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Damaged engine - looking for guidance


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Hello All,

I'm new here - found this wonderful site while looking for Boxster info. I've got a '98 with 45,000 miles and severe engine trouble. It does not seem typical of what I've read about here though. I have antifreeze in my oil, antifreeze being blown out the tail pipe, and no compression on the passenger's side front cylinder (running on 5 out of 6 cylinders). The spark plug on said cylinder is smashed but the piston (from what I can see with a lit mirror) is OK. Are these engines known to "drop valves", or something of the sort?

Thanks in advance for any input.

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Hello All,

I'm new here - found this wonderful site while looking for Boxster info. I've got a '98 with 45,000 miles and severe engine trouble. It does not seem typical of what I've read about here though. I have antifreeze in my oil, antifreeze being blown out the tail pipe, and no compression on the passenger's side front cylinder (running on 5 out of 6 cylinders). The spark plug on said cylinder is smashed but the piston (from what I can see with a lit mirror) is OK. Are these engines known to "drop valves", or something of the sort?

Thanks in advance for any input.

You probably won't know what the real cause is until you pull the engine. And depending on your repair choices -- you may never choose to find out.

Either way you are looking at a complete rebuild most likely, salvage engine, or crate engine from Porsche.

Depending on who does the work, guessing ~$6-8K, ~6k-$7k, $11-13K, respectively.

I bought an '00S with a blown freeze plug in the heads, but I didn't have any cylinder or spark plug problems.

Root cause was a bad water pump.

My friend had a shattered spark plug, but he had the engine replaced by the dealer -- he never had it disassembled.

If you are in/around Austin, Texas -- I can help you, otherwise good luck,

M

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You may have a damaged cylinder liner. The engine has many faults with no compression and oil/coolant mix. Best to start shopping for a exchange,used or rebuilt unit. I believe the cylinder head can be removed with engine in place but it wouldn't be an easy job. Best of luck with everything.

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Does anyone know if you can remove a cylinder head without removing the engine from the car??

Someone will be able to answer definitively -- but i do not think it is possible.

The heads sit along side the block and you would have to get access from the side.

mike

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With coolant coming out the tail pipe raw, its a very good possibility that you have a slipped sleeve, and with a physically damaged spark plug it sounds like it could be a full blown D chunk failure..

Raw coolant out the tailpipe has never been anything other than a D chunk for me thus far..

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Bummer on the D failure likelyhood. Is there any remotely easy way of checking for this? I was able to see the top of the piston thru the spark plug hole and it didn't look damaged - if that means anything.

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Bummer on the D failure likelyhood. Is there any remotely easy way of checking for this? I was able to see the top of the piston thru the spark plug hole and it didn't look damaged - if that means anything.

You can only view a very small percentage of the piston. The fact is you have a major failure if coolant is escaping into the areas you stated. Start saving your pennies for another power plant.

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The portion of the piston that fails is not visible through the spark plug hole in most cases.

Something crushed that spark plug and you can bet that it did some damage to the chamber as well and probablt bent the valves if nothing else.

Foreign Object Debris in the chamber is not good..

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Seafeye, now that's what I'm talking about!! Thanks, and thanks again. I have to say I'm really surprised at how many people just seem to throw up their hands with the motor issues. Yes, a "D chunk" is pretty catostrophic, yet still apparently repairable by some. I own a reasonably sophisticated machine shop, so I don't plan on walking away from the car without some effort first (I just don't like to waste effort). I guess if you've never worked on an engine, these are not what you'd want to start on. I'm not trying to play down the knowledge and skill of those that are supplying the aftermarket. But if everyone is too scared to work on these things few people are going to want to own one and that isn't good for those of us who still have them and those that supply parts for them.

Anyway, it aint over till the fat lady sings, and I haven't heard a peep out of my ex :-).

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The borescope can be used to diagnose this, in more severe cases.. Small voids can still cause big problems but not be very notable with a simple bore scope.

This engine is VERY hard to work with internally, even for most that work with engines everyday. Not many engines require as many special tools or procedures to assemble and this is THE hardest engine I have ever assembled, including turbine engines for Aircraft.

The machine work to repair a D chunk is extensive, since most of the time a chunk of the cylinder is totally missng that can be as large as 1/3 of the bore..It can be done, because we do it but it took two years to perfect...

I have been working to train shops how to do this work and have classes beginning in the Fall of '09 for enthusiasts as well.. We can't build them all and I don't want to!! All I want to do is develop and perfect and build a few bad boy high output engines per year.

Look for my video series to be released mid next year with a full line of DVDs for the Boxster/ 996 Owner including a DVD on the assembly of an M96 engine.

I do not mean to discourage anyone, but rather put in plain and simple terms what is required to do this job.

For a taste of what assembly is like, see this link to one of my builds.

http://www.flat6innovations.com/engine-assembly

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Thanks Jake, I had already perused your site. I wasn't suggesting everyone attempt a total disassembly and rebuild like you show. But in my case if the damage was due to foreign object ingression and not a cylinder failure I could be lucky enough (ugh, can't believe I'm saying that) that the damage is limited to the head, which I was assuming (perhaps erroneously) to be a much less complicated repair than shown in your video. That's why I'd like to diagnose the failure if I can before I start tearing things apart. If it is the cylinder wall then I'll likely look for a used motor and swap them out when I get it (don't like tearing things apart and letting them set - always seems easier to put things back together shortly after taking them apart). If it's the head then I may have some options. Thanks again for the input, it's appreciated.

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If its the head you have man options and I can easily assist you with the procedures and special tools to do this work correctly..

If it is the cylinders the entire engine needs to come apart to be repaired.... Thats when the men are separated from the boys.

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If its the head you have man options and I can easily assist you with the procedures and special tools to do this work correctly..

If it is the cylinders the entire engine needs to come apart to be repaired.... Thats when the men are separated from the boys.

Jake,

Having rebuilt a 3.2L S with a young mechanic only familiar with air cooled 911/914 engines, and this being my only engine rebuild experience,

what in your mind makes these engines difficult to work on?

i'm not questioning your wisdom, experience or opinion, I just don't know any better -- and I am curious to know what specifically

I should have considered hard. In some ways it all was, and in other ways everything seemed so well thought out and engineered

that things just made sense.

I'm sure our success was somewhat luck, a lot of ignorance and naivety, and a good bit of diligence and inherent skill by my colleague.

I will say making the connection of the connecting rod and the pistons and putting the bushing on with our homemade tool was

a little harrowing, but most other things seemed reasonable.

thanks,

Mike

:renntech:

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Mike,

One thing that makes it more difficult than most is the fact that cylinders 4-6 must be assembled blindly with the special tools used for every portion of the piston installation.

A lot of the engineering of this engine does make sense, but as an assembler that uses the sense of feel more than anything else I dislike the fact that I can't feel the procedures of piston installation and moreover I can't see the components without the use of a borescope.

There are some aspects of the M96 that are more simple than an aircooled Porsche engine, including the cam timing and the special tools that make that so much simpler than an aircooled 911.

Perhaps the biggest mistake and set back that can be made is a wrist pin clip that doesn't properly seat into the piston. If this occurs as soon as the tool is extracted the clip flies into the depths of the engine and is lost, usually requiring disassembly to fetch it and that costs a day. Lots of dealerships have called us after making mistakes with engine assembly. The most commo failure stemmed from a wrist pin clip not being seated all the way on the 4-6 bank, which allowed the clip to dislodge during operation and the pin wasted the cylinder.. That has happened no less than 4 times and twice on the same engine at the same dealership!

I have seen some pretty costly mistakes made by those who have a ton of experience with other Porsche engines that tackle an M96 thinking it's similar to an aircooled 911. A lot of engine building is luck, and every time I assemble an engine I end up with a different set of challenges and some things that are more simple than they should be..

if you really want a challenge start adding stroke and bore to the engine.. Adding 100HP to a 3.2 "S" spec engine was the most difficult experience I have had yet.

Having our own tools made has been the key, especially for the lower tension rings that are compatible with our Nikisil liners as they are a real ***** to install with a normal ring compressor..

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Mike,

One thing that makes it more difficult than most is the fact that cylinders 4-6 must be assembled blindly with the special tools used for every portion of the piston installation.

A lot of the engineering of this engine does make sense, but as an assembler that uses the sense of feel more than anything else I dislike the fact that I can't feel the procedures of piston installation and moreover I can't see the components without the use of a borescope.

There are some aspects of the M96 that are more simple than an aircooled Porsche engine, including the cam timing and the special tools that make that so much simpler than an aircooled 911.

Perhaps the biggest mistake and set back that can be made is a wrist pin clip that doesn't properly seat into the piston. If this occurs as soon as the tool is extracted the clip flies into the depths of the engine and is lost, usually requiring disassembly to fetch it and that costs a day. Lots of dealerships have called us after making mistakes with engine assembly. The most commo failure stemmed from a wrist pin clip not being seated all the way on the 4-6 bank, which allowed the clip to dislodge during operation and the pin wasted the cylinder.. That has happened no less than 4 times and twice on the same engine at the same dealership!

You are Spot on here -- this was the #1 concern of ours -- we must have practiced a dozen times external to the engine, and sweated

out the process when we did it for real.

We crafted our own little tool to do this and used light and mirrors to confirm the "wrist pin clip" was properly seated... but

what a PITA!

I have seen some pretty costly mistakes made by those who have a ton of experience with other Porsche engines that tackle an M96 thinking it's similar to an aircooled 911. A lot of engine building is luck, and every time I assemble an engine I end up with a different set of challenges and some things that are more simple than they should be..

if you really want a challenge start adding stroke and bore to the engine.. Adding 100HP to a 3.2 "S" spec engine was the most difficult experience I have had yet.

Having our own tools made has been the key, especially for the lower tension rings that are compatible with our Nikisil liners as they are a real ***** to install with a normal ring compressor..

Rings were tough to get on as well -- but with some patience -- then we got it after a few tries on each piston. Almost had to go the Nikisil route :-)

but didn't have to experience that his go round.

We also had some trickiness getting the new IMS seated properly with the Timing Chain -- we had to disassemble the chain and redo it.

Not sure why it didn't go right the first time. but dropped in effortlessly the second time.

Jake -- thanks for taking the time to respond -- you are an invaluable resource -

I design computer chips for a living -- we don't get to look at or feel anything -- so I guess I'm used to a little blind faith :-)

Still doesn't make you anymore comfortable though......

thanks,

Mike

Edited by txhokie4life
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