Core plug popped out!

[shleppy]

I boosted 1 time on my eight mile drive to work today and it backfired pretty viciously around 7 grand in first so I got out of it. Around 2 miles from work I noticed the rpms wouldn't go down below 2500. About one block from work, maybe two min later at a light I noticed a little white smoke coming from under the hood. Got to work very quickly without the car overheating and popped the hood and there was coolant everywhere but no leak so I shut it down. I noticed the vacume line from my intercooler pipe to my mbc had come off, which I figured was why it wouldn't idle down. When the car had cooled down I opened the rad cap and no found no coolant(I had just checked it this early this week and it had been full). I then started to fill the rad to find the leak and after putting in half a container of coolant it started pouring out from the now missing core plug right above the tranny. I've never heard of a plug just popping out-does any body have any idea why it happened? I have around 8000 miles on the slowboy stage two shortblock and it's been in the car for around 20 months. The motor was running fine, and there's no coolant in my oil and yes, I've changed the antifreeze many time due to turbo swaps, etc. And slowboy did use sealant since I found a thin round plug it sitting on my tranny.

 

[Goobdog]

The ONLY time ive ever blown a freeze plug out is when I blew a headgasket. The gasket would fail and let the compression go into the coolant passages and pop the suckers right out.

 

[TSIfreek]

The ONLY time ive ever blown a freeze plug out is when I blew a headgasket. The gasket would fail and let the compression go into the coolant passages and pop the suckers right out.

Yea they need exsesive force to blow them out.

 

[shleppy]

I'm pretty sure the headgasket is ok. I'll find out for sure in a few hours when I take the car up to my friends speedshop. I'm just going to put a rubber plug in it so I can drive it, then we'll clean everything up and weld one in. My friend Dj who owns the shop says its common in the 6bolt motors to blow out that plug when running high boost and making good power due to flex and strain on the motor from the location or the motor mounts. He said he blew out the same plug when he dynoed his car. I guess live and learn. If I learn anything else interesting I'll post it.

 

[TSIfreek]

I woudnt weld it in but put JB weld around the new plug before you install it. I have never heard guys blowing them out? I guess J shep blows all his out on a 45 psi pass???

 

[TwoLiterLaser]

I would only weld that if you are never going to have that block machined ever again. I would not even JB weld it. It is possible that it was seated incorrectly or that it was faulty. No point in ruining a block just from one freak occurrence...

 

[GVR4592]

I'm pretty sure the headgasket is ok. I'll find out for sure in a few hours when I take the car up to my friends speedshop. I'm just going to put a rubber plug in it so I can drive it, then we'll clean everything up and weld one in. My friend Dj who owns the shop says its common in the 6bolt motors to blow out that plug when running high boost and making good power due to flex and strain on the motor from the location or the motor mounts. He said he blew out the same plug when he dynoed his car. I guess live and learn. If I learn anything else interesting I'll post it.

Your friend must be misinformed, because that is not true. The freeze plug most likely came out beause of faulty installation. Was there any kind of locking compound or sealer on it?

 

[red91gst]

Your friend must be misinformed, because that is not true. The freeze plug most likely came out beause of faulty installation. Was there any kind of locking compound or sealer on it?

Actually, I've seen this happen a few times, twice on my car while on the dyno. I always took out the one above the trans or in the back of the motor right above the motor mount. At big power levels the block distorts enough that it can chuck a freeze plug.

The reason Shep and Rau don't is because the motors are hard blocked, all coolant passages filled with cement. Can't blow them out if theres not coolant in the block .

I actually fixed it with a rubber, excuse the lack of the proper name, hole plug thingy from Advance Auto. Its a rubber plug with a metal washer on either side and a stud with a nut that runs through the center. Stick it in the freeze plugs hole, tighten the nut, and the rubber expands to plug the hole. I ran all of last season and went very low 10s with that little guy in there.

Nate
TPG

 

[shleppy]

Cool, thanks Nate. I put a new one in myself and just jb welded it. I guess I'll see how long it stays in. At least now I can get the entire job done in two hours if I have to.

 

[GVR4592]

Actually, I've seen this happen a few times, twice on my car while on the dyno. I always took out the one above the trans or in the back of the motor right above the motor mount. At big power levels the block distorts enough that it can chuck a freeze plug.

The reason Shep and Rau don't is because the motors are hard blocked, all coolant passages filled with cement. Can't blow them out if theres not coolant in the block .

I actually fixed it with a rubber, excuse the lack of the proper name, hole plug thingy from Advance Auto. Its a rubber plug with a metal washer on either side and a stud with a nut that runs through the center. Stick it in the freeze plugs hole, tighten the nut, and the rubber expands to plug the hole. I ran all of last season and went very low 10s with that little guy in there.

Nate
TPG

There's a bit of a difference between the 650+whp you made and the 400 or so he's making. I myself have never had one come out up to 500whp, but I always use loctite on them.

 

[shleppy]

Actually not trying to bench race, but we are estimating closer to 475-500whp. Last night we logged an accurate 53.2 lbs at 28psi with 16 degrees timing and zero knock at 7450. I've done 4 pulls against a supra thats done a 10.9 and we were dead even. I really just ned to get it over to nate to see what it does but I'm real short on cash right now. Currently I'm still tuning to get rid of some minor issues before we take it to the track. Plus I think I can still add a bit of timing and I have to hook up no lift to shift. However most likely it was a combination of it not seating properly on a fairly new motor plus high boost and strain. Thank god it wasn't the head gasket as some suggested.

 

[TSIfreek]

Thats great everthing worked out (remember this only a few times this will with dsms). What fuel are you using??

 

[shleppy]

I'm using 93 plus 50/50 mix of water and meth. I'm still on the compressor map for the turbo at about 68% efficiency so intake charge temps are still pretty low. This should give me a bit of room left to play with the timing.

 

[Hammer_Gaidin]

The only time other than headgasket i've had one blow out was when the plugs I got were the incorrect size. I was given standard instead of metric. So now i just order them from the dealer.