I'm having a few problems.

My motor is a 408" stroker, 11.5:1 w/ .051 cometics and ARP studs. I'm using trickflow heads (nice thick decks), and it was all built/assembled by LME. I've now got 100hp pills in my Nitrous Outlet plate and have run about 3/4 of a bottle. The car is running about 11.5-11.8 on spray, 'bout the same on motor.

I'm running TR6's gapped at .035 and 22* of timing. I am showing some detonation on spray, none on motor. I ran it a few times in a row and the detonation got worse and worse. I could even hear it inside the car. When I got home, coolant had come OUT of my radiator cap and sprayed on the fender/battery. This happened 2 weekends in a row. The first weekend I almost slung the crank pulley off, but I fixed it. I attributed the coolant spray to that (hoped that was the problem lol), but it's still doing it with that problem solved. I checked a few of the head studs and the few I could get to clicked the wrench at 70 ft-lbs, didn't try it any higher than that.

I'm making 530+rwhp N/A. I've got a makeshift overflow "test bottle" made from a coke bottle and some hose to test if it pushes with a new radiator cap too. The stock cap has been on since 1997 and for 13400 miles. I've heard of people pushing water and solving the problem with a new cap lol.

I was told those plugs in my motor would be fine to a 150-200 shot, but I'm thinking they may be a bit warm. Could they be glow-plugging on me at these levels? I think I may kick it down to 20* timing and put in TR7's, does that seem like a good thing to try before I pull the heads? Help me out here guys, I'm ready to pill it up!!

-Casey

PS - I'm running Shell 93 octane.

 

Sounds as if you may not be logging your runs, as you don't mention how much knock, and say you hear it? Anyway, that's why I log every run at those levels, which you have to consider overall HP not just your spray size. I was running 18* on mine when hitting just over 600rwhp. You really need to be reading your plugs to see where you need to be and/or can be with the timing. So, very hard to do diagnostics over the net. With that said, pushing water already, at that level, hmmm... You sure your not just getting hot? I guess your puke bottle will tell, and what was your engine temp after your sprayed run? If you don't have a log, that would be another reason to have a tuner program, so as to go back and look for anomalies. Just some thoughts here. You may want to do a leak down test before spraying again, as that could make matters worse not knowing where you stand and spraying again. good luck
Robert

 

While I dont have a good answer for you someone may chime in for me. I am going to be running Autolie 103's (AR103) lots of myfriends and the local guys are running these for spray because you dont have to file the ground at all. Anyone else used these?

 

Good point, and I forgot to add that I have melted down the tr6 with to much timing and about 550+hp. I will only run the tr7 now, as they do not have the extended tip like the tr6. We should all know by now that the tr6 is not the best plug for spraying, IMO. Yea, I am not real sure anyone will have a definitive answer, but may luck out and guess the issue out. We need a little more info on this particular run, or at least some diagnostic info.
Robert

 

I was logging with hpt. I was showing 2* of kr, which is what I have set for max wot now that I think about it. My knock sensors have always been bitchy even after updating (98 model), so I put a restrictor plate on them in the tune lol.

The coolant temp never gets above 185 or so. I was just spraying for maybe 2-3 seconds at a time, not making full runs, it does not have a lean spike either. I have a long straight freshly paved "testing strip" near my house lol.


It may be getting hot just for that short time though, I will have to look at the log when I get home. I also think that if the radiator cap letting it spray all over the engine bay, there has got to be a problem with it. the rubber part was kind of jacked up after inspection.

This motor was built for a 300 shot, it shouldn't even notice a 100 shot lol. I sure am hoping that its just making a little heat and it's not a head gasket.

 

once you push water the gaskets are never the same. also 93 octain is probably your issue with your set up.
log all you want do all the fancy computer crap i guess it works, but imo its to much compression with spray, and im guessing you must have a cam that holds cylender pressure so the hole mix with shitty 93 octain and 22* is your issue. again, its my opinion so computer logging guys dont get mad at me.

 

ps, what do your plugs look like?

 

Sounds like too much compression/timing for the fuel, or not enough octane, depending on how you want to look at it.

ONce it's done the whole pushing water thing once, you're changing the gaskets if you want it to stop, they are not gonna seal back up right after that. If it's doing it as bad as you're saying, I bet a dyno pull n/a would probably push water at this point.

You're pulling heads, and swapping gaskets.

Now, for the future to get this to not happen again, with the compression you are running, if you are going to continue with pump gas I'd put the timing back to 18 degrees and start there for starters. The a/f is probbaly o.k., i'd get it back to about 11 to 1 on the bottle though, to be safe. What jet sizes are you running to get the 100 shot, not every kit is the same, hell I've seen the same kit from the same manufacturer come with different jetting, so go figure. Another thing you definately need to do, and I preach this to people even though 99% of the idiots on this website don't listen, START WITH A COLD PLUG ANS WORK YOUR WAY UP! the #6 plug is probably ok n/a, but with the nitrous it is too hot for sure with your setup. stock compression that plug is o.k. with a 100 shot, no more then 100, and no more compression then stock. You need to be running that plug with your compression, nevermind with nitrous. Get a set of #8 and #7 plugs, start with the #8 and see how they look. IF you aren't seeing any signs of heat in the #8 after a run go to the #7... but if the #8 shows a little heat, then that is what you need to be running on the juice. Yes they will foul out easier in traffic or by letting the car idle, all I can say is live with it, it'e better to foul a couple plugs out then to melt stuff, send head gaskets for a ride out the motor, that type of thing.


I don't even have knock sensors, so I can't even tell anything by what they are doing, the only way, I repeat the ONLY way to really tell what's going on in the motor is to make a run on fresh plugs and pull EVERY single one, and read them. Tune off that, and you will stop hurting stuff, rely on the computer, and you will become an expert at taking that motor apart in a real hurry.

 

mine did it at 600 rwhp. popped the gaskets apparently and just kept getting worse til it wouldnt even spray anymore without loosing a large amount of coolant and running like ***. put new gaskets in and walla. all good.

 

jl, for what its worth, i run my car with 14-1 compression and high timming with tr6 plugs, NA and with the 100 shot with no issues. a hot plug is more prone to melt faster making the car nose over sooner leaving you a little extra time to get out of it befor you melt a pistion. the plug thing is pretty much bs. you will see that once you start messing with the spray a little more alot of it has to do with octain, cylender pressure. if your cam isnt working right it can hurt you.

 

Brad you can do whatever you want, but what I suggested is safe and will not get more parts hurt in the guys car.

Most people on here won't ever notice anything nose over, they'll stay right in it until there's a hole melted thru the head if the end of the track doesn't come first.

 

nothing for nothing but ive been messin with spray for a while now, and im a cold plug melts much slower and at a higher temp in turn melting parts more easy then a hot plug. a hot plug is going to melt and put out the fire befor the pistion melts there for nose the car over. by the time you melt a cold plug its probably to late. trust me. yes once a car is tuned in a cold plug works, but a tr6 will work fine in his set up. its and fuel with to much cylender pressure. also, the timming at 18*, is not nesesery either. i used to think so, but it isnt again i tried it all

 

No not mad, it's just looking at some good logging you can usually find something out of whack. A good gut feeling guess does work for some, I know my car well enough and have been a mechanic for a long time so I can actually sense/feel/hear an issue. However, this last time I had the melt down I did not hear it stalling out/nosing over, and when i went to the logs there was mucho info to digest, and I was able to pin point that the timing was being added not pulled Try that one with a guess, lol, you would never know, and thus a place for logging on the new tech cars. I think both work well together. Now, do we even know yet if it pushed water?

Brad you are correct on the plugs, however, here's the issue, one small problem and the extended tip tr6 turns into a blow torch. So, and most of the real experts will tell us this, run a non extended tip plug. Your one of a very few that run at that level and still run an extended tip #6, kudos to you, but not for me, and imo, it's not the best for others either, after a certain point.

Keep us updated. I hope it's not really pushing water. What are your cam specs? Maybe Brad can comment once they are posted?
Robert

 

Robert, im not saying logging is bad, it is a very good thing, but experiance is a much better thing, ive had alot of been there done thats. lol i have been in the same spot as he is, and i know whats wrong with his car i dont need to see the logs. again, been there done that. lol i will bet if cam specs are posted i can give him a tune up and some quick info to fix his issue. the logs are good, but the old school way works as well.

ive also done the old plug swap with cold/hot plugs and i know again what each will do. im no machanic, but i know what i know, and i think i know it pretty well, and i know logging wont fix all

 

Thanks for all the help guys!

I have some TR7's on the way as well as a new OEM radiator cap. I am going to turn down the timing, pill it down to a 50 shot and see what happens. Like we said before, it may not be pushing water at all, but if it is I'm yanking heads. The good news (I guess) is that I'm just going to go with a set of GM MLS instead of the Cometics, since they are the same size, and I read that they do just as well for a fraction of the cost.


Cam is 242/246 .621/.614 112LSA +2, XFI/XER, Patrick spec'd it for me. I have a 253/263 sitting in a box if need be lol.

I ran the car all day on Sunday before I parked it (no spray though) and pulled the plugs out. None of them were melted. The car ran like a champ N/A, just like normal, didn't push any water either.


I had been running 28* with no problems, so I yanked 4* for the 100 shot (2 per 50hp rule).

 

I would run some 104 octane with the pump gas when you spray the car. The above posts had some great info. I always run good gas, pull some timing, and check the plugs. The GM gaskets are the best out there. I run the later model multi layer steel with the teflon around the water ports. I've had no problem with them. I've run projected tip plugs and they work good, but you have to check them. I've had them burn up on the tips with no indication of a problem. I couldn't tell they were bad till I pulled them.
I agree about the hotter plugs giving you a warning that something has gone wrong. I ran real lean at the Texas Mile a couple years ago, when the car nosed over I knew something was wrong. I found 6 destroyed plugs and 1 brunt exhaust valve. I replaced the plugs and drove the car home with the bad valve.
Good luck with your car it should haul when you get it dialed in. Get some help with your tune.

 

How fast is the car?

I'm running 11:1, 150 shot, mix of gas, and TR8 plugs. I ran the TR8 plugs on motor too.

I think you are running too much compression AND timing. I'd get a new cap, change head gaskets, and run 18 degrees like the other guy reccomended. Personally I would run TR8's, they idle just fine. I have been running more timing than you ran but I have been running a mix of 112 and 93, and I have lower compression (11:1).

 

put gaskets in it, and add race gas and your good. lol

 

Are you ABSOLUTELY sure your compression is 11.5? Did you gather all the specs and calculate it yourself? If not just double check it to be sure.

Your making great power on motor and the cam speced by Patrick sounds like its doing its job NA very very well at 530+ rwhp on a 408 with 11.5 compression. Have you checked your DCR? If your DCR is making a ton of cylinder pressure but your static compression is 11.5 that can throw you off a bit. You may indeed be in the area where you will need to run some 100 unleaded for spray.

And it may be as simple as the head gaskets on there never got a good seal or had a piece of trash in them.
Either way you will need new gaskets. Have the head surface looked at closely and ensure they are smooth and flat. IMO dont go above 75 ft/lbs on the head stud tq. Going too high can actually induce a curvature in between the bolt holes and make things worse.


So the question is...when you change head gaskets and get the new ones sealing well....do you want to figure out if you can run pump gas? Or just go for race gas. As Noyzee said above....if you change gaskets and always run 100 unleaded when spraying you should be golden.

 

good info, and just one more thing. commetic and gm gaskets work well. i found the felpro mls to work GREAT. they seal very well. thats what i have been running lately