pcv for a while will not hurt anything.


Your plugs show no obvious sign of burning 1 qt of oil every 75 miles but…
 
So it's definitely the poor design on the baffle that caused my issue. I found an old post from tmoss on some random website and it basically stated that the Chinese lowers had a faulty two peice baffle instead of the nice one piece on the original Cobra. I am all set with that intake, and instead of spending the money to modify it I am going to purchase a better one.