Time to address rebuilt engine oil consumption

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my5thmopar

my5thmopar

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72 Dart 318 has used oil since it was rebuilt. Get a little smoke at start-up and when accelerating hard. Probably a quart or more every 1k miles, never really measured but, I have to put oil in it a lot. Recently I've been smelling antifreeze. No leaks to be found yet and no oil/water mixing. This has prompted me that I need to get plan together to address these issues. I've had issues with the new Eddy 2176 intake and I'm going to take a second look at it. The rebuild consisted of: New intake valve guides, .030 pistons/rings, cam, oil pump, gear set, rockers, bearings, crank turned, valves reground. So you can see just about everything was replaced.

I'm looking for possible issues and some sort of test plan to get to the bottom of this. I'm probably starting with compression check then a leak down test. Thanks Craig
 
What's the mileage on it now?
 
8425 when I checked the other day. Intake has been off once since rebuild to fix oil being sucked in #7. Replaced gasket and used gasket cinch, last time I checked plugs were normal looking with good mixture signs.
 
With 8k miles on it ,, if it's burning oil,, it'll show on the plugs..

Take the plugs out and scrutinize each as it comes out,, you're looking to see if the deposits are accumulating on one side of the electrode,, or is the plug base evenly covered in oil..

Then a compression test is in order..

The plugs should tell the story.. Post some pics of the plugs..

hope it helps
 
inertia said:
With 8k miles on it ,, if it's burning oil,, it'll show on the plugs..

Take the plugs out and scrutinize each as it comes out,, you're looking to see if the deposits are accumulating on one side of the electrode,, or is the plug base evenly covered in oil..

Then a compression test is in order..

The plugs should tell the story.. Post some pics of the plugs..

hope it helps
Click to expand...

I put a lot of facts in the post but wanted to give the gurus enough information. I'll post the leak down tests in the next post. Or look at the pix first and come back to my comments.

Plugs are Autolite 65s. Here are a few observations.
There is oil on the washers of every plug but, pretty heavy on 1&4.
Also the treads are oily on all plus just a little lighter on 3,7,8.
All insulators have discoloration.
Plugs 4&6 have the most deposits. This is the last pix. I've had a slight miss lately and I think it may be #4.

Compression 1-150psi, 3-148psi, 5-152psi, 7-148psi, 2-148psi, 4-155psi, 6-150psi, 8-149psi. They all build quickly at about 3-4 turns. If i keep cranking they will build up to about 175psi but, I didn't go that far.
 

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I see no oil fouling but some of those gaps look awful tight.
 
#4 and #6 are sucking oil,, they seem to be evenly coated, rather than accumulating on one side,, I'm inclined to think rings, but a compression test,, and/or a leak down test would be more definative..

better pix of 4 & 6, from opposite sides and a down shot could be helpful..

sorry,, hope it helps..
 
Next quart, add 20-50w. I hope your running 10-30 dyno oil.

Thanks for playing!
 
I don't think so. Oil will be black and wet.
 
A few things to add from the earlier post. The tops of the pistons have an oily build up on them. I looked at each piston when it was TDC. I think this would be the case since the oil is going somewhere. Kinda hard to think rings with the compression and 9k miles. There is oil all over the threads and plug gaskets.

Compression 1-150psi, 3-148psi, 5-152psi, 7-148psi, 2-148psi, 4-155psi, 6-150psi, 8-149psi. They all build quickly at about 3-4 strokes. If I keep cranking they will build up to about 175psi but, I didn't go that far.

I figured the next step would be the leak down test. I actually ran it twice because, I didn’t trust the gauge I was using. It was good practice anyway. The test was run after the engine reached normal operation temperature. I removed all of the plugs for the test. I figured if something was off, I could just put the plug or plugs back in. Here are my observations and results. I could hear the air escaping the through the valve cover. I’ll comment on this in a minute. There wasn’t any air through the carb or exhaust. I also checked the adjacent cylinder for air and didn’t hear any. If you didn’t catch this earlier, the engine has less than 9K miles. I used 100psi from the regulator.

Leak down loss from 100psi: #1=10% #3=8% #5=8% #7=13% #2=12% #4=9% #6=11% #8=9%

Addressing the pressure loss, I don’t think overall it is too bad. Since air is entering the crankcase it seems there is one of two places for that to occur. The oil is either is passing the rings or being sucked into the cylinder from the bottom of the intake runner from the valley.
 

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What pistons are you using?
I forget which ones, but there is one piston thats made out of a certain type of material that requires you to use special rings for them and if not, you will get oil blow by. Sorry I cant remember all the information but someone on here with greater amounts of engine building knowledge should know what I'm trying to say.
 
4 and 6 are ash fouled.Ash is usually from the oil, but also usually fouls all the plugs, not just 2.
The oily threads tells me the valve cover gaskets are leaking and the oil is accumulating in the plug pockets. The oil then ran down the threads as the plugs were uscrewed.
The compression test may have been prematurely terminated.The engine has to be cranked until the highest pressure is attained.No exceptions.
The results of the leakdown test are not good. Since you say that all the air went into the oilpan, there is something wrong with the rings for sure, or the top of the cylinders have problems, or the tool lies. There is almost nothing as bad as a lying leakdown gauge.A good ring seal will get you numbers in the single digits and all pretty even,and with tight gaps closer to 4% . At least half of those are excessive.
If you unbolt the rockershafts, you can repeat the LD with the pistons at the bottom.That might tell you a little about the bore roundness.You can do a leakdown at any point in the stroke, and find gouges this way, and you can do a moving LD test;you just cant do it with 100psi.With the engine anchored in the frame, you might be able to use 40 or 50 psi though,depending on the length of the bar,your body weight, and physical strength. Its just a matter of re-calibrating the tool. This can help determine the source of the disappearing pressure. If your LD tester has2 gauges, make certain that they both read the same,all across their faces. I hate lying LD gauges.
 
If you have poor/sticking oil rings, then the compression tests will typically turn out decent due to the sealing of the compression rings by the oil, even if the compression rings are not in good shape. So in this case, I would not take the compression tests as the data on which I would make a final decision, especially since all cylinders build evenly and quickly. But it would indicate that the head gaskets are sealing so a leak there seems unlikely.

A bad or no PCV system can cause crankcase pressure that can cause oil burning too. The OP has not mentioned the PCV system installed. We need to know that.

From the 1st post, the burning of oil out the tailpipes when at or near WOT cab a pretty conclusive sign of poor ring sealing, ASSUMING that the intake is sealed well AND the PCV system is working. The rate of oil burning also points to the same thing.

My plan would be to:
1) Examine and reseal the intake and test to be sure that is not the issue.
2) Look at the PCV system too.
3) Get ready for a re-ring or rebore/re-ring job. I would look hard at bore taper and roundness if it was not done before, and follow proper break-in procedures. When you get to that point, it might be well to discuss what others do.

I have rarely done leakdown tests (except on a small aircraft engine) so have to follow the judgement of others on that.
 
I was hoping the pix would show a definate accumulation of oil deposits on one side only,, which would indicate the oil is coming from a direction,, mainly the intake runner,, which would mean a bad guide seal,, guide, or intake gskt leak..

But that final pic has tar all around the base,, which kinda makes me think a ring..

I'd yank the heads, looking for an obviuos intake gskt leak into a runner,,.

I'd move #4 & #6 pistons half way down the bores,, and fill all the cylinder full as possible with clean Varsol, and wait..

Cyls with poor rings will drain quickly,, Cyls with good rings,, may hold fluid overnite.. that'd be my test.. Rotate crank,, and re-fill cyls that didn't get much fluid the first time, noting suspect cyls... My bet is 4 and 6 drain quickly, others to varying time, with a few holding fluid indefinately...

there are several reasons a ring can break,, and you may have some..

hope it helps...
 
How is your PCV system set up? What lift is the cam and when the heads were redone did they use stock valve seals or Perfect Circle type seals?
 
First…Thanks for the help and suggestions. Maybe we can get a test plan together after today. If something needs to be corrected in my testing, let me know.
Rather than quoting all the suggestions, I’ll try to answer some of them. One clarification about the leak down. I listened through the RH valve cover and not the dip stick. Since it is painfully obvious that there is an issue, I was hoping diagnostics would pinpoint the issue.

1) Valve covers are not leaking, there is actually dry dust around the holes.
2) The PCV is stock breather RH and valve LH. It is working, I checked suction and rattle.
3) Pistons and rings were cast Speed Pro stock flat top 4 valve relief and gap per their spec. The block was professionally bored to .030 and the machinist had the pistons to check with.
4) I can redo the compression test and I think all will go to 175-180 range. I did this once before.
5) The first time I did the leak down I had 2-5% and thought that must be wrong but, I’ll change the gauges or get a different tester.
6) Comp Cams XE256 with their springs. Used stock seals. I removed the Comp seals when all this started because I thought they were the issue.

I guess I’ll have to redo the compression and leak down test. In case you missed my ramblings, I’m concerned with a few things I found. Maybe they don’t have anything to do with the issue but, it isn’t normal.
1) Oily piston tops. I see black oily build up.
2) Oil on all plug threads and washers. Valve covers are not leaking.
 
Just a "novice" suggestion, intake leaking into lifter valley. Will suck oil and hard to find. Only so many places for oil to intrude. That is the least likely. So sometimes overlooked or not scrutinized thoroughly. MT:burnout:
 
Check all the pushrods are straight,, and how's the intake lobes on cam of those cyls.. There's a chance if the intakes weren't opening, it'd suck oil,,, but it'd run the sh!ts..
 
So what valve seals are on there now?
I usually put the PCV on the passenger side(but thats no never mind). Pull the PCV hose off completely and check it internally for oil.
I have never seen oily oil migrate up the plug threads, and the firing tips be dry. Wont say it cant happen. Just in 40+ years, Ive never seen it.
You have a good plan.
I cannot understand how the LD test could give such wildly varying results. You can see though, why I hate a lying LD gauge. If your compression test results had been a little lower, coupled with the huge LD, and the oil burning/oil loss, It would have pointed straight to a tear-down. And Who would be the bad-guy, when you couldnt find anything wrong at that time? Phew, that was almost too close for me.
I have another test for you.Plumb a vacuum/fuel-pump gauge onto the dipstick tube. Pull the PCV out of the cover and lay it and its plumbing aside. Then seal all the breathers. Start the engine and watch the gauge while it idles. The gauge should absolutely not show vacuum. In fact it could begin to register pressure.That would be normal.Do not let the pressure rise above 3-4 psi, as it will begin to want to blow out anywhere it can.And if it succeeds, thats just more work for you.Oh this test will prove that the intake is not sucking oily air from the valley.
Ok so carry on....

Oh, and if your results of the compression test do come in that high, you will be in good shape for a bigger cam,should the bug bite.Heh-heh...However, once the pressure goes that high, timing the beast can become a challenge.
 
my5thmopar said:
I guess I’ll have to redo the compression and leak down test. In case you missed my ramblings, I’m concerned with a few things I found. Maybe they don’t have anything to do with the issue but, it isn’t normal.
1) Oily piston tops. I see black oily build up.
2) Oil on all plug threads and washers. Valve covers are not leaking.
Click to expand...
I think everyone pretty much locked onto those symptoms. Sounds like the PCV is fairly well ruled out..
 
My suggestion is to compare the ring selection to the bore finish.I would bet that you have moly rings and the bores were honed for cast rings which is too rough.
 
were the heads milled a bunch? is the angles of the intake will not match very well.
as far as smelling coolant and not finding any leaks, check the heater core.
 
Just came in from the shop. Here is some more info. I did the test AJ suggested. No vacuum pulling on gauge. I did notice slight pressure by feel not gauge. I repeated test and saw oil mist from breather hole when PCV was disconnected & plugged. I also repeated the compression test with similar results. I was mistaken and didn't get very much more when cranking for maximum. Compression 1-148psi, 3-150psi, 5-152psi, 7-150psi, 2-155psi, 4-155psi, 6-156psi, 8-154psi. AJ-The seals are stock OEM type.

Next steps:
1) Pulling valve covers watching valve train.
2) Pulling and checking push rods. #1 intake was a little noisy on startup but, quieted down.
3) Repeat leak down. I'm buying some new gauges.

I'll report back in a few days. Again Thanks! Craig
 
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