rebuild or not ? Help !

[martiniqueln]

Well I have a 186k 3.2 1989 Silver Anniversary .
Leakdown test shows 24% on # 6 .
My wrench thinks it might be a piston .
Uses 1 Qt every 400 . Probably valve guides .
Should I fix ( top End ) or look for a decent 3.2 engine replacement ?
What do you guys think ?
My wrench will have an estimate in a couple of hours .

Any support will be appreciated

vinnie in Ventura

[Eric-325I]

If you have the cash and will keep the car a long time, I'd vote for a performance rebuild (hp)... That's what I plan to do when needed with my baby...

Eric

[Groesbeck Hurricane]

re-build from a reputable shop i.e. John Walker, etc.

Seach the website for information on different shops. With a quality re-build you will know what you have and can have confidence in another 150+K. JMHO

[martiniqueln]

David ,
thanks but do you think that a top end on a 186k engine is worth it ?
If one piston is bad now maybe another will be bad in another year .

Maybe I should look for a 3.2 to drop in if I were to keep the car.

JMO

[petrolblue83911]

if you find another 3.2 that's fine, but what will the new 3.2 cost + whatever it needs as well, if you put an unknown engine into the car you won't know what you have. if your motor is otherwise sound, it may therefore be cheaper to re-build it than to buy an unknown engine into the car and hope for the best

[Eric-325I]

Originally posted by petrolblue83911
if you find another 3.2 that's fine, but what will the new 3.2 cost + whatever it needs as well, if you put an unknown engine into the car you won't know what you have. if your motor is otherwise sound, it may therefore be cheaper to re-build it than to buy an unknown engine into the car and hope for the best

Very well said and is why when my 3.0 eventually needs internal work I will go with a full re-build... May cost the same as a replacement or even a little more but I'd rather know what I have than take a chance...

Eric

[Grady Clay]

Vinnie,

With 24% leak from #6, why does your mechanic think it is a piston? Ask for the details.

Does it run correctly?
What did the spark plugs look like?
Have you driven it and repeated the cranking compression and cylinder leak tests?
Is there any noise?
What is your oil consumption?
Can you find someone with a cylinder bore gauge to inspect in the cylinder?

Don’t do anything until you are absolutely sure of all the facts. A lot of diagnosis goes a long way toward your being able to make the best decisions.



There are some questions you need to ask yourself. Some are easy but some you can’t know the answers but you need to ask yourself anyway.

What do you want to do? What Porsche fantasies do you have?

In real life, how deep do you want to reach in your pockets?

Do you intend to keep the 911 over the long haul? Ten years … 30?

How do you intend to use it? Do you think that will change much over time?

Don’t post your answers, write them down for yourself.


If you want a nice, reliable, fun 911 then make your engine better than Porsche built it originally. A lot has been learned since your engine was new. As they say “Experience can be the best teacher.” Sure enough you can build it better and longer lived than PAG did.

Part of the reason is that you (and everyone) has the benefit of hindsight. Another is you are not as constrained with importation regulations. There also have been improvements in technology over the past 20 years.

One of the great things about the 911 is you have the opportunity to pick and chouse. You can rebuild yours as original. You can swap engines, even outside your 911 Carrera years. You can add all sorts of performance enhancements with little change in reliability, emissions, economy or longevity. In fact the change can be for the better. The difficulty is in deciding which way to go.

Clearly you should do something. Sooner or later the problem will become worse, they seldom heal themselves. Whatever you do probably doesn’t have to be done today. You have time to research in depth all the options. You can even buy another engine and rebuild it to your liking while driving.

If you decide to start with another engine, preserve and keep your original. There is increasing value with “numbers matching” cars.

You are in the right part of the world to have many good choices. You are asking the right questions. Feel free to ask more.

Best,
Grady

[Groesbeck Hurricane]

Grady,

You are one of my HEROES!!!!

[martiniqueln]

thanks so much Grady.
I'm not jumping into anything yet.

I will try to answer some of your questions .

I starting using 1 qt every 300 miles .
I am hearing chain noise after the car is good and warm
Car still has great oil pressure , no smoke from back end .
Still pulls strong .
Wrench says one plug full of oil . he did not say that it was for sure a piston but did not rule it out until he opens it up .

186k miles Grady , what is your best guess with the rattle which only is heard after warm and under a load.

Thanks in advance

[scottb]

Since you're in Ventura, you might want to give TRE in North Hollywood a call. Dave and the guys will treat you right!

Scott

[martiniqueln]

I have heard nothing but good things about them .

I am meeting Dave at the fairgrounds this weekend to discuss my options .

[Grady Clay]

I don’t want to GUESS – I want to know; at least the best possible.


“I starting using 1 qt every 300 miles”
Not good. Did that start suddenly or did it creep up to that point?

”I am hearing chain noise after the car is good and warm”
How do you know the noise is from the chain and not something else?


”Car still has great oil pressure, no smoke from back end, Still pulls strong.”
Good.

”Wrench says one plug full of oil. he did not say that it was for sure a piston but did not rule it out until he opens it up.”
There is a lot of diagnosis to be done first.
If it isn’t too inconvenient, I would spread the diagnostic tests around several shops. This will allow you to meet more shops and evaluate their skills (communication, technical, organizational, etc.) It will also allow varying perspectives on the problem. No one person has seen everything.

You need to organize driving in from some 30 minutes of continuous driving (not the 101 parking lot), park the 911 and have some tests done without restarting the engine. You want a cranking compression test and cylinder leak test on all six cylinders. When doing the cylinder leak test, the mechanic can tell where the leak air is going – it can be one or more of only four places: intake valve, exhaust valve, rings or head-to-cylinder interface.

They need to remove the valve covers and check only the valve clearance. (no sense paying for an adjustment now, you just need to know none is tight.) At the same time all the head studs should be checked.

Find someone with (or buy it yourself, $15) the tool (like a can opener) to cut apart the oil filter. You need someone with a sharp, experienced eye and a hand microscope to see if anything is there. Ideally your filter hasn’t been changed in a while. Drain the crankcase oil into a clean container and pour through a paint filter. Save the old oil. Inspect the magnetic drain plug. Save on a clean cloth whatever you find.

It is worth the money to additionally take it to a Porsche dealer for electronic diagnosis.

Once you have determined that one cylinder is having a problem, find someone with a fiber optic bore scope and have a look.


”186k miles Grady , what is your best guess with the rattle which only is heard after warm and under a load.”
The noise is of great concern. You need to determine VERY SOON that there is not a rod bearing failing. I think looking in the oil and filter will tell - do that first.

I can envision the situation where a bearing has been failing gradually and the piston can now touch the head. That deforms the edge of the piston and prevents the ring from moving freely. The combustion gasses go past the ring, overheating it and causing it to quit sealing. In extreme cases the ring will break up into pieces. In any case there is a lot of oil in the cylinder and that cylinder runs poorly. The cushioning effect of cold oil prevents the noise when cold.

This goes from running and easily fixable to total destruction in a heartbeat.

Yes, I am trying to scare you into determining this isn’t the problem asap. I don’t think this is the problem because it usually degenerates very quickly. It just isn’t worth the risk to not know.

Best,
Grady

[GothingNC]

Martin,

How is the condtion of your car as a whole?
Tranny, bodywork , interior, suspension, tires, brakes etc.

Have you had it for a long time and invested a lot of money in it?

If the body, tranny and suspension is getting tired You might want to consider selling the car (don't know what you can get for it at this point) if the motor needs a full rebuild and look for one with less miles with a recent top-end rebuild and recent clutch & tranny work for around 15k.

[martiniqueln]

Thanks so much guys for all your help.

More info from the wrench .
Leak down test
# 1 12%
# 2 18%
# 3 18 %
# 4 8%
# 5 18%
# 6 25%

# 6 had oily residue

He said he would charge me $1500 to open it up .
If piston was not cracked he would do the valves , valve guides etc , top end . 6 to 8 K .
If piston cracked then add another 3600.00 which includes the clutch .

I absolutley will have TRE look at my car at the show next week .

Any more imput would be greatly appreciated.

thanks

Vinnie From Ventura

[martiniqueln]

John on condition of car other than engine .
Wrench said tranny was in excellent shape as well as body.
My interior is a 8 +
Body is a 8 +
Tires 8
Suspension 8

How much should I ask 12,500 ??

[GothingNC]

I don't know how much to ask but the 89 Carrera is a desirable model.

Hope all goes well with the lookover by TRE.

Do you have any pictures to post?

[JeremyD]

TRE - and I would do a full rebuild at 186k - not just a top end