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

[AdamVR4]

Originally Posted by DoctorDex

So, from what you guys are saying I'm going to pretty much need new/used/rebuilt shortblock & head work (at the very least)?

I would absolutely love to get a Merkel/Pampena shortblock with forged pistons + some DR stage 3 heads, but at the moment I just don't have the cash. I think I'm just going to have to settle for a used (25K miles) 4 bolt longblock (with DR stage2 heads).

There are a few other things that need to also be done while the engine is out which are going to seriously add to the cost of this rebuild:
1. Send transaxle to Kormex to have them fix the excessive transaxle backlash + strange rubbing noises in my tranny.
2. ? Bell housing reinforcement
3. New clutch capable of taking a beating. Considering the RPS 6 puck with sprung hub. At the moment I have DR650R's with a centerforce dual friction setup, but have plans to upgrade to either Evo3-16g's or DR800/1000 kit in the next summer if everything goes well with this rebuild/engine swap.
4. 120K service. At the moment my car has 100K on it, but might as well do it a bit early and start as fresh as possible.
5. Buy beater to get me around for the next year.

A few dumb questions for you guys:
1. Is it possible to swap out the stock pistons without having to do a full shortblock rebuild? Could I just take a used shortblock (in good working order) to any old machine shop and have them swap in some forged pistons without paying outlandish sums of money? Or is this just asking for trouble?

2.Are the 2nd gen pistons any stronger than the 1st gens? I know they are both cast, but are they the same part number?

AdamVR4: It appears I put too much faith in the knock sensor. I'm assuming a broken ring land points towards knock induced damage? Its too bad I can't change the title of the thread.

Forget the upgraded heads. You can always upgrade the heads later. It's a 1-2 day job with the engine IN the car. You can have the damaged combustion chambers in your current heads welded and ground smooth or you can get some parts-car heads and transplant some of the components from your heads onto them. Either way, I wouldn't spend more than $1000 total on your "new" heads.

What makes you say there is excessive transaxle backlash?

You have a 5 speed, don't worry about the transaxle reinforcement. My bell housing is still not reinforced (although I might be regretting that soon). It's the 6 speeds that split them apart at your power levels.

The RPS 6 Puck is pretty good, but I remember hearing that IPS is selling a clutch that supports around the same power for around the same cost. I'd contact Jeff because a lot of people have issues with the RPS 6 puck. Take your time on this decision.

With rebuilt heads (new valve stem seals) and a new bottom end, your 120k would be limited to only: new oil pump, new water pump, new timing belt, new timing belt pulleys.

Good call on the beater.

1) Actually, yes. The machine shop would undoubtedly recommend a slight over bore, so the machine shop costs would be significant.

2) 1G stock pistons are actually stronger than 2G's. The 1G's actually have a thicker upper ring land.

How old is your knock sensor? Had it seems dependable in the past? Mine has never let me down and always produced knock counts when I expected it.

Since you have E16G/DR800 dreams, stock pistons would be unwise, but stock rods will be unwise as well. It might be time to sit back and really contemplate what you want out of this car and what you can afford. I'd set-up a spread sheet to analyze all of your options.

[DoctorDex]

The Merkel shortblocks are definitely reasonably priced and they would be ideal from a performance standpoint. I'll talk with Jeff tomorrow am to see what the deal is with the core charge.

The other option is a used 4 bolt longblock that comes with DR stage2 heads for $1700. This seems like the most economical option for getting my car going quickly. However, I would really like to upgrade the bottom end, as I really don't want to have to do this all over again if/when I go bigger turbo. Then again, pulling the motor to add some DR800's/E16G's is probably easier than doing the "in-car" install and maybe I could upgrade the bottom end at that time? I'm bored of my maxed out DR650R's and I would like to move up to something bigger, problem is I just can't do it all in one shot.

Originally Posted by AdamVR4

What makes you say there is excessive transaxle backlash?

I have an awful clunking, not only when shifting, but also when cruising at low speeds at <2000 rpm that causes the car to jerk violently back and forth. I have replaced my rear dif (everything is within spec), carrier bearings, double checked lash in the transfer case, had new VCU dowel pins made (to take up the slack in the 18 spline VCU holes), installed solid rear dif. bushing and solid motors mounts and I still have a horrible clunking. It has gotten slightly better after all of these mods, but it is definitely still there. I took my car into the dealer and they confirmed that the only place I have an excessive lash is from within the transaxle. Plus, there definitely has to be something wrong with the transaxle (even though it shifts great). At <2000 rpm I can hear this strange metal on metal noise, similar to lightly touching metal to a grinding wheel, that tells me something is definitely amiss.

Originally Posted by AdamVR4

You have a 5 speed, don't worry about the transaxle reinforcement. My bell housing is still not reinforced (although I might be regretting that soon). It's the 6 speeds that split them apart at your power levels.

My 17 year old case seems so brittle, I'm scared to look at it the wrong way. I have a broken ear on the bell housing that came off with very minimal force and I was thinking I might have them weld on some sort of reinforcment plate while they are repairing the ear.

Originally Posted by AdamVR4

How old is your knock sensor? Had it seems dependable in the past? Mine has never let me down and always produced knock counts when I expected it.

I believe it was the original (17 year old knock sensor). Up until this event it always seemed reliable for detecting knock, but I did have an issue with phantom knock at cruise in the 2600 - 3500 rpm range, which I never could figure out. Maybe its related?

[1stStealthN/A]

If you have the room to store your car, buy a beater and take your time with the rebuild. That way you won't have to put every penny into the car to get it running and you can still enjoy life.
There's some good deals in the for sale section if you have patience.

Good luck.

[DoctorDex]

Originally Posted by 1stStealthN/A

If you have the room to store your car, buy a beater and take your time with the rebuild. That way you won't have to put every penny into the car to get it running and you can still enjoy life.
There's some good deals in the for sale section if you have patience.

Good luck.

That would be ideal, but it would mean storing the car for 2 years+. By that time, I'll probably forget what its like to have a fun car, I'll end up losing my hair, getting fat, getting married, having kids and being forced to trade it in for a minivan. lol.

[1stStealthN/A]

No beater then.....a set of new Wisco forged pistons with rings about $650.00. Slight overbore and hot tank the block about $200.00. Rebalance the rotating assembly assuming you have a good useable crank about $275.00.
Resize the stock rods with new ARP bolts around $300.00.
Or...a new Mitsu shortblock with cast pistons, around $2700.00.

Hey, I'm getting fat and losing some hair, married, had kids AND have the mini van!
But I also have my toys yet, lol.

[cbehnken]

Originally Posted by AdamVR4

So, what forged pistons can you find for anywhere near $300? Stock pistons can be had for essentially free. Stock pistons are fine if you keep the A:F rich, even well above 600 AWHP... Which he won't ever sniff with those turbos.

The only reason one might conclude that stock pistons are the weak link is because they keep cracking them in people's cars. My stock pistons are fine. I expect my stock rods to fail due to fatigue before the stock pistons. Freak failures and tuning accidents claim the lives of our stock pistons... Not pure, clean combustion. At least, I've yet to see a true example suggesting otherwise.

He only has DR650's, stock pistons are fine. If he wants to spend some money, he should buy an assembled block at whatever stage he wants from one of the proven reliable engine builders (Merkel, IPS) or he should just get a new OEM shorty. I think Merkel was selling assembled shorties with forged pistons for the same price as new OEM blocks. That's pretty reasonable pricing.

seems like by the time someone really NEEDS forged pistons they are getting close to the limit of the rods anyway.

In my mind run stock bottom end or upgrade both pistons and rods. I've had enough detonation to melt a spark plug on this car and still at 145K miles it has great compression. I'd rather not have the piston slap that forged engines have when they are cold.

[DoctorDex]

I talked with Mike @ IPS (Jeff is on holidays) and he said that the core cost is not included in the price of the shortblocks. In addition, if I wanted a forged crank I would have to pay for the cost of the crank and I'd have to pay to repair any damage to my block. I have a feeling this would increase the cost dramatically, so it looks like I'm just going to go with the used longblock for the time being.

With regards to the clutches, he said that the Southbend > RPS clutches and I'll be getting the low down on their whole line up later this afternoon.

Its a really nice day out today, so I'm going to screw off to the lake for the day. Will look at pulling the motor tomorrow as the forecast is calling for rain.

[oohnoo]

Broken ring land, been there myself. If your on a budget you can probably get away with replacing that one piston, quick hone and be done with it. If your lucky nothing happened to you heads and/or turbo's.

[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.

[AdamVR4]

Originally Posted by cbehnken

seems like by the time someone really NEEDS forged pistons they are getting close to the limit of the rods anyway.

In my mind run stock bottom end or upgrade both pistons and rods.

Agreed!!!

I'll read the rest of the thread later when I have a bit more time.