Head Gasket leak?

[Dave WM]

no smoking gun, head gasket looked fine, I could see no evidence of a problem. I did see about a teaspoon of coolant in 3 of the cylinders.. I don't see how that could have gotten there, I had drained the coolant before loosening any of the bolts.

Anyway a new gasket is next.

oh and I could see no cracks and the head had no detectable warp (I could not get a .003 in any where along the head in multiple tries). So even though the gasket looked fine I see no other option but to replace it with a new one and try again.

I have scraped the block down and will get some gasket remover and plastic razors to work the head. The gasket came off leaving very little residue, fully intact.

[Dave WM]

shamefully joined the club of not securing the timing chain jam tool, despite being warned by my buddy Jeff.

So hours later after removing the timing chain cover its nearly all back together.

I was careful to mark orientation of dizzy drive. just have to reinstall oil pump, water pump, damper, torque head, reinstall the cam gear (more carefully with tool now, which by the way a home made wood one is better IMH, the plastic thing does not fit well and is prone to slipping).

[Patcon]

2 hours ago, Dave WM said:

shamefully joined the club of not securing the timing chain jam tool, despite being warned by my buddy Jeff.

So hours later after removing the timing chain cover its nearly all back together.

I was careful to mark orientation of dizzy drive. just have to reinstall oil pump, water pump, damper, torque head, reinstall the cam gear (more carefully with tool now, which by the way a home made wood one is better IMH, the plastic thing does not fit well and is prone to slipping).

Yeah, I did the same thing. Was really frustrating to have to dig in further for a silly mistake

[siteunseen]

The plastic one I bought lasted one time.  I used it as a template for a new one I made out a piece of hard oak wood.

Garbage...

[Dave WM]

 

[Dave WM]

Its all back together now, just have to find my gasket making material to replace the oil spray bar gasket (one of them failed when removed it cracked off). Manifolds back on, everything hooked up but the radiator. New crank front main seal sine the old one looked like crap. I did NOT bother to replace all the timing cover gaskets. It came off pretty clean, and frankly I just want to see if the test kit still shows exhaust gas in the rad. I can handle some oil leaks. I did replace the water pump gasket since it cracked in have on removal. I did the FSM 3 stage torque setup. The head is still filthy as seen on the video, but the bottom sealing surface looked very good. I will prob be able to fire it off something this weekend. Have to do some other stuff so the engine does not take ALL my spare time.

[Dave WM]

ok no change at all, Still fails exhaust gas in radiator chemical test. Still pukes up water until the thermostat opens ( a lot of water, like 1/2 gallon). Exactly the same as before the head gasket, which is really no surprise since the head gasket looked fine. Guess I should be happy that I did not harm and have now done a head gasket pull. Engine still gets hotter than I think it should with extended idling (guess about 10 min it will get to 180ish even with a 160 T stat and a 3 row alum rad). I figure that has to be something in the head I am missing (or the block I suppose).

I still have the maxima head and another head gasket on the way. I think will put on the maxima head just to see if the same results happen. Its going to up the compression due to the less volume in the head, but I figure it will just be a test to see if I can confirm this darn problem is a head issue or not.

Before I do that I am going to make a proper timing chain holder tool. I realize now I had the wrong tool, It was smaller than what I should have gotten based on pics and now a PDF diagrame of the correct tool.

[Dave WM]

done for now, tried my 75 car engine, it warms up without any water puking, and passes the chem test perfectly. will post again once I get the maxima head on. I retested the spare engine compression test again, 165-170 across all. I also tried pumping up the rad to about 15 psi and then bore scoping the cylinders with a warm engine, could not see any obvious water leaking in. oh well its a mystery for another day.

 

[Zed Head]

Cylinder pressure pushing gases into the coolant channels would be much higher than coolant pressure the other way.  Plus gases are less viscous than water.  Interesting problem.  Good to have two engines to compare.

Here's a thread with some chopped up heads that might show you where a crack or erosion could cause problems.

https://forums.hybridz.org/topic/59029-head-cooling-on-cylinder-5-solutions/page/2/

 

[Dave WM]

I was thinking of trying to disable one cylinder at a time (disconnect FI plug) just as the eruption of water starts to happen (it last for maybe 10-15  seconds) After that the thermostat must open and no more issue (other than the orig problem). If just one cylinder is a problem, I figure no combustion no pressure, stops the eruption of water out of the rad, the water that comes out is not hot at all.

Kind of moot though, I want to see if the maxima head solves the issue, then I will know for sure.

Ok after sleeping on it, the plan is to start one cylinder at a time, remove plug, attach spark lead so spark has someplace to go, disconnect the FI plug. This way there is no compression, no spark, no fuel just a air pump. Then start engine on 5 cylinders and see if the water temp come up without the gusher. Do this on each cylinder away starting cold since I want the T stat to be closed for the test (the gusher does not happen without the T stat inplace).

Hopefully I can at least isolate the problem to a specific cylinder. What I do with that knowledge who knows but still I like to experiment so give me something to do. I can pickup a new head gasket and install the MN47 Tomorrow if I have the motivation for that. I am getting pretty good at removing and installing manifolds now, and since I just installed the head, I don't see any complications on the removal. I suppose I should plane on some 93 octane fuel, but for idle no load testing I assume I will be ok.

Edited May 26, 2019 by Dave WM

[Dave WM]

after some more reading it seems this is a popular combo (N42 block/MN47 head), as my spare engine has dished pistons, perhaps the CR will not be as big an issue as I thought.

[Dave WM]

Test one

left spark plug in, just pulled FI plug #6

started (miss obviously) let it warm up, NO GUSHER, water temp when T stat opened about 165ish per meat thermos on rad neck.

after letting run for a while like this I do the blue chem leak test (pull air from rad thru sieve into blue chemical look for change in color. NO change stayed deep blue.

finally hooked #6 FI plug back on while running engine speed picks up adj idle back down, NO GUSHER but then that was expected since the water was moving freely, but it did FAIL the chem test (could see it change from blue to green, would have been yellow eventually.

So sure looks like I have an issue with #6. Since the ONLY change from gusher to NO gusher was pulling #6 FI plug I will test results one more time, only change will be putting #6 FI plug back on and restart cold engine, if GUSHER then I would say that proves it beyond a doubt.

after that I will pull the head and look under a magnifying glass to see if I can locate any cracks. IF not I guess it could be a block issue, which would be bad since I have the spare head but not a spare block. I will reinstall the new head anyway since I don't know how to test the block. If new head has issues and #6 is the fault, then that would tend to make me think its a block issue since it would seem unlikely that both heads would have the same issue in  the same cylinder.

 

Edited May 26, 2019 by Dave WM