Buying a Boxster that jumped timing
 

Hi guys, I'm new the the Porsche world but no stranger to mechanics. I have a couple of highly modified Corvettes and engine and transmission builds are a breeze for me.
I recently ran across a '99 Boxster. The seller doesn't seem to know anything about the car and it was towed to a dealer where he was told it jumped timing. It's red with tan interior, 80k miles, auto, comes with hard and soft tops and he's asking 5500.

Here is my question, If the IMS bearing failed, and the valves bent, can i just replace a few parts, get the heads rebuilt and be good to go or is there something else that happens that I don't know about that takes out the whole engine? Basically, labor is free since I can do the work myself but I'm concerned about the cost of parts and exactly which parts are affected in this type of failure.

From what I have learned on this forum and Pelican Parts forum is if the ims failed then there can be metal throughout the engine. Then you have a major rebuild on your hands. I am not a wrenchbender myself but I would think that you need to establish what caused the timing to go out. As they say a cheap Porsche can end being up a very expensive one.

Sounds like you have a good idea of the best case scenario, figure about 4 times the labor hours required for a LS1 type engine. Worst case scenario if the IMSB completely failed & the debris circulated thruout the engine making most of the parts useless. Easy way to check for that is to remove & inspect the oil filter. If you are trying to flip this $10K retail value car you may earn the lowest hourly wage of your life. If you are going in wanting to build this car despite worst case scenario you can install a simular year 911 engine & discover why people pay more for these cars than Corvettes. Search the forum for plenty info.

If the IMS failed and the pan is full of grenade frag, it's a boat anchor not worth your time. A motor from a dismantler can be had reasonably cheap though.

If it was me as I am not a wrenchbender and if I bought that car for say $5000 and found an engine for $5000(risky!) and then had it installed then my outlay would be in the teens $$$$. Instead if I bought a running one I could have it for less particularly the ones with 2.5l engines.

Do you want to go through all that trouble to make that engine right even if you do it yourself? Actually $5500 is too much for as they call it a roller. Probably $2-3k would be more realistic.

I bought my car about 2 years ago for $7500 and other than the usual repairs for a high mileage Boxster, I've had no problems and the car runs and looks like a champ. So I would never pay $5500 for a car that neads a new motor when I could pay a couple of thousand more for a car that needs nothing.

Even if you got the car for $1000, a used motor is around $5k, which already has you at about what the car is worth.

Anyone have an estimate on rebuilding one of these engines? If metal fragments went into the engine, I would assume the real expense is if you needed to bore it and replace the pistons... other than that, main and rod bearings, machine crank (maybe), rings, hone cylinders, and a gasket set doesn't seem terribly expensive. and depending on damage to the intermediate shaft... anything I'm missing?

Of course this is all assuming a worst case scenario.

There are no oversized bearings for these engines; damage the crank, throw it away. The 2.5L engine is well known for having cylinder wall issues, thinning out the walls by over boring it will not help this problem. Many rebuilders replace the OEM cylinders with CNC machined billet replacements called "nickies", which while excellent replacements, are not cheap.

Because of the way the M96 is assembled, you have two cases that split to reveal the alloy crank carrier assembly that holds the crank and rods. Because of how this goes back together, several special tools are required as just putting the retainer clips back that hold the wrist pins in place is done through a small hole, much like building a ship in a bottle.

Add in the fact that when an M96 "jumps time", a lot of really bad things can happen very quickly:

http://i1140.photobucket.com/albums/...headdamage.jpg http://i1140.photobucket.com/albums/...casedamage.jpg

I think you need to look into what is involved a bit further...............

It's a breeze really. Just machine all your internals from billet stock and you are good to go. :cool:

I don't know JFP, I think we can still work with those heads. :)

A little dab of welding here than there, and pretty soon you'll have a real nice boat anchor.............

I'm doing exactly what you are asking about with a 2003 S (3.2 liter). The car belonged to a coworker. At a stop sign the engine started sound like rocks in a can so the previous owner turned it off. Then re-started it and drove home. There was plenty of metal in the oil filter. The IMS bearing and shaft were both toast. So here is was the damage:

The oil filter did its job and kept the metal upstream of the delicate workings. There was plenty of shrapnel in the oil pan, imbedded in the timing chain guides, and pretty much throughout the lower part of the engine. The valves did not meet the pistons, so there was no upper end damage.

So the cost due to the failure - $1500 for a new shaft and bearing, $250 for seals, $200 in various tools and cleaning solvents. $10 at the local electronics parts outlet for rare earth magnets to pull the chips off the aluminum (works great). Plus various manuals.

But as the engine has 120K miles, new bearing set Rods and Mains $225,(and did it need it!) new rings, about $200-$300 for a custom ground set, about $1200 for Porsche. Head work about $800 without new valves. new air oil separator (AOS) about $100.

Expect to pull every nut and bolt apart on the engine because that's what replacing a failed IMS (bearing and shaft) entails. The bearing tends to redesign the shaft during the failure.

Porsche parts are hyper expensive. If the valves had hit the pistons I'd have gone for a 911 motor - easy to do, but replace the IMS bearing first thing with an improved bearing if you go that route.

So all told - broken car $3800, IMS parts and supplies about 2k, about 1.5 k for the mileage so a little under $7500.

New 911 motors go from $7500 to $10K depending on what you get and how proud of it the owner is.

Jim

I'm doing exactly what you are asking about with a 2003 S (3.2 liter). The car belonged to a coworker. At a stop sign the engine started sound like rocks in a can so the previous owner turned it off. Then re-started it and drove home. There was plenty of metal in the oil filter. The IMS bearing and shaft were both toast. So here is was the damage:

The oil filter did its job and kept the metal upstream of the delicate workings. There was plenty of shrapnel in the oil pan, imbedded in the timing chain guides, and pretty much throughout the lower part of the engine. The valves did not meet the pistons, so there was no upper end damage.

So the cost due to the failure - $1500 for a new shaft and bearing, $250 for seals, $200 in various tools and cleaning solvents. $10 at the local electronics parts outlet for rare earth magnets to pull the chips off the aluminum (works great). Plus various manuals.

But as the engine has 120K miles, new bearing set Rods and Mains $225,(and did it need it!) new rings, about $200-$300 for a custom ground set, about $1200 for Porsche. Head work about $800 without new valves. new air oil separator (AOS) about $100.

Expect to pull every nut and bolt apart on the engine because that's what replacing a failed IMS (bearing and shaft) entails. The bearing tends to redesign the shaft during the failure.

Porsche parts are hyper expensive. If the valves had hit the pistons I'd have gone for a 911 motor - easy to do, but replace the IMS bearing first thing with an improved bearing if you go that route.

So all told - broken car $3800, IMS parts and supplies about 2k, about 1.5 k for the mileage so a little under $7500.

New 911 motors go from $7500 to $10K depending on what you get and how proud of it the owner is.

Jim

Thanks Jamesp! That's exactly the information I was looking for.

I love working on cars and have learned and gone about as far as I can with the new Chevrolet stuff and went through a boosted honda phase. I figured it would be fun to tear into a porsche just for the heck of it. With that being said, I probably wouldn't keep it once it was done and would like to make at least a little profit so unless I can talk the guy down on price, I think I'll pass on this one.

Thanks for all the responses.

can you scope the bore to see if any scoring, valves out of place, etc., prior to purchase?

I assume you are in the Texas area. I saw the same ad on CL. The car looks great but I would negotiate him way down. $5500 is too much IMO.

Assume that the engine is toast. These engines are not worth the number of man-hours required to rebuild and no one will want to buy a car with a DIY backyard rebuilt engine. Dismantler engines are readily available and cheap. Engine + install should be around $6K.

Happy to give my perspective WhiteSmokeLS1. I love rebuilding cars too. I've been doing it since I was a kid. Before I was even legal to drive I was in a Corvair stage where my buddies and I all had them swapped engines and transmissions and drove them like fools after getting our licenses. I think that is what drew me to an opposed 6. There were a few classic restorations thrown in along the way. I think this is my grown up stage, gives me a hobby after work. Just getting the crank and new bearings installed in the bearing carrier so I've begun building back up. Good luck on finding something to rebuild. I was kind of hoping for upper end damage so I'd have an excuse to drop in a motor with a little more horsepower, but my cheap side is fairly happy with the way things are working out, after all I end up with essentially a new motor, and I know exactly what I've got.

Definitely talk him down on price and also be aware that you can probably get and easy $1k (or more) for the hardtop if you sold it after getting the car.

The biggest thing to me though, is if you were able to rebuild the engine and wanted to flip it, is that I wouldn't think there is a very large market out there for a 2.5 tiptronic.

Not quite the same motor. I'm rebuilding a some what good 3.2L motor. 3 cylinders had low compression no real damage on heads valves or bottom end. My end cost is looking to be right around $8500. I am doing all the assembly work. I had to buy about $700 in tools to assemble the motor so My end cost is going to be $9200. LN sleeve, JE pistons, pins, rings, rods, and bolts $6100. New stock valves, springs, stem seals, retainers, spring caps, all seals, gaskets, water pump, 170 deg. thermostat, ARP Assembly bolts The end result is a better balanced motor that is 3.6 L.

There is a market especially with spring now here. Now what people are willing to pay is another issue. I wouldn't think you could make any money if you had to pay for labor. DIY, maybe a little.