thought I heard a noise in this motor lol (pics inside)

[REDS HOT AIR]

seems it got a little weak in the knees

 

[turbo2nr]

Red, are those stock two dots? Where did those come from? So low 10s may be the limit for the stock rods, might get lucky and hit a few 9s.

 

[REDS HOT AIR]

yes they are stock 87 turbo rods still with stock bolts

there is nothing broke in this motor .. it still ran fine but picked up a slight noise so I tore it down

Just like any other parts some are stronger than others

my old shortblock cracked the crank and the rods are still strait .. this one folded the rods but the crank looks fine by eye but I'll be taking it down for magnaflux

when you push the limits of stock parts that are not designed for even 1/3 the hp things are going to give .. just a matter of time

your not looking at it right .. this combo went low 10's on a easy launch and a smoked tranny ... 134 mph with a slipping tranny says it was making plenty of hp for 9's and thats at 3600#

this was a test on stock bottom end .. well it failed

guess its time to break out the good stuff

next track rental should be real interesting

 

[Bmason]

WOW!

Hey:

"S" rods huh...are those the new "off-center" design?

I ended the day with a slight noise too, but all I found was a severly cracked header and a fuel level that was too low for comfort. Hopefully I didn't hurt anything and my rods don't look like those.

How bad are the bearings?

What about the walls, are they scuffed?

FYI=> We'll probably do another rental soon. I'm hoping to come with the "Wanna-Be" car and not the driver, to see what it'll do with the new combo that's in the works.

-Bobby

 

[Hognose]

What's wrong with it?

Just kidding.

Bobby,
Don't forget me when the track rental comes up. I still vote we do that once a month!

Matthew

 

[REDS HOT AIR]

Originally posted by Hognose
I still vote we do that once a month!

Matthew

holy cow

once a month ..

 

[REDS HOT AIR]

Re: WOW!

Originally posted by Bmason

How bad are the bearings?

What about the walls, are they scuffed?


-Bobby

believe it or not the bearings in the motor looked pretty good consitering what was going on in there .. of course they show wear on the sides of the rod bearings on the bent rod journals from the rod trying to lay down on the job

the pistons cocking in the bore dint seem to hurt the bore but It did get some fine scratches down in the lower parts of the bore from metal getting tossed up in the bore and getting between the skirt and bore
the metal was from the sides of the bent rods where the sides of the rod journals were trying their best to hold the rods up strait

parts are being ordered already ...

you should check out how the tranny pan looked

 

[NJVetteGuy]

Wow....

 

[ijames]

Those are the on-off-on-off-off center rods . That's pretty amazing; rods normally give up in tension not compression.

 

[TurboJim]

Looking at the skirts it looks like that thing was detonated hard.

 

[REDS HOT AIR]

Originally posted by TurboJim
Looking at the skirts it looks like that thing was detonated hard.

can you explain that

 

[Intercooler]

Blow a head gasket and fill the cylinder? Maybe coolant in the cylinder?

 

[broke1]

Originally posted by Intercooler
Blow a head gasket and fill the cylinder? Maybe coolant in the cylinder?

He bent the rods pouring power to it.They arent bent from hydra-locking the motor.At least thats what I read into his posts...

What kind of RPM's were you turning Red??

 

[REDS HOT AIR]

head gaskets are in great shape ...(steel shims)

thats the motor that I had tranny issues with and it would get hung on the rev limiter on 3rd gear shift at 6650 rpm

Im betting the rev limiter hits at that rpm had a little to do with it

 

[straycat990]

Hey Red,

Any guesstimate as to what flywheel HP that engine was putting out when the rods decided to cry uncle?

 

[Russ Merritt]

6650 ain't sh!t. The stock rods will take that.......... I set my rev limit at 7500. Have gone to 7200 no sweat still makin power. Stock crank and rods.

If the rev limiter caused that, you better make sure you don't hit it....

 

[TurboJim]

Originally posted by REDS HOT AIR


can you explain that

Exerpt from excellent article:

"Detonation
Unburned end gas, under increasing pressure and heat (from the normal progressive burning process and hot combustion chamber metals) spontaneously combusts, ignited solely by the intense heat and pressure. The remaining fuel in the end gas simply lacks sufficient octane rating to withstand this combination of heat and pressure.

Detonation causes a very high, very sharp pressure spike in the combustion chamber but it is of a very short duration. If you look at a pressure trace of the combustion chamber process, you would see the normal burn as a normal pressure rise, then all of a sudden you would see a very sharp spike when the detonation occurred. That spike always occurs after the spark plug fires. The sharp spike in pressure creates a force in the combustion chamber. It causes the structure of the engine to ring, or resonate, much as if it were hit by a hammer. Resonance, which is characteristic of combustion detonation, occurs at about 6400 Hertz. So the pinging you hear is actually the structure of the engine reacting to the pressure spikes. This noise of detonation is commonly called spark knock. This noise changes only slightly between iron and aluminum. This noise or vibration is what a knock sensor picks up. The knock sensors are tuned to 6400 hertz and they will pick up that spark knock. Incidentally, the knocking or pinging sound is not the result of "two flame fronts meeting" as is often stated. Although this clash does generate a spike the noise you sense comes from the vibration of the engine structure reacting to the pressure spike.

One thing to understand is that detonation is not necessarily destructive. Many engines run under light levels of detonation, even moderate levels. Some engines can sustain very long periods of heavy detonation without incurring any damage. If you've driven a car that has a lot of spark advance on the freeway, you'll hear it pinging. It can run that way for thousands and thousands of miles. Detonation is not necessarily destructive. It's not an optimum situation but it is not a guaranteed instant failure. The higher the specific output (HP/in3) of the engine, the greater the sensitivity to detonation. An engine that is making 0.5 HP/in3 or less can sustain moderate levels of detonation without any damage; but an engine that is making 1.5 HP/in3, if it detonates, it will probably be damaged fairly quickly, here I mean within minutes.
Detonation causes three types of failure:
1. Mechanical damage (broken ring lands)
2. Abrasion (pitting of the piston crown)
3. Overheating (scuffed piston skirts due to excess heat input or high coolant temperatures)
The high impact nature of the spike can cause fractures; it can break the spark plug electrodes, the porcelain around the plug, cause a clean fracture of the ring land and can actually cause fracture of valves-intake or exhaust. The piston ring land, either top or second depending on the piston design, is susceptible to fracture type failures. If I were to look at a piston with a second broken ring land, my immediate suspicion would be detonation.

Another thing detonation can cause is a sandblasted appearance to the top of the piston. The piston near the perimeter will typically have that kind of look if detonation occurs. It is a swiss-cheesy look on a microscopic basis. The detonation, the mechanical pounding, actually mechanically erodes or fatigues material out of the piston. You can typically expect to see that sanded look in the part of the chamber most distant from the spark plug, because if you think about it, you would ignite the flame front at the plug, it would travel across the chamber before it got to the farthest reaches of the chamber where the end gas spontaneously combusted. That's where you will see the effects of the detonation; you might see it at the hottest part of the chamber in some engines, possibly by the exhaust valves. In that case the end gas was heated to detonation by the residual heat in the valve."

So I would venture to guess it detonated at high boost which exerted a huge amount of pressure on the piston, overheating it causing the scuffed skirts AND bending the rods.....

 

[EightSecV6]

Looks like that thing got punished! What boost, timing and type of fuel? A/F ratio? I have never seen a cast rod bend that far without breaking, one more pass would have probably done her in!

 

[REDS HOT AIR]

pm ya