3.0 tear down finally complete!!!

Groovy911SC · 01-28-2004, 08:43 PM

Well gentleman, I've completed the tear down of my 1980 911 3.0 engine. The reason for my tear down is attributed to a slight grinding noise I heard while participating in a DE in September. I've posted here before, asking questions that would help in diagnosing the engine's problem. I have had genuine responses from the very experienced to novices, like myself. All have been extremely helpful!!
Tonight, I cracked the case open to reveal the problem of my engine. In Wayne's book he says when you open the case, this is where you go "ooooh.... ahhhhhh....." Well, I did... I was so excited to get to this point! I knew, one look inside the case and after marveling at the craftsmanship, the engine problem would jump out at me! Well...it didn't....the problem that is....I cussed.......alot. Everything looked fine. I had fear that what I was doing was wrong. It was then I wished I was "Steve at Rennsport", or "Wayne" or "John Walkers Workshop blink blink"....then I would know what I was looking at! After starring at this fine looking assemblage of wonderfully crafted metal parts for about an hour, I decided to remove the oil pump and crankshaft. Still, all looked like it did in the pictures of Waynes book. Nothing was ripped apart. More worry. After listening to a bit of Pearl Jam (lost dogs)... I started to think.... this may not be as bad as I was making it out to be. If there were no glaring twisted bits of metal everywhere, this might be good news!
It was then I noticed the copper-colored bearing surface of the intermediate shaft. Same color of the glitter I found in the sump screen and the oil filter. I could be on to something here!
Question... Would the intermediate shaft bearings be the victim of a poor performing oil pump?? Or is there another problem like bad bearings or improper installation?
If you have read this far and still feel kind enough to offer suggestions, I would greatly appreciate any and all responses. I'll post a pic or two to define what I found. Thank you in advance!

Wayne 962 · Wayne 962's Garage

What was the problem with the engine again?

-Wayne

Groovy911SC · 01-29-2004, 04:22 AM

The engine was making a slight grinding/rattling noise. Very slight. At first I thought I lost a chain tensioner. When I removed the chain covers, I did find the left chain loose. I replaced the tensioners with the pressue fed ones and thought all was well. I decided to do as much service as I could at that point so when removing the oil sump plate to replace the gasket, I cleaned the sump screen and found tiny bits of copper colored metal. Someone here suggested I carefully cut open my oil filter and look in the folds of the filter. There was a good bit of copper glitter in the filter. It was then I stared to tear down the engine to find out exactly what had happened. There is a good bit of wear on the intermediate shaft bearings. Could this me the only problem with the engine? Or is there something else I need to investigate?

Groesbeck Hurricane · 01-29-2004, 05:16 AM

How many miles on the motor? From the photos it does not look like your bearings were turning. I am wondering if something could have blocked the lubrication ports on your motor, this is just uninformed rattling but I am curious. Can you take a can of compressed air and blow backwards into the ports to make sure they are clear? I also understand that the bearings will wear out over time. I replaced mine even though they looked good to me and measured within spec. Have not regretted it.

Just rambling, but I would think your silvery metal is the bearing material. I would have the shaft measured and make sure there are no unusual wear points. I do not know if the bearings could be what you have heard. How was your oil pressure? Did you have issues with cooling? Oh, while your in there, investigate changing the head studs! Tensioner update, and any other modifications/improvements. Now is the time to do it.

Groovy911SC · 01-29-2004, 05:42 AM

Thanks David for your help. The bearings all look good except for the intermediate shaft bearings. I intend to follow Waynes book in terms of replacing everything that I should replace.
My oil pressure leading up to this was good. The oil pressue guage in the car never read too low or too high. The cooling was excellent. I ran the car in Louisiana during this past summer and never had problems cooling. The engine has around 156,000 miles on it.
I will send all parts to Memphis to be cleaned, measured and machined. There is a shop up there with a fine reputation for doing quality work.
I was really hoping the problem (copper metal particles in the engine) would be very easy to see where the issue started. I will take your advice and blow out the oil passages. Thanks again!

Groovy911SC · 01-29-2004, 05:45 AM

Head Studs, none were loose at all!!! The lower were the dilivar. Should I replace all with the stock steel studs? Raceware and ARP seem overkill to me for a stock rebuild. However, if the opinion is to upgrade....I will do as the Romans do!

jgparker · jgparker's Garage

My last set of intermediate shaft bearings looked just like that. My symptom was the oil pressure would dip when I went from WOT to engine breaking at high RPM. I believe this was due to the slop in the bearing, and the shaft coming off the oil journal on deceleration. Make sure you measure the bearing surfaces on your intermediate shaft carefully to see if they are reusable.

Good luck,

JP

Groesbeck Hurricane · 01-29-2004, 09:44 AM

I would replace the headstuds as a preventative measure. It is cheap insurance. I used the steel ones on upper and lower. My car is used on the streets and I do zero eventing. I agree, Raceware and ARP seem like overkill for my application.

Groovy911SC · 01-29-2004, 10:29 AM

Here is a picture of what happened. After reading jgparkers post about intermediate bearing slop, thank you by the way!, I went back home and looked at this area again. Last night I was looking for a spun bearing. Today, looking more closely, I discovered the teeth of the large gear on the intermediate shaft had been chewed on. That accounts for the slight grinding noise! The picture is not that good. My el cheapo camera does not focus well upclose.Why or how does this happen? Age of the parts, driving style?

Tim Walsh · Tim Walsh's Garage

Those steel teeth look quite shiney as well.. have they been chewed on (socket depth off?)

ChrisBennet · ChrisBennet's Garage

The gear on the last 3.0 I worked on had that same look - "gear worm."

-Chris

Superman · 01-31-2004, 07:45 AM

The bearing wear you describe is very very normal. The gear issue needs to be resolved, and measuring everything while you have it apart is good advice. Measure crank bearing journals. Perhaps have the rods reconditioned. Replace the wrist pin bushings. Now is a good time for new valves, guides and seals. Remove an exhaust valve and measure the stem, and the play in its guide, and I think you'll find the valve stems are out of spec.

Groovy911SC · 01-31-2004, 04:13 PM

Thanks Superman,

I've discovered yet another issue. The journal bearing has disintegrated on the #4 connecting rod. It is the further most point from the oil pump. I am suspectecting a bad oil pump and perhaps clogged oil passages. I can only assume this means having to do some sort of repair to the crank. I will post a picture of the bearing. If anyone has seen this before, please let me know and what to expect for the repair...

rcwaldo · 02-02-2004, 08:00 PM

That rod bearing looks to be a source of your rattling. I had the same type of noise in a 2.7. Turned out to be #4 rod bearing was coming apart. Looked to be caused from detonation.

was the worst half of the bearing in the upper (main) part of the rod or the cap?

Groovy911SC · 02-03-2004, 05:14 AM

The worst part was the upper (main) part of the bearing. I didn't post this but the #3 journal bearing is worn almost as bad but not quite as much. It seems odd to me that the "ends" wore so much more than the bearings in between. The bearings in between seem to be in good condition.
I'm sending the crank to be inspected. I hope it not damaged beyond repair.

Groovy911SC · 02-03-2004, 05:16 AM

Guess I need to understand detonation so as to not re-build my motor with the same problems as I had initially.

Wayne 962 · Wayne 962's Garage

Shoot - that looks bad. Hopefully you won't have to grind your crank...

-Wayne

rcwaldo · 02-03-2004, 12:28 PM

Quote:

Originally posted by Groovy911SC
The worst part was the upper (main) part of the bearing. I didn't post this but the #3 journal bearing is worn almost as bad but not quite as much. It seems odd to me that the "ends" wore so much more than the bearings in between. The bearings in between seem to be in good condition.
I'm sending the crank to be inspected. I hope it not damaged beyond repair.

Since it was the 'upper' bearing, this has been noted to be caused by detonatioin inducing shockloads down the beam of the rod into the softest part of the assy., the bearing. Sometimes the get beaten' enough to fall apart and eventually spin..

Like Wayne said, hopefully your crank is still good. Avoid machining the crank as you will have to have it rehardened..

Chris