New Engine Burning Coolant!
08-09-2003, 11:06 AM
#1
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Thread Starter
Join Date: Jul 2001
Location: S. Florida
Posts: 629
After working through porting, rebuilding and installing my Cosmo 13BRE into my 95 FD, it now appears to be burning coolant. First big, white cloud of smoke appeared yesterday at startup.
I've been upping the boost slowly and tuning as I go (PFC w/Datalogit and wideband o2). I'm now up to about 8kg/cm2. I noticed last week that the car was running a bit rougher and I believed it to be nothing more than needing new plugs as the plugs (non plats) in there were installed when the new motor was dropped in. I'm at about 3500 miles on the new motor. Break-in was 1,500 miles and I went to extensive lengths to keep temps in check. They run between 82 and 87 celcius with a front mount. If the sun doesn't come out, it'll sit at 80 forever.
Now the rough running has been coinciding with boost increase but my vacuum readings at idle have not changed. I monitor everything and knock hasn't been present (most of my readings are single digits with 39 being about the highest ever).
Yesterday I did a short run in third to log some data. I get home and the engine is running rough. Look at the logs. Fuel is fine. No knock. I shut it off. Start it again, big plumes of white smoke and the tell-tale sweet (ironic) smell of coolant. I shut it off in disgust and go in for the night.
Here's where it gets wierd. I get the same thing in the morning. Hard to start, coolant smoke coming out the back. It clears up a bit and I drive down the road (did the same thing leaving from work the day before). Eventually it clears up. Idle is fine. Buttery almost. Vacuum is right where it should be. If I boost however, especially above .5kg/cm2, it'll run rough and blow white plumes out the back after shutting the car off and turning it back on.
I have no doubt it's a coolant leak which is allowing coolant to get into the combustion chamber. What I'm wondering is why does it get better as the car gets warmed up (metal expands, provides better "sealing"?) or is the pressure of combustion keeping the coolant in place? I boost and it forces the combustion pressure in and some coolant out? Just seems like it would leak ALL the time and steadily get worse as the car warmed up.
We'll run some tests on Tuesday and probably end up pulling the motor again. It's really getting old. I honestly don't think the motor was torqued correctly and/or the tension bolts and threads were not cleaned which causes a bit of separation between housings/plates under boost. An OEM motor should be able to withstand 2.0kg without dowel pinning...you'd think 8kg would be nothing!
I've been upping the boost slowly and tuning as I go (PFC w/Datalogit and wideband o2). I'm now up to about 8kg/cm2. I noticed last week that the car was running a bit rougher and I believed it to be nothing more than needing new plugs as the plugs (non plats) in there were installed when the new motor was dropped in. I'm at about 3500 miles on the new motor. Break-in was 1,500 miles and I went to extensive lengths to keep temps in check. They run between 82 and 87 celcius with a front mount. If the sun doesn't come out, it'll sit at 80 forever.
Now the rough running has been coinciding with boost increase but my vacuum readings at idle have not changed. I monitor everything and knock hasn't been present (most of my readings are single digits with 39 being about the highest ever).
Yesterday I did a short run in third to log some data. I get home and the engine is running rough. Look at the logs. Fuel is fine. No knock. I shut it off. Start it again, big plumes of white smoke and the tell-tale sweet (ironic) smell of coolant. I shut it off in disgust and go in for the night.
Here's where it gets wierd. I get the same thing in the morning. Hard to start, coolant smoke coming out the back. It clears up a bit and I drive down the road (did the same thing leaving from work the day before). Eventually it clears up. Idle is fine. Buttery almost. Vacuum is right where it should be. If I boost however, especially above .5kg/cm2, it'll run rough and blow white plumes out the back after shutting the car off and turning it back on.
I have no doubt it's a coolant leak which is allowing coolant to get into the combustion chamber. What I'm wondering is why does it get better as the car gets warmed up (metal expands, provides better "sealing"?) or is the pressure of combustion keeping the coolant in place? I boost and it forces the combustion pressure in and some coolant out? Just seems like it would leak ALL the time and steadily get worse as the car warmed up.
We'll run some tests on Tuesday and probably end up pulling the motor again. It's really getting old. I honestly don't think the motor was torqued correctly and/or the tension bolts and threads were not cleaned which causes a bit of separation between housings/plates under boost. An OEM motor should be able to withstand 2.0kg without dowel pinning...you'd think 8kg would be nothing!
08-09-2003, 12:17 PM
#2
Senior Member
Join Date: Jun 2003
Location: Grand Prairie, TX
Posts: 917
Who rebuilt the motor? What's the history on it?
It does sound like that either one of the rotor housings is warped (tell tale sign is the lower dowel pin will be stuck in the housing) or one of the inner water jacket o-rings is pinched (likely, seeing how the engine is new and could've happened during assembly).
B
It does sound like that either one of the rotor housings is warped (tell tale sign is the lower dowel pin will be stuck in the housing) or one of the inner water jacket o-rings is pinched (likely, seeing how the engine is new and could've happened during assembly).
B
08-09-2003, 01:17 PM
#3
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Join Date: Jul 2001
Location: S. Florida
Posts: 629
True true...I did think about the pinched ring. It's a used Cosmo 13B RE imported from Japan. Took it apart and it looked virtually brand new inside. We used new everything inside with upgraded stationary gears, oil pressure regulator, etc...anything that was better in the FD's design we used on the Cosmo. The shop (remaining nameless for the time being) said everything was checked including the plates for warpage, etc...I do know that if you don't clean out the threads and bolt holes, it'll give you improper torque readings as well.
08-10-2003, 04:55 PM
#6
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Thread Starter
Join Date: Jul 2001
Location: S. Florida
Posts: 629
I tell you though, it's really wierd. I'll get rough running immediately after boosting. No smoke. I shut the car off. Start it up again after letting it sit, smoke. Run the engine for a bit by driving it around and it clears up. I can drive it all day at very small boost levels or no boost at all and it runs as normal! Normal vacuum, etc...
I actually didn't put the engine together, a local shop did. I'll be a bit better educated on what I'm going to do when I pull the engine and take it apart. Who knows, I may be calling Judge to build me an engine :-)
Michel
I actually didn't put the engine together, a local shop did. I'll be a bit better educated on what I'm going to do when I pull the engine and take it apart. Who knows, I may be calling Judge to build me an engine :-)
Michel
08-10-2003, 08:57 PM
#7
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Join Date: Jul 2001
Location: NJ
Posts: 17,839
don't call him yet. he is on vacay in puerto rico. i told him to bring me back something cool 
my engine is great.... its the only thing i don't have a problem with. its everything else that i break.... now having ignition problems woohoo
my engine is great.... its the only thing i don't have a problem with. its everything else that i break.... now having ignition problems woohoo
08-10-2003, 09:42 PM
#8
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Join Date: Dec 2002
Location: Misawa Japan
Posts: 826
I was in the same boat as you were, after putting it back in just to have the same problem. I ended up having a small crack in the front intake port that was let the coolant in. I wasn't the best person to be around that week.