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While those are both possibilities and I won't totally rule them out I think the probability is pretty low. I was extremely careful with the sealant - but who knows, I'm certainly not infallible. The scavenge pump I marked before I took it out, and i did only one side at a time so i'm fairly certain it's oriented properly... I'll post back whern I find out what's going on.
The scavenge pump orientation marks are difficult to see with the engine in place - Use the Smart Phone camera to be sure - takes a few minutes and eliminates doubt.
I used a paint pen on my pumps to ensure the orientation was easy to see.Ugly but effective.
Ok, I got up to the shop last night and pulled the sump plate (after draining the oil of course!!!). I really was hoping to find the swirl pot(s) clogged up with pad material, but was disappointed - both of them were clean. The oil and magnet were also clean (only 1000 mi. on fresh DT40) but I did find 2 little chunks of aluminum (non-ferrous/non-magnetic) in the pan. My blood pressure rose slightly for a few seconds until I did the magnet test... I'm thinking maybe I loosened up a piece that had been inside the block while I was turning the engine over on the stand while working on it (I don't know how many times I turned it over but it was quite a few). I can't think of where else this chunk may have come from...I also wonder if it could have had anything to do with my green cam cover plug popping out? Are the cam end plugs aluminum (the ones that seal the cam shaft)? It doesn't seem nearly large enough to constitute the entire plug...Would the rest of it still be up under the cam cover? I won't be able to get back to the car until next week, but in the meantime, I re-sealed the sump plate and ordered a few more of the green cam cover caps. I think before I re-fill it with oil, I'll pop off the green end cap and check for the cam end plug. If that thing is floating around in there, I don't want to start the engine 'til I get it out! If the cam end plug turns out to be where it should be, I'm thinking it could just be a case of excess cam cover sealant clogging the oil return...I suppose I'll cross that bridge when I get to it...
The excessive+sealant-plugging the oil return hole problem is a theoretical possibility with a noob who hasn't read this Forum. I can't imagine you made that mistake. You'd have to plug all/most of the holes. If you badly fumbled reinstalling the cam cover and smeared excessive sealant maybe?
The DHarn camshaft 'freeze plug' issue is one only you could evaluate - did you use a diy tool to lock the cam ?
So is the cause
1. a localize high pressure jet of oil behind the cam plug or
2. a general pressurization of the cranckcase?
The answer to that leads in 2 different directions for the hunt.
I was incredibly careful with the sealant - that being said, I did find a very small amount in the oil pick-up in the sump (1 little blob that was wrapped around 1 of the wires of the screen - I can't imagine it would clog anything, but who knows what else is up under the cam cover). As for the freeze plug - No, I used a factory tool to lock the cams and I was very careful not to put any inward pressure on the cam plus - finger tight only enough to seat against the plugs and hold the cams down
[i]
These were the chunks of aluminum that were in the sump near the pickup tube
These plugs typically eject when someone re-seals the cam covers and uses so much sealat that the "drains" at the back of the aft camshaft journals become blocked with sealant.
Unable to relieve waste oil, the pressure within the camshafts increases, and the expansion plug becomes ejected.
There are also times when the primary oilmpressure relief valve becomes stuck, elevating oil pressure, resulting in the same net effect.
Loctite 620 (wicking) is used on all expansion plugs that we do not thread here. Just as a precaution.
These plugs typically eject when someone re-seals the cam covers and uses so much sealat that the "drains" at the back of the aft camshaft journals become blocked with sealant.
Unable to relieve waste oil, the pressure within the camshafts increases, and the expansion plug becomes ejected.
There are also times when the primary oilmpressure relief valve becomes stuck, elevating oil pressure, resulting in the same net effect.
Loctite 620 (wicking) is used on all expansion plugs that we do not thread here. Just as a precaution.
thanks for checking in Jake. As I said earlier, I was extremely careful with the amount of sealant I used so I'm pretty doubtful, but I guess anything is possible. I'm going to pull the cam cover end cap back out on Tuesday and check the expansion plug. If it turns out to be the expansion plug I'll figure out how to deal with it.
I made it back up to the shop tonight after work. I pulled the green Cam cover cap back out so I could take a look at the end of the cam to see if the expansion plug was still present (Even though I thought I felt it in the end of the cam shaft before I replaced the green cap - I wasn't consciously checking for it so I couldn't be totally sure). Sure enough, the plug was there...Hmmm, I suppose that's good news but I'm still not sure why the green cap popped out. I put everything back together and refilled with oil. I didn't have time to start it tonight...will have to wait 'til tomorrow...
The only remaining ,likely cause for ejecting a correctly fitted cam plug (that I can think of) is pressurization of the crankcase .
What I can't imagine is how any part of the work you just did could result in that problem.
Presumably the problem did not show before you did this work?
The usual cause is badly worn rings/cylinders or valves but that happens gradually ,not suddenly
^^Yeah^^ nothing like this happened prior to any of the work I did. Also, the fact that I drove close to 1000 miles before it took place makes it strange as well. The oil pressure never looked unusual. Jake mentioned that perhaps the oil pressure relief valve got stuck and caused pressurization of the crankcase. I suppose it's easy enough to check that. I did change the spring and piston when I did all my work, but there was nothing unusual about it at that time - very simple job, the piston and bore were both smooth.
The upgraded piston that you used has a small bevel on the leading edge of it's circumference. So that makes it much less likely to stick than the original style that you replaced. At least this is my understanding.
Easy enough to remove,inspect ,measure,lube and replace.
The upgraded piston that you used has a small bevel on the leading edge of it's circumference. So that makes it much less likely to stick than the original style that you replaced. At least this is my understanding.
Easy enough to remove,inspect ,measure,lube and replace.
Yup^^ This is the plan (pull it out and check it), but I don't foresee any problems there. We'll see... Once I get everything back together and running (I'm basically there - just have to get it back off the jack stands), I'll just have to monitor for oil leaks. I'm really hoping that whatever caused this has cleared itself in much the same way as it "appeared". If not, I'll have to drop the engine again and check the cam cover sealant.
I got back up to the car this afternoon. First order of business was to pull the oil pressure relief valve. When I first loosened and unscrewed the cap/spring holder, very little oil came out at first (maybe a couple ounces). It wasn't until I pushed the spring back up into the piston that it really started to flow (at which time I promptly screwed the cap back in). This leads me to believe that maybe the piston did get stuck in the bore - I don't know why that would happen though (it's the upgraded piston and spring). Now that the oil is totally surrounding it, maybe that wont happen again!
09-07-2017, 12:19 PM
). I really was hoping to find the swirl pot(s) clogged up with pad material, but was disappointed - both of them were clean. The oil and magnet were also clean (only 1000 mi. on fresh DT40) but I did find 2 little chunks of aluminum (non-ferrous/non-magnetic) in the pan. My blood pressure rose slightly for a few seconds until I did the magnet test... I'm thinking maybe I loosened up a piece that had been inside the block while I was turning the engine over on the stand while working on it (I don't know how many times I turned it over but it was quite a few). I can't think of where else this chunk may have come from...I also wonder if it could have had anything to do with my green cam cover plug popping out? Are the cam end plugs aluminum (the ones that seal the cam shaft)? It doesn't seem nearly large enough to constitute the entire plug...Would the rest of it still be up under the cam cover? I won't be able to get back to the car until next week, but in the meantime, I re-sealed the sump plate and ordered a few more of the green cam cover caps. I think before I re-fill it with oil, I'll pop off the green end cap and check for the cam end plug. If that thing is floating around in there, I don't want to start the engine 'til I get it out! If the cam end plug turns out to be where it should be, I'm thinking it could just be a case of excess cam cover sealant clogging the oil return...I suppose I'll cross that bridge when I get to it...
