Another novice rebuild complete

[sehorntx]

Just finished rebuild on my 996. Failure secondary to intermix from cracked block. Rebuild with spare block. Running strong. Keep the faith. Working thru P0410 and P0411. Stalling sometimes at low idle coming to stop but fires up immediately. Learned alot, didnt buy any of the tools, made them myself.

Tim

[Dharn55]

Tim

Lets here some more details on the rebuild. I guess I got away lucky on mine!

[GOB]

Really curious on this one as even the ex head mechanic of the local dealer refuses to crack open these motors. Apparently parts and tools are hard to come by.

[logray]

Was there anything wrong with the donor engine or did you find a "second hand" block out there?

Interesting...

[sehorntx]

Thanks for the interest. My initial failure 4 years or so ago was bilateral cracked cylinder heads. Performed similar repair as Dharn55, removed engine had cylinder heads repaired and put motor back in all in the garage.

I had recurrent intermix about 1 1/2 years ago from unclear source. Engine out again and cylinder heads sent off for check. Cylinder head repairs were intact. I had to assume a cracked block. during the last event I had purchased a 996 engine off ebay with a spun bearing just to get the extra cylinder heads (for $1000.00).

Dissasembled my engine down to the crankshaft. Havent taken it to the shop. The only defect I could detect was that the coolant passage gaskets between the two halves of the block were distorted and deformed. So I suspect this allowed coolant under pressure to enter the oil passages after the car was shut off.

Rebuilt the engine with my spare block and all my original parts from the first engine. New bearings, rings, valve job... The specialty tools I constructed myself. I had already made some for the cylinder heads during last rebuild. The other ones were mainly for placing the circlips to fix the rod wrist pins in place. Nothing terribly complex but a slow tedious process. I once again decided against the new IMS bearing. Did remove the outer plastic covering to allow better oil circulation. Bearing moved nicely no play.

One of the more frustrating points was broken bolts and some striped bolt holes. Had to drill out several and re-tap, that was a pain in the arse.

Fighting through the p0410/p0411 codes now.

Cheers

[Ahsai]

Also curious to see more details. That's quite a story.

"I once again decided against the new IMS bearing" <- So you took the whole engine apart but decided to reuse the original IMSB or put a new OE IMSB?

[Dharn55]

Tim

I am also curious on the IMS bearing. Did you buy a new OEM bearing or just reuse the old one?

I guess I have been lucky with my fix as it is now 4 years and 22,000+ miles and the car is still running strong. My oil pressure is a little low when the car is warmed up. This might be from loose tolorences after running the engine with contaminated oil for an unknown period of time. Who really knows.

There is a local guy who did a full rebuild here that found a flaw in the casting of a head. Not sure how he found it though, it was not a crack but a flaw that started leaking.

He also bought an inexpensive bearing, made a spacer and used it for the IMS.

[JFP in PA]

He also bought an inexpensive bearing, made a spacer and used it for the IMS.

Statement like this really make me weak..............

[sehorntx]

Sorry about the confusion. I inspected my bearing found it to be in good nick and resused it. Lubricated it like hell and left it alone in the intermediate shaft tube. I did get a new cover plate though. I had no idea if the car would actually run again, so I decided to roll the dice on the IMS.

[sandersd]

Where did you get all the rebuild specs like bearing clearances, etc?

[gnetwerker]

Well, kudos to you, but I am perplexed by the juxtaposition of the words "novice" with "rebuilding a 996 engine". Also "didn't buy any of the tools, made them myself". This seems a small step below "I knitted myself an aircraft carrier out of steel wool".

[dylanjl]

Awesome bro

[sehorntx]

I am a novice for sure. Only prior experience was taking out the engine before and removing/reinstalling cylinder heads after crack repair. I did have the spare block examined by my local machine shop to ensure no gross defects. The tools I literally made myself. For example to install the circlips on the 4-6 side through the little hole I measure the ID of the side of the piston then found an aluminum broom at Home Depot cut it to appropriate length. Then crammed those circlips in the tube by hand and installed those bad boys.

I felt I had nothing to lose, car was just sitting in my garage and I didnt feel like popping for a new engine or used engine which may implode at any instance.

Keep in mind my project could blow at any point but it seems to drive with good power at this point. This project is doable for anyone on this forum for sure.

Cheers

[sehorntx]

I have been through two intermixes now. If I see it again. I'm going for a track day and driving like a madman until the engine implodes then walking away :)