Looking for a solid 928S4

[winstonbike]

I am doing a PPI on an 88 S4 that has had solid engine work done by a good shop here in DC area but cosmetically could look a little better (though its not bad). The PPI should go well as service records are good and the seller is open to any question/inspection, etc. (you never know of course)

If anyone knows of a car in the 10-14K range I should be looking at, let me know as I will be paying this to somebody next week.

Thanks

Mike

[Xlot]

Beware of poor 928's that are in a poor cosmetic state.

Regardless of PPI and service history, most S4's need a lot of catchup maintenance: (edit: these are just the parts prices for a DIY'er.. you really don't want to know how many paid workshop hours it will be..)

intake refresh = $2k for new FUEL LINES, sensors, gaskets, hoses and various other bits
timing belt job = $1.5k for new belt/sprockets/tensioner bits etc.
suspension = minimum $1k for shocks/bolts/rubber bits

This is all stuff outside the service schedule, but that needs doing after 20 years. PPI's usually focus on making sure the car runs, brakes work, visible leaks, and if you're using a good 928 mechanic, checking crank end play (do not buy an MY84-onwards auto without a crank end play measurement!).

Now all those costs aside - fixing cosmetics is the single most expensive part of owning a 928. You're *much* better off financially starting with a 928 that looks good inside and out and then doing all the catchup maintenance to make it run right. Reckon on $10k to do an "ok" cosmetic job (i.e. reasonable paint, and installing a decent used interior), rapidly progressing to $20k for a good job (better paint, new window seals, re-cover seats).

The flip side is, if a car's super-cheap, you do your own wrenching and read a manual/forum, cosmetics don't bother you, and you just want to drive the crap out of it, then cosmetically poor examples of barely running 87/88 S4's can often be picked up for sub-$5k and make an excellent daily driver for well under $10k total spend.

Lastly - if anything in this post confuses you - you're not ready to buy a 928 yet and will likely get burned. I'm not trying to patronize you - there are some nasty gotchas you need to understand about before you spend hard earned cash, like Thrust Bearing Failure. If you have questions about any of the above - ask and people on the forum will happily answer questions.

[harborman]

Question: You mentioned "(do not buy an MY84-onwards auto without a crank end play measurement!)."

How do you determine which car has this?? I have an 86 928S Automatic.

[MPDano]

Originally Posted by Xlot

Beware of poor 928's that are in a poor cosmetic state.

Regardless of PPI and service history, most S4's need a lot of catchup maintenance: (edit: these are just the parts prices for a DIY'er.. you really don't want to know how many paid workshop hours it will be..)

intake refresh = $2k for new FUEL LINES, sensors, gaskets, hoses and various other bits
timing belt job = $1.5k for new belt/sprockets/tensioner bits etc.
suspension = minimum $1k for shocks/bolts/rubber bits

This is all stuff outside the service schedule, but that needs doing after 20 years. PPI's usually focus on making sure the car runs, brakes work, visible leaks, and if you're using a good 928 mechanic, checking crank end play (do not buy an MY84-onwards auto without a crank end play measurement!).

Now all those costs aside - fixing cosmetics is the single most expensive part of owning a 928. You're *much* better off financially starting with a 928 that looks good inside and out and then doing all the catchup maintenance to make it run right. Reckon on $10k to do an "ok" cosmetic job (i.e. reasonable paint, and installing a decent used interior), rapidly progressing to $20k for a good job (better paint, new window seals, re-cover seats).

The flip side is, if a car's super-cheap, you do your own wrenching and read a manual/forum, cosmetics don't bother you, and you just want to drive the crap out of it, then cosmetically poor examples of barely running 87/88 S4's can often be picked up for sub-$5k and make an excellent daily driver for well under $10k total spend.

Lastly - if anything in this post confuses you - you're not ready to buy a 928 yet and will likely get burned. I'm not trying to patronize you - there are some nasty gotchas you need to understand about before you spend hard earned cash, like Thrust Bearing Failure. If you have questions about any of the above - ask and people on the forum will happily answer questions.

Great way to put that into a well written Reality Check. Make sure the PPI is someone who actually "knows" the 928. Also, put your location in your Profile so we know where your from. Maybe one of could be close enough to assist you in your PPI.

[Xlot]

Originally Posted by harborman

Question: You mentioned "(do not buy an MY84-onwards auto without a crank end play measurement!)."

How do you determine which car has this?? I have an 86 928S Automatic.

From 84 onwards, all automatic 928's are susceptible to Thrust Bearing Failure, as the torque tube creeps in the front clamp and the flex plate applies preload to the thrust bearing surface at the center main bearing.

Prior to 84 the torque tubes were machined for, and had fitted, a circlip which prevented shaft migration (although if those cars have been serviced there's a chance the clips were left off in which case you're prone too).

Your 86 auto is susceptible - the "fix" is firstly to measure the crank end play to make sure the thrust bearing is still within the factory-stated acceptable wear limit.

The spec for a new thrust bearing is between 0.06mm and 0.19mm. The wear limit is 0.4mm.

If you have more than that then you should consider either separating the girdle and replacing the bearing, or buying a spare used engine while they're still available relatively cheaply.

After measuring to make sure your bearing isn't worn, it can be prevented by regular maintenance of releasing the flex plate to release any preload that's built up since last service, and undoing and re-torquing the rear torque tube coupler at the gearbox, followed by retorquing the front clamp.

There are also couple of aftermarket heavier duty clamps to replace or supplant the weak factory one.

Thrust Bearing wear beyond the wear limit will result in a spun bearing and often machining of the girdle and ultimately cracks. If the bearing has spun, odds are you need a new short block as crank and block/girdle will be damaged. "Visible" symptoms are an engine that turns over slowly with the starter motor, or can't be turned by hand - this means the bearing face is gone and there's block contact - so the engine is already toast. Another common symptom is measuring zero crank end play - although that can be measurer error. If you measure zero end play, pry harder

[Danglerb]

Giving yourself a week to find a good 928 may not be the best plan. No more than half a dozen really nice 928's show up in a typical year. If you can't wait, talk to a broker like Willhoit, but expect to pay a premium for the convenience.

Willhoit Enterprises -- Used Porsche, Used Ferrari, Used Sports Cars.

[Landseer]

On rennlist, do a simple search on the words Fly Navy.
1987 S4 for about $7500. Williamsburg.
PPI would be important, but I think it would be a pretty good starting point.

[harborman]

Originally Posted by Xlot

From 84 onwards, all automatic 928's are susceptible to Thrust Bearing Failure, as the torque tube creeps in the front clamp and the flex plate applies preload to the thrust bearing surface at the center main bearing.

Prior to 84 the torque tubes were machined for, and had fitted, a circlip which prevented shaft migration (although if those cars have been serviced there's a chance the clips were left off in which case you're prone too).

Your 86 auto is susceptible - the "fix" is firstly to measure the crank end play to make sure the thrust bearing is still within the factory-stated acceptable wear limit.

The spec for a new thrust bearing is between 0.06mm and 0.19mm. The wear limit is 0.4mm.

If you have more than that then you should consider either separating the girdle and replacing the bearing, or buying a spare used engine while they're still available relatively cheaply.

After measuring to make sure your bearing isn't worn, it can be prevented by regular maintenance of releasing the flex plate to release any preload that's built up since last service, and undoing and re-torquing the rear torque tube coupler at the gearbox, followed by retorquing the front clamp.

There are also couple of aftermarket heavier duty clamps to replace or supplant the weak factory one.

Thrust Bearing wear beyond the wear limit will result in a spun bearing and often machining of the girdle and ultimately cracks. If the bearing has spun, odds are you need a new short block as crank and block/girdle will be damaged. "Visible" symptoms are an engine that turns over slowly with the starter motor, or can't be turned by hand - this means the bearing face is gone and there's block contact - so the engine is already toast. Another common symptom is measuring zero crank end play - although that can be measurer error. If you measure zero end play, pry harder

Thanks for all the info on this issue. My car has very low mileage (45K) yet so I hope it will be good for sometime. This is good to know and I will copy this in my folder.

[Landseer]

They have failed sub 40K miles.

I thought surely you would have already performed the flexplate release, the endplay baseline measurement and the addition of an auxilliary clamp on your car?

My 86 came home with 73K miles and its flexplate was nearly 4mm deflected. Fortunately the endplay was still within specification.
It had been owned by a couple for 22 years. They were nearly retired when they bought it and certainly not car thrashers.

[harborman]

Originally Posted by Landseer

They have failed sub 40K miles.

I thought surely you would have already performed the flexplate release, the endplay baseline measurement and the addition of an auxilliary clamp on your car?

My 86 came home with 73K miles and its flexplate was nearly 4mm deflected. Fortunately the endplay was still within specification.
It had been owned by a couple for 22 years. They were nearly retired when they bought it and certainly not car thrashers.

No, I have not done this. Just more to do I guess.

[Mrmerlin]

make sure to retorque the rear pinch bolt if this is your first inspection as they are usually loose

[harborman]

Originally Posted by Mrmerlin

make sure to retorque the rear pinch bolt if this is your first inspection as they are usually loose

Thanks for advise!!!!!!

[winstonbike]

Thanks so much. I should have been clearer. I have been looking for some time, did one PPI that failed badly, doing another one this week that looks good. Car serviced, engine work done by Auto Therapy in Gaithersburg, MD which appears to have 928 experience (they have done some work on my old 912).

The cosmetics are not bad - two chips on the front spoiler, no chin spoiler and a crack in the pod (big enough to notice) and thin one in the dash. Other than that a nice looking car and all I would address is the chin spoiler. Buyer described as a 10-footer and I would agree. I just did a multi-stage detail on my M5 and without a doubt this 928 is in better shape.

Asking to have crank end play measured - 200K on chassis, 11K on rebuild. All records covering last 50K, since 1996.

Anyone have other thoughts?

[Danglerb]

Originally Posted by winstonbike

Asking to have crank end play measured - 200K on chassis, 11K on rebuild. All records covering last 50K, since 1996.

Anyone have other thoughts?

Why was it rebuilt, what was replaced, and when was it done?

If you can hook up with a local owner its always a good idea to let another objective set of eyes look over the car and deal in general.

Cars with clearcoat your a bit limited on what a detail can do, but the solid colors can respond really well to a good detail.