GC996

Two more quick questions.
1. How long were you out on the track in the session before it blew?
2. What does the water pump look like?

De Jeeper

Yes rod bearing, sorry. Not sure why its always the #1. My motor did have 200k miles in it but yea its heat and oil starvation. Also, the track version uaos helps keep the oil level at a good height, but I have no opinion on the uids pan as u have not seen adaquite data in the 996 platform to give an opinion and i real dont care because i wont fo back to a m96 platform for the track.

Here is my rebuild thread....enjoy.

https://rennlist.com/forums/996-foru...-the-dust.html

pdxmotorhead

A L33 would be half the price of a LS3 ,, good cam + manifold 450 to 500 NA hp... LS engines need a accusump for road track use. (Except for the dry sump ones.
OR if you want ot make a statement, run a 2014+ Gen5 4.3 V6 with boost.. Just cause I think it would be fun.. Light weight, 300HP almost stock, inside has all the cool parts...
And with the 6 and the right exhaust it would still kinda sound right..

Porschetech3

200 tread wear tires
100k mile engine
Stock AOS
Stock sump
Race Track ;; extended session
From the owners manual :::"The fitting of racing tires (e.g. slicks) for sporting events is not approved by Porsche. Very
high cornering speeds can be achieved with
racing tires. However, the resulting transverse
acceleration values would jeopardize the adequate supply of oil to the engine.
Porsche therefore will not accept any warranty
or accept any liability for damage occurring as a
result of non-compliance with this provision."

Track work is a big boy event....you gotta pay to play...The modern 200 TW tires can reach the cornering G-forces of the 20+ year old racing slicks...

What happens is the high cornering loads will shift the oil to the side of the oil sump and away from the pick-up tube...The pick-up tube will start to receive foam or oil/air at the surface of the oil level..This air will reach number 1 rod first and worst since it is the closest to receive the air...This will cause the temperature to spike and the clearance to open and jerk on the rod , breaking the rod and the rest is collateral damage...

LS engines::

There are 40 different variations of LS engines.

Half of them don't make more power than a stock 3.4 m96.

Only three of them have forged cranks..LS7, LS9, and LSA

None of then have Nitrided cranks.They are all induction hardened..

All will suffer from oiling issue on the track ( even the "Factory dry sump ones" )

All will have a higher CoG than a flat six...( it kills me when people tout corner ballance as proof of COG validation)..

They sound like ****..low tech ..

All Facts

zbomb

Even if this is true, who cares ? He mentioned LS3, an LS3 made 400HP from the factory. I think that is, like, a whole lot more than an M96.

NOT a fact. The dry sumped LS3 motors came with forged cranks. And, so what ? 4 digit HP numbers on the stock cranks are common on boosted applications.

https://help.summitracing.com/app/an...3-engine-specs

The factory dry sump is a lot better than the wet sumps but I would generally agree with this statement as long as you are talking about stock oiling system parts. But, you can actually buy effective solutions that fix this problem from actual proven companies in the aftermarket that actually use engineers, data and testing to develop their products (not paying customers who think they are getting a fully tested product). As I said above, no such option exists with the M96 (maybe the system LN and Jake are developing will change this (it will likely cost a left nut).

Again, who cares ? The car will be faster around the track (TON more HP), more reliable, have less expensive parts and not have to cost $25K plus to rebuild, but it could if you wanted it to. You throw this CoG thing around like its going to ruin the driving experience, I would love to hear what kabuki method you used to come up with that.

kondata17

Curious how you define the word "fact". M96, either a 3.4 or a 3.6 make what, 240-320whp max? and thats with a generous dyno. A 4.8 will lay down 300hp completely stock. Literally any LS variant will make more usable/reliable power than an M96. LS internals have been proven to handle 600-800hp easily for many years, forged crank or not. Any engine will suffer from oiling issues when pushed hard enough, i dont care what your autometer/factory dummy gauge reads, you'll starve the pick up at some point.

I get it, you hate chevy engines. Ripping out one of these beautifully crafted m96 engines... that hold up so well over time... in place for a ls variant isnt for everyone. For a track car though, especially if you want something faster, its by far the best way to go.

1bz9670

A lot of great thoughts!

A few details, answers and more questions:
- I did not look inside the AOS - but it was still connected at both ends and no oil leak (as in the case with @De Jeeper )
- The water pump was new (maybe 1,000 miles on it) - but I did not take it off - somebody asked how it looked - I will take it off to see
- I did find a connecting rod screw inside the engine (just like @De Jeeper again...) - it was bent and looked beat to death.
- Connecting rod #1 was not connected to crankshaft any longer and the crankshaft looked beat in that area (same as @De Jeeper )

I continue to be surprised by the lack of any blueing where the #1 rod was connected to crankshaft. It seems that the main bearing (main bearings, not rod bearings) saw some heat but no blueing either. Is it possible that the rod just broke?? Or some sort of failure of one of the rod screws??

In regards to the car and its engine - I don't want this to turn into an M96 type of dispute. I knew it could happen. Also, I really like the chassis. I am underwhelmed about another M96 mainly because of the power, but also because to make one reliable for the track (LN sleeves, bored out, worked over heads, race AOS, IMS replaced, replacing all the chain/guides) will be $20K or so. Therefore, I'm thinking an LS3 because it has more power and because there is a company that sells a kit to adapt it (CPE). This will also be $20K+ but it has more power. It has to be an LS3 (or LS7 - but that is too expensive) because of the adapting harness that this company sells. This would be for the street. I am very aware of the LS3 oiling issues on track. It blows up like clockwork on track (it seems) due to oil starvation and oil getting stuck up in the heads. So - I am thinking to put in a crate LS3, return the car to daily driving duties. Now - if I like it (I don't know if I will because V8 in 911 chassis - how knows) and can't avoid taking it to track (I have a different track car now), then I will dry sump it with a kit from Aviaid, put a cam in it and widest tires I can fit. Any suggestions about what dry sump kit (I only know of Aviaid) are welcome.

Thanks.

zbomb

Dailey Engineering

kondata17

Virtually any dry sump pump/kit manufacturer makes a set up for the LS engine. ARE, Peterson, Barnes, Auto Verdi...but the best is Dailey Engineering. You could even get used NASCAR stuff and make that work. Lots of options.

De Jeeper

Although breaking a rod or connecting bolt is a lot more rare without seizing a bearing it still happens. Also it is possible as others have said these blocks can d-chunck and cause the piston to do catastrophic things. There is always the possibility of hyrolocking from an overwhelmed aos or a crack in the head dumping antifreezr?

Vid from when mine let go.

GC996

1bz,

How long (approx minutes) were you on the track when the engine failed? Any idea if the water pump you replaced 1,000 miles ago had all its bits in place or if a few of the blades broke off?

GC996

Ibz,

FWIW, I did a google search on Porsche 996 D-chunk and an oldie but goodie article from Total 911 popped up from 2006 written by Philip Raby tiled "Exploding Myths" who interviewed Autofarm and JZMachtech in the UK. I remember this article well because at this time we were all trying to identify the issues and mitigate them.

As a side note, quite a bit of early mechanical information before 2007 came from these shops. "The Essential Companion" referenced their work quite a bit.

This article came out after the RMS Go-No-Go panic and way before anybody had any idea that the water pump props could break off and lodge in the engine creating heat and cracking, as well as way before Bore Scoring became a top 3 term used in our vocabulary. Interestingly, at that time, the deep sump was not a mainstream solution nor was there an IMS Solution. Also at that time, folks started to migrate from the AOS to the Motorsports AOS realizing the oem AOS was about as durable as a Fiat. Take a look. You may find the article of interest.

As a side note, it was theorized at the time that D-Chunking in the early 996.1s was caused by how the factory held the engines with a clamp thru the production process. The use of these clamps in production was eventually eliminated as the Factory recognized the issue. Don't know the accuracy of this theory, nor do we hear much about D-Chunking today. Why, I don't know. Maybe we are just fixated with the headlights, IMSB and Bore Scoring.

But i will say this, we would have less engine failures on the track if folks would do the following...

1. Replace the WATER PUMP more often so the plastic bits dont get lodged in the engine creating heat and cracking.
2. Run a BETTER AOS to prevent intermix and hydralock, as well as handle more oil quantity and flow to improve oil pressure instability and mitigate oil starvation.
3. Run a BETTER SUMP that can increase the amount of oil in the system and mitigate oil pressure drops and oil starvation.
4. HEAT and COOLING is important. Don't track your 996 at speed on the track longer than 20-25 minutes unless you have a world class oil cooling system on the car.
5. Yep, make sure you have replaced your oem IMSB with a better one.

Try this link. Other one wasn't working

https://www.scribd.com/document/4950...otal911-July06

1bz9670

Yes, all great advice. I was looking at deep sumps right before it blew. Also - at the time, I was migrating towards a different track car, so I didn't buy it before that last event. At any rate, with my experience now, I would be very leery about taking another M96 on track, even with motorsports aos, deep sump, and all. The pity is that I really, really love the car on track (and on the street).

In regards to your previous question - I think I was out on track for 30-35 min when it blew.

De Jeeper

Except i had or did all of this and it still went kaboom. The m96 is a good engine, just not great for the track....even upgraded. My motor did have high miles and i knew it was gonna go eventually, so when it did, i was prepared and made lemonaid.

GC996

Appreciate your thoughts. In contrast, I would in fact track my m96 powered 996.2 again on the track and plan too. After a 14 year stint on the track with all the stuff on the list I gave you, I never had any problems. But, I am not blind to the issues every engine may have and the preventative medicine that's needed. Don't care if it's an LS, K24, Mezger or M96. But we can't change the fact that nothing is perfect. I guess it's a mechanical reality.

Whichever path you take on your engine, I wish you the best of luck. I would love to see a proliferation of engine swap threads that objectively discuss the pluses, minuses and things to be aware of, versus "the M96 is the worst engine and my _____ engine is the greatest thing since sliced bread."

Please keep us posted on your progress! We all have an interest.