Well, main thing is uniformity, so just one troublemaker. But a coolant pressure test might save you from pulling one head off. And try that oil test in cylinder 3, I know you have a jug of Rotella by the door...

 

Thanks I will try that test.

One thing that doesn't make sense is even if the HG is bad, where would the coolant come from? Cylinder 1 and 2 are next to the coolant passages, but cylinder 1 has good compression and cylinder 3 isn't next to any coolant I can recall. Am I missing something?

 

That might depend on how gasket had failed, a fold or crease, factory defect, etc. We don't want to think about a cracked block. When block was out, did they do a pressure test? That is done by blocking those water passages with a plate, and running up the PSI. You can rent tools to do it.

Maybe coolant is leaking into oil passages and then into valve areas, pooling in the cylinder. Seems like you have white smoke on start up, it goes away as warmed up (and burned off), motor may smooth out some. Then repeats. So maybe valley pan is still the issue? Wonder if you cranked it up, let smoke go away, warmed up, then turn off and remove coolant cap, would it repeat after motor cools off? Of course, this does not tell us where it is getting in. Valley pan is certainly easier to get off.

If it is leaking only into #3, the quantity of white smoke would be impacted by where #3 piston came to rest.

Could you remove #3 spark, and do a coolant pressure test, and use a Q tip or such to check for fluid? Should see coolant PSI drop slowly over time. Leak could be somewhat temp sensitive, in that it only leaks under "X" PSI and and "Y" degrees. So it might leak while warming up (fast) or cooling off (slow).

Knowing that leak was in a cylinder that is not adjacent to coolant port might make a stronger case for valley pan and intake.

You are out on the edge here, don't see how you could avoid valley pan coming off, but testing may need to be done before that to rule out one side or the other, etc.

 

your numbers are lower overall because the rings havent seated yet.

i still wouldnt expect to see more than 190 or so on a cold motor unless it has a really high c/r.


you can also try a leakdown test, as i suggested in your other thread and if you do it on #3, it may show you bubbles in the expansion tank...
or you could just go straight to pulling the head.

have you rechecked the torque on the headstuds since running it?
were the headstuds oiled before assembly then torqued? torquing them dry will give you false/uneven numbers.

 

and rings not seated yet will increase oil consumption. Keep eyeball on that oil level from time to time. You think there is coolant in oil?

 

What about that flourescent glow additive that is made to show leaks with the special goggles. I know I did not dream that up?

If you did not use RTV on the Valley Pan, I think that also weighs in favor of that being the culprit.

 

ok the rings not being set yet, and the other factors makes sense why the compression would be 150-160. 120 is definitely too low though. And the plug being black while the others are all silvery says #3 is definitely the problem.

Wish I had the equipment to do a leakdown test, so I may just have to tear it down again for visual inspection. I'm getting pretty fast at it though. Way too familiar with this engine bay now. My worry is I'll find nothing visibly wrong. Uncertainty is the worst.

I used ARP thread lube generously on stud threads, washer faces, and nut threads. I made sure to go around the head studs multiple times, very slowly torquing until torque wrench clicked.

The coolant glows pretty well in UV. I've been using a blacklight to detect leaks around hoses and such.

I'm not sure about coolant in oil or not yet. My oil sample has sat a few days and I can't find any signs of coolant. I replaced the oil to eliminate the engine assembly lube as a possiblity, so I'm going to take a new sample from the new oil and check it tonight. If there's coolant leaking into oil then it should definitely be in this oil.

 

In addition to last post...

I've got an idea but not sure if it's a good one. What if I unplugged injector and plug wire for #3, then started it, and looked for smoke? If it didn't smoke then I'd know only #3 was burning coolant and the coolant wasn't being burnt from getting into the oil. Bad idea?

 

Actually injector plug for 3 is hard to get to. Will it stop injecting fuel if I just unplug the spark plug?

 

A cylinder that is burning coolant/water usually will have a very clean, shiny steam-cleaned plug. The water when vaporized will remove carbon build-up (not present here since it's a fresh rebuild) and not allow any black build-up on a spark plug. If it's a long-term coolant leak into a cylinder, then there usually is a white or brownish build up, but not black.

Not sure that pulling the #3 injector plug or spark plug wire would be a definitive test. If there's coolant in the cylinder, even if the cylinder is not firing I would suspect the coolant would be carried into the exhaust system and hit the hot pipe or cat and turn into steam. It would come out the tailpipe as white smoke as you're getting now.

I'll say it again (just as others are doing) - do a coolant pressure test and find the source before tearing down the motor. I'd recommend doing it both cold and hot (but be very careful when messing with a hot system) - start with cold since that seems to be when the white smoke shows itself (and it's safer for you!).