rocker shaft

[gigem75]

First post, recently acquired:
70 911T 125k miles, oil pressure not the best when hot but around 45 lbs at 3 grand (when hot).

Has anyone ever had a rocker arm shaft drop out of the head? I thought I had dropped a valve but the shaft just slipped out. No real damage.

I went ahead and dropped the engine/gearbox and am in the process of reconditioning. So far no appreciable wear on moving parts that I have gotten to so far.

One tensioner was really hard to compress to put retainer pin in, the other was what I would consider a firm amount of force in vise to compress (with protection of course).

As far as I can tell the motor has never been apart except for a new clutch around 10 years ago.

[nabilious]

I have heard of that before but forget the fix and all the other stuff your itching to know....I'm curious too so enjoy the bump. How did the pinch bolt look? what about the shaft bore? oblong or wider at the ends?
my right side chain broke....im in a world of hurt.
Nabil

[gigem75]

Thanks for responding. The 5mm was loose, no visible diff between all the others. I have yet to mic it or the bore.
One good thing (which I would have not known but for the info here) is the tensioners have been up graded.
The motor was tight, had great snap, I was more concerned with the oil pressure when hot.
I see oil pumps are quite expensive, is there a rebuild on them? In my mind there is no sense on putting new bearings in an engine with a worn pump.

I plan on doing as much as I can by myself. Kid is grown and it keeps me out of bars. This is my first Porsche, had Alfas in college (Gulietta spider veloce, that's where I learnded about Webbers and a couple of GTV's later on) and have a fair amount of experience rebuilding them. I'd say they didn't leak any oil afterwards but I doubt anyone would believe me

[nabilious]

Well I'm in the midst of my first full rebuild as well. The oil pumps that you could put in there would be an upgrade and at a good price. Grab a 2.7L pump and it'll cost you a couple hundred$$'s. The low oild pressure after it hot is probably due to worn main bearings ect. I'm glad your use to leaking oil....you (like me) will probably get reaquinted with it once your back up and running!
Cheers and good luck.
Nabil

[911 tweaks]

I hope that table saw can take the weight of engine ~350#'s + trans/clutch~150#'s = 5-600#'s??

Be careful there and best of luck!

Bob

[gigem75]

Thanks, for the tip on the oil pump solution. I'm keeping the hoists on it until I get my tripple square bit set in so I can release the throwout bearing fork and get the transaxle off the block.
Good luck with yours!

[AZ911E]

I had the same shocking moment years ago after my first '71E 2.2 rebuild. A few redline exposures will allow those rocker shafts to drift off center. Surprisingly, they'll slide right back in, and you do your best to tighten the fasteners. I'm sure out trusty moderator can guide you toward a past forum string.....

I'm also a new forum user, and you'll find tons of help here. Good luck. The table saw is a very nice touch.

[robmog]

do not use the table saw to remove the transmission, it unbolts!
i tried using the saw and broke several blades before i found this website.
good luck with your rebuild.
bob

[Eagledriver]

You need to read the books to help you with these things. The oil pump from a 76 or later 911 will be an upgrade for you but the case needs a modified oil pressure relief circuit. 45PSI at 3k is fine. The rocker shafts sometimes creep out of position. You just need to realign them and tighten the pinch bolt more. There is a specific position for these and it is not with an even amount of space on both ends.

-Andy

[gigem75]

Thanks for the input. I have ordered the "book". I chipped several teeth on several blades before I figured out the saw would not work.

So if 45 psi is fine should I even replace the oil pump?, what is "new" oil pressure at 3k? When the engine idles the dang needle of the guage is just barely off zero and that scares me. I would think that around 20 psi at idle would be normal?

[911 tweaks]

per Bruce Anderson, he knows a few things, ;-) , 1 bar per 1,000 rpm's.
So if idle is at 1,000 rpm's you should be around 1 bar. = 10 psi.
For your mileage, I would guess that you are ok. I am not an expert though. Just well read on this board.

If no smoke blowing, plugs are not fowling, basically no major driveability issues, you are driving a 130,000 mile car that is 30 yrs old!! What do you want?? It is not a twin turbo!

I would suggest that you determine what you want the car to do and go from there... post that on this board. MANY HAVE BEEN THERE AND CAN ADVISE APPROPRIATLY.
***CAUTION: to take a perfectly running Porsche AND to try and make it do more than it was originally designed to... or to make it as new... or such will cost you $5,000 for openers to split & then reseal the case, replace crank main bearing, clean/measure check all internals and replace what is at or near wear limit, ...(main reason why low oil pressure - probably worn crank bearings) and a couple of other item!!!!!!

Chew on that for a while. Be warned that the "while you are in there" syndrome will hit you to some degree... seems to be a greater amount will be spent on the "while you are in there, the more you surf here on or Rennlist.

I would drive it as is AND ENJOY IT!! If it is not about to grenade itself, enjoy. There are ENDLESS ways and places to spend $$ on Porsche... IN ADDITION TO LIFE, a nice diner with a bunch of buddies, or a chic, ... !!!

ENJOY AND BEST OF LUCK WITH WHAT EVER ARE YOUR DECISIONS ARE!!!

Bob

[hcoles]

small comment... 1 bar = 14.5 psi approximately

[gigem75]

at sea level

[hcoles]

I think 1 bar = 1 bar at any altitude ;-)

[gigem75]

and 14.5 psi is 14.5 psi at sea level and 35,000 ft!