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240dkw

Engine Burning Oil

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19 hours ago, 240dkw said:

I have spent the last few days trying to solve my engine problem with no luck so far. The motor has been running for a week with oil pressure that would get higher with engine RPM.

I think that he's had his car for a while and drives it often.  Maybe the relief valve in the pump did get jammed.  Who knows.  But he's in the "might as well" zone now.

Might as well do some work on the head while it's off.  Might as well check that oil pump for wear.  Might as well put a high performance cam in it.  Might as well buy another engine so I can work on this one....

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20 hours ago, 240dkw said:

#1 - 158
#2 - 159
#3 - 160
#4 - 160
#5 - 158
#6 - 157
I then did a leak down test
#1 - 100/92
#2 - 100/94
#3 - 100/92
#4 -100/94
#5 - 100/81
#6 - 100/80
I can hear the air leaking somewhere on both 5 and 6
So I pulled the head off.

These numbers aren't making sense to me, your compression numbers are quite consistent, that's good (did you also do a wet test?), your leakdown numbers say 5/6 are working at 80% but we already know those two cylinders are holding good compression. Sometimes when doing a leakdown test as the air pressure is dumped into the cylinder the piston will move down and the intake valve will open a bit and it shows as a leak.  I'm going to suggest that the bad numbers for 5&6 don't really exist because your compression numbers prove that they can't exist.

So it seems the only two things to diagnose is the puff of blue smoke and what looks like a rich condition on the sparkplugs and pistons.

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11 hours ago, 240dkw said:

Captain: Sorry for the confusion

Thanks for the additional clarification and I'm really sorry, but I'm still not sure I'm getting it.

Is this right?

You had the engine rebuilt 600 miles ago and everything seemed perfect including the oil pressure.
Then 100 miles ago, all of a sudden, your oil pressure (as indicated on the dash gauge) shot up. But other than the oil pressure, nothing else seemed wrong.
Then just a day or two ago, while investigating the high oil pressure, it started smoking badly and that's when you pulled the head.

Did I get it that time? I feel so dense. If I don't get it this time, I'm going to just keep my mouth shut and stay completely out of it!    LOL

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Did you ever check the dipstick to determine how much oil had been consumed in what amount of time and or mileage?  If it was around 600mi since rebuild, was there break in oil still in it?  I guess that's kind of irrelevant, but what I'm asking is, How much oil did the engine lose in the 600 or so miles since the rebuild in actual quarts?

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1 hour ago, Captain Obvious said:

Thanks for the additional clarification and I'm really sorry, but I'm still not sure I'm getting it.

Is this right?

You had the engine rebuilt 600 miles ago and everything seemed perfect including the oil pressure.
Then 100 miles ago, all of a sudden, your oil pressure (as indicated on the dash gauge) shot up. But other than the oil pressure, nothing else seemed wrong.
Then just a day or two ago, while investigating the high oil pressure, it started smoking badly and that's when you pulled the head.

Did I get it that time? I feel so dense. If I don't get it this time, I'm going to just keep my mouth shut and stay completely out of it!    LOL

That is close, the pressure did not shoot up, it started following the rpm’s. like the pressure relief was not working. At the exact time that my pressure problem stopped it started smoking. I pulled the head because of the smoke and the fact the leak down test showed something wrong with #5 and #6. I have just finished cleaning the head and changing the valve seals. Because I have not found anything wrong so far, l am going to put the head back on and run it. It is very possible that it is a very rich problem, before I put the carbs back on I will have a good look at them.

Edited by 240dkw

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1 hour ago, Reptoid Overlords said:

Did you ever check the dipstick to determine how much oil had been consumed in what amount of time and or mileage?  If it was around 600mi since rebuild, was there break in oil still in it?  I guess that's kind of irrelevant, but what I'm asking is, How much oil did the engine lose in the 600 or so miles since the rebuild in actual quarts?

It did not lose any oil, as it only ran while it was smoking for a hour or so while I was trying to find out why it was smoking. 

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4 hours ago, grannyknot said:

These numbers aren't making sense to me, your compression numbers are quite consistent, that's good (did you also do a wet test?), your leakdown numbers say 5/6 are working at 80% but we already know those two cylinders are holding good compression. Sometimes when doing a leakdown test as the air pressure is dumped into the cylinder the piston will move down and the intake valve will open a bit and it shows as a leak.  I'm going to suggest that the bad numbers for 5&6 don't really exist because your compression numbers prove that they can't exist.

So it seems the only two things to diagnose is the puff of blue smoke and what looks like a rich condition on the sparkplugs and pistons.

I am sure that I checked the movement of the pistons and made sure the cam lobs where up. And I cannot say enough as to it was not a puff of blue smoke, but a large plume. 

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#4 looks like the only oily cylinder in your first picture. from the picture of the head.

Odd problem.  Your valves don't look like they're getting very hot either.  Have you had it out for a good run at temperature or are you babying it because it's new?

Could be a stuck oil scraper ring.  It happens, from what I've read.  The cure for stuck rings is hard usage of the engine.  These engines like to be used.

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5 hours ago, 240dkw said:

I am sure that I checked the movement of the pistons and made sure the cam lobs where up. And I cannot say enough as to it was not a puff of blue smoke, but a large plume. 

Sorry, I didn't mean to minimize the blue smoke, used the wrong term.  I only only mention the compression/LD numbers because it is so easy to get lost chasing problems that may not be there.  Regardless, there are many conditions that could cause a low reading but the only condition that could cause an artificially high reading would be wet oil in the cylinder and 5/6 in your photos look dry.

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how about this oil pressure a non issue, sudden consumption on freshly rebuilt engine from a valve stem seal that has popped off?
Did we try the high vacuum (down shift while throttle closed) run then suddenly get on it for a cloud of blue smoke after sucking in oil during high vacuum?
I would be tempted to pull the valve springs off and at least check to make sure they are all seated.
That sounds a good candidate to me. I've had a couple of toyota engines with stuck oil control rings that used a lot of oil, but didn't smoke. The one I had that smoked had knackered valve stem seals.
Does the engine have a modified cam and big lift?

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 I'd also check that the valves are sealing by pouring solvent into the intake and exhaust ports (with the valves closed) to see if there's any seepage past the valves. I'm curious if #s 5 and 6 have a slight leak.

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Ok I am really starting to believe I did in fact jump the gun on my motor, I went through everything while it was apart and all I could find is a small leak on the exhaust valves for 5 & 6, just like you said @Mark Maras. I did a quick lapping on them and it stopped the leak. I then cleaned the head up and put it all back together. It now runs great and the oil pressure is right where it should be. Nothing wrong with the carbs as well so if in fact it just decided to run really rich for a while I have no idea what caused it. cleaned.jpg

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They all looked good, but of course I change them all, so that could have been one of the issues.

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I got the head done complete with new valve seats about 600 miles ago.

Edited by 240dkw

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I have to commend your initiative in just diving in and taking action.  Obviously you know a lot about how things work.  I've found myself well down a path I wondered about taking before.   If it happens again at least you'll know what it's not.  Maybe.

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Well, the problem has come back, and this time I took a deep breath and started trouble shooting before tearing into anything. Much the same symptoms as before, running really rough and smoking. The more it ran the worst it got. To the point it was backfiring and would not stay running. I finally tracked it down to a bad capacitor(brand new) on the points. Once it was replaced to ran like a top for about two days and started again, once again it was another bad capacitor. I do believe my old style electronic external voltage regulator has failed causing the caps to burn up. I replaced the VR with a old mechanical style one and another cap. Seems to be running great again, but I have been here a couple of times already. Is there any thing else I am missing that would fry the cap?

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I know too little about points systems but what I would ask is the dumb question: are you sure it’s not and Electrolytic capacitor connected the wrong way?

The only things I’ve seen in the past burning caps are:

1. over voltage

2. incorrect orientation of electrolytic caps

3. Excessive heat (i.e. how are your engine bay temps when this occurs?)

4. Ferroresonace / harmonics with the source that result in undamped oscillations


If we say 4 is highly unlikely and 2 is also not the case then you are left with voltage and heat. If you were dramatically over-volting then should other things not be affected also? E.g. gauges etc? Or could there be a 5. Rubbish quality Chinese capacitor being rebranded and sold as a quality item.?


The easiest way to troubleshoot is to get a high voltage cap from Radio Spares (RS) with the same uF capacity and a high heat rating. Then test run it. Ideally a ceramic cap if you can get it in the required capacity.

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