Help with 3.2 engine diagnosis

[Klax]

I'm looking for thoughts from you all on my engine photos and extent of needed rebuilding. Car is US model 1987 Carrera with 120k miles. I've owned it for 17 years and put on 45k of the miles, mostly a weekend cruiser, no track unfortunately. This is my first time taking the engine out and probably only the second time its been out in its life. I've been using RotellaT 15-40 for the last 10 years changed every 3-4k miles, and used synthetic 0-40, 5-40 before that. 10k miles since last valve lash adjustment and plug change.

I appear to have all the leaks which was the reason for finally pulling the engine: breather cover, thermostat, right side chain box, left side cam housing, return tubes, maybe a few rocker shafts, behind the pulley, and this mess in the fist pic which is new.



I wasn't planning on a full top end rebuild, just a reseal with new gaskets, but after stripping the engine down and looking at the ports, and looking at what is leaking, maybe its time to have the heads done since so much is going to be disassembled and the thing is filthy.

My primary question relates to the exhaust ports, there is a wide variance in appearance. #4 & #5 are pure white, #2 & #3 have build up, and #1 & #6 are in between. Is this a symptom of bad valve guides, bad valve adjustment, fuel injector problem?






The intakes all look like this pic.



And here are the plugs.




Thanks for any tips and insights!

[Trackrash]

I'm no expert on these motors, but a couple of things I do know.

Probably a good time to get the injectors tested. That may be causing some lean fuel on some of the cylinders.

Carefully check the lower head studs. You may want to consider just replacing them with steel to prevent future head aches.

And these motors will tend to have worn valve guides, so a valve job should be considered.

After that it is a slippery slope.

Do you have Wayne's book?

[Jeff Alton]

How is your oil consumption?

Are the exhaust ports that are dark dry and just black with carbon?

Guides are a known problem, but your plugs don't seem to show excessive oil getting past the guides, again, reference your oil consumption.

Thankfully, you are not using 0/40 or 5/40 any more...

The oil leak in your pic look associated with that oil line/pressure sensor. A leaking chain box or cover will not put oil up in that area.

Update us with what you find.

[Klax]

Thanks for the feedback thus far.

Yes, I have all Wayne's books. My headstuds are all there and intact although I haven't put more than wristful of torque on them to test.

The black coated exhaust ports are all dry to the touch. On #2, in the photo you might be able to see some glossy sections and while that is dry to the touch, I just picked at it with a tool and it is soft and scrapes off easily. Perhaps oil washing out the accumulated carbon? but not a lot of oil just a light coat.

I haven't been closely monitoring the oil consumption mainly because I do know that I am not 4 quarts low from one oil change to the next (3-4k miles). I generally fill it to the top mark on the dipstick, and my dash gauge works, and I think I go though about .5 to 1 inch on the dipstick in between changes. I wasn't even thinking rebuild until I got the engine out and saw all the leaks and started reading the books on how to repair and it seems I'm going to be pretty far in. I didn't mention that I sheared off 4 of the tin mounting bolts on the left side cam tower, so I think it would be best if that comes off and goes to machine shop, and yes the main leak is the pressure sensor but I see moisture on the lower back side of the right chain housing where it meets the case.

Thanks

[911pcars]

Sounds like you want to have an excuse to rebuild it. If so, and you have the budget, go for it. How's the compression and/or leak down test? That's a definitive sign it's time to think about rebuilding. I'd wait til then. As Mr. Alton pointed out, the plugs don't seem to indicate excessive oil in the chamber.

Your oil consumption sounds better than good, and external oil leaks don't necessarily indicate impending engine failure, just a normal occurrence on air cooled engines that rely on oil for lube and cooling. Suggest you degrease the top of the engine, then run it briefly to help ID the source of the oil spray. Then fix that. Go from there.

Sherwood

[Walt Fricke]

I've not seen the pressure sensor being a source of leakage. At least not like the idiot light sender at the other end of the engine. I assume the fittings on the cam oil line are reasonably tight? But not so tight that the hollow bolt which goes through the pressure sensor mounting block into the case has been cracked? Because it is hollow, you can't twist it as tight as you could a regular bolt. Easy to see -- just remove it and inspect. When detaching/attaching the oil line fitting, counter holding with a second wrench is in order.

Another possible source is the rubber hose connecting the two steel tubes. Over time these can leak at the crimp fitting. You could remove it and fashion a way of pressure testing it.

With the intake valve cover off, easy to see how messy it is at the ends of the rocker shafts - and if all the shafts are where they should be.

Twisting off any of the 6mm short bolts which hold the tin on is a new one for me - how could those get so corroded in place that loosening them would exceed their twist limit?

Condolences.

You can do rough checks of valve guides with the valve covers off - with each valve closed, and also just a bit opened, push sideways against the top of the valve stem. If you have some worn guides, you should be able to compare how much or little compared with the force you are using on a screw driver or the like each one moves.

Leakdowns are very useful, but they won't tell you if the guides are worn, just if the valves aren't seating or the rings are shot. Looks like those who commented think you may be lucky in this regard.

[KTL]

I agree that it doesn't appear you've got guide issues right now. The white exhaust ports are not uncommon on the 3.2 engines. I've seen them on quite a few of our local guys' engines. However I can appreciate your cause for concern when you see black, coked ports on the other side of the engine. The black ports are not uncommon either and are more typical of what you'd see on other air cooled engines.

Looks like you had just one exhaust stud back out? Usually us DIY'ers aren't patient or experienced enough to heat the nuts SUPER hot to avoid breaking a stud, even if we do use a good dose of penetrating lube.

Agreed with the guys that your spark plugs don't show anything alarming. #2, #3 and #6 are showing a tiny bit of potential for fouling, with #3 being the worst. But nothing concerning. You know you have a serious guide issue when you see a spark plug like this one below or sometimes you can see a port with a small pool of oil in it. The pictures below were from cylinder #6 of a 3.2 with 78K miles on it. #6 also had a broken lower stud







So it's up to you if you feel like you need to address the heads. The dark ports are showing a bit of coking but no big deal. If you don't have a noisy valvetrain (valve guides AND rocker arm bushings cause this) then you could leave things alone and just keep on driving. Oil consumption is the way you've got to analyze this. I will also say, DO NOT APPLY ANY SIGNIFICANT TIGHTENING TORQUE TO THE HEAD NUTS. Leave those alone. Any lower studs that are a problem will show themselves all by themselves. You don't need to help them break. Nothing wrong with putting a 10mm bit socket in there to check them for severe looseness by applying a LIGHT amount of tightening torque. I highly doubt you'll find any loose ones.

Nothing looks glaringly bad right now. Just some external leakage that can be fixed with numerous gaskets, seal, o-rings. I would replace the cam housing oil supply lines because I bet the pictures showing the oil on top of the chain box is leaking from the crimp collars around the rubber hose like Walt mentioned. If those oil lines are original, that hose is at least 33 years old.

Yeah unfortunately with an engine that's seen some weathering and rust, not uncommon to have the lower sheetmetal screws shear off in the cam housing. I've got a couple housings on my bench with broken screws in those holes.

Take the opportunity to clean things up really well since you have the engine out. Replace the typical gasketing and seals and o-rings. Get a look inside the chain boxes as long as you have the engine out. Look closely at your cams for any pits around the lobes. Check your clutch (do you have the updated cross shaft assembly) for wear and transmission for any leaks- the input shaft seal and drive flange seals are usual suspects. Put it back in and keep on enjoying it. Run a can of Berryman B12 Chemtool through the fuel system to clean out those exhaust ports. That stuff is VERY good at removing carbon build up.

Once you open these things up, even just a "top end," the while-you're-in-there things start to happen. Head studs, valves, timing chains, reconditioning rocker arms, rocker arm shafts (maybe) & RSR shaft seals (good insurance against leaking following disturbing the rocker shafts), can you re-ring the pistons, do I open the engine case,........... it gets silly in a hurry. If you can, do the frugal thing and just fix the leaks, put it all back together and drive.

All the stuff that people share on these forums tends to make others think we must tear into these engines and replace a lot of things. I tend to think most people that own these cars have a bit of money to spare. So they figure "might as well since I have it apart" when in fact a lot of things can be left as is for a LOT more miles.

Keep us posted with other things you encounter. We'll gladly burden you with more things to think about..........

[911pcars]

Walt writes:
“Twisting off any of the 6mm short bolts which hold the tin on is a new one for me - how could those get so corroded in place that loosening them would exceed their twist limit?”

Possible when initially overtorqued, coupled with unlubed threads and years of corrosion between dissimilar materials. To be proactive, treat the threaded joint with a spritz of Kroil or equivalent before attempting breakage.

S

[Discseven]

Originally Posted by Klax

Kev, I didn't get beyond this pic, nor did I read all posts prior mine so pardon if this is redundant. Those pressure senders can be significant leakers from the hidden seam---seam where top of sender unit is crimped around bottom of unit. Solution I tested was to remove old pressure sender... get new sender and gel epoxy that seam entirely on new unit, install and monitor it. No more leaking.

Looking at pic there's more oil to right than I'd think would migrate from pressure sender (to right side.) Am thinking this right hand oil is possibly weeping from joints between flexible hose and hard line. A fine touch that can eliminate weeping here is to align the hard ends at both sides of the flexible hose so they point directly to each other. This means slightly---carefully---bending the hard ends. Purpose is to eliminate any stress between the flexible hose and hard ends.

[Klax]

Thanks for all the replies and tips, much appreciated! I feel like I’ve won the engine lottery given the fairly healthy guides, and I have 11 fin cylinders which I believe means Nikasil. Looks like there is a place locally that can clean and flow test injectors so i’ll Do that, and i’ve got the new cam oil lines and pressure sensor already.

I bought a leak down tester so I’ll adjust the valves and do that test. Question on that, I’ve dumped pretty much all the oil out having it upside down with breather cover off and thermostat out. Do you think that will influence results?

The tin bolts that sheared off were all right above the cat, the 2 on the backside that attach where the end of the camshaft ends and 2 around the corner on the side. I’ll try drilling out at least 2 of them.

Would anyone recommend removing and replacing all the exhaust studs? I have a mapp torch and a stud puller. The bore for the one stud that came out is pretty clean.

Looks like I can fix a couple leaks, monitor the oil consumption, and drive it.

[Walt Fricke]

I'd leave the studs, but be sure to apply anti-seize to them when you get to putting the exhaust back on. The usual problem is breaking one or more studs off when removing the header, and you didn't have that happen. Sure, you can try pulling and replacing all of them. You can get stainless studs. But you risk breaking one or more doing that.

The camshaft end has three threaded holes, but only two are used for the tin? You could just drill another hole in the tin - one fastener is enough.

If you can't drill out the stubs on the side (and just maybe a reverse twist drill would back them out?), you could perhaps use a very small hole saw - one with about a 6mm ID - and drill the rear one out, then drill to the right size for a tap for an 6mm Helicoil or the like, and insert that?

I would not try that at the cam end - less meat there.

But if you have good bits (cobalt might be a good idea), the Dremel type tools to make the broken part concave to get a bit started in the center, or if a punch works, and a steady hand since you aren't going to be able to get the whole engine up on a drill press at the right angle, maybe you will be able to get all these broken bits out. And damaged threads can be repaired with Helicoil or other inserts.

[KTL]

I agree with Walt that you are usually better off leaving the exhaust studs alone. Clean up the threads with a wire brush and some penetrating lube. Then use antiseize on the threads for reassembly. When you reinstall the exhaust, use all new nuts and don't overtighten.

However, if your exhaust studs are looking really bad? You would be wise to replace them. But it's easier said than done. Some of the studs will probably break trying to twist them out. A really good tool that someone on the forum would probably let you borrow is this one

https://www.stomskiracing.com/products/exhaust-head-stud-repair-kit

This trick tool originated here on the forums with the wisdom of John Walker, Tim Hancock and A Quiet Boom and then others like Stomski produced it for purchase. The method of using a locating disc in the port works SO well. I have a friend who's a long time pro mechanic and he bought one of the tool sets from A Quiet Boom. He said it works perfectly. Drill the broken (or cut off) stud with the bit and then pull out the remnants in the threads with a pick tool.

Does anyone sell a fixture for drilling broken exhaust studs

[Walt Fricke]

One of the benefits of a complete teardown is the fact that, if you end up with intractable broken studs or bolt ends, you can take the part to a shop which has an EDM machine. When they are done, your broken part is gone, and the threads are good as new. This is especially helpful if the broken part is of a harder metal than the usual 8.8 grade.

[boyt911sc]

Kevin,

If the exhaust studs are still in good condition, leave them alone and replace only those that are really bad. Some of the old exhaust studs come off easily or they simply break upon removal. Do not attempt to replace these old and exhaust studs if you don’t have the exhaust jig kit because you will regret it later. Using the exhaust jig makes you drill out the old broken exhaust studs conveniently and precisely. If they come off easily like the one in your picture, then you simply install a replacement exhaust stud.

Most of the time, the old and rusted exhaust studs will just snap or break during removal. So having an exhaust stud jig handy will make this work more manageable and fun.

Tony

[Klax]

I went around all the cylinders a couple times and found significant leak down on #2 and #3 which are the cylinders with the most buildup. 4, 5, and 6 were all consistently good. I think i’ve found the culprit on #2-

[Trackrash]

Are you saying it was leaking from the rings?

[Klax]

That photo is the #2 exhaust valve. A real small crack in the foreground and it’s hard to see but a much larger crack/hole on the back right. I’ll try to get a better pic, but i’m Assuming this is a burned valve based on other photos i’ve Seen on here of burnt valves. I have a little video cam that I can get a view of the interior of the valve and cylinder.

Here is a different pic.