Blew up my LT5, Let the grieving begin.

[Torchred96]

Dumbest thing I've ever done to an engine. Well, I did it. Having done all the work to the upper half of my engine and ordering a chip from Marc to take care of all the mods that I did, I let the engine get away from the other night. It's a hard KNOCK KNOCK KNOCK....oh no!!!

How did I do it? Well, I think (I may be wrong here) that there were 3 main factors that contributed to the meltdown. 1: A loud radio. 2: A broken tach, and the 3rd was, if I'm not mistaken, no rev limiter or fuel cutoff allowing the engine to overspeed before my senses kicked in to shift. I never really knew when to shift this car, just relied on my instincts to tell me it wasn't pulling as hard. That rev grumbling that you feel when the car starts to vibrate is addictive!!!, and it's hard to let off.

Noticing it was down on power, but still not hearing the knock because of some good old time rock n roll, I drove it home about 3 miles from where I think I over rev'd. Pulling into the garage and turning down the radio, I heard the knock. Not the misfire type knock that I had before the injectors and ignition repairs, but a serious clunk that sounds a lot like something let go internally. (it wasn't the water pump unfortunately)

I think what happened also is the fact that I run it hard quite often and use the seat of my pants as a tach. I think I got used to the revs and continued to push the limits, thinking possibly that it would shut down, before self destructing. In the past, I remember hitting the rev limiter many many times on my old hot cammed lt4 and never blew it up. I'm actually not sure, but i think this engine is limited by air and fuel and not anything else. I certainly never had a rev limiter kick in....it just kept climbing until it let go.

So, I'm forced to make a decision. Buy another motor, another car, or fix this one. Keep in mind I still owe about $6500 on this car.. I'm a pretty good wrech turner but I've always stopped short of attempting to rebuild mostly due to the compounding of problems that could go wrong with tolerances and lack of machine work where I live.


I've put a lot of money and time into this car and I really do like it. I wouldn't feel the same in an c6. It's just not my generation that first made me fall in love with the corvette in 1983. What to do... Sorry about the long post, I guess I'm grieving.

thanks
Sam

[ZZZZZR1]

Sam

I'm no expert but I doubt you have ruined your whole motor

I would call Pete and or Marc to see what they think. (or Corey / Aaron)

Don't panic and wait to hear from experts first.

Might not be as bad as you might think



David

[captcorvette]

Sam news like this really makes me feel like I swallowed a lead balloon. Sort of a sick to my stomach. Are you sure the engine is knocking and not the clutch? Have you given her a quick look from down and checked to see what the computer is telling you? I mean sure if you are sure its a rod or a bad valve rattling?

If its a toasted engine just give it a rebuild. Lots of help around and this group of folks are some of the best, biggest hearted and most helpful I have ever found and I have been playing with cars a long time. I think there will be lots of folks offer all sorts of help. Yeah go ahead and grieve but don't give up quiet yet.

[USAFPILOT]

time for a 368 build

[XfireZ51]

Originally Posted by Torchred96

Dumbest thing I've ever done to an engine. Well, I did it. Having done all the work to the upper half of my engine and ordering a chip from Marc to take care of all the mods that I did, I let the engine get away from the other night. It's a hard KNOCK KNOCK KNOCK....oh no!!!

How did I do it? Well, I think (I may be wrong here) that there were 3 main factors that contributed to the meltdown. 1: A loud radio. 2: A broken tach, and the 3rd was, if I'm not mistaken, no rev limiter or fuel cutoff allowing the engine to overspeed before my senses kicked in to shift. I never really knew when to shift this car, just relied on my instincts to tell me it wasn't pulling as hard. That rev grumbling that you feel when the car starts to vibrate is addictive!!!, and it's hard to let off.

Noticing it was down on power, but still not hearing the knock because of some good old time rock n roll, I drove it home about 3 miles from where I think I over rev'd. Pulling into the garage and turning down the radio, I heard the knock. Not the misfire type knock that I had before the injectors and ignition repairs, but a serious clunk that sounds a lot like something let go internally. (it wasn't the water pump unfortunately)

I think what happened also is the fact that I run it hard quite often and use the seat of my pants as a tach. I think I got used to the revs and continued to push the limits, thinking possibly that it would shut down, before self destructing. In the past, I remember hitting the rev limiter many many times on my old hot cammed lt4 and never blew it up. I'm actually not sure, but i think this engine is limited by air and fuel and not anything else. I certainly never had a rev limiter kick in....it just kept climbing until it let go.

So, I'm forced to make a decision. Buy another motor, another car, or fix this one. Keep in mind I still owe about $6500 on this car.. I'm a pretty good wrech turner but I've always stopped short of attempting to rebuild mostly due to the compounding of problems that could go wrong with tolerances and lack of machine work where I live.


I've put a lot of money and time into this car and I really do like it. I wouldn't feel the same in an c6. It's just not my generation that first made me fall in love with the corvette in 1983. What to do... Sorry about the long post, I guess I'm grieving.

thanks
Sam

Whio would have given you a calibration without either some knock retard or fuel cutoff?? That's just plain stupid. Marc H would never do that.

[A26B]

If it ends up being a rod knock, there are lots of good take-out piston/rod/sleeves out there. I know Todd Pepmeier has a good set for sale along with a stock crank, in the event the crank is toast. I have a couple of dozen take-out sets if Todd's are sold. Cranks are nitrided & tough so there is a good chance it may have survived. A new set of rod bearings is only $40.00 and you may only need to put in one replacement piston/rod assy.

Let's just hope it not a spun main brng or a broken valve. That can be a bit more expensive, especially if the head is damaged very bad.

Figure out what is hurt. You'll get a lot of support from the Registry Forum members.

[LGAFF]

I think most of the over rev damage is related more to extended trips to 8K+ Sure its not a coil and a noisy dual mass?

[HIZNHRZ]

Originally Posted by LGAFF

I think most of the over rev damage is related more to extended trips to 8K+ Sure its not a coil and a noisy dual mass?

I'm with Lee. I had a couple of injectors that were in the processes of going bad. Car sounded and ran well cold and at low RPMs. As the engine warmed up and the revs inreased, a knock would start. The bad injectors caused a miss, the miss caused the noisy dual mass. It's amazing how much a noisy dual mass flywheel sounds like a bad main bearing knock.

[FU]

Originally Posted by LGAFF

I think most of the over rev damage is related more to extended trips to 8K+ Sure its not a coil and a noisy dual mass?

Read the LGAFF's post.

[Torchred96]

You guys are great....thanks for the support. I don't want to give up on her. But it is heartbreaking because it's still a really good looking car and most of the bugs had been cleaned up, and it's been great cruising to the keys on the weekends too.

Like I said before, don't know if it DIDNT have a rev limiter, I just never felt it kick in like I always did when the lt4 revved too fast...it (lt4) would fall on its face quick, let me know I screwed up and I'd have time to back off.. I really couldn't tell you how many r's I ever pushed the lt5 to since the tach was dead...it just seemed to keep on revving so I am only assuming I pushed it too far, having gotten use to the effortless way it spun up. Marc's chip it to be credited with the power it had, which really blew me away. Also never even had an engine light come on since doing the work. Btw, It's never over heated and oil pressure has always been good since I've had it.

I'm not ready to start working on it as I need to clear out the garage of other projects before digging in. When I do though, be sure I will be here asking for you help all along the way. That's good reassurance to have.

Thanks again for your support...great suggestions and generous offers. Gives me ambition not to give up!

Sam