16 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
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Discussion summary
YOUR RESEARCHGuess why my engine blew up! with picture clues
Leading reported evidence
Use on the oil pick-up tube screen
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
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0
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1
Discussions
Read evidence and context
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Performed · outcome unconfirmed
It has to be made...use the same mesh that is used on the oil pick-up tube screen.
Leading evidence: 'Use on the oil pick-up tube screen' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check scavenge pumps' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion
Check your scavenge pumps to see if one is locked up..
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Suggestion
If everything was running good before the valve dropped, probably lots of other good 'core' parts.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
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Suggestion
It has to be made...use the same mesh that is used on the oil pick-up tube screen.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
16 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261027T070717Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hi all, new member here, I will be asking for help so I thought I would start with a fun game of guessing what broke in my engine. I just picked up a 1999 911 which needs an engine. The previous owner just had the car painted (very nice work) and he stated it made a loud bang, rattled, and then he shut it off. I did an exterior inspection and everything looks normal for a 150k mile car, but did notice the variocam solenoid wire was broken off. No other clues externally. No oil in the coolant, and no coolant in the oil. The engine isn't locked up.
I pulled the sump and found a couple plastic bits, and two metal shavings. Sump had a bit of metal paste, filter was clean.
Bores didn't look terrible, but I did find some metal in cyl. 6. Plugs were old and oily.
I will upload the pictures of the culprit tomorrow night, its an ugly scene. In the meantime does anyone have a 3.4 engine (or longblock) in good shape for sale? I heard a 3.2 from a similar year boxster S is a possible match as well with a couple mods.
Well, my initial thought was your dual row IMS bearing that hardly ever fails especially after 30k miles let loose, but when mine failed (or was in the process of failing) last year there was a ton of metal in the filter�
if one of the vario cam actuators had no power maybe it fails in the open position putting undue pressure on the chain, wearing through the pad causing the engine to go out of time�but the chunks of plastic would be more yellow/cream in color. However, the metal paste in the sump would indicate a chain riding on a metal surface if a pad had been worn through. So that�s my final answer� vario cam pad gone/worn through. 😁
The Variocam solenoid failing in either direction won�t cause any metal to metal contact, so that didn�t directly cause the issue, IMO.
But based on what you provided, I�m going to go with a chain failure issue. As for why there�s no debris in the filter, that could just be good luck and prudent decision-making by not trying to restart the engine.
Pulled the plug from #5 and ouch! I took a couple pictures inside and found a broken valve head stuck under the adjacent valve. I am planning on seeing if the chains are still in one piece. I wonder if anything in the engine is reusable or not.
Well, "thermodynamicly" speaking, once you get it apart for a good look, think you might find a nuke went off in that cylinder.
If everything was running good before the valve dropped, probably lots of other good 'core' parts. Guess valve seat drop out is also a problem in some cars that have suffered low speed detonation... we can talk about this but for sure you won't know till you get it all apart and evaluated.
jmo
Check your scavenge pumps to see if one is locked up..
All it takes is a small piece of metal to lock the scavenge pump, then it breaks the timing chain, then the valves hit the pistons..ect. ect....
If you are building an m96 it's a good idea to put screens on the inlets of the scavenge pumps to keep out debris....( or if you are not re-building yet, put a magnet on the outside of the metal plug near the inlet)....
It has to be made...use the same mesh that is used on the oil pick-up tube screen.
I'm pretty positive if you buy a $75K m96 it will have mesh screens protecting the scavenge pumps so a small piece of metal doesn't turn a $75k engine into a boat anchor...
if we are speculating as to what happened; I'll throw my $0.02 at a dropped valve seat (which is a known issue) which stressed the valve and caused the head to snap off. If you got super lucky perhaps it only dinged the piston but highly likely it scored the bore as well.
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