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 :)

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

Loren worked like a champ thanks!

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.

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

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

Hey Loren,

996 Rebuild complete. Car running strong.

Another lost radio code

996 C2

Becker CDR 220

Type 4462

48/98

Serial #: X5018933

Thanks,

Tim

Thanks guys. I had a recurrent intermix in my engine about two years after having cracks repaired in both cylinder heads. Engine cam out again and I have sent heads back to machine shop in California, but alas the cylinder head repairs checked out OK. After some procrastination I have now dissassembled down to the crankshaft. Previously I had purchased another 996 engine with a spun bearing in case I needed the heads.

Now my assumption is that I have a cracked block and I am rebuilding with the block from my other engine. I had this block cleaned at checked out with a local machine shop, no defects. Wish me luck. This crap is turning me into a decent mechanic though!

Here's a question: Do I have to have my crankshaft polished or checked before reassembly. Car was running fine but just intermixing. I am planning on making my own tools for the circlip placement, this looks doable without the cost of the porsche tools.

Thanks for the replies. I am down to the crankshaft. Just disassembled the bearing carrier. Many thanks.

Anyone know cost effective site to purchase above, or is Porsche only supplier?Thanks, rebuilding 99 996

Ditto on draining the oil. That will easily tell the tale. Also had ugly stuff on dipstick. Believe me I hope its nothing. I have 996 on blocks in garage with engine out. Still not sure what to do since my cylinder heads are not recracked. Cheers!

I hate to be a pessimist but having had 2 intermix issues that looks suspicious

I have been on break, sorry. I originally had cracks in both heads repaired about 2 years ago. the pressure testing was done at Costa Mesa R & D in California with John Edwards. Waiting on word on the oil cooler but I think its a long shot.

I've looked closely at the cylinders and they look fine (no cracks). The coolant surrounding the cylinders was clean. I was only getting coolant into oil, no evidence of contaminated coolant.

Thanks Dharn55 hope yours is running well.

My 99 C2 996 which sufferred intermix from cylinder head crack (bilateral). Had new intermix recently. Removed engine, unfortunately pressure testing of heads is ok. Testing oil cooler next.

Anyone seen intermix from a block crack?

Anyone looking to buy a 996 sans motor?

Both heads were resurfaced during last repair

Head gasket for 1-3 head looks good (just removed)

Pistons/combustion chambers 1-3 look good

Can AOS cause intermix?

Had oil cooler replaced prior to last head repair but am sending it in to machine shop for pressure testing

Cracks were visible to the eye extending from spark plug recess #1 toward the valve spring adjacent to it

Got engine out this time without losing any fingernails, I'm getting better but still an amateur!

Have had both heads repaired for cracks in the spark plug recess of cylinder 1 and cylinder 6. after removing spark plug tubes no evidence of visible cracks like before. Diagnosis still unknown.

Plan to remove heads again send to machine shop for presssure testing, and look at block for evidence of damage/cracks.

Anyone convert to full electric vehicle? :)

I'm on the hunt for recurrent intermix issue. Failure is not an option. Well, if engine is toast I'm shipping the car back to Stuggart (Cash on delivery) :)

I have engine ready to drop. Once down will pull plugs and scope the cylinders. if coolant pooling found will have decision to make as you have pointed out. Will keep you posted.

Thanks for replies, definitely have coolant in oil. Kept losing coolant (warning light flashing). And when I drained oil it was clearly badly contaminated. I agree dont quite get why no oil in coolant. Gonna pull heads and have them repaired. also will throw in a new oil cooler for good measure. Thankfully its winter in Texas and good work time in my garage.

99 C2 with prior cracked heads. Removed heads, had them repaired. Car ran great until recently noted recurrent coolant emulsification in the oil. This time only have coolant in oil and no oil in coolant (perfectly clean). Preparing to drop engine again and look for recurrent head cracks. Any ideas? Had new oil cooler put in by indy before figuring out the real problem myself with the help of Dharn55.

PTEC

Had my 996 at an Indy who incorrectly diagnosed me with Oil Cooler broken. Replaced it without change in intermix. Wasnt going to spend the $ for new engine in this vehicle. Didnt identify the crack until I had the engine out and removed the spark plug tube for cylinder #1, then the crack was visible in the base of the recess. Unfortunately for me after having cylinder head 1-3 repaired found additional crack in Head 4-6. Thankfully hadnt put engine back in car. These cracks are visible to naked eye. And by note mine had a negative compression test as well. I have some nice pics of my crack if you're interested.

Tim

Do a search here and on the other boards, there is a lot of info available. The dealer and most mechanics are going to tell you that a new/re manufactured engine, or a used engine is the only solution. Don't believe them! This is what I was told and I fixed mine for less than $2,000 (I did most of the work myself so this does not include labor). I now have over 5,000 on my fixed engine and it is running great. Mine was a cracked head with oil in the coolant and coolant in the oil. The less you drive it until it is fixed the better, but I did not find my problem until it was totally intermixed, could have been hundreds of miles, and the engine is running fine. I have worked with several other owners who have had an intermix and are fixing there engines.

Keep us posted.

I will second Dharn55. I also had intermix from bilateral cracked heads. Dropped engine and did everything except machine work in my garage. Have 500 miles on my head repair and going strong. Saved many thousands of dollars. Would not have been possible without the kind help of the man who posted above me. I agree! It can be fixed!

Highly recommend the LN Engineering Oil Filter Adapter, a little pricey but well worth it.

All the specs porsche gives for cam timing are relative to the crank not the actual rotation of the cam itself. The actual advance of the cam in an early motor is only 12.5 degrees of cam timing. It is 25 degrees of advance relative to the crank. Below are some excerpts from the service manual supporting my claim.

-Todd

Seems like it makes sense to me. With the Crank -- it knows where TDC is. And so relative to that tells you where the pistons are, etc.

If the main chain were off and you were measuring at the cam (i.e. locally) -- you might be fine there, but off globally.

mike

Dharn55,

What are the "roller" youre referring to? I had both heads off my engine for intermix, and somehow got timing correct by using your instructions. The chain is specifically marked to match the notches on the cams, where were the rollers?