So Alice threw a rod out of the bottom of her block again. Short block was replaced at 62k, now at 113k I have another engine inspection port. Needless to say I'm done with stock engines. Still need to assess damage to see if the head is salvageable (which I suspect it is) but I'm looking for something that will be a bit stronger. Not looking to make more power than I have with crazy built internals or big valve heads, just want a setup that will hold what I already have done.

 

Did you replace the connecting rod bolts when you added the larger turbo? How many pounds of boost were you running? Any idea what caused the previous rod failure?

Thanks.

 

he's running a bigger turbo on a tune that deadens the knock sensor, it's going to break. We see it all the time
Rods/pistons are a minimum. Water meth with that stage 3 will make it last longer. (just noticed you had meth, maybe start running a higher concentration)

 

I'm running 100% meth with a .8mm injector on the Howerton kit. I wasn't in boost when the engine failed, I was cruising on the highway at 80mph. Engine was making a little bit of noise all weekend but I thought it was the timing chain beginning to rattle. Head is off now, not bent valves so that's fine. I just need a short block.

 

the engine was damaged from before, it just finally let go
if you were running that much meth and it failed, the tune is way off

 

Okay, maybe I came off wrong. I'm not trying to be an ******* here. Personally, I think a detailed assessment of what happened to your car and the conditions that led to catastrophic failure would be beneficial to the community. Having said that, on the previous failure you were not using the plugs Manic recommends. Is there a reason for this and do you think it has any relation to your failure? What spark plugs were you using and what fuel (91, 93, E85 mix)? How many foot-lbs of boost were you hitting normally? When you replaced the motor, did you do a complete replacement or just cannibalize the parts that you needed? Where is your WMI nozzle located and why did you choose to use 100% rather than a mix?

Again, I think this would help everyone. Thank you.

 

At the moment I am running NGK 1422s at the recommended gap. Running 93 octane gas on the 93 octane map for Manic. The peak boost is 22.5 psi on that map. The last replacement, only the bottom end was swapped for a 2013 stock Cooper S short block with 50k miles on it, at the time of failure this time it was at ~102k miles. My WMI nozzle is located in the post intercooler charge pipe as per Howerton's instruction manual for the car. I run a 100% mix because I'm lazy. But I never had any issue in the year and a half I was running methanol or the almost 3 years since my last engine replacement. Changed my oil religiously every 5000 miles. I was pretty much abusing my car all weekend at Tail of the Dragon in the days before the failure and I was getting a slight ticking from the timing chain. But again, at the time of failure I was cruising at 80 in 6th gear on the highway. I don't believe I was low on oil because I checked it the previous day.

EDIT: Also worth noting I actually sent my oil out for a Blackstone test and that oil change was done about 1k miles before the failure, so I'll be able to see if the failure was over a long period of time or instantaneous.

 

Thanks

 

You sure there was no boost? My experience with a couple of turbo charged cars (VW TDi, 996 Porsche Turbo, and my JCW) and one supercharged car (Hellcat) is at 80mph some boost is being made.

At any rate the failure reads like detonation. Detonation is not limited to WOT operation. Part throttle operation at reasonably low engine speed can result in real good cylinder filling. Normally the engine controller would also increase timing advance. I have observed with other cars under these conditions fuel mileage really improves.

But if the mixture is not right and if the timing is too far advanced and if the engine controller is not able to monitor for detonation... the engine can break.

 

I run DashCommand on an iPod right in my line of sight. Boost pressure is the biggest number. Almost positive it was reading -0.7 psi at the time. Might have even been going downhill at the time.

I have the whole engine stripped down to the short block. Doesn't look like and cylinder wall scoring. Other pistons look fine. The connecting rod bolts snapped clean off, and the connecting rod is bent and snapped in half. Piston is chewed up but I think that happened after the fact.

 

How long ago did you install the larger turbo? Were the connecting rod bolts OEM or ARP?

 

If I'm not mistaken, the maximum pressure the MAP sensor can read is 22.4 PSI. If you are using an OBD based app or device, then the max it will show is 22.4. My OBD based scan gauge matches my mechanical boost gauge right up to 22.4, at that point the scan gauge stays at 22.4 and the real gauge keeps climbing.

Did you use any other method to verify that you were not going beyond 22.4?

 

My peak is usually 22.5 but I have seen over 23 a couple times. Can't be sure if that's the actual reading or some sort of weird scaling going on between the dongle and my iPod.

 

If no piston damage or scoring, sounds like a bearing let go.

 

We have the same turbo. With Manic stage 2 I was hitting 26 on my mechanical gauge while the OBD gauge would read 22.4. Waste gate adjustments didn't help, anything more than +/- 2mm would cause more issues. I sent the DME in to have RPM stage 3 flashed over Manic to retain map switching ability. It was still hitting 26 and the map switching ability was totally gone. I sent the DME back again and had Manic wiped and RPM stage 3 loaded fresh. Everything appears to be operating correctly for now.

What I'm getting at is, you may have been pulling 26 and had no idea. I'd take a long, hard look at that turbo because when combined with Manic, it seemed hell bent on killing my motor.

 

I wasn't even seeing 22 on my OBDII gauge until i had adjusted the wastegate to where it is now.

 

Stock rod bolts let go or ARP?

Talking with another builder on here.... He said that ARP rod bolts are a good measure... even on a stock turbo and map.

Have had issues on SBC engines when I skimped on the Rod bolts... so wondering if Scotty was onto something.
And... believe it or not... on one motor...switching to Evans coolant made a difference in eliminating hot spots in the jacket-cooling.



Any updates on your causes.?? ... learning as I go !

Wondering if you ever found out what stock pistons are made of...alloy wise... 2618, 4032 or similar forging alloys etc...
Not sure if a full 2618 Forged (vs 4032) is worth the tradeoffs in anything but a race motor that gets rebuilt on a schedule??

Thanks in advance for any light you can shed.

.

 

I wound up buying a short block from Sneed4Speed with Supertech rods and pistons, King bearings, every fastener is ARP. Been running perfectly since early June when I finished rebuilding, have about 10k miles on the new engine now.

When I pulled apart the engine it definitely seemed like it was just the rod bolts on piston 4 failing. There was basically zero metal in the oil pan, the bearing looked fine aside from being mashed up from the piston letting go. Crank had no scoring. My oil test from Blackstone also showed no metal in the oil from the oil change immediately before the failure.

It makes sense the rod bolt failed. They were stock, bottom end had 100k on it. I absolutely thrashed the car on the Dragon for 4 days before it all let go. Probably just fatigued to the point where they couldn't take it anymore. The timing chain guide was cracked at the bottom as well, but I don't think that had anything to do with it, just explains the noise I was hearing.

 

Thank you for the thoughtful follow up.

Sounds like dropping the pan and installing ARP bolts ... is a good idea on these cars??



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