Chipped piston, blew motor, L32 going in (updated w/ injector flow data)

This morning on my way into work i was egging on a R/T Charger and during a pull I lost power at about 85mph / 5k rpm. SES light starts flashing and i was down a cylinder.
Limped it to work running on 5 cylinders and did a quick scan on my way. Showed P0304 (cyl 4 misfire).
Never heard a bang or anything, just lost the cylinder so i figured the wire may have jumped off the coil. Got to work, pulled the plug and saw this:



Replaced the plug and reset the code and it seems to be running OK. Im sure the ceramic part that broke off is still in there but i cant get anything in there to remove it so its going to have to find its own way out in little pieces.

Guessing it ran lean; this this morning was a cold 45° down here in FL.
Judging by the damage, and how it was running after the new plug, i dont think the piston is chipped. No oil in exhaust.
Any thoughts? I just ordered a new coil pack since the one that runs cyl 1 and 4 is original with the white numbers. (232k miles on the motor, sig needs updating)

wires - delphi 2 yrs old
injectors -used 42# but i run seafoam every 6 months
fuel filter - delco 3yrs old
plugs - AL103 3k miles on them
fuel pump - original 20yrs old 232k miles

Any thoughts?  was i just lucky enough to kiss the plug and not do any real damage or do i need to tear it down?

Something caused the insulator to crack - looks like the electrode is smashed, so my guess is it might be a chipped piston. You could do a compression test on #4, or use a scope to inspect inside the cylinder.

Maybe the chip was small, or you got lucky and it was sucked out the exhaust valve before it lodged between the crown and head. If this is what happened, the rod bearings might be okay. If it did make contact, your bearing might fail. You'll hear deep knocking in the bottom if this is the case. You could also find that piece of piston lodged in the head.

If compression is good, and you don't find any debris stuck in the head, you can run the car as long as there's no rod knock. We know something broke loose in there, but could be gone by now. Hopefully that's the case. Good luck, Matthew!

Detonation can do that to a plug. I'm sure the porcelain chip is long gone through the exhaust valve. hopefully, you didn't chip a piston. Ever had your injectors cleaned? One clogged fuel injector can mean a lean cylinder. Even if the PCM commands full enrichment, the injector can't supply it. Everyone I have ever known that blew a 3800 did it at sustained WOT. Detonation is the most lethal event for any engine at WOT.

I've seen that on many 3800s. Most likely: you chipped a piston, the chunk smashed the plug while pummeling itself and then went out the exhaust port and is gone. Do you have an inspection camera?

Chances are good that the rings are sealing for a little while so it runs 'okay' but it won't last long.

Thanks for the responses.
Larry, ive never had these injectors pulled and bench cleaned, only the occasional seafoam treatment.

Running the car home it did surprisingly well. saw normal boost and little to no Kr on the few WOT pulls i did. (less than 2° at 60 and i let off)

Im sure im on borrowed time now with this bottom end. I dont have a scope handy at the moment but might be able to use one at work in the future. ill upload a pic of #4 piston if im able to get it.

Is it possibly the piston had enough slop to make contact with the plug tip? how much clearance is there normally?

New coil pack ordered for #4, getting fresh oil and filter tomorrow and then ive got no choice but to drive and hope it last until i can find a new bottom end L32.

Mr.Riviera wrote:

Thanks for the responses.
Larry, ive never had these injectors pulled and bench cleaned, only the occasional seafoam treatment.

Send the injectors off to mr injector, very affordable.  http://www.mrinjector.us/

Mr.Riviera wrote:

Is it possibly the piston had enough slop to make contact with the plug tip? how much clearance is there normally?

There is no chance the piston actually hit the plug tip.  That could only happen if the plugs were of the wrong reach, and even then. I have seen detonation do that to a plug before, but in the 3800, it's usually a piece of the piston flying around and hitting the plug.

Next time i can have the car down for a few days ill send the injectors out.
Working on getting a borescope to take a look.

The key part for me is the deformation of the plug electrode, indicating a collision with something other than the plug itself. I agree with Larry about a lean injector being a possible cause. When mine chipped (#1 under similar circumstances), I pulled and marked all the injectors, sent to Mr. Injector for a blind flow test and cleaning. The results showed #1 was the worst flowing of all the cylinders. If you don't mind spending $100, this could give you some closure on what went wrong.

It's very possible your bottom end is fine. The loss of compression from the chip (if that's the case) could burn some oil and power won't be 100%, but otherwise the situation could be livable for a while until you can replace the piston. I think it's possible to swap a piston+rod out through the bottom, or maybe just pull the engine and rebuild. 3800 is one of the least expensive rebuilds, so it's something to consider. Pulling the engine was way easier than I thought it would be. Re-installing it was very satisfying!

the borescope i had avil didnt fit into the cylinder. this is all i was able to see:


Not sure if the shinny top left area is a chip or not.

Yep, that's a chip; looks just like mine did. The shiny part is the top of the ring. The thin dark line is where the ring meets the cylinder wall. Beyond that line is a reflection of the ring on the cylinder wall.

Sucks, but at least you know what happened.

Should i stick a magnet in there to try and grab and parts of the piston still there?
Are the pistons even ferromagnetic?
Definitely going to send injectors to mr.injector and find out if #4 was flowing low.
Assuming the chip is minor enough to keep driving on until i can get some parts together for a bottom end repair.

Pistons are aluminum. A magnet will not stick to it.

Also, I noticed in the first picture of the plug, it looks as if you have a lot of anti seize on the plug threads.  There really is no reason to use anti seize at all.  Our plugs are steel and taper seat, and they go into an iron head.  1/16th of a turn past finger tight is all it takes.  Anti seize can interfere with heat conduction from the plug tip to the head.  Using that much anti seize can make the plug overheat, another inducement to detonation.

Good to know. never heard that before about anti-seize on plugs.
I change them pretty often so they shouldnt get stuck anyways.

Looks like im on borrowed time although its driving just fine right now.

Anyone selling a low mile L32?

Some might disagree, but if there's no loss of compression, and it's not burning too much oil, you could drive it as-is for quite a while.

The biggest risk for damage has passed. I'm not sure if a chipped piston is prone to chipping again, but that would be the biggest reason to fix, imo. Take it easy on the throttle and should be okay.

Mr.Riviera wrote:

Good to know. never heard that before about anti-seize on plugs.
I change them pretty often so they shouldnt get stuck anyways.

Looks like im on borrowed time although its driving just fine right now.

Anyone selling a low mile L32?

My 1970 GS455 has aluminum heads.  If you use a steel plug with unplated threads, a dab of anti seize would be OK, just a dab.  I use NGK plugs and the threads of the spark plug are plated.  Plated threads do not require any anti seize at all, and I use none.  I have had the plugs in and out at least 7 or 8 times.

Hard to say whether you are "on borrowed time" or not.  I'd do a compression check or a leak down test on that cylinder.  I'd also keep an eye on that plug for signs of oil burning.

Like I said, detonation is the most lethal threat to any engine.  Momentary WOT blasts are no problem, but if you are going WOT for an extended time like on a race track, you need better fuel.  I never run my GS down the track without some race gas mixed in.  Under racing conditions, you'll probably never hear the detonation until something lets go.

Adding to Larry's warning: detonation is especially damaging in forced induction applications. The effective compression (under boost) in a modded L67 can be >17:1. IMO, the onset of detonation is much more sudden and abrupt compared to N/A version, also more heat and pressure inside each cylinder, especially in an iron block like ours.

I dont disagree. Ive had these same mods installed for ~5yrs now and go WOT every day, many times for prolonged periods from 0-80 or 50-120.
232k miles and the last 140k driving like this, im really surprised it has lasted this long.

Today on my way into work i jumped on it coming out of a turn and held to 80. No oil or smoke coming out exhaust and the maxima didnt pass me lol. Warmer out than when Cyl 4 chipped (60° out at 7am).

Time will tell how much longer this will last, in the mean time ill work on obtaining a L32 with less than 100k on it. Seems like they are going for between $1200 and $1500. Anyone want a low mile Gen V blower?

If you want to keep driving it, remove the supercharger belt. That will prevent you from chipping more of the piston...  At this point you might as well keep driving it until you get your replacement lined up. You can't damage it any worse than it already is if your long term plan is to replace the motor anyway.

edit to clarify - I mean, sure, you can damage it worse...  but it's not going to impact anything else, just ruin an engine that's already damaged goods.

Most likely the chunk of piston got broken up and went out the exhaust port a while ago.

Rebuild cost might be lower if the bores don't require machining, but otherwise... yes, I'd keep driving it.

I do 'want' the Gen V, but I'm not buying any car parts right now.

OK ill keep you in mind if the L32 i find comes with a blower.

Rebuild seems like more trouble than a used L32, seems like i can find them for $850-$1500 with decent miles. just need a engine crane and im cooking.

On the used motor, see if you feel up to 'rolling' in new bearings and sliding in a better cam. If you want performance, a cam is the ultimate.

Motor still running strong with a chipped #4. Still getting on it daily too One of these days i know im going to be towing it home lol

So long as the rod bearing isn't damaged, you should be able to drive it like that for a long time, maybe indefinitely.

...and the motor just blew.
Anyone got a low mile l67/ l32 for sale?

yup, comes attached to a 98 riv.