"Louros" (louros)
07/23/2014 at 11:11 • Filed to: None
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"Louros" (louros)
07/23/2014 at 11:11 • Filed to: None | 0
| 14 |
Thinking about a 986 with a hardtop for my next project. Pros: Mid-engine, faster and more comfortable than my Miata.
Cons: Potential IMS failure, harder to work on than a Miata, will look like CEO of hair salon.
I've seen decent examples for well under $10k. Does anyone here own one?
crowmolly
> Louros
07/23/2014 at 11:13 |
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My boss has one. '03 S six speed.
He mentioned that CV boot tearing can be a problem. Just something to watch out for I guess.
MazdaMonkey
> Louros
07/23/2014 at 11:14 |
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Not exaggerated at all. The issue was fixed during the model run, although I don't remember exactly when. Just don't buy a one in the bad VIN range.
ncasolowork2
> Louros
07/23/2014 at 11:15 |
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IMS = Indianapolis Motor Speedway. Your subject line makes no sense.
Brian Silvestro
> Louros
07/23/2014 at 11:16 |
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I can't explain why I like the car in this picture so much. Maybe it's the hardtop.
Browsing some forums should prove helpful.
Nothing
> Louros
07/23/2014 at 11:17 |
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Cons: will look like CEO of hair salon
As opposed to simply looking like a hair salon employee?
BoxerFanatic, troublesome iconoclast.
> ncasolowork2
07/23/2014 at 11:29 |
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InterMediate Shaft bearing.
Porsche flat 6 engines, M96 and M97 type, drive the overhead camshafts from opposite ends of the engine, for each side... Since pistons have to be offset on the crankshaft, the cylinder blocks and cylinder heads have to share that offset. The timing chains are arranged to run at the ends of the cylinder block and heads by taking up that offset space.
http://www.cheetahonline.com/technical-arti…
The intermediate shaft runs underneath the crankshaft, at half the crankshaft's speed, which is the same speed as the camshafts. It ties the cam timing together, and allows for smaller 1:1 chain sprockets on the IMS and cams... The cylinder heads and cam sprockets being smaller is a significant packaging advantage, by saving engine bay space, and cylinder head casting weight.
the 2:1 timing reduction is on the timing chain that drives the IMS from the crankshaft.
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ncasolowork2
> BoxerFanatic, troublesome iconoclast.
07/23/2014 at 11:31 |
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IMS still = Indianapolis Motor Speedway
Jayhawk Jake
> ncasolowork2
07/23/2014 at 11:39 |
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It doesn't HAVE to be that, jeez. In the context of a Porsche the IMS is the IMS bearing.
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BoxerFanatic, troublesome iconoclast.
> Louros
07/23/2014 at 11:41 |
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I have read that it can affect as much as 20 percent of M96 engines... and tends to affect the smaller displacement ones more, and also tends to affect lower mileage, and gently used engines more, due to lower average oil pressure starving the bearing for oil.
IMS bearing, and rear main oil seal retrofits are often done at the same time, as they both require access to the engine case behind the flywheel, with the transmission removed...
As long as the upgrades to superior parts are done before the problem gets bad and damages the engine case, or bends the intermediate shaft, the engine can be prevented from IMS failure damage, or rear main seal leakage.
The Intermediate Shaft is driven from the 'front' end of the engine, opposite the transmission, if the bearing on the 'rear' of the engine seizes, the torque of the crankshaft twists the IMS along it's length, creates a severe imbalance, and ruins at least one bank's camshaft timing, likely causing valve damage, and perhaps even ruining the pistons and cylinder head. If the IMS gets bent/twisted bad enough, it could skip teeth on the chain, and ruin both sides.
When shopping for a Porsche, documentation is important... especially with an M96 powered 996 (911) or 986 (Boxster).
If the engine has been replaced already, with a known-good engine...
If the engine has been upgraded with preventative maintenance improved IMS bearing, and likely also an improved rear main crankshaft oil seal...
If the car is from a VIN group after Porsche improved those aspects at the time of manufacture...
If one of those three criteria are met, and documented, it should be fine.
If not... and the car runs... take it to a good Porsche-familiar mechanic, and have the engine inspected, and have the improved parts installed as preventative maintenance, and negotiate a discount in the sale price of the car to help cover that expense. An un-documented Porsche should be considered an un-maintained Porsche... and inspected to verify it's mechanical condition... and likely a cursory inspection even if it does have documentation.
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BoxerFanatic, troublesome iconoclast.
> ncasolowork2
07/23/2014 at 11:49 |
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An acronym can be used more than once... but yes IMS certainly can refer to the brickyard.
HFV has no HFV. But somehow has 2 motorcycles
> Louros
07/23/2014 at 12:10 |
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I have also though it'd be a cool car, but have my imaginary pick was always an S2000. a clean Boxster S goes for 12-14k than same price as a S2000, the S2k IMO looks better plus its a Honda, and therefore will more tune-able, and will be more reliable even if(WHEN) you add boost. Also F22Cs are bulletproof.
Manuél Ferrari
> BoxerFanatic, troublesome iconoclast.
07/23/2014 at 13:01 |
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This is a great comment! Very informative
Ferg
> MazdaMonkey
07/23/2014 at 13:24 |
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Not true at all... IMS is still very much an issue with any M96 motor. Even the motors replaced under warranty during the time period. Anyone purchasing a used boxster 996 ect should have a very detailed PPI and budget the aftermarket IMS solution (replacement upgraded bearing) into the price.
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MazdaMonkey
> Ferg
07/23/2014 at 14:04 |
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Ahh, I confused it with what I now see is the cylinder liner problem the early cars had. Man, I'm always amazed when manufacturers take the better part of decade to fix a problem. Thank god for the aftermarket