Rb25 Neo, Overheated & Locked, Cold & Its Ok

[Lopin18]

Well today i kept testing my rb25 swap, left the laptop at home so i didnt have any Coolant Temp readings.

Seems i left all my luck at home, i blew the coolant hose that comes from far back of the block, lost all coolant while driving home.

At one point i saw smoke behind me and the engine died in the traffic light as i stopped. It would crank 1 turn and then stopped, like it was stuck. After some minutes it cranked and started.

Kept going, idle was kind of rough, light smoke from the tail and died, did the 1 crank turn and lock thing again.

Long story short, i traveled SEVERAL miles, until it turned off again a third time and i saw the smoke from the broken hose.

Checked Oil, looks ok, engine was smoking from the head breathers. I was overheated as $!@%!@%.

Fixed the hose, let it cool down, water in, and the engine was ok again, feels good, oil still good, coolant looks not contaminated. power feels ok.

Havent tested compression but could i be seeing damage to the piston skirts or cylinder walls?
I found that cranking lock really weird (imagining the pistons expanding and locking in the cylinders), first time i had seen that happen in engines ive tried. (not that i overheat them)

Not gonna sleep today at all.

[75coupe]

So you continued to drive even after seeing smoke, it was hot so you started it again and drove...

At what point did you not see the temp gauge and thought hmm its really hot and there is smoke maybe i shouldn't continue to drive it considering it stop whilst driving as well...? Are you trying to invoke engine dramas?

[Lopin18]

RB25 on a 240sx, so i have no working temp gauge yet, i was using consult in the laptop to check it, which i left at home, today of all days. Wish i had seen the smoke clearly, seems all the water was out, there were no big smoke signals, only very light puffs of smoke from the starter area, and since the starter seemed to be "locking" i thought it was it going bad.

In all the drama i didnt even feel the block heat. Too focused on the starter. Lost sight of all the little details :|

Just ordered a comp tester and a borescope.... Lets see whats up by Thursday

Edited May 11, 2014 by Lopin18

[Ben C34]

It's dead.

A temp gauge is pretty cheap for next engine.

[GTSBoy]

^^agreed. Everything will have been rooted. Cylinder head could quite easily be damaged. Pistons/bores more than likely. At this stage the ONLY thing you can do to that engine is dismantle it and see how bad it is.

[75coupe]

You can usually tell if an engine is overheating when driving, it just dont feel right... If you could see smoke off the starter you would of been able to feel and hear the heat in the engine bay surely, what a waste!

[Adriano]

I would just drive it, any damage is already done, nothing to lose

[Blackkers]

doesn't sound good mate. I would continue to drive it though, you never know

[Lopin18]

After repairs, i did drive it home, weird thing is that it felt exactly as before, no hesitation, no problems boosting, nothing, all the same, oil looked ok etc.

Hopefully luck was on my side, but testers will say. Worst thing is the starter locking up signal.

Edited May 11, 2014 by Lopin18

[Lopin18]

Comp tested. Cil 1,2,4,5,6 165-170 psi

Cil 3 150 psi. Added oil, 175 on cil 3

Engine was cold. I think i dodged a bullet....

[scotty nm35]

The piston in cylinder 3 most likely expanded due to the heat and grabbed in the bore. It will have scuffed the bore and piston skirt a little, but you may get a fair life from it, depending how bad.

[Lopin18]

Well, light random puff of white smoke from the exhaust, light graish color on the oil cap (its night and its rainy so i dont really know on both signs) but i think i blew a headgasket.

Teardown is going to happen. Thanks guys. Time to pay for my carelessness

Edit: Race mechanic going to check the car, says theres hope. Lets see what happens.

Edited May 12, 2014 by Lopin18

[Shibbby]

Stock head gaskets are a great fail safe and I'm gonna say their might be hope for ya yet

Whip the head of anyway and do another stock gasket and inspect the bores.

Fairly easy and common mistake when doing engine conversions after a long last stretch getting it running etc with no instruments hooked up and being tired and excited.

Hope it works out for your mate

[BrynDETT]

lol .. use the standard ca24 temp sensor.. it should just thread in...

[Lopin18]

Ohhh boy im so relieved. Sunny day. Started the car again. Checked everything, no signs of smoke or misfires or contamination. No bubbles nothing.

Heated the engine to 80c running good. Tested again revving etc. No signs of anything wrong.

Compression tested again and im getting 180 across the board.