'87 930 PPI results & questions

[Kirk911SC]

Car in question is a '87 930. Very nice condition from photos.

87,000 miles.

37,000 miles on rebuilt engine. Garrett turbo, B&B exhaust, boost set at 1.0 bar. Updated cams (SC i believe), larger oil lines, hardened head studs. Tranny rebuilt about 5 years ago.

Compression: "All cylinders from 125 to 130 PSI"

Leakdown: "Leakage from 5-8% all cylinders". I believe this was done cold, but still have to check with technician.

Some small oil leaks noted. Right booster fan inoperative.

2nd gear grinds on some upshifts and downshifts.

I have been speaking to the seller for a long period of time now, and I have many receipts for work done on the car, including the engine rebuild and tranny rebuild (with hardened gears). The seller is very forthcoming with info.

Do these leakdown/compression numbers look good?

How difficult/expensive is a 2nd gear synchro replacement in a 930 tranny?

I have not personally driven the car. It's located in the Tennessee, and I'm in Canada. Price is good, but I'm concerned about upcoming tranny problems and driveability.

My SC has a slight balk into 2nd gear also, so I'm familiar with how a 915 tranny shifts (slowly.......). Never tried a 930.

PPI done by Renntag Motorwerks (Wicky Laurie) in Nashville.

Any advice would be appreciated. Thanks!

Kirk

[Nine9six]

I believe the compression and leakdown numbers to be in line, but as you know, these numbers should be collected after a good spirited drive.
Was the PPI performed by someone who does not know the seller, and paid for by you? Was it an independent assessment? What does the PPI say about the rest of the car?
2nd gear synchro replacement = dropping the motor. Are you sure there is a problem with the syncro? Did the PPI report state this was an issue?

[Kirk911SC]

PPI was done by the shop that regularly services the car. I have many receipts from their shop going back at least 5 years.

PPI doesn't mention much else about the car other than "left upper valves noisy - adjusted". The PPI doesn't specifically mention the synchros - just the grinding.

Receipts over the past 7 years total over $21K.

I paid for the PPI.

Kirk

[hobieboy]

I think 5-8% leak down is acceptable. Rebuilding 930 synchros is not that difficult but you'll almost certainly need the specialty tool to separate the syncho from the gear. If it grinds on shift, you may also need dogteeth. The most expensive part is probably dropping the engine/tranny bit.
Where are the oil leaks? And what oil lines are larger?

[Kirk911SC]

Slight oil leakage from cam/chain housings. Owner is running synthetic oil.

Not sure exactly which oil lines are larger. At the office and paperwork is at home right now.

[javadog]

Kirk,

A few random observations, based on buying and owning 930s for the last twenty years:

The miles are a little high for a turbo. These cars usually don't get driven as much as a regular 911. Cars with half that many miles are easy to find.

Why did they have to rebuild the engine at only 50,000 miles? Likewise, the trans should not have needed rebuilding that early. It bothers me that it has been rebuilt once and now needs work again. These things don't speak highly of the owner.

The leakdown numbers aren't great fo a 37,000 mile engine. They should be 2-4%.

The last 930 gearbox I had overhauled was $840, plus parts. The original problem was a notchy third gear. The "while I'm there" syndrome ran the bill up quite a bit.

There is no such thing as a cheap 930, so if the selling price is attractive enough that you are using it to offset in your mind the problems the car may have, you are probably going to want to see and drive the car in person prior to purchase. I have bought a lot of cars sight unseen and have found that the representations of a seller coupled with a good PPI have disappointed me, more often than not. Airfare is cheap.

My advice is to buy the nicest, most original, lowest mileage, one-owner car you can find. You'll pay more initially but, in the end, I think you'll be happier. I have bought neglected 930s from owners that shouldn't have owned them. I have this gene in my DNA that requires me to save cars from bad homes. Buying one for $20K and then spending another $30k to get it fixed up is not smart but I have done it.

If you ever sell the car, a car with good history will sell quickly. A car that has been rebuilt will not.

My two cents,
JR

[Kirk911SC]

Apparently the owner previous to the seller had the boost adjusted to 1.2 bar. 2nd gear was wrecked. Tranny rebuilt with hardened gears. Boost turned down after that.

I believe the engine rebuild was done along with the installation of the new turbo, exhaust, cams, etc. to ensure the engine could handle the extra power.

Kirk

[hobieboy]

JR brought up some good points... I think it depends on your expectation & intended use of the car as well as the ultimate price.
If you want a collector's car - then walk away from this one.
If price is so good & you are willing to gamble on $x on repairs, then its a different story.
On the one hand, I'd rather buy a cheaper car & do all the repairs myself so I know its good/bad than paying for a premium and still gamble on the outcome. But then JR's comments on resale might come into play...

[Kirk911SC]

This car will not be a garage queen. I intend to drive it alot. I'm not looking at it as an investment, and resale isn't a big concern.

I just want to have a mechanically sound car. I intend on doing as much DIY as possible, and having a mechanic tackle anything I don't feel I can handle.

My SC ownership has been great, with mostly DIY work, and periodic checks and odd work done by a factory trained tech (who I bought the SC from).

I've looked at several 930s, and this is one of the few that I've had a "good feeling" about.

[javadog]

Kirk,

Do you have receipts showing exactly what was done when they rebuilt the engine and gearbox? Who did the work?

The reason I ask is that from your last post it implies that most of the engine modifications were done after the previous owner ran the boost at too high a level. There has been nothing mentioned of a better intercooler, twin ignition or additional fuel enrichment - all of which are examples of things you would need to add to a 930 to run that kind of boost. Running 1.2 bar on a mostly stock engine is a recipe for disaster. Damage to the pistons, cylinders and heads is not out of the question. I'd want to look into that history a lot further.

Wrecking 2nd gear from running too much boost on a fairly stock engine actually translates to an owner that didn't shift it correctly. 930 gears are stout and can take that kind of power (and torque) plus a lot more. I normally replace all the wear items associated with a gear, not just the synchros. Usually, there's enough wear to justify it. I'd want to know just what they replaced. If the gears have been "hardened" I'd want to know who did that work, too.

JR

[Kirk911SC]

I have receipts for the engine rebuild and gearbox. Paperwork at home, but the rebuilder was Music City Motorsports I believe.

I think the engine rebuild and mods were performed. Then 2nd gear was broken. I have a dyno sheet (395 hp/430 lb/ft at flywheel) with 1.2 bar. Then tranny rebuild performed. Boost turned down. Seller bought car shortly after this.

Stock intercooler, stock ignition, not sure about fuel enrichment.

[carmad]

I agree with the previous advice, but would walk away from this one. Running even 1 bar of boost on pump gas on hot days with stock intercooler will take its toll on the engine. Too much of an unknown.
Also did they replace the rod bolts with ARP or Raceware, the stock bolts were a weak link.

[javadog]

If he ran it on pump gas at 1.2 bar, I'd wager he got detonation, if he knew what to listen for. Too much of that and you will damage pistons and cylinders. If that happened AFTER the rebuild, I'd be nervous.

1.2bar was a normal endurance race boost setting for the 935s. Of course, they had better cooling, richer mixtures, twin ignition and race gas.

Good luck,
JR

[Kirk911SC]

If this did occur would the leakdown and compression test show any problems?

I guess I really should talk to the mechanic involved.

[javadog]

Maybe, maybe not. Usually the area above the ring lands gets weakened and damaged. The engine goes from running (and detonating) to running on 5 cylinders in the blink of an eye, when the piston on the leanest cylinder fails. Now that the boost is turned down the biggest concern may be ring wear. Incidently, I wouldn't run even 1 bar without an aftermarket intercooler, on today's pump gas. Especially if you live in an area with 91 octane (R+M/2) or oxygenated/reformulated gas or any gas with alcohol in it

As far as I am concerned, the leakdown numbers are already too high. If he did the test correctly. with the engine fully warm before starting the test, I'd expect the numbers to be 2-4%, as I mentioned previously. I consider a leakdown of 10% to be the limit on a turbo at the end of it's useful service before a rebuild is needed. If the leakdown test was done with the engine cold, then as far as I am concerned you should throw away the results and get another one done, by a different shop.

Take a look at the receipts for the rebuild. If they did not replace the original pistons and cylinders at that time, then you have fairly high mileage (for a turbo) pistons and cylinders in a car that was owned and abused by an idiot (the previous owner.) If you intend to put a lot of miles on such a car, you'll end up rebuilding it again at some point. If that happens, you'll spend a bunch.

I know nothing about the shops you have mentioned. I'd feel a little better if I knew them well enough that I felt I could trust them. Unfortunately, if they built the engine and set it up to run 1.2 bar as you have described it, I'd question their judgement. The guys I use in my neck of the woods would not do that, regardless of what the owner wanted. And if it was the shop that recommended the modifications and not the owner...

JR

[Kirk911SC]

Thanks for the input. I'll try and get some more info from the seller and the mechanic that did the PPI.

[JeremyD]

Tough finding a turbo at a decent price that doesn;t have some (or many) issues... and the ones that are low mileage tend to be really spendy. The leak down and compression don;t look bad - they actually look pretty decent with a cold engine.

If you are going to drive it - then you need to figure what you'll deal with, and go from there. SC cams and garrett are two good moves.

[hobieboy]

Don't forget having only 20,000 miles on a 20 year old car is not necessarily a good thing neither.