RicoJay

First of all, I really appreciate all the good information on this forum. I learned a lot and believe I made a great purchase. Something about the raw energy and charisma of the 911 completely trumps the 951 I totaled last week (not my fault, I'm the one who the cop hit). The 951 was a bit more cultured on the interior and definitely an easier drive. But I digress...

Two minor things I've noticed which may or may not be problems. I already searched this forum, but couldn't seem to find anything.

1. At highway speeds of around 80mph, things are very smooth on normal surfaces, but there is a significant thumping/punching sound from the rear when going over rougher highway. Is this just a normal thing for a 911 due to the extra weight in the back and the stiff suspension? Or could it be worn rear shocks. My car only has 66K miles on it, I wouldn't think shocks go that quick.

2. I noticed that even with the e-brake off and the tranny in neutral, the car doesn't seem to want to quickly drift off down my parking garage's minor grade. Did the factory that did the PPI and my own test driving both miss bad wheel bearings causing increased static resistance? What else could this possibly be? I didn't smell anything on my 2 hour highway/backroad drive today, so I wouldn't think it's the e-brake locked on or the brake pads hitting the rotors.

Jay H

Congrats on the purchase. I really like '86 cars.

911's are pretty stiff on uneven pavement. However, if the shocks are original 1986 shocks, they are most likely no longer up to spec. Very worn or aging tires can degrade ride quality too.

ked

"Something about the raw energy and charisma of the 911 completely trumps the 951 I totaled last week"

this is a nominee for "classic 911 owners statement of the month", intended or not. congrats!
1) could be a number of things or "normal" - get a long time 911 ('80s era) owner to drive it where you note the harshness & see what he says. some 911s exhibit a sort of beat frequency oscillation on certain surfaces. can be ameliorated or exacerbated by tires (design, pressure, age), shocks (wear, age, settings), torsion bars, bushings, engine & tranny mounts, even rear allignment & combinations of all.
2) there is a wide tire contact patch of inertia to overcome. you might raise the car (be sure to jack at the CORRECT POINTS) and turn the wheels by hand to get an idea of resistance, if there is one wheel dragging, etc. also, you can test this while driving by sensing if the car slows down in a hurry from speed when you coast on a slight downgrade. comparison to other examples might help here too.

the 911 is a unique-feeling car, different from any other, even Porsches (except the 356). it will take some time to adjust, but those first months are special. enjoy!

imcarthur

Congrats on your 'upgrade'. Post a picture when you can.

The rear end noise could be broken rear sway bar mounts - a common problem. Have a look at them & see if they are cracked or broken off from the body.

Ian

RicoJay

Here's a picture.

1. Beat frequency occilation sounds exactly like what I'm experiencing. Suspension is probably in normal condition, but yeah over a certain stretch of highway where there were the same dips and valleys from poor highway wear and tear, there was definitely a wierd beat frequency coming from it. It feels and sounds completely normal other than that.

2. Regarding wheel resistance, on the highway I was going only 3K RPM at 80 mph which looks normal from the car's manual, so I just assumed maybe it was tire resistance or something like you mentioned.

BER

Nice looking car and welcome to the world of 911 ownership. Be careful, these little cars can become pretty addictive.

Take Ian's advice and check your rear sway bar mounts (where the mounts attach to the pan); it is fairly common for these mounts to crack on the 3.2 Carreras.

Additionally, your rear shock attachment points could be loose, especially the nut on the top of the rear shock (up near the firewall in the engine compartment).

My 911's make noise going over rough surfaces, but not to the magnitude your describe.

Enjoy.

Peter Zimmermann

Also, before your next drive check your tire pressures - 29F/36R. Check your sidewalls for the date code, if your tires are older than 5 years you could be picking up harshness from them. Regarding shocks, if they're black they are Boge, if green they are Bilstein. There is also a slight chance they are yellow, in which case they will be Bilstein Sport. If they're original Boge's they probably need replacement. If they're yellow they've been replaced and are (in my opinion) too stiff for a street car (and, as Bruce said, the upper nuts could be just a little bit loose). If they're green they are probably still OK, but worn to the point that they can't dampen all conditions. In any case, twenty years is probably enough for any shock... With all that said your symptom sounds like something more than "normal."

Regarding wheel drag. Did your PPI technician give you the dates on the brake hoses? If they're original they should be replaced ASAP, and the brake fluid flushed. Also, 911s don't "roll away" quickly when the e-brake is released. Something about that engine hanging out over the rear wheels, inertia, all that sort of stuff.

Enjoy the car!
Pete

rnln

RicoJay,
same expereicen. I bought my 87, wide body conversion, just now and same experience. My car is sitting way too lowed and I feel like it is bottomming out every second on rough freeway. But after several driving and testing on this issue, I don't thinking it is bottomming out the shocks but it's rather that because it is too "hard", pressure to high? The reason I think this is because I don't get bottom out going over potholes and speedbump. Only at high speed and not perfect freeway surface. The rythm is continuously and quick.

Anyone know how do people nomally lowered this car? it seem like my car doesn't have any suspension springs. I feel this is weird, but again, I am new to porsche.

ked,
If I want to jack at the middle of hte car (front and read) to put the jack stand on both side, please let me knoe the good jack points. Middle of the bottom of the engine, tranny, ot the arm?

RicoJay

My vehicle is not lowered. My tire pressure however was very high in the front, 36-38 cold pressure. I dropped it down to 29. Rears were right where they should be. I have the original black shocks from what I can see through the front wheelwells. I rarely drive on the highway, and can certainly live with a little thumping from time to time, so I don't think I'll replace the shocks all around just yet. Much like rnln, I don't get the thumping over potholes or anything, it's just a random frequency that seemed to throw off my suspension a bit and hopefully was due to the extra pressure in the front tires. With the condition this car is in both inside, out, and mechanically, I would be quite surprised if the shocks have somehow sneakily taken a big time beating over 66K miles to warrant replacement.

ChristianR

Rico, where in TN are you located?

Christian

Dan J.

Hi,

You might consider replacing your suspension bushings, tie rods and maybe shocks. I just finished doing new busings, tie rods and shocks in my '86 Carrera and it makes a huge difference in the handling, feel and noise...a huge difference. I also did the same to my '72 911 E a few years back. This is subjective, but in my experience with both cars, I thought they were great when I purchased them, but after changing out worn bushings (especially the spring plates) the car is so much tighter, more solid and quieter. It just transforms the car.

Enjoy your car.
Dan J.

rnln

Question to everyone,
How do you know your spring plate is worn? The plate is the plate, when I looked at it. I can't really tell. Also, how do you know your shocks are gone? My shocks are imposible to tell either since they are like rocks.
PS: my car is lowered, extremely lowed. Can someone tell me how do people lowered a 911? I used to lowered many cars alerady, include BMW and MB, but to 911, I have no idea. I look under the car and found 4 black shocks with black "cap" on them. No spring at all. So people replace shocks/struts with lowered one? Or replace spindle as truck? Or revalve?
Now I would like to raise my car up a bit if the cost is minimal since I scape the front spoiler everywhere. And I do know how to take care of lowered cars but still.
Thanks.

rnln

What the turbo tie rod can do to my car?
Anyone care to tell me? Handle better, but how? And how much better?

Sometimes, more than 50% of the time, when I reverse and steer, I hear and feel clucking noise come from the front. Not exactly clucking but "clicking". Sorry I don't know how to describe it. And the feeling at my steering wheel. When I get under the car and turn the wheel to max, I can hear a "knock" inside the left boot. Th sound as you knock both metal parts together. The both boots look like new to me. Does that mean my tie rod end(s) has problem? Or it is normal?

Thanks.

Dan J.

observations/suggestions based on my non-professional experience

There's a pair of large rubber bushes that are inside the spring plate cover. Those bushes support the rear of the car on the torsion bars. On my '86 (original bushings with 175k miles!) the spring plate end (protrudes through the spring plate cover) wasn't centered in relation to the spring plate cover. If the protruding spring plate end and the cover don't line up, I think it's safe to assume that the bushings inside are out of round and need replacing.

Also, think about the age of the rubber in your busings. Those bushings have spent 20 years and how ever many thousands of miles supporting your car. I'd think that even if they weren't visually worn, the rubber wouldn't be in the kind of shape it was new.

You could pull one or both of your rear shocks and move them up/down by hand. If they compress or extend easily, they might be candidates for replacement. Not sure how to tell for sure how close to spec they would be w/o a shock dyno.

Not sure what to say about your tie-rod noise, although any noise produced by the steering is worth having someone look at. You don't want that to fail!

There's probably a lot of info posted on Turbo tie rods available here if you do a search. They will make your steering feel more precise, as the turbo part doesn't have rubber isolators built in like the normal non-turbo rods.

If you decide to replace bushings/shocks it may be worthwhile to do the tie rods at the same time.

Dan J.