I think my engine just blew on the dyno last night at road race engineering. The engine is a stock evo 8 with 120,000 miles. I did the 120k miles service at road race and decided to upgrade to gsc s2 cames from my hks 272 cams. So since I had to redyno might as well get an duel map tune with e85 as well. Before the car made 387whp on 91 octane at 22psi with the hks 272's. now it made 404whp on 91 octane at 22psi with the gsc s2 cams. We then put e85 in and it made 500whp at 24psi.

On the last run it started missfireing and bucking I believe the engine got hurt and it blew the dip stick out of the car. On the ride home I hit boost once and it started bucking. When I got home I notice the coolent overflow was bubbling. I check and change the oil and there was no coolent in the oil and there was no oil in the radiator. I pulled the plugs and cylinder 4 the plug broke apart. I did a compression test and cylinders 1-3 are at 170 psi. Cylinder 4 was at 135psi. I put a littler oil in the cylinder and it shot up to 170psi.

Next I did a leak down test. cylinder 1 was leaking 15%, cylinder 2 and 3 was only leaking 4% and cylinder 4 was leaking 35%!. During the leak down test the coolent in the radiater was not bubbling, so I assume the head gasket is ok.

When the engine was healthy it will pulling -13psi not its only pulling -8psi at idle. I plan to run the car off boost until the e85 is out and switch back to 91 octane.

Is the engine gone? Is there a chance its only a head gasket?

car has stock 120,00 miles with the majority of the miles on this htagt2582r
setup is gsc s2 cams, valve springs and retainers, arp head studs
full race t4 twin scroll manifold
HTA gt3582r with t4 1.06 ar
ets 3.5 intercooler
full custom 3" exhaust with no cat
buschur ported stock intake manifold with stock ported 65mm throttle body
rc1200cc injectors with aeromotive 340lph pump


blown plug


404whp on 91 octane at 22psi


500whp on e85 at 24psi

 

You should plan to not run the car at all until you get it fixed. Anything you do now aside from fixing it is only going to make it worse.

Head gasket is unlikely, it's much more likely a piston issue if you are missing bits of the sparkplug. Prepare to pull the head and look at all your pistons

 

Either way you are going to need to pull the head.

 

I agree that the piston or cylinder on #4 took some damage from the broken plug. Pulling the head will answer your question. Get us some pics if you do.

 

Looks a little bit like detonation damage on that plug.

 

I talked on the phone with Benton and went over things in detail several hours before he posted here. We also spent a lot of time before tuning the car explaining the risks with pushing a motor with this kind of mileage to this level. Everyone was made well aware of the risks and consequences before hand. Myself, Scot and Robert all explained in many different ways how it isn't normal to push a high mileage stock motor this much with the turbo setup that he has. It was _all_ we talked about before and during the tune.

The car is very well setup. It is a beautiful manifold and dual wastegate setup. It all just needs to be on a stronger motor that is sealed up better. Scot went very soft on the tune knowing that he was basically being handed a grenade with the pin pulled. Even if it is just a head gasket, I cant imagine changing just that alone on a motor this old. This car is a super clean '03 in search of a built motor with all the bolt ons he has.

Mike W

 

Just a thought, replace the plugs and put 20-30 normal miles on the motor and then go back to perform a compression and leak check. If that plug was jacked it would not ignite the fuel and wash out the cylinder. Also, when you performed the leak down, where was it leaking?

 

Looks like #4 ran lean causing detonation and melting of the spark plug. Most likely you have piston melting also hince the leakage. I would test your injectors before installing another engine. Find the root cause before have another accident. It happens man. Good luck!

 

had a similar experience...turned out to be head gasket...either way head has to be pulled...considering miles and mods a built motor should be high on list....

 

Well first off that sucks man, its always ****ty when u blow your motor....I did mine about 40 k ago. But imo based off your pics I don't believe lean caused your detonation..... If your cyl pressure shot up with a bit of oil in it problem could've started by either worn rings, or a distorted cylinder wall with which 120k and your turbo setup. I can believe that could happen to anyone. And with bad compression can cause detonation or if the spark plug tip broke off could've pre detonated in the cylinder, how do the piston tops look....?? Personally i would spend it right take the head off n replace any bearings rings upgrade your main and rod studs pistons and con rods. Do a full rebuild its more money but take care of her shell take care of you. Good luck. Rre they'll take care of you.

 

That plug looks like it has some traces of coolant on it. Doing a compression test and a leak down test will not work if the head is lifting from boost.

 

If you're lucky, it would be a damaged valve only! I don't think that stock internals are good enough for an HTA35!

 

my vote is a piston ring land......if oil or pressure is pushing the oil dipstick tube out, then it is on the lower end of things.... if it was a valve, it would run like it had no power....if it was a head gasket, i think it would show on two cylinders and not one cylinder on the leak down test he did....

this is based upon the info he provided. either way, as a few have suggested, you will have to pull the head...OR oil pan and look up at the pistons. you may have damaged the piston walls as well with the electrode missing off the melted plug....

good luck sir. keep us posted...and nice numbers before the grenade..

 

Mate take this as a golden time to sent your motor / car off to a top shop and get a build 2.3

 

Where did it actually leak down from? Might give the viewers a better idea of the kind of damage.