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Freeze Plug Gone!


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When I have had time over the last month or so, I've been working on tuning my freshly built engine.  I'm using a wide band O2 sensor.  I had just recorded a few runs to the Innovate LM-2 SD card.  I pulled off the interstate and swung around to the on ramp on the other side to go the other direction.   I stopped on the side of the on ramp... pushed record, and eased away in first.  I ran through the first 3 gears pulling just north of 7000 in each gear...

 

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I slowed down and merged onto the interstate and stopped recording.  But within a 1/2 a mile, I noticed some very light  smoke spiraling off the right rear of the car.   Since the exhaust is on the left, I really didn't know what it could be.  I pulled over, popped the hood and ran to see what was going on.  Immediately I see fluid around the starter area.  I wipe some with my finger and smell it - it is coolant.  I yanked on a couple of the hoses, but didn't see any coolant spurt out.  The hoses looked fine.  So, not knowing how much coolant I have lost, I run to check the temp - (the car is idling) and see the guage is at about 240 - definitely south of 250.  A tenth of a second later the car is off.  While I am waiting for the car to cool down, I keep looking until I see the problem:

 

post-4218-0-28345000-1364174398_thumb.jpg

 

So... how the heck?!  I've never heard of anyone experiencing this before.  I am aware that there are mods that are done as precautions...  In fact, I have an old Bob Sharp prepared L-20B block that I have been hanging onto forever, and it has these:

 

post-4218-0-72751100-1364174419_thumb.jpg

 

I don't have a handle yet on how much power my engine is putting out, but I wouldn't have thought this mod necessary.  My front timing cover is modified for a Maxima diesel pump, but I am running a stock pump because I haven't been able to locate one.  Don't see how this could be an issue...  

 

Anyone else have this happen to them?  Engine seems fine, by the way.  I think (and hope) that I caught it in time.

 

Garrett

Edited by inline6
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Sealant doesn't hold those in. The interferance fit does. I'd look at the plug being not installed correctly or the wrong size (metric vs. standard) plug being driven in because "it's close enough".

 

In this case, I got the plugs from Nissan.  Of course, it is possible that it wasn't installed correctly but that brings up the question.  How does one install them correctly?  Is there a trick to it?  The engine builder said he uses a 1/2 drive socket of a suitable diameter to fit inside the cup... but as close to the walls as possible.  And he has a old 3" long, half inch drive extension that he doesn't mind beating on with a hammer (or something like that).  He also said he put a little bit of Permatex on there.  I think you can see that in the pic.  Could the Permatex be a problem?  I wouldn't think so...

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I had the same thing happen to me, My freshly rebuilt motor with deisel pump was one lap into the first track day and I used exactly the same method as you. I had done many months of road driving before the track day with no issues. I refitted another plug at the track to enable me to get home.

 

Afterwards I ran a bead of JB Weld around all the plugs similar style to your picture above, no issues since. I applied it with an angled syringe to allow easier access under the headers.

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Very common, actually. Most engine builders will stake them into place as the Welsh Plugs just don't stay in place with pressure surges.

 

Put a gauge on your pump outlet , my bet was at temperature you were well over 45 psi on that plug. Generally 45 + 15psi cap = 60psi in the lower block.

 

I would think a good surface prep on plug and block and JB weld with a stake in three places should do it.

 

I have seen some builders use less aggressive sealants, but use some small machine screws and washers to hold the plugs into the block.

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"I used exactly the same method as you."

 

Afterwards I ran a bead of JB Weld around all the plugs similar style to your picture above, no issues since. I applied it with an angled syringe to allow easier access under the headers.

 

Which method are you referring to - just installing the welsh plug with some Permatex? 

 

Very common, actually. Most engine builders will stake them into place as the Welsh Plugs just don't stay in place with pressure surges.

 

Put a gauge on your pump outlet , my bet was at temperature you were well over 45 psi on that plug. Generally 45 + 15psi cap = 60psi in the lower block.

 

I would think a good surface prep on plug and block and JB weld with a stake in three places should do it.

 

I have seen some builders use less aggressive sealants, but use some small machine screws and washers to hold the plugs into the block.

 

I have an "18-22 lbs." Stant radiator cap.  Any idea what stock rubber radiator hoses will handle? I have rubber upper and lower - though I have  a Jags That Run (JTR?) radiator kit that utilizes some metal connector sections in the middle of both the upper and lower hoses.

 

I am told the "rivets" in the pic I posted above are called "U drive screws".  

 

http://www.smithfast.com/udrivescrew.html

 

I'll go ahead and clean the opening and install a new plug.  Then, I'll fill up the cooling system with water so I can run the engine a bit and do a couple of tests... before I pull the motor out of the car and install U Drive screws on each of the plugs.  

 

Garrett

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YES! They are also called Rosette Rivets as well. OEM's will use them to attach data plates to castings. I didn't mention them because I couldn't tell you where to find them! I stole a ziplock bag from the production floor in either Davidson or Export...some time ago, probably Davidson, but could have been Holyoke as well... 

 

Small sheetmetal screws are similar in action.

 

Real high-dollar answer is to get a flush-seal plug that size and tap it (like in the head under the valve train...)

 

Unless you are a production shop, the cost for the two or three tap sizes you would need could be considered "prohibitive"... definitely not NPT!

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Which permatex?

 

I'm not a big fan of the non-hardening brown stuff because I've seen this happen before as well as seen gaskets using non-hardening permatex products actually squeeze out from between the two parts they are sealing a few hours later.

 

You come out the next morning and find gaskets sticking out.

 

Some swear by no sealant at all but that strategy depends on a perfect surface.

 

At toyota, I used only a very thin film of their red threadlocker and installed them right before I went home.

 

I like loctite 603 or 609 now.

Edited by HowlerMonkey
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Looky what I found -  :-D

 

post-4218-0-70277500-1364955672_thumb.jpg

 

I just assumed it was gone on the road somewhere, but when it came off, it managed to shoot out of the motor hard enough to land on the passenger side frame rail and get caught there.  

 

Anyone see anything unusual about it?  

 

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I'm not feeling great about the job I've got ahead of me of taking the engine out and installing the u drive screws... especially since there is a welch plug behind the front timing cover.

 

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Using a hand drill to drill holes in the assembled block for these screws...  Ugh.   :ugg:

 

Edited by inline6
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Happened to me at Pocono. Permatex on the new one and good for the last 7 years.

 

Joe

 

 

Same here - Permatexed mine because I built the 3L block at Rags house. Seriously though I have always seen people use permatex when installing "freeze/core" plugs. 

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