DsDw40

Guys,

I'm still shopping for my 1st Porsche(2mos now) & have a good lead on an '86 911 Cab. Do I need a leak down if the compression test is good?
Also, pics suggest this car is straight & clean, 98k for $17.5k, please comment on the purchase price as well.

Signed,
Can't wait to be an owner

ron mcatee

Always do a leakdown along with the compression test. $17.5 seems quite high for that car. There are so many Cab's on the market, you should be able to find one with lower miles for less money. LOL.

fixnprsh

eh, you dont list your area, but here in socal cabs are realitivley easy to come by, I would pay that price if it were exceptionally clean even with 89K on it, and if it has good colors and well optioned.

if your already doing a compression test, its not that much more work to do a leak down test,

Pics can suggest alot, thats why you get a PPI.

Jim Chambers

The Porsche mechanic I use says only do a leak down if compression is poor. He says leak down is a diagnostic tool to learn why compression is poor. If air escapes through exhaust or intake, the respective valve is not sealing. If into the crankcase, it is getting past the rings.

Noel

I agree with Jim. ONly necessary to track down the reasonwhy compression is low.

Bill Gregory

While there are opinions on this, I personally like a leak down test and compression test prior to buying. Just a little more information to make an informed decision with.

imcarthur

Re: Leakdown

You're paying a lot for a 18 yr old car so for the small extra cost, leakdown just tells you more as Bill said.

And outside of CA, $17.5K is not out of line for a '86 Cab, if the PPI is good. For some reason (maybe the AC), '86 MY cars seem to demand a heathly premium over 84 & 85 & not too far behind 87s.

Ian

john70t

"I'm not a mechanic, but I play one on t.v."......
The price of the car will depend on a lot of factors, which are entirely up to the buyer.
In terms of a leakdown and compression test, both really do the same thing (measure combustion chamber sealing) but in different ways.

The compression test uses starter-motor-speed compression(around 100- 200 rpm?) to pump air into the cylinder. Having a warm engine will make the results the best they can be, but doesn't quantify the cold engine clearances. Also, bad valve timing, a weak battery and leaving the throttle-plate closed while testing will give a false low result. Alternatively, excessive carbon, aftermarket pistons etc.. may give a false high.

The leak-down test uses air pumped into the spark plug hole from a compressor(~100psi?)-while the crank is held at the pulley bolt- to see what percentage of air is being lost, and from where (air cleaner/intake valve..tailpipe/exhaust valve.. pcv hose from crankcase/worn rings). This seems a more complete test, and too much information shouldn't hurt. The leakdown is a static test, meaning the pressure is tested in a relatively unmoving cylinder- which disqualifies racing engine which have cam overlap/high compression pistons and will give very bad readings.

Both of these only measure low-compression sealing, which are well below normal operating pressures where low-octane gasoline is ignited while trying to push a vehicle/trail up a steep hill... Normaly a function of compression rings is to be pushed out against the cylinder wall by the gasses behind them, and expand to seal the ring gap, so even worn rings/cylinders may give false positives.
Neither test shows wear in the rest of the engine: valve guides, timing chain, etc...
but if the rest of the car is in good shape, the owner may likely have cared for the engine as well.

DsDw40

Thanks Guys I appreciate your comments.
My research suggests the price is below other comparables in my area(connecticut). Not sure If a convertible is for me though, I will need to modify the rear seats with harnesses for my 4 & 2 yr old.

Dan Cobb

There is no need to modify anything except your current car seat/booster. Go to your local Porsche dealer and look at the car seat that is designed to fit in the rear of a 911. There are at least 3 different types/sizes/styles to accomodate your child AND the law. Mind you, they are not inexpensive. If I recall correctly, the booster was nearly $400.
Some might say this is not the place to save money, and others will say it is simply more practical to put children of this age in a different car.
I take my 4 yo son in the front seat of my 84. I use a booster seat and have never had any issues with fitment or the local police. I'm not sure what kind of protection is possible in this small of a car, but in the booster, he is as safe as he can be in a 20 year old Porsche.
Part #'s in this "Tequipment911" catalog for the seats only show from 98-04 & 05 model years. I saw them at the dealer over 5 years ago.

SVU-Boat

Price is good, if visual and PPI ck-out. And yes on the leak-down.
P.s. 2-months of searcing, ain't nothing

I "only" looked for about 6-7 months when the right car basically fell in to my lap... a little earlier than I was planning to plunk down for the commitment. In fact, while I was looking, it was common for owners to relay their long journeys to their 911 and they AVERAGED a full year of searching... several of them spent nearly two years. One fella had paid for 3 PPIs over the span of 1-1/2 years... amazing, the fanaticism.

The asking price was $17.9k on my (below-pictured) '86 cab with 82k miles back in April '04. It came with custom rims (some would admonish me stearnly for that) but came with the standard Fuchs rims too. It also had a $2k stereo installed and a custom, extra-capacity A/C, which works amazingly well. It also had, what I would judge to be, an above-average number of small stone-chips/nicks all along the front facia (bumper, hood & mirrors)... this is in Arizona afterall, the pebble capital of the world : | And a few cracks or small tears on the driver's leather seat.

That all said, for the first time, I considered a cabriolet... previously looking only at coupes and targas for their rigidity... but I loved it. Going topless is immensely easier in a cab than a targa, and vice-versa if you need to. And hearing that engine accelerate on a quiet Sunday!!.. In Az, in the last 6 months of wknd driving, there has only been one time where weather kept me from my morning drives... so the cab was an excellent call for me. And points out that usage and location are pivotal factors in determining the "right" car for you. If I was in the north/midwest, I'd probably prefer the coupe.

Initially, I told the owner that I (err.. my wife) had a spending cap of $15k on this mid-life necessity.
At first he was reluctant, but the owner had already ordered/paid-for his next vehicle, so he was also anxious to sell. He could see/hear that I was wild about my first 911 and eventually confessed that he simply wanted to clear $1k over his remaining loan amount... which happened to be $14,200. Wa-La!!
I told the ol' lady I got it for $15k... and just bagged lunch for a while to make up the extra $200

The mechanic that I had inspect this car said $17.5 would be a very good price to settle on (he'd seen it advertised at $17.9 as well). I didn't have the heart to tell him that I was about to get it for $15k and change.
It will need rear-brakes in about 7-8k miles and a main fan-belt sooner than that. At some point, some oil lines will need replacing, as they're "oozing" but not dripping. Other than that, nothing pressing, save for routine maint.
I know karma smiled on me that day... knock-on-wood... but damn-it, I've had it coming.
This is all a long way of saying that $17.5 is a good price for a clean 86 cab... esp if it is the color/style you really want. In my case, black/tan was first choice; Iris blue or navy blue was second. But like I said, she fell in to my lap and I simply couldn't get her off.

Best regards... and luck!