RobWilson

Okay....the wait is killing me, so I'm hoping someone out there has had a similar experience.

Right now, my '03 coupe is sitting at my trusted Corvette mechanic's house and has been since late last week. He is away on the Hot Rod Power Tour until this weekend, so he won't be able to look at it until early next week.

Some background on my car....the engine has a TSP 225/225 .591/.591 114 LSA cam, 5.3L TSP race heads, UD pulley, ceramic coated Kooks 1 3/4" headers, and TSP dyno tuning. I have been running this setup for 26 months and almost 15k miles. The rev limiter is set to 6700 rpms and my shift light is set for 6400 rpms.

I recently had a lot of gear whine in my DTE stage 2 differential with 3.90 gears. After driving 1400 miles round trip in March to run the Texas Mile, I decided I couldn't deal with the gear whine. I had the differential pulled and shipped back to DTE for a rebuild with 4.10 micropolished gears. There is a 350 mile break-in period for the DTE differential. Just to be safe, I did a 450 mile break-in. From the time I ran the Texas Mile, until I got the rebuilt differential broken in was about 2 months. In that whole time the car had not been driven hard.

Last week, I was driving on a 2 lane highway with a coworker to our warehouse. We got behind a big truck hauling rocks, so we passed him when the road was clear. I downshifted into 3rd gear and shifted at about 6400 rpms into 4th and then accelerated up to about 100 mph in 4th gear. At that point we were safely around the truck, so I got off the throttle. Up to this point everything felt normal. When I got off the throttle, I see a big puff of white smoke blow out my exhaust pipe. It is visible in the sideview mirrors and rear view mirror. My coworker saw it, too. At this point, I'm thinking that can't be good and am listening for any abnormal noises. I didn't hear anything, so we continued on about 3 more miles, where I came to a stop light. When I slowed down for the light, I noticed more white smoke out the exhaust. As I come to a stop, I can smell coolant and hear a knocking coming from the engine. Not knowing what else to do, I drove it 2 more miles to my destination at *very* low rpms....listening to the knocking noise the whole way. It reminded me of when I bent a pushrod in my LS1 Camaro SS. At my destination, I backed into a parking spot and shut off the motor. I could smell coolant, but there were no puddles under the car and no fluid in the engine bay.

At that point I called TSP to let them know I may be needing to buy some parts from them and called my mechanic to let him know I needed to bring the car to him. I called a tow truck company and had it flat-beddded about 30 miles to my mechanic.

So any speculation regarding the problem? Blown head gasket? If so, what did I likely bend?

Could a broken valve spring cause something like this? I had one break one my LS1 Camaro SS with a MTI cam, but it stayed in place and was an easy fix, after having it towed to Fastech (I lived in Dallas back then). I'm wondering if a broken valve spring could have dropped down and caused problems. I can't remember the exact valvesprings, but I think they were the gold springs that Patriot used back then (2004) and were supposed to be good for higher lift than I was running and weren't supposed to need to be changed for 40k miles or something like that.

Let me know what you think. Don't worry about scaring me, I'm already figuring I may have to build a new stroker after this.

RobWilson

No replies, yet?

One other thing I thought of that shouldn't make a difference is that I had filled up the gas tank with 91 octane the night before. We don't have 93 octane in Tulsa anymore, but I have been running 93+ octane for the past year by adding Torco to 91 octane. This particular tank was straight 91 with no Torco.

The reason I don't think this would make a difference is because I ran 91 octane 2 summers ago, when Tulsa first stopped selling 93 octane. I ran the car hard in the heat of the summer with no problems. The compression is about 10.5:1, according to TSP, and the car should run on 91 octane with no problems.

95BlueBomber

I would just guess a ringland. If you have stock pistons and rings chances are its a ringland. I have been there twice now. Boost on stock parts are on borrowed time. Get that compression down and the boost up and come back making more power!

WKMCD

Head Gasket.

Smoke-N-Shot

95BlueBomber

Could be a headgasket too. The noise it what brings ringland to mind. Does the noise seem to move all over the place or in one cylinder?

AU N EGL

Head gasket or cracked block.

Look at the #7 cyclinder area.

Mr. Jones

I can't remember if its possible-
have there been any reports of these heads cracking from excessive
porting and allowing coolant to enter a port? this could also cause a knock from rocker relocation.
I would not crank the engine anymore for fear of hydrolocking a cylinder.

jordanfd

White smoke usually = coolant in engine because of blown headgasket,
(BEST CASE FOR YOU) cracked head, cracked cylinder in block. Hope the best for you. Let us know what you find out. Frank

RobWilson

I have stock pistons...stock bottom end. I'm not sure what you mean by boost. It is just a heads/cam/headers setup...no forced induction.

Assuming I have to rebuild, I'm considering adding forced induction.

jordanfd

Help me out here. How would a broken ringland cause you to smell coolant and have white smoke (really steam) coming out the exhaust?
Thanks Frank

RobWilson

I'm with you on the blown headgasket. That is my guess, too. If a cracked head and cracked cylinder is best case, what is the worst case?

RobWilson

I definitely won't crank the engine anymore. I'm waiting for my mechanic to start digging into it.

RobWilson

Couldn't say for sure, because I was only hearing it from the driver's seat....but I would say it was coming from one cylinder.

RobWilson

Thanks for the tip. Why that particular cylinder?

95BlueBomber

When my ringland let go it was white smoke. I guess when the ringland goes it could take the headgasket as well. Again it was white smoke when mine blew.

95BlueBomber

My bad... I stay in the forced induction all the time, I thought everyone was boosted. In that case I would not say ringland... Still seems weird that the engine is making noise. A headgasket shouldn't make noise.

95BlueBomber

I was reading on this issue a while back. The intake design creates more flow to the #7 and leans on it more than any other cylinder. If the tune is aggressive chances are the #7 is in a danger zone. Thats why I always run a little rich.

WKMCD

There was a little history on early - 97/98 - blocks cracking liners but I've not heard of it on later N/A setups.

RobWilson

I don't think the tune is all that aggressive...but I guess everything is relative. When TSP dyno tuned the car, I asked them not to tune it for max hp. Street manners were very important, because my wife drives the car sometimes.

I'll ask the mechanic to look at cylinder #7, first when checking everything.

What could have caused a blown head gasket?