1977 911s engine rebuild?

[petercli]

Hi ,

I have a 1977 911s with a magnesium engine.

It is approaching 100k miles.

Any links on how I can prepare for the rebuild?
And how to know when I need to do a rebuild ?

( I am not a mechanic, but I want to get educated on what to expect)

Thanks,PEter

[Trackrash]

Here is your homework.
Report back and then spend some time in this forum. It's all been answered numerous times before.

[boyt911sc]

Originally Posted by petercli

Hi ,

I have a 1977 911s with a magnesium engine.

It is approaching 100k miles.

Any links on how I can prepare for the rebuild?
And how to know when I need to do a rebuild ?

( I am not a mechanic, but I want to get educated on what to expect)

Thanks,PEter

Peter,

Welcome to the forum. It is a common practice or protocol for new member to post a picture of his/her car. That is almost a tradition. This is the first time I see a first post and seeking rebuilding advise. Time has really changed that quick. Good luck.

Tony

[E Sully]

You would probably only want to do a top end rebuild. Once unbolted, case work to true up magnesium is a bit expensive.

[petercli]

this is my car (Not original paint)



How will I know that I need a rebuild ?

Peter

[spyerx]

Leaks bad or worse than you can tolerate
Makes weird noises
Runs poorly
Smokes a lot
Low compression
High leakdown numbers
Consumes a lot of oil

[Walt Fricke]

Broken exhaust head stud or studs, which reveal themselves in a variety of ways, but definitively when you remove the exhaust valve covers (as part of checking/resetting valve lash, for instance).

[Trackrash]

Walt, it's a mag case '77. The head studs won't break, but could pull from the case.
So when doing a valve adjust you may, if brave, check the tightness of the head nuts. Take a long allen wrench and just using hand torque see if any are loose.

Porsche says if it uses more than a quart of oil every 700 miles or so, that is probably a sign that your rings are gone.

Smoking after warmed up and being driven? Failed smog test? High mileage? Low oil pressure?

You could do a compression or a leakdown test.

BTW, I just got all this info from chapter 1 in Wayne's How to Rebuild and Modify Porsche 911 Engines.

[boyt911sc]

Originally Posted by petercli

this is my car (Not original paint)



How will I know that I need a rebuild ?

Peter

Peter,

Sorry. I was just kidding you about the 1st post. You got a nice looking ‘77. While it has some known mechanical problem/s, they could be corrected. And once corrected, people swear to love them to death. The cylinder head studs have to be checked and addressed to give you a better understanding of the engine condition.

Take it one day at a time and enjoy driving the car. My only suggestion to you at this time is to find someone who has a similar car like yours and share their experiences. There are hundreds of this car with happy owners in this community. Welcome to 911.

Tony

[Saadi996tt]

Hi Peter,

Welcome to pelican; I also have a 77s and am slowly repairing issues with a fuel leak/oil leak. There is a wealth of information on the forum and everyone is glad to help us new guys. I also was fortunate to attend Tony’s (boyt911sc) engine rebuilding class in 2018 and it helped get rid of the fear of tearing into the project.

Thanks,
Saadi


Sent from my iPhone using Tapatalk

[Richey]

Is it a California car with thermal reactors ? Hopefully not , but can't answer your questions without this info .

[Eagledriver]

Originally Posted by Trackrash

Walt, it's a mag case '77. The head studs won't break, but could pull from the case.
So when doing a valve adjust you may, if brave, check the tightness of the head nuts. Take a long allen wrench and just using hand torque see if any are loose.
.

I think the 77 is the first year of Dilivar studs. Walt is right about looking for broken studs. Good news is the studs may have prevented the threads from pulling.

-Andy

[E Sully]

Car looks very nice. How does the car run now? Does it start and run smoothly. I would pull the spark plugs and see if they are clean at the very least.
Any history from the previous owner regarding maintenance or repairs? Any idea on last basic tune up, plugs wires, distributor lube, cap, rotor, points, filters, valve adjustment, fuel line replacement to deal with alcohol in current gasoline? Has the clutch ever been changed.
Suspension should be checked also for worn rubber bushings, front wheel bearings greased.

[Trackrash]

Originally Posted by Eagledriver

I think the 77 is the first year of Dilivar studs. Walt is right about looking for broken studs. Good news is the studs may have prevented the threads from pulling.

-Andy

Maybe so. According to Bruce Anderson, it was a mid year upgrade.

[petercli]

Thanks for the info (I only understand 10% of what you say)

Saadi, can you PLEASE provide details about Tony’s (boyt911sc) engine rebuilding class !!!

Ed, I did replace the linkages initially($). I live in Wa. state, so emission test is not a Legal issue so far. But I feed bad for the environment when it smokes during start.


Gorden, I will ask my mechanic if I have Dilivar studs. It smokes when I start it and seems to clear up after it warms up. My mechanic said oil pools at the bottom because it is a flat v6..

Last week my mechanic replaced heat exchanger set, muffler etc ($) but I observe backfire at low rpm so I will take it back and ask about that issue....

another ailment is having to turn the ignition key awhile to start. they replaced the 'thermo time switch' - what else could it be?

Yesterday I reached 100,000 miles !
regards to all,
Peter

[unclebilly]

It’s probably fine. Drive it

[Walt Fricke]

Peter
Fairly shortly after I had the heads of my 2.7 rebuilt (due to missing a shift and bending valves), the head of a valve fell off, blowing up the motor. I don't think any mistake I might have made in putting these professionally rebuilt heads back on caused this.

I bought a used 2.7. Leakdowns were in the 10-12% range. A disinterested shop owner suggested that if the head studs held torque, I just run the motor and periodically check things. That worked fine for a year, but the track bug had bitten me and the performance, as measured in lap times, seemed not to be quite there. I bought a used 3.0 as a replacement.

The guy I sold the 2.7 to, who put it in a track 914, said it ran fine for him.

So I think the approach is not to take too much counsel of your fears. You now know some things you can look for. Measure and check. After a year or so, measure and check again. Have the leakdowns changed for the worse? How much? Is one cylinder now much worse than the others? Are the head studs still holding torque? How is the oil miles per quart doing? What about miles per gallon on some kind of comparable driving?

If this is a daily driver, or a weekend cruiser, you might think of resisting the urge to rebuild unless you just (as some of us do) like doing that kind of thing. And keep reading - and using the search function - on Pelican. The suspension uses rubber bushings. As these age, they can change shape. The torsion bars can start rubbing on metal housings. This can make noise. At some point, the wear might become a "stress riser," which is where a crack in metal can start.

Rear wheel bearings don't last forever. The sign of failure tends to be noise when turning one way, but not the other. This is also true about the CV joints, which also don't last forever. The good news is that typically neither of these actually fail, leaving you stranded, until they have made noise you can't miss for quite a while.

Or you can spend vast amounts of money pretty much disassembling the engine, transmission, and suspension, and replacing all sorts of parts which wear, whether they are at a sensible limit or not. You now have basically a new 40+ year old car. Having cost you more than buying one 30 or so years newer?

Some issues are an inflection point - finding that broken head stud for instance. You can drive for a while that way (certainly to get the car to a shop, if you don't do rebuilds yourself), but long term not good. Or suspension noises. Or worn transmission synchros - you can learn to double clutch and drive a long way that way without making things worse, but a rebuild is in order when it is convenient. Others you can live with a long time, like minor oil leaks.

Which is a wordy way of saying you could do worse than to follow Uncle Billy's advice.

[Trackrash]

Originally Posted by petercli

Thanks for the info (I only understand 10% of what you say)

Gorden, I will ask my mechanic if I have Dilivar studs. It smokes when I start it and seems to clear up after it warms up. My mechanic said oil pools at the bottom because it is a flat v6..

Yesterday I reached 100,000 miles !
regards to all,
Peter

Smoking on start up just happens sometimes. Especially if you park up hill and your oil tank is full. I have blown some big clouds occasionally when starting up.

As long as it clears up in a minute or so, no problem. My old motor did that for years, decades?, and never was an issue, except at times embarrassing.

As long as you aren't smoking obviously when warmed up, you are OK.

One key thing to watch out for is oil consumption. If you are using a quart every 600 miles or less, then probably time to at least do a top end. They all use oil. A quart every 1000 miles is fairly normal.