I need some advice (kinda long)

01-22-2002, 04:34 PM

I hope this is the right place to get it.
I'm faced with a set of unknowns and am not at all sure how to evaluate my options.
I bought a '77 911S last summer and didn't do my homework - water under the bridge at this point. The body is in excellent shape, the interior needs a bunch of TLC. I have no history on the engine/transmission, only what I observe. The tensioners have been upgraded to hydraulic units, there's a pop-off valve, and the thermal reactors were replaced with headers. No idea at all what's under the covers.
I've had cold-start problems and gotten a lot of help here trying to track them down. Last week I decided that I wasn't going to be able to invest in the time and tools necessary to fix it and dropped the car off at a shop I trust. They're pretty certain it's the WUR, which makes a lot of sense.
Next step in the process was to be a compression test. Trouble is, the mechanic couldn't get the spark plug socket seated on a couple of plugs to remove them (I think he tried 2). When he investigated he found a headstud nut lodged against the bases of plugs two and three, blocking the socket. I replaced the plugs in October, just after getting the car, and those nuts weren't there then, so they've worked loose since (3000 miles or so).
The mechanic's advice is to drop the engine and go for a case-out rebuild (seals, valve guides, head studs, oil return tubes, upgrade valve covers, look at the clutch, etc., I don't remember if he said rings or not, but that seems likely). An alternative is to pull the heat exchangers, valve covers, and sheet metal and try to retorque the headstuds. If successful, the cost would be significantly lower (now) but I'm not at all sure what sort of problems I might be in for down the road.
I can see a couple of possible scenarios and I'm not sure what the odds are on each. Did the headstud nuts shake loose because the studs have already pulled out of crankcase? How likely is it that the case is intact? If they can be torqued to spec, what's the next likely point of failure and when. Is the rebuild inevitable? Can I buy some time with this band-aid? How likely is further damage? How bad could it be already? It is possible that the PO did the studs when the tensioners were installed, but we won't know without looking more closely than is possible at the moment.
I'm torn between (1) handing over my credit card and (2) taking a more step-wise approach. I have the skills to tackle a rebuild myself and could save a lot on the labor, I know, but time is not something I have a lot of for this particular project, unfortunately. I suppose I could try selling the car as a project for someone else to take on. That's not a happy solution, but it might be a wise one.
There it is in a (very large) nutshell. Thanks for reading this far. If you've got any help or comments to offer, I'd appreciate hearing from you.

Clark Griswald · Clark Griswald's Garage

First, grab a beer sit down and relax.

It's a big jump from loose head stud to rebuild. You need to find out what's happening.

Pull off the valve covers and have a look. You might find the studs became loose. It happens, just retorque and put it back together. Drive on. It happened to my '77 several years ago and I've been driving without incident since.

Or you may have broken studs. But it is a simple thing to open it up and find out. So put that card away, cool off and see what you've got.

This is a another good reason to keep on top of valve adjustments. I'm now in the habit of adjusting annually and while in there I check the head stud torque and valve guide wear. When you take your covers off, be sure to adjust those valves

Good luck and let us know what you find.

makaio · 01-22-2002, 04:50 PM

Ditto to what Clark said. It shouldn't take you very long to pull the valve covers and see whaqt the problem is.

Good luck!

RoninLB · 01-22-2002, 04:57 PM

My understanding is that you did not break any studs. Stud nuts should be retorqued at 10,000 - 15,000 miles along with intake nuts, IMO. You did not mention any noise comming from head. If no noise I would put the nuts back on and eye ball every thing, IMO. Avoid rebuilding till you find out what you are dealing with. I am not a pro. Full rebuild is big bucks.

Eric Coffey · 01-22-2002, 05:25 PM

Look at it this way: If the engine does in fact need a complete rebuild, and the costs are off the map, this might be your opportunity to gain some power with an engine swap for a 3.2L or 3.6L! The cost for a good used 3.2L/3.6L transplant is bound to be less expensive than a full rebuild on the 2.7L. Just something to think about.

RoninLB · 01-22-2002, 05:56 PM

I did a full rebuild in my 2.7. Bullet proof street engine. Naturally there is associated parts, heater hoses, eng paint, stainless tin fasteners, motor mounts, etc. I did all labor and assembly. I have a seperate folder for rebuild because $9,500 creates mucho paper work. That does not include the E-cams and SSI and Monty and EGT gages and _ and _ and _ and _ and _ and _ and _

01-23-2002, 02:44 AM

Thanks, everyone.
I'm feeling a little better about it all this morning. I'm leaning heavily toward re-torque the studs, valve adjustment, and wait-and-see.
Ronin, what sort of noises would have been evidence of broken studs? Only thing I've noticed is some harshness in the exhaust note when I'm really on the throttle, hard to describe.
Engine swap is a possibility also, but not a path I'm ready to follow just now. Given that all the engines have their quirks, I might be trading one set of troubles for another.
I'm keeping my fingers crossed that the PO swapped out the thermal reactors early, kept the temps down and everything is still intact, just loose from years of neglect. One possible scenario is that the car has sat for most of the last 6-8 years, not run at all.
I'd probably need a few things tightened up after that amount of dis-use too.
I'll talk further with the mechanic and see what he thinks the possible and probable outcomes are for this route.
Will keep ya'll posted

RoninLB · 01-23-2002, 05:09 AM

Dave...the noise is from the head and cyl. seal leaking. If no noise replace nut, retorque every thing, do comp test, etc. If neurotic about possible sealing leak use hose/tube[one end in your ear, one end to probe around] or stethascope[sic] to check for noise. Many 911 guys go thru this "head stud" BS. Don't worry 'bout it. After every thing is running OK buy 911 repair books, 101 Projects book, Up-fixin books, tools and more tools. It gets better all the time. You owe this board your future knowledge, don't forget that. I'll be waiting.

01-23-2002, 07:56 AM

Further discussion led to a decision to proceed slowly with fingers crossed.
Compression check, re-torque nuts with engine in car, adjust valves, replace cover gaskets, drive away.... with each step dependent on good results from previous step.
We shall see.

johnco · 01-23-2002, 08:47 AM

one thing puzzles me. How do head stud nuts get out from under the valve covers to down next to the spark plugs when they weren't there when you replaced the plugs 3000 miles ago? just curious

VenezianBlau 87 · 01-23-2002, 09:01 AM

John, glad somebody else asked that first. I'm scratching my head about that too.
----------------
Bob Sauerteig
'87 Carrera

johnco · 01-23-2002, 09:16 AM

I'd hate to think they were planted by someone trying to wrangle a rebuild job on an engine that doesn't really need one. I've known people that have done things like that

724doorE · 01-23-2002, 09:39 AM

Yea Dave, listen to these guys, be careful what you get yourself into. Your dilema is what makes a lot of us work on our own cars.

I don't have mine apart to check the proximity of things but, check the head nuts, cam box nuts and make sure if the head nut/stud is out of place that it is not a pulled stud. Even if it is and your engine shows good condition otherwise, you should be able to install timecerts in the case and put the top end back on. It will be a LOT cheaper if you do it yourself. But if your not comfortable with that then procede carefully!

So I vote for the DON'T DO THE COMPLETE OVERHAUL, at least not just yet!

Good LUCK,

Dennis H.
72 911E
other junk
69 spitfire "Lucas, the prince of darkness"

01-23-2002, 09:40 AM

Maybe I misunderstood where the nuts came from.
They look like little cylinders, ~3/8" diameter x ~1/2" long, internal thread at one end, hex socket at the other. Sound familiar?

I, too, would hate to think they're planted. I'd be very suprised if that were the case.

Superman · 01-23-2002, 10:13 AM

I'm not necessarily concluidng that they were planted, but that's where I'm leaning. I too wonder how they could migrate from their original homes to the spark plug area. This is a pretty big question and I am very skeptical about the shop you're dealing with.

At a minimum, I'd take possession of the car and in the quiet (and cold) of my garage, I'd reinstall those barrel nuts and drive the car for a while. Maybe a long while.

Tim L · 01-23-2002, 10:32 AM

I just looked at some pictures of my heads when I had them off last month, and I think thats where the nuts would end up if they were the one just above the plug.

Tim

Britwrench · 01-23-2002, 10:39 AM

I'm in the "remove the valve covers and see what's really going on, camp" If the head nuts are loose, re-torque tham all and drive the car.

If you have a broken/pulled stud thread ; on any 2.7 engine you WILL need to do a total rebuild or it will start leaking again after 2000 or so miles. This because the crankcase is warped, so timeserts do not cure the problem.
Complete rebuild with case machining is around $5k - 6k.

01-23-2002, 10:48 AM

Can someone look at (or photograph and post) the area in question on an engine on a stand?
It would help clear up a lot of potential issues.
Thanks

Tim L · 01-23-2002, 11:49 AM

picture of cam housing with head nuts

johnco · 01-23-2002, 01:15 PM

is there enough room under those low valve covers for the nut to unscrew enough to fall off and down to the plug? 911 beginner here just trying to learn before something happens to mine. I guess I'll have to move up that valve adjustment and check mine. PO records list a possible head stud problem although I can't seem to hear or see any evidence of one until the valve covers come off and I check. no noise or leaking yet. (from this area)