What are the classic symptoms before a top end overhaul?

I think my engine ticks a bit and wonder if the last valve adjustment might have been a poor job. Someone looked at my mileage (157000 KM / 98000 miles) and mentioned that my valve guides could likely be in need of replacement.

I know it's a common fault on a number of 911s, but what are the typical symptoms? Isn't it a large puff of smoke at startup and if it's really bad also during driving? Oh and large oil consumption is another typical sign, right?

My engine doesn't consume much oil. Actually I don't know how much or little it "drinks", but it's not much. At startup I sometimes see white smoke (sometimes a lot) but it goes away after a while. I've seen other 911s do the same.

I'm hoping that maybe the last valve job was poorly done and that having the valves adjusted again will make the ticking go away? What do you think? Having the top ends overhauled now is not something I'd like to happen.

[Milu]

The symptoms on my daily driver were: a dramatic increase in start-up smoke from cold, smoke on start-up when warm, blue smoke on hard acceleration, increase in oil consumption and a loss of performance. What staggered me was that it did not happen gradually but almost overnight.

[89911]

Originally posted by Milu
a loss of performance. What staggered me was that it did not happen gradually but almost overnight.

The excess oil burning is fouling the spark plugs. Interesting about the progression. Mikkel, I think every late model 911 goes through this worry. I just assigned myself that it will need done in the near future. The problem is all the other things ($$$$$$) that I plan to do then!

[RoninLB]

I would check valve guide wear first if concerned about a valve job......Ron

[Rick Lee]

Yeah, I'm afraid I have this in my near future and it happened almost overnight too. I don't get any smoke at start-up and don't smoke at red lights. But it's drinking a lot of oil all of the sudden.

Originally posted by Milu
The symptoms on my daily driver were: a dramatic increase in start-up smoke from cold, smoke on start-up when warm, blue smoke on hard acceleration, increase in oil consumption and a loss of performance. *What staggered me was that it did not happen gradually but almost overnight.*

Now if only you hadn't written the last part

I have to say that my car doesn't smoke much. I believe the amount of smoke coming from mine is perfectly normal. And as I mentioned the oil consumption is very small.

I talked to an experienced Porsche mechanic today. I asked him what he thought of the engine's sound (slight ticking). He said it sounded like one that needed a service He said I should have the valves adjusted next time the oil needs changing (in about 5500KM/3418miles).

Forgot to tell that this whole thing started with a mechanic who adjusted the valves for me about 4000KM ago. I don't think he did a good job. It may be set too loose.

[dickster]

50k, 100k miles?? is that about the correct time for a top end overhaul? can't remember.

imho it should be done as a matter of normal servicing, rather than wait for the symptoms described above.

i'm not saying thats what i'm doing but that its the correct way. like most here i haven't got the money, so hopefully regular oil changes etc will delay the inevitable.

[JavaBrewer]

How about pulling up to a stop with the windows down and getting a good whif of oil smoke? I split my time looking forward by looking backward (all mirrors and head out window) in search of smoke. I can't see it but others have said they see a bit on shifting. The only time I see the smoke is in the morning on first startup. Sometimes very little other times one big cloud. I do know 2 of my return tubes have slight leaks and I've got a couple of drops on my garage floor. The exhaust pipe tip is still dark brown...definitely not black.

Anyone else smell oil smoke when rolling to a stop or is my condition worse than I expected. Have not had a compression/leak down/valve guide test done yet. Current oil consumption is 600-700 mile/qt. MPG is good and power seems normal.

edit - Oops forgot to include I'm at 108K miles, engine totally stock except for cat bypass.

[Rick Lee]

I try to sniff for oil smoke at red lights, but only get the strange fuel smell from my cat by-pass pipe. It definitely smells a lot stronger than before I put that pipe on about 6 wks. ago. But I'm told that's normal.

[Bo]

Just yesterday evening, when taking the car for a spin, I thought about the light ticking I sometimes can hear from the engine, when I pass closely to something that reflects the sound of the car (a building, or something like that) at low speeds. Can't hear it from inside the car at all.
My engine consumes very little oil, and I haven't seen a single puff of smoke coming from it since I installed it four months ago, hot or cold regardless. Not a single drop on the garage floor either.

Ticking in itself shouldn't be something to worry about then, if all else seems fine?
The valves were adjusted when the engine was installed. Have only driven it about three full tanks of gas since.

(sorry, I have no idea of how many miles the engine has on it at all, but all the test done on it so far seems fine).

[nostatic]

sounds like a bad valve adjust...you don't have any of the other "classic" symptoms. My car will blow some white smoke on cold startup, but I'm thinking that is condensation burning off from sitting. It is worse when I back down my driveway that has a steep slope...I figure the condensate runs to a area that is hot and burns off. At least that's my story and I'm sticking to it.

Follow the advice of the 2nd mechanic...adjust the valves and see what happens.

[89911]

Originally posted by Mikkel
Forgot to tell that this whole thing started with a mechanic who adjusted the valves for me about 4000KM ago. I don't think he did a good job. It may be set too loose.

Actually, you can get an idea of valve guide wear when an adjustment is done. When its in the right position, you can rock the valve's back and forth and the amount of play is an idicator of the guide wear. My mechanic showed my how, so I am a bit sketchy on the details.

[APKhaos]

Mickkel,
If you oil consumption is reasonable [<1qt/800miles] then its unlikely you need a top end rebuild. The valve guide issue gets lots of play, but its not the only issue and does not automatically happen to all 3.2 engines.

My 140,000 mile 3.2 was puffing blue smoke on startup, and burning 1qt/300 miles. No sign of oil smoke when running. Classic valve guide symptoms, right? Wrong!

When I pulled the top end, the valve guides were decent, but the rings were so badly coked up that the oil control rings were seized in their grooves. The Ps & Cs were gorgeous when they were cleaned up - very minor measurable wear.

Two usefull things to do:
1. Check your oil consumption carefully. If <1qt/800miles, then top end rebuild is not for you!
2. When you do your valve adjustment, carefully check for end play on the valve stems - although I'll be surprized if you see any.

A good tech can listen with a mechanical stethoscope and determine where your clicking is coming from - probably loose valves.

BTW, here is the pistons before/after - to give you an idea of what can happen.

[Sean Hamilton]

Originally posted by APKhaos
When I pulled the top end, the valve guides were decent, but the rings were so badly coked up that the oil control rings were seized in their grooves. The Ps & Cs were gorgeous when they were cleaned up - very minor measurable wear.

What causes this to occur?
Is there any way to avoid it?
Could they have been de-coked in-situ, i.e. adding an additive of some sort to the fuel or spraying Carbie Cleaner into the intake whilst the engine is running?
Did you notice any difference once they were cleaned up?

[RoninLB]

Tony..great pics..what engine oil was used?? that's enough coke to make someone nuts......Ron

[APKhaos]

Sean/Ron,
Listening to the gurus, the amount of buildup you see is not unusual in a 100K mile plus [mine was 145K at rebuild] engine that has been run lightly - lowish revs, not thoroughly warmed, typical "gently gently: treatment from the PO.

Not sure what oil wasn used, but I have receipts for every oil change from AutoSport Haus in SFO, and looking at the service prices I doubt they used cheap oil. That said, some oils are more prone to coke deposition than others.

Given that it took the best part of an hour per piston to get from 'before' to 'after', I really doubt that squirting anything into the chambers would have helped much. Its kinda nasty stuff.
I had run two bottles of Techron before the rebuild.

After the rebuild - rings, heads, rod bearings, Racewear rod bolts, everything static balanced, compression balance, and all, the engine runs like a dream, and delivers appreciably more SOP power. Great payback when the engine needs the work, as mine did, but Mikkel's engine sounds like it might have lots of miles before he needs a rebuild.

[HarryD]

Hi,

My guy is in definate need of a top end. How did I know? several things:

1-Oil consumption-1 qt/2-300 miles
2-Large blue cloud on decelleration. Little or no smoke at speed or accelerating.
3-Lousy leak down on two cylinders
4-At the last Last valve adjust it was noted that there was quite a bit of valve play.

9 months ago, when I first was aware of these symptoms, I asked my wrench about a top end. His response was, that as long as I was not overly stressing the engine (not too many trips to redline), I didn't mind adding oil frequently, was not embarassed by the blue cloud, I could wait with no additional damage. I decidded to enjoy the summer driving season and this winter, I will be in for a top end rebuild.

In the meantime, enjoy your ride. Me and smokey have had a great summer!

[stone43]

Gulp!

So how much is a top end rebuild (Black Forrest or Extreme in San Diego as reference if anyone has had it done there)?

I am using a lot of oil, only see smoke on startup--seem to use less when I drive the car more (don't ask me why).

Car is running great, a little ticking.

Not sure what in the hell to do after reading this thread.

[APKhaos]

Stone,
Relaaaaax! HarryD is right - this is not a catastrophe waiting to happen.
The oil smoke is kinda non-PC in CA, but that aside you can drive it without a worry. The engine wil be soft - not as crisp or powerful as it would [will?] be with a fresh top end, but still fine.

The only reason I did mine last winter was because I got the DE bug fairly badly the summer before, and wanted to be sure I had a strong engine for this season. If the car was a driver, with no track plans, I'd probably still be driving it and adding oil regularly.

Not sure on CA costs, but you can figure 30 to 35 hours of shop time plus say $2000 in parts/head machining/ etc. A DIY job can come in somewhere around $2000, assuming your Ps&Cs are OK and no nastys like head studs/burned valves et al.