Andy Ericksen

What do I need to replace on the new (used) engine before installing it in the car?

So far I'm thinking:

• Oil Filter
• Air Filter
• Fuel Injectors
• Water Pump
• Air Oil Separator (AOS)
• Spark Plugs
• Coil Packs
• Mass Air Flow Sensor (MAF)
• Rear Main Seal (RMS)
• Intermediate Shaft Bearing (IMSB)

What's missing from the list? Is anything on the list overkill? Should I replace the O2 sensors, are they easy to get to after installation?

hatchetf15

Maybe put some 997 swirlpots, low temp thermostat. Check primary and secondary oil pumps for debris.

Andy Ericksen

thermostat is a good one, I missed that.

what are swirlpots?

cds72911

I personally wouldn't bother with injectors or coil packs unless they are bad, but others might.

I'd add the oil pressure sensor, not because it is bad, but because they fail frequently, are cheap, and are super easy to replace with the engine out.

I'd also add a serpentine belt to go with your water pump, gasket and low temp thermostat.

There is a plastic water line junction near the crank pulley that often breaks, and there is a metal aftermarket option (rauch and spiegel). Easy to do while the engine is out. 996.106.226.52/157. 516.252.

Check for brittle vacuum lines, leaky o-rings, sealing washers, hoses, etc. Replace as necessary.

Start a list of the small stuff - tensioner sealing rings, flywheel and pressure plate hardware, cam cover caps, wicking green loctite, Loctite 5900, etc.

Swirl pots are in the sump, pick up oil and remove air. Easy swap out while you're in there.

Deeper sumps are a popular option. Add a skid plate.

I'd evaluate and replace both motor mounts and the transmission mount.

Andy Ericksen

Good advice, I'll do that

I already ordered the belt.

First time I've seen the Porsche part cheaper than aftermarket

Tensioner seal rings are for when I change the IMSB, correct? Is that the only time I'd need them?

I didn't think about the flywheel/pressure plate hardware. Even though I plan to reuse the flywheel and pressure plate I still have to replace the bolts once I remove them. Thanks for the reminder.

I'm hoping others will chime in to expand on the etc.

Is there a particular part number you are aware of? Searching doesn't seem to work, I'm guessing because they are for 997 not 996?

I'll most likely do the deep sump on the original engine rebuild, not the temporary engine.

Skid plate is a good idea.

Good advice.


Thank you for the feedback.

Porschetech3

I agree with checking the end play and also check the runout for crankshaft bending at the flywheel/flex plate outer circumference . This is more critical for the manual engines with the heavy DMF, and since this is a Tip, is much more supported. There is no need for DME, immobilizer,, cluster, HVAC ect, as both engines can use the same Motronics version. The tiptronic engine harness WILL have a couple more wires and vacuum lines for the tip changeover valve that controls the coolant flow to the trans cooler, but the vaccum lines can just be swapped over or capped, and the extra wires can be just left disconnected/taped out of the way..All other advice seems to be spot on...Dr. h.c. Porschetech3

Andy Ericksen

I asked the seller to test the end play, they said they would and that they'd send a report with the engine, but I'd like to verify myself. Any advice on the best way to test both of them myself when I receive the engine and also what values/ranges would be considered good vs bad?

Thank you

Porschetech3

For the end play, set up a dial indicator on the crank shaft end and push-pull the crank, should be .002-.010 thou.

For the runout set up dial indicator on the outer edge of flywheel/flexplate and rotate engine, there is no spec, but less is best, I would like to see less than .010 thou...

User 63031

I am one of those. My IMSB was shot to bits, caught it in time, no skipped timing yet. Debris looked kinda like yours. Flushed the engine, cleaned as well as I could, installed my own sealed IMSB. Disabled oil-bypass valve. Flushed it again after a few hundred KM. Cost me a whole 300$ in materials. Happy camper so far.

This was one and a half years ago, and 15k km has been driven since.

Don't let the fear mongering get to you. Some have actual monetary incentives (want to sell you something, yes it's true..), and some just desperately want you to walk the same expensive path they walked, so they feel validated in their own expensive choice. Don't let em get you. That engine can probably be saved with minimal cost if its oil filter bypass valve is still in good condition.

Contrary to popular belief, if that bypass valve was good and your filter wasn't torn, none of those debris will have gone through any critical parts of the engine. It will always have had a pressurized clean stream of oil, and debris cannot flow stream-upwards to critical bearing surfaces. Simply doesn't happen.

NuttyProfessor

Yea, I read your thread and you definitely dodged a bullet, but with all due respect, I'm a little apprehensive about the longevity of these engines when we tell other owners to just "flush the engine and it will be alright". I believe the best course of action when an engine exhibits this much metal and other debris in the sump, is to advise them to have the engine removed and fully rebuilt. I guess if the owner doesn't care about loosing the engine and/or the new bearing, then he could take your route, but it's bad for companies like LN Engineering when they're sued for killing an engine with the replacement bearing. Charles Navarro has said in past threads that quite a few have tried that. It costs him valuable time and money to fight the cases. I guess that explains why they won't warranty a product without it being installed by a certified installer that put the engine through a pre-qualification procedure.

cds72911

I wouldn't advocate doing that either, but it is funny when I contrast the ultra conservative approaches we take for our cars with some of the dirt cheap and pragmatic mechanical repairs I've seen in India and other parts of the world with fewer resources. Makes me chuckle when I see people on Internet forums getting worked up about oil viscosities and little stuff like that.

Prelude Guy

Andy,

If you are interested in trying to save your engine by replacing the IMSB, let me know. I have a brand new IMSB that I would be willing to offer up as a sacrifice to the M96 Gods. Lol

I'm curious if the engine can be saved.

PM me and we can figure something out.

User 63031

The "best" course of action is of course to buy an entirely new motor and then some several k$ to address all 'popular weaknesses', and this is basically what some people on here basically suggest every time they see an engine that has issues. "Throw 20-30k $ against it and you'll be good!" Yeah thanks for the help, I guess?

But. If the engine oil filter and bypass valve were good, I see no reason at all to take apart and rebuild the entire motor. On that premise, debris will not have made it to any critical parts of the engine. (unless you started it in arctic subzero temperatures with a broken IMS, and even then you'd only have a few seconds of dirty oil at most, after which the debris is rapidly flushed out).

Has the filter or valve failed? Yes, rebuild, period. But the failure rates on these valves is not nearly as big as some (some that have quite an expensive solution to that 'issue' to sell, mind you, monetary incentive) would want you to believe. In fact, they never shared any numbers on failure rates, only "I've seen numerous bad valves so I will always recommend my 'invention'". Whether 'numerous' means several-thousand or 'less than 10 from a sample size of 1000 engines', the story never tells, but when lacking actual numbers take a wild guess which one is closer to the truth.

For one I couldn't care less what's good or bad for LN Engineering or any company. I care what's good for the individual that's having issues. But at the same time, if you're replacing the IMS yourself I strictly recommend not buying any LNE bearings, period. They're basically glass bearings, designed to only go into a pristine engine. Any debris in the sump from whatever source, even if something unrelated fails after installation? RIP bearing. They're not suited for a hostile environment of any kind, which is why this whole pre-qual procedure exists in the first place.

If your IMS failed, you buy a sealed replacement IMS bearing, to make it resistant to any leftover contamination in the sump. Stay away from LN bearings or any other open one.

Again, the only piece of that engine that is contaminated is the sump and maybe the chains from minor splash. No critical parts (bearings, lifters, cylinder walls, crankshaft) will ever see the debris-laden oil if your filter is good.

Prelude Guy

I agree with you 100% for engines that are still running. For my personal situation, if I had an engine that suffered an IMS failure like the OP's, I would do exactly what you did with your engine. I see no reason to "DANGER DANGER!!!! OMG!!!! Stop driving it and get it rebuilt!!" I think it's best to try to get as much life out of it as possible. If you decide to go with a full rebuild, there are PLENTY of other non-running engines out there to use as a core.

If we were talking about a Nissan or Toyota engine and it had some common problem, I would suggest rebuilding the engine because those are fairly easy to rebuild. But when you're talking about the M96 that is expensive no matter which way you go, you might as well try to roll the dice to see if you can keep it running.

For the average person looking at these cars, I will always suggest people buy a roller and have the engine rebuilt the correct way. IMO, it's the best option to fully enjoy the car with the least amount of headaches and potential expenses. However, for people who like to tinker like me, I think trying to fix a running M96 is never a bad idea. That's what I tried to do with the first 996 I bought with a blown engine. Wasn't as lucky as you though. The timing chain was broken.

Byprodriver

A bit conflicted there aren't you.