Spark plug and cooling issue...

[KC240RB]

So for my new setup I went with a BKR6E spark plugs. I tried to get BKR7Es but the autostore did not carry it. So I settled. I gapped all the plugs down to .032". Took the car out for the first time with the new turbo and supporting mods. Car pulled great in first then even harder in second and in third the car was just plain rediculous. So I call up a friend to see if he would race me with his 592 RWHP '03 Cobra. He came over and we did a highway pull. Started in second gear... As we take off we are dead locked until I shift into third, where I start to pull away. As I shift into fourth gear the car begins to pull then starts stumbling all over itself. Thats when the car began to smoke. I pull over and find out the coolant is all over. Temp gauge read warm but nothing that ever concerned me. So I immediately thought head gasket. Checked the dipstick and it showed no signs of coolant in the oil. So I have another friend tow the car home where I then pull the spark plugs. Here is a picture of what I find. What could of caused this? I was running some race gas. Also I was thinking about the cooling issue today. I am not sure if I did this right but the stock RB20 turbo is water/oil cooled. The new turbo is a Holset WH1C and they are just oil cooled. So I plugged the coolant lines up. Should I had connected those? Thats the only thing I could think that caused that problem.

In order 1-6 cylinder (left to right)
Modified by KC240RB at 6:02 PM 9/21/2009

[KC240RB]

After some reading I see that my plugs could be caused to thermal expansion due to sudden heating and cooling. Is this a good indication to go to a step colder plug? BKR7E for example...?

[Joe]

you are worried about your plugs when you sprayed coolant all over?

your priorities are backwards man.

[KC240RB]

you are worried about your plugs when you sprayed coolant all over?

your priorities are backwards man.

LOL. Just keep adding coolant right? I am pulling things apart to check out the issues, but just curious what plugs people are using with power in the 350 RWHP range. I heard both BKR7E and BKR6E. The BKR7E's are cheap so I'll just go grab some of those. Also did you see I asked about the coolant lines? Was I not suppose to block the lines going to the stock turbo? That would help me move on with that scenerio. I am going to do a compression check tomorrow night.

[PorkChopExpress]

did the detonation knock the insulators off? id look around in your cylinders ,valves, turbo

[KC240RB]

my wideband shows me at 11.8 first coming into boost then by redline at full boost it's reading 10.9. never above 11.8 while in boost. so i dont see why there would be any detonation.

[PorkChopExpress]

dont know if you had knock or not but it doesnt look like there are insulators on one, four,and six. they dont just fall off.if so id check around those cylinders for them, compression test and check your turbine for damage.

[gawdzilla]

After some reading I see that my plugs could be caused to thermal expansion due to sudden heating and cooling. Is this a good indication to go to a step colder plug? BKR7E for example...?

sorry to say this, but it's a good indication to start shopping for a new motor.

this reads more like:"I put a big turbo on my rb20, tried to race my friend without a proper tune, and detonated so bad that 3 of my spark plugs shattered"

do a leakdown test and see what kind of damage you've done. the ceramic from the plug and the metal tips don't just go nowhere. they destroy your motor.
Modified by gawdzilla at 8:37 AM 9/22/2009

[240z4u]

You walked a 600hp cobra with an rb20? Your buddy is full to the eyeballs with crap if thats his claimed dyno number.

You detonated those insulators off. Ignition timing? High intake temps? Fuel isnt the only reason for detonation.

[KC240RB]

I'm going to do a leak down and compression test tonight. I will also take a picture of my setup and see if maybe I should reroute something. I tried cutting down on heat by header wrapping the exhaust. but the intake and cold side of the intercooler was warm too. Is it possible to melt or burn the isolators away? Reason I ask is because they look like they've been melted away and not broke. As for timing I'm not sure where CarlH tuned my setup to.

[WhatsADSM]

At least you won!

Good AFRs is not the end all be all to detonation. Poor timing and/or fuel octane is more often what causes detonation.

I doubt they melted off, typically the plug electrode tip will look clearly melted if stuff gets too hot in there. Sure looks more like detonation to me.

As a side note I also agree with 240z, no way a 600rwhp cobra would lose to a 350whp 240 especially at those higher speeds.

[KC240RB]

well, i'm going to pull all the gas out of the tank and get some fresh premium in there. after i make sure everything else checks out.i agree a 600+ hp cobra should not lose to a 240sx such as mine. but I have a great weight reduction to mine and weighs in at 2,700, where his cobra weighs in at 3,700. so that helps me some.

[Carl H]

that looks like detonation, but even running one of my tunes you shouldnt get that all.i set timing rather conservatively...insulators look like you're running something else here; coloration doesnt look like proper combustion.a customer of mine had his cas slip and end up at 15* advance over base and still not have issues...

what kind of gasoline is in the tank?what is your base timing set to?what is your base fuel pressure?Boost pressure?any kind of power adder ontop of the system?

[240z4u]

How old is your fuel that is currently in your car?

[KC240RB]

that looks like detonation, but even running one of my tunes you shouldnt get that all.i set timing rather conservatively...insulators look like you're running something else here; coloration doesnt look like proper combustion.a customer of mine had his cas slip and end up at 15* advance over base and still not have issues...

what kind of gasoline is in the tank?what is your base timing set to? what is your base fuel pressure?Boost pressure?any kind of power adder ontop of the system?

Well, I am going to hold my head down in shame right now. I had my sister go grab me some race gas. LOL, so I thought. Come to find out she had forgot to where I said to get the gas and asked a guy friend. He said to just go to the local airport and just grab 100 LL. So I was running leaded fuel. Boost gauge only reads 15 psi and pegged it on the few runs I made. The boost controller is set all the way down and just let the wastegate open at 1 bar. So I am going to grab a new gauge to verify it is in fact 1 bar. No power adder on top. I have never messed with the timing but I have had the CAS off and on a few times so I better go check and see where the timing is at? Any recommendation to where I should set the base timing?

As for the cooling issue, I still have the stock radiator in place with two 12" electric fans (one on the front side and one on the back). Not sufficient enough huh? After I do the leak down and compression inspection I am going to pull the radiator out and get a upgraded one immediately.
Modified by KC240RB at 6:41 PM 9/22/2009

[Carl H]

1 bar = 14.7psi...if it was going higher than you're running more boost than you think.o2 sensor will need to be replaced as leaded fuel is death for the sensor...what kind of fuel pump is in the car?

[KC240RB]

1 bar = 14.7psi...if it was going higher than you're running more boost than you think.o2 sensor will need to be replaced as leaded fuel is death for the sensor...what kind of fuel pump is in the car?

Running the 255 lph walbro.

[KC240RB]

Here is my setup. I did all the work myself and if you see something that looks odd or needs changed please let me know. Thanks.

[KC240RB]

Now here are pictures of my compression check... Cold tested since I dont want to start the car until other issues are resolved.

Cylinder 1

Cylinder 2

Cylinder 3

Cylinder 4

Cylinder 5

Cylinder 6
Modified by KC240RB at 6:17 PM 9/23/2009

[mott6904]

from those numbers you melted some s***. Now its time for a rebuild.

[240z4u]

I totally disagree, actually looks alright to me. The percentage of variation is very low.

Evan

[mott6904]

90 psi doesnt seem low to you

[240z4u]

90 psi doesnt seem low to you

It is low, however a cold motor and a closed throttle plate could yield numbers like that. I would be shocked to find out he damaged ringlands in every cylinder.. however impressive that would be.

OP, was the throttle WOT when you did this?

I wonder if the timing belt jumped now...

[MoogLe]

were you doing WOT cranks during the compression test??

unless you have a VERY thick head gasket and maybe low compression pistons those numbers sound extremely low to me.

i got 145psi across the board last time i did mine and i associated the lower numbers with my 1.7mm headgasket and that was with a COLD motor

[KC240RB]

Motor is stock. The compression test was with the throttle wide open. From my readings of other cold compression tests these numbers were very similar. I will do a warm compression test tomorrow after I get off work. See if I see any better results. I am not going to tear the motor down just yet. LOL. Wife won't be happy if I have to rebuild, but I wouldn't mind beefing up the internals.

[240z4u]

Motor is stock. The compression test was with the throttle wide open. From my readings of other cold compression tests these numbers were very similar. I will do a warm compression test tomorrow after I get off work. See if I see any better results. I am not going to tear the motor down just yet. LOL. Wife won't be happy if I have to rebuild, but I wouldn't mind beefing up the internals.

KC, I have a friend in IL who has a fully built 25 longblock with forged pistons etc... that has never been started. Email me if you want his information, it would be a fast turnaround if your head is in good shape.

Still seems odd to me that the compression is low on all cylinders by the same, Do a leakdown test, you may have slipped the cam timing belt.

Evan

[l0nestar]

Numbers seem fine. I would verify the timing belt hasnt skipped a tooth, then re-install the timing cover. After that, I would look into a leak-down test.

[mott6904]

So after seeing the melted spark plugs and low compression numbers you think there is no engine damage at all? Where did the melted pieces go? I have never seen a spark plug melt like that and not have any engine damage.

[240z4u]

So after seeing the melted spark plugs and low compression numbers you think there is no engine damage at all? Where did the melted pieces go? I have never seen a spark plug melt like that and not have any engine damage.

On the contrary, I just don't expect to see lower end damage honestly. Unless he damaged every cylinder which is unlikely. Valves that don't close properly and or cams that are out of time would create a low compression reading.

Evan

[KC240RB]

On the contrary, I just don't expect to see lower end damage honestly. Unless he damaged every cylinder which is unlikely. Valves that don't close properly and or cams that are out of time would create a low compression reading.

Evan

Yeah I agree.

I did not have time to inspect the engine further tonight, but I do want to thank you all for giving me ideas in what I should inspect. Had I not asked for advice I would have probably got carried away and tore the engine apart since my mind was just racing with other things. I will inspect the belt and base timing, also do a warm compression test tomorrow night. It will give me a good reason to get away from the wife and drink some beers.