I broke a rod and blew a hole through my block but made a discovery that I wanted to ask about when I pulled my head...







Two of my pistons are melted and have the ends of valves melted into them and I noticed a black substance on the end of two of my injectors as soon as I pulled the fuel rail. These are the two injectors over the melted pistons. My timing belt was destroyed and not even on cam gears if that is relevant but I was guessing that's normal after a broken rod? Any explanation?

 

Rod breaks, sends piston into head, slammed valve, stops the cam, breaks the timing belt. My best guess..

The engine doesn't come to an instant halt because the rod broke. That's sucks man. Going to be an expensive rebuild. Hopefully the head is salvageable.

 

The two melted pistons is more what I was curious about but thanks for explaining in detail how the belt broke.

My head looks like the pistons right above them so unless a good bit of material is removed when porting and polishing I'm going to have to buy a head.

 

Doesn't seem melted to me. Looks like a good ol boxing match betwen the pistons and valves during interference. You need to realize how much contact can be made per second at something simple as 3000rpm. That is 50crank revolutions per second. I have seen it worse. The black stuff on the injector is just a byproduct of E85 fuel which I'm assuming you're running. Find out why the rod let go.

 

Are these 2000 cc injectors? Why did you need that big . What's your set up and when did it happen.

 

Didn't even think about it just being from being being beaten by the valves. The rod let go at almost 8k RPMs so it definitely would have made some serious contact before the motor revved down. The other two pistons actually looked good and it was only the two above the injectors with that build up on them so that's what made me curious. I do run E85 and have used only E85 for over six months. I'm guessing the rod just eventually let go from too much torque for the stock rods. I was somewhat pushing it for stock rods and had a couple times I over boosted bad enough to do damage to those rods.

The injectors are ID 1300s so not that big. I was running a 73HTA Green and S3 cams with standard supporting mods. I was logging when the rod broke and it was in the middle of a pull. Car didn't lean out or anything so it seems the rod just broke and caused the failure.

 

Yea, Pistons aren't melted. Just beat up from hard contact.

 

OK. Cool. Just making sure I didn't have some other problem. I don't guess it makes a difference because I'm basically replacing everything now.

 

If you're concerned, I would still get the injectors cleaned and flow tested. It's only $100 for peace of mind when it goes back together.

 

I'm selling them and going bigger. I'll probably upgrade turbo and even if I stayed with the 73HTA I would probably be pushing it. I was around 90% IDC and the car will be put back together with ported and polished head and probably ported manifolds and throttle body also. Maybe even a different manifold for EFR or Precision turbo. I will probably send the injectors in before selling them.

 

I think people need to be reminded that it's good to pull injectors and get them cleaned every few years. I had the same injectors on my car (only 91 pump) for about 7 years, and they were pretty out of whack.

On all future cars, I'll probably pull injectors once a year just to check.

 

I put my lunch money on the two injectors in the middle being clogged up and they didn't flow enough fuel at most critical moment (high RPM and boost). Those two cylinders went lean and melted and chunked off.

 

The valves smushed into the piston indicates a rod failure throwing the piston into the head. A lean condition doesn't break a rod.

 

Rod failure for sure. I had my head off doing head gasket, springs and retainers, head studs, and cams a couple months ago and the injectors were not like that so it wasn't a long time build up.

 

Kaboom