Catastrophic engine failure, suspect pre-ignition (Pics to follow)

[Drweldin]

Originally Posted by badass3000

do you have 2 EGT probes or just 1?
was it reading #3?

I dont get this, this probably wasn't caused by too much power, and it sounds like your tune was rich enough. Plus IIRC the Meth should have helped with knock and lowered EGT's. So what was the cause?
could #3 just have not received the same fuel as the others and just ran lean?
this scares me...Im about to run 6 EGT probes, if I can figure out a way to do it.

I agree...kinda spooky....all injectors good I wonder....?

[badass3000]

he had them flow checked

[tfw a-ok]

Originally Posted by Dj4play

i agree to a point. but anyone who resbuilds a motor without forged piston is a retard. The factory rods are fine to 600 hp wheel

I threw a rod with less than 600 awhp on the dyno and I wasn't the first. I think anybody rebuilding for over 500 to the wheel should seriously reconsider using stock rods.

Tommy

[bluemax_1]

Originally Posted by cbehnken

I'd rather not have the piston slap that forged engines have when they are cold.

Piston slap on a cold engine with forged pistons all depends on the pistons themselves and how well the machine shop knows their stuff.

I've been driving a fully forged bottom end for the past 4-5 years (since I was forced to rebuild due to a stupid local shop spinning a bearing on my car from joyriding in it WITHOUT my permission when I took the car in for some suspension part replacements ).

I have ZERO piston slap with the off-the-shelf Ross 6g72 pistons when cold and I daily drive this car even through the winter. When I took the block to get it machined, the shop called me back and asked me if I intended to run nitrous on the car. I said no and asked why. They said they bore for looser tolerances for nitrous due to the higher temps (and resultant piston expansion). Since I wasn't going to run nitrous, they called Ross and checked what the allowable tolerances were and bored to that (OTS Ross pistons require an overbore anyway due to being 93mm IIRC).


Max

[cbehnken]

Originally Posted by bluemax_1

Piston slap on a cold engine with forged pistons all depends on the pistons themselves and how well the machine shop knows their stuff.

I've been driving a fully forged bottom end for the past 4-5 years (since I was forced to rebuild due to a stupid local shop spinning a bearing on my car from joyriding in it WITHOUT my permission when I took the car in for some suspension part replacements ).

I have ZERO piston slap with the off-the-shelf Ross 6g72 pistons when cold and I daily drive this car even through the winter. When I took the block to get it machined, the shop called me back and asked me if I intended to run nitrous on the car. I said no and asked why. They said they bore for looser tolerances for nitrous due to the higher temps (and resultant piston expansion). Since I wasn't going to run nitrous, they called Ross and checked what the allowable tolerances were and bored to that (OTS Ross pistons require an overbore anyway due to being 93mm IIRC).


Max

I'm glad it worked out for you, but it doesn't always work out that way. The factory didn't just use cast pistons because they were cheaper. Long term wear on stockish power is going to favor the stock pistons because they have less expansion and therefore a more stable bore to cylinder clearence.

The bottom line is really I don't see a point in running forged pistons with stock rods or even if you are under 500AWHP or so. Sure, there are ancillary benefits such as cooler running pistons, maybe slightly less prone to detonation, etc, but as far as straight durability and reliability I don't see the benefits.

Most of the rebuilds I see blown up on here are the people who went stage 3 everything as soon as their stock motor wore out. Too many people feel the need to upgrade when they really just needed new or rebuilt factory items.

[DoctorDex]

Originally Posted by badass3000

do you have 2 EGT probes or just 1?
was it reading #3?

I dont get this, this probably wasn't caused by too much power, and it sounds like your tune was rich enough. Plus IIRC the Meth should have helped with knock and lowered EGT's. So what was the cause?
could #3 just have not received the same fuel as the others and just ran lean?
this scares me...Im about to run 6 EGT probes, if I can figure out a way to do it.

No EGT probes, just a WB. EGT probes x2 were on the list of things to do, but just never got around to it.

If it is possible to crack a piston without breaking it and then being able to limp around on it for a week, only to have it fragment later while at full boost, then perhaps I can lay blame on the check valve solenoid of my meth kit. Approx. a week before this fateful event, the valve seized which resulted in the worst knock I have ever seen, ie. 24 counts x 6 - 7 data points (in 1st gear). I later repaired the valve (it just needed to be loosened off 1/2 a turn), only to have the motor frag. on my first WOT run after the repair.

As far as finding a new motor, the deal for $1700 turned out to be too good to be true... bit of a mixup between myself and the seller. Back to the drawing board. Really need to figure out where I'm going to go with this car and where I am going to find the cash. Maybe I'll try the bank for a line of credit. lol.

[Dj4play]

Originally Posted by cbehnken

I'm glad it worked out for you, but it doesn't always work out that way. The factory didn't just use cast pistons because they were cheaper. Long term wear on stockish power is going to favor the stock pistons because they have less expansion and therefore a more stable bore to cylinder clearence.

The bottom line is really I don't see a point in running forged pistons with stock rods or even if you are under 500AWHP or so. Sure, there are ancillary benefits such as cooler running pistons, maybe slightly less prone to detonation, etc, but as far as straight durability and reliability I don't see the benefits.

Most of the rebuilds I see blown up on here are the people who went stage 3 everything as soon as their stock motor wore out. Too many people feel the need to upgrade when they really just needed new or rebuilt factory items.

different piston manufacturers use different amounts of silicon in the forgings. This is one of the factors that determines how much expansion a piston has . Ross runs loser piston-to-wall clearances than say a cp, or a wiseco, GENERALLY. Usually by .002-.003. To answer your question yes. You can crack a piston and not see the effects till days later until the ringland/or piston gives way

[Dj4play]

PS. i think dex found the culprit to his engine failure guys. A piston is just like anything that can crack. Say you have a glass vase. And it cracks. The vase can remain in tact cracked fro some time, but the more you handle it, the more prone it is to coming apart where it cracked. I think a stock motor would be fine for your dex as long as you dont have your nozzle sticking again

[DoctorDex]

I got working on pulling the motor today. The motor is _nearly_ ready to come out, just need to get my hands on a cherry picker, which won't be possible until this weekend.

One thing I was't sure what to make of was the fact that when I drained my oil, there was more coolant in my oil than there was oil in pan. In addition, there was fair sized chunk of metal that became lodged in the drain hole.

[oohnoo]

Not sounding good at all. Blown head gasket and probably that one piston has a hole in it.