Cross Post - Another "what's this noise" thread

[sobamaflyer]

I laugh whole heartedly at myself on a regular basis, please feel free

for personal growth....which part was the chuckle for (the time out, the haven't yet or the taking it out for what should be a simple repair?) I happily admit the downtime is excessive, I have a 3 year old, a wife that appreciates attention, a stressful job and most recently a return to college. All take away from any real garage therapy time but are more important in my grand scheme (and I don't have funds to drop my toy off to be fixed for me).

I'll take your advice and drop that header before I go further and see what I see, gotta be fixed anyway right?

If I get out of this w/o a rebuild I'll have a good excuse and funds to do something about my [somewhat] bobo exhaust. I would kinda like to have a stock set of HEs and a non-Flowmaster (although I've grown to somewhat enjoy it)

[Grady Clay]

“Simple repair” – no such thing.
It always turns into “while-you-are-there”.

I’m a strong proponent of diagnosis and planning.
I like to think-through a few steps farther along any situation.

In your situation, it is easy to say “time for rebuild”.
That may not be necessary.
Yes, it may be what you (secretly) want.
If so, buy another engine and keep your 911 functioning.


3-YO, I’m jealous. In spite of the stress, I miss it at 70+.
I make-up tutoring/mentoring an 8-YO tomorrow. I hope to live to attend Nathan’s PhD dissertation.

Best,
Grady

[sobamaflyer]

"Secretly want the rebuild".....sure the allure of breaking this down and KNOWING what's in there that remains a question mark a couple years of wonderful, enjoyable ownership....... I'm not afraid of it, I've rebuilt a couple of VW motors w/ success. But the reality is I "shouldn't" if I can at all avoid it, I have too many other places to spend $.

I love my little family, I love that I'm passing along to my son the love of these old greasy things. I can't be out in the garage working on anything without him climbing on top of me/it wanting to know what he can do. He's getting good at finding me the 10/13/15mm wrench lately.

I'll report back with new data with any luck tomorrow morning.

[sobamaflyer]

Morning report, right bank open....

Engine is close to TDC on #1 - I have noticeable (but not awful) valve looseness on #6 exhaust, and #5 intake. There is NO play in any other tappet, I CANNOT budge any of the 6 valves (springs) by hand.

I didn't have time to go ahead and dig into the left bank to see if I found the same there.

Did I need to rotate the engine to feel the spring play I've read about in other "broken spring" posts?

Intake:






Exhaust:







Inside of Valve covers - There was a small amount of debris but as before I didn't really find any flaking or metallic stuff, just a bit of crud

[sobamaflyer]

correct me if I'm sorely mistaken but I've always taken these for fairly decent stainless headers, they are dirty but they do polish up

I've got mixed feelings about the Flowmaster, it may need to go regardless and today's lesson was that it wasn't too awful lowering that header to get access for a valve adjust



And one of my sad state car:

[sobamaflyer]

Very confused - I took the left bank covers off this morning and found more of the same from last week. I cant really budge any spring using a screwdriver while carefully studying each w/ a mirror and light. They all "look" normal.

Makes me wonder if it's a break I just can't find or a past repair I'm just now finding a piece of?

Any suggestions to my next step?

[Grady Clay]

“Very confused” yes

I would guess there is a high level of probability that the piece of valve spring may be from some previous incident.
That said, I would not discount there is currently a broken spring.
It may be that you will want to disassemble and reassemble each valve spring in-situ.
This is a pita and may not yield anything other than the confidence there isn’t a continuing issue.
Your only cost are the two valve spring compression tools (easily resold later).

Diagnosing and devising a correct course of action are difficult when you don’t have all the historical information.
You don’t know what PO or some hamburger mechanic may have done over the past 37 years (and there have been a lot of opportunity).
This brings up a difficult decision faced by many owners and not just limited to our ‘old’ 911s.
This is one reason many completely ‘rebuild’ a fine old 911 – to insure you know every detail of its condition.
I’m not suggesting this in your case, just making an observation.


So … what to do?

I think you have some ‘soul-searching’ decisions to make.
These are probably common to many (most?) mid-year 911 owners.

First, I would objectively analyze the condition (rust, prior crash damage repair and overall) of your 911.
Unless you are committed to this car (your dad’s first Porsche?), you should consider the cost of investment in repair compared to the resale value.
We all ‘love’ our Porsches but reality must take some position.

I think the investigation of the valve springs may be a ’pain’ in terms of effort but may confirm (or not) the issue with only your investment in time and effort.
The cost of the two tools (and eventual resale) are insignificant.

All this keeps in mind that there may be other issues (noted above) like wrist-pin bushings, broken piston rings, head studs and more.
Your 3-liter engine is very robust compared to the original 2.7.
That doesn’t mean it doesn’t have issues needing repair.

I’m a long-time proponent of fixing things right – given the 30+year experience, repairs can be better than original.
You can have a nice 911 far better than Porsche built it originally (rust and prior crash excepted).

Decisions….

Best,
Grady

[sobamaflyer]

To date I'm into this car for ~$8k (purchase and 2 years of parts replacements/additions), it has no historical or sentimental value other than being my first 911 after having dreamed of having one for 25 years prior. It's rather Franken-porsche-ish being a mish-mash of parts (but I am very fond of it's state in general)

I have no illusions that it's really worth a lot more (running) than I have in it now. This is my main hobby, I don't golf, fish, hunt, go to football games so cars are a place I choose to "waste" $. I accept that at some point I'll have far more in the car than I could ever sell it for. And I've at least had the idea pass through my head of trying to sell it running and get another ~10-12k 911 but I keep coming to the conclusion that I'd just be re-starting with a new set of unknowns (given my req'd price range).

That said......

I need to get and will get the spring compressors so that will happen this week.

If I check out each spring, even if I find 1 broken and replace it and put it back together. Do I hook everything back up and try again for a harder ID on the new knock in the middle (hoping/assuming I've addressed the "tick" with springs and valve adjustment.

Or am I bandaiding and would be better off to go ahead and open this up?

[timmy2]

Sounds like you have a decision to make...
If it were me, I'd get Wayne's engine rebuilding book, determine the parts and tools needed to do the work, make a plan and do it right.

[sobamaflyer]

Check, got it a few weeks ago and read through most of it.

I've been stalling I guess hoping the magic Porsche fairy would show me a loose nut and put me back on the road

Sent from my SCH-I535 using Tapatalk 2

[sobamaflyer]

I'm well down the rabbit hole trying to diagnose my errant noises.



My wife and son have been out of town for several days so I've had actual time to tinker. I broke my engine mount cross-member at the left weld (hoping to catch one in the classifieds). My first 911 engine drop went surprisingly smooth otherwise (after I figured out I'd not unhooked the clutch cable & then reverse lights).

I am waiting on a PP order to get spring compressors & cam tools. I haven't found anything really disturbing so far, knocked the biggest chunk of grime off right after I pulled it. I have 4 header studs that came out but visual inspection inside the valve covers so far doesn't cry out anything crazy and the head studs all "appear" intact (I'll confirm that for sure soon).

Obligatory "dude in an engine bay" photo:



Not bad for not having a soul around to lend an extra set of hands.

[sobamaflyer]

Made a little more progress today (a little)

I have the top stripped down, chain covers off, cam nuts are both loose.

I continue to feel like this engine was rebuilt not terribly long before it was put away, everything inside is relatively spotless, seals are all fairly fresh.

I don't seem to have Carrera tensioners but they look odd (anodized collars on the top?), any hints as to why they look different than what I've seen in pictures?

I have the valve spring compressors on-hand but have yet to delve into exactly how to use them. I'm continuing to follow the book so...

[sobamaflyer]

I'm looking for those in the know to comment on what I've found so far.

Clutch:
I'm in need of a new disc? Resurface the mating surface or can I clean it w/ a scotchbrite pad?




Cylinders:
All look like this, some carbon buildup on the crowns but the cylinders seem to be in nice smooth shape. Given my good leakdown and compression numbers I'm thinking about removing the pistons & cylinders as a unit (as described in the book). Not messing with them/the rings?





Heads:
Also (aside from dirty) appear to my untrained eye in decent shape (I may be corrected in this) the valves appear to seat but I need to look into this further. I also still need to take off the valve springs to check them and see if one is broken. I foolishly bought the 2 seperate tools when I needed the 1 big c-clamp one.


Studs:
I'm thrilled! Every single dad-blame nut came off without incident. Hoping someone can tell me what is here, they are not magnetic, they are black and slimmer in the middle than the threads.


I continue to hypothesize that this engine was rebuilt some time before it sat for at least a few years. I have no basis for judgement of the quality of the rebuild, what was done, what wasn't. I highly doubt this is a stock, original '78 3.0.

I still have a way to go, I plan to at least get all the way inside to find out if there is a bearing messed up causing that knock. (I will be at a loss if I find nothing amiss as I have so far)

Thoughts, opinions, tips, hold on moron what are you doing??(s)

Thanks, Travis

[timmy2]

Looks like you are really digging in.
Here are some answers, personal opinions and questions for you:

Here is a link to the chain tensioner collars you have. :Pelican Parts - Product Information: 99-0458-053-M230

Is there any lateral play in your rockers on the shaft when they are not on the valve(loose) ie: can you rock them at all from left to right?
I'm wondering if the rockers weren't rebuilt or were mixed up when assembled.
If they aren't worn with the cam they will be noisy.

Measure the thickness and if more than 50% worn, replace the clutch and have the flyweel resurfaced so you don't have to go back in there in a year....

Head studs look like the Canyon ones but if not magnetic at all then perhaps the updated Dilivar.
Pelican Parts - Product Information: 10-0115-101-M105
Pelican Parts - Product Information: 993-101-170-53-M260

I bought this spring compressor for my OHC Toyota, I'm sure it would work for you.
Heavy Duty Motorcycle & Car Valve Spring Compressor Kit SET | eBay

[sobamaflyer]

Thanks Dennis,

I agree, the studs do look like the Canyon ones. I had come across the collars last week after asking, and also read about them in the book while re-reading that section. I'm afraid a tensioner upgrade is not in the cards at the moment so I hope they are ok for a while.

Given how close some of the little rivets are to the surface I have to believe that clutch disc is almost gone but I haven't measured it to truly compare. It's going to be on the shopping list.

[sobamaflyer]

I really thought I'd find something significant at this point......

Trying to capture the amount of play I found on the rods. This is indicative of all 8, I can wiggle them side to side less than a mm.



(pardon my shop helper in the background)

Pistons:
All look exactly the same, all rings visually appear clean, solid, ok. Surfacing is clean, mar free.















Dennis, I tested my rocker arms for play, when off the cam I can wiggle them maybe 0.25mm back and forth (all of them)

So where do I stand? Do I keep going since I'm this far? Do I finish taking it apart the case? Shouldn't a failed bearing have presented itself at this point? Or maybe that was never the cause of my disturbing knocking (and if not what was?)

Hoping someone will tell me check this or that or notice anything good or bad in my photos. I'm in too far to just put this back together without ensuring (to some measure) that I will get some significant mileage out of her before doing this again, but I also don't want to waste $ if it is fine.

[timmy2]

Without being there to inspect, feel, mic and measure it's hard to say!
I'm thinking you should proceed with the valve train disassembly. Most of your noise in your first post seemed valve related.
See how tight the rockers fit to the shafts once removed, (don't mix them up) check/Measure the bore of the arm, inspect the wear on the rockers, the shafts and the camshafts. Any pitting or heavy wear?
Then once you have your compression tool check the valve springs, seats, seals etc.
Did you measure your rocker arm clearances on disassembly?

[sobamaflyer]

The heads at the moment are still fully assembled. I may have misunderstood what you suggested? I merely managed to wiggle some back and forth and could wiggle others similarly if I rotated the camshaft.

The camshaft itself is not pitted or scored at all, polished and shiny.

sent from my Galaxy S III

[porsche930dude]

you should be able to identify excessive rod play by just push and pull. you cant tell much from rocking them back and forth. atleast thats been my experience from rebuilding vw and briggs engines

[timmy2]

Originally Posted by sobamaflyer

The heads at the moment are still fully assembled. I may have misunderstood what you suggested? I merely managed to wiggle some back and forth and could wiggle others similarly if I rotated the camshaft.

The camshaft itself is not pitted or scored at all, polished and shiny.

sent from my Galaxy S III

I was referring to play on the rocker shafts. if they aren't at a close tolerance on the shaft they can wander, bounce and rattle.
Try a torque wrench on the rocker shaft nuts set at 8 ft lbs and see if they are tight.
Should be tighter according to most builders. Around double that amount on an old engine.
I'm just looking for a source for the noise.

My camshafts looked great when assembled.... replaced both due to pitting on 3 lobe tips.



My workbench last fall: