Engine Failure Pic's

[thstone]

After disassembling the engine, the source of all of the metal in the oil filter (http://986forum.com/forums/general-discussions/52494-aos-more.html) was pretty obvious - lifter carrier and lifter.

The consensus is that the lifter carrier cracked and when it failed pieces broke off and some of the larger pieces were pounded under the lifter. This damaged the lower skirt of the lifter and created all of the debris that was found in the oil filter.

The piece of lifter carrier being held by the tech is well worn and almost smooth from knocking around in the engine.

The original IMS bearing (136,000 miles + 89 track days) hasn't been removed from the intermediate shaft yet but it feels firm, has no play, and is perfectly smooth when rotated by hand.

Variocam actuator pads and cam chain tensioners were in surprisingly good condition (I was expecting them to be well worn and ready to fail).

The remainder of the engine was in very good condition except for two crank bearings that were pretty well scored.

Engine rebuild pic's will be posted under my Spec Boxster thread in the racing section (Spec Boxster Build).

[Jake Raby]

Classic.. The engine was ran with a bad lifter for way too long.. Excess valve lash really beats on the lifter carrier and creates this issue. In 2012 we saw 30 cases of this, more than any other time.

Thats repairable.. Its a better case scenario failure, BUT now your challenge is to remove the residual debris from the engine before it takes out more internals AFTER the rebuild. I hope the shop has a powerful ultrasonic cleaner, its the only way to remove the debris from the passageways within the engine and internals.

[thstone]

The rebuild is being done at Hergesheimer Motorsports in Lake Forest, CA and they have a very nice ultrasonic cleaner made by Pro Ultrasonics. It looks like a deep fryer for a mad scientist.

[Porsche9]

Thanks for sharing as you promised.

[Perfectlap]

How do you diagnose a lifter that should be replaced before this happens?

[Jake Raby]

Originally Posted by Perfectlap

How do you diagnose a lifter that should be replaced before this happens?

It starts with a ticking sound.. Like any noise, it isn't good.

Ultrasonic machines are required to work with these engines… You'll never remove the debris without one. Best purchases we ever made, I outfitted every building with one.

[Perfectlap]

For these 20 cars with excess valve lash (that's a new failure term I hadn't heard before), were they mostly like TheStone's? high mileage cars? Lot of track mileage?

I thought the sub-100K mile lifter issues with the m96 engines was more premature degradation in performance than a possible premature failure.

[thstone]

Originally Posted by Jake Raby

It starts with a ticking sound.. Like any noise, it isn't good.

I readily admit that my engine had a noisy lifter for quite awhile (as Jake quickly concluded from the failure evidence).

Is there a recommended course of action for a noisy lifter? How long? How loud? Under what circumstances is opening up the engine warranted?

[Topless]

Well, it could have been much worse. Glad to see she is repairable and 136K with nearly 100 track days might be a new record for durability. Should be much quicker after you slip those 3.6L pistons and sleeves in there.

[jaykay]

Originally Posted by thstone

I readily admit that my engine had a noisy lifter for quite awhile (as Jake quickly concluded from the failure evidence).

Is there a recommended course of action for a noisy lifter? How long? How loud? Under what circumstances is opening up the engine warranted?

If one is going big bore on a rebuild....what is the cost of waiting for the failure to occur vs addressing it premptively? You would be incurring a lot of labour twice....weight that against collateral damage that can occur.

I ask as I have an intermittent lifter tick (or so it sounds)....usually shows up after the car is idle for a time and then disappears when the car is used regularly

[thstone]

Originally Posted by Topless

Should be much quicker after you slip those 3.6L pistons and sleeves in there.

Hey brother! I thought that we were keeping the "3.6 thing" just between you and me? There might be a few PCA Stewards on this site and I need to keep this on the lowdown.

In all seriousness, the engine will be rebuilt ALL STOCK except where allowed to deviate by the Boster Spec rules (such as the replacement IMS bearing) to the extent that I could pass an engine teardown inspection if something that drastic was ever needed.

However, I am taking advantage of the downtime while the engine is being rebuilt to further reduce weight in the car. If my calulations are right, when its all re-assembled I should be able to manage the car to min spec weight by adjusting the fuel load.

New engine + min weight = no excuses.