Did I just Grenade my Engine?

[A&F]

Well in the spirit of consistency here is the latest in my 911 ownership experience. Previously I thought I had blown up my transmission backing out of a driveway. Turns out the axle just fell off, common issue (on Porsches!!) apparently. This saga then lead into me destroying lug nuts and wheel studs because the PO/Mechanic decided that impacting aluminum lugs onto steel studs was a brilliant idea. Also highlighting the insanity off aluminum lugs on a street car was the fact there are drill marks on the wheel from someone else having busted lugs in the past.

*deep breath*

That is all squared away now. All new bolts, all new studs and all new steel lugs. I even got some Nord-Loks on the recommendation of the forum to prevent this common occurrence of… my axles falling off. (I have never heard of such a thing… insanity)

Ownership Day 193 : Dear Diary,*today*I blew up my engine… backing up to leave work.

So full disclosure, full story:

I bought the car toward the end of last year. The car the owner claimed the engine was rebuilt. I’ll spare the world names and details as I don’t care to blame anyone at this time. The car has 130k miles and the engine and trans do look minty fresh. The car is rust free but is clearly an southern car with faded paint, nicks, dings and an interior that was baked in an oven. Dash is cracked, all the seals are dried out and the leather and seat foams are toast. On the other hand the car ran great, sounded great, shifted granted, drove straight and stopped as expected.

After the first few days I noticed a lot of other stuff not mentioned that should have been. So I took the car to a local independent German specialist for a work over. They changed the oil and checked everything out. He had a list of a bunch of new issues (license plate light bulb etc), but also stated the power train was in tip-top shape, it just needed plugs and wires. Oil looked good as well.

So now I have about 1,200 miles on the car. Saturday, drove it up to Silver Beach, no problems, no noises. Sunday, changed out the spark plugs, changed out the seats for some nice 944 ones I had and life is good. Wed. I drive the 911 to work and in the morning it sounded like the valves may have been a bit noisy. So at lunch I decide to take it out and get a bite. Once again, it seemed… off.

Now I don’t have any experience with Air-Cooled 911s. The ban being as noisy as it is makes it difficult for me to *hear things. Now I’ve read several times about the “expanding” and cold-engine noises and that they should be ignored, but without any reference point I really don’t know what is “normal”. *So while out I look at the oil level gauge and it appears a bit low.

Now the car has been dripping oil. The leak is from the forward portion of the passenger valve cover (930 covers) and from the fitting that is on the hose going to the oil tank. Everything else is clean. The car does not smoke. The oil pressure gauge is also sporadic and seems to run high and constantly twitch. The shop said the sender was going out but the pressure should be good.

So knowing I’ve been dripping oil I pull into an auto store to check (engine was fully warm, running and on level ground). Sure enough it was a bit low, but not below the min-level. So I grab a quart and add it. This brings the level closer to “high” and sure enough the gauge in the car goes back to the higher spectrum. I return to work (2 miles).* All the while the car just sounded “off”, it was like it was missing or had valve chatter or something. God damn fan is so loud I can hardly tell.


Leaving work. I fire the car up, and start backing up. I then stop and go into first to proceed to leave. I rev up to 3-Grand and just as it hits 3 grand (where I’d normally shift into second), I hear this loud rattling-clapping sound. Like gear grinding you hear in movies when an idiot shifts a semi-truck wrong, that “Errrrrr arrrr reeer” or whatever.* I slam on the brakes, pull the e-brake and listen for a second (alls normal, but with that slightly off sound I’ve been talking about).


I get out immediately thinking one of those damn axles was lose. Nope. Did I leave off the oil cap? Nope. The fan belt seems to be lose.. the alternator had been charging low… so I think, maybe the fan or alternator are screwed up. So standing outside the car, and leaning back so I can kind of see into the engine bay, I stretch out with my left foot and press the throttle. (At this moment, I even though, maybe this is dumb). I blip the throttle up to 3-3.5k and “eeerrrr arrrrrr BANG… clank clank clank” and the car immediately starts running like ****. I kill the ignition instantly.*

No oil on the ground, no oil leaks. No smoke… and no oil pan to drop.


Solution Approach:


How do I inspect the engine to see if it busted a rod? Normally I’d just drop the oil pan. Could it have busted a rod? I can’t imagine it just spun a bearing as it has not been knocking. But having seen 3 guys bust rods, normally the engine ends up with a hole or a crack in it… and normally those busted engines had too much boost or over-rev.. not a 3k blip on a 200hp engine.


Two people have already suggested “timing belt”… but, uh, duh. There is none. I am beside myself with frustration and rage. The whole point of the car was the power train. Everything else I can fix at an affordable price. Looking around on the forum and “Porsche 911 Engines” book and everyone is quoting a DIY price of $4-6k. Insanity.

First things first I guess. I need to get the car towed home and drain the oil. If the engine is toast, I don’t know what I’m going to do. $6k for a 200hp engine just does not bode well with me. Then again, any justification of a higher-power transplant is then wasted on the fact the trans is made of glass and would need replacement and* down the rabbit hole we go….

[emcon5]

Chain tensioner? Do you have pressure fed tensioners?

What year is the car?

[whiz05403]

I'm no expert but sounds like a chain tensioner problem. Search YouTube and you might find the same sound.

I doubt you blew your motor, but sounds like there is work ahead.

[vesnyder]

Here's hoping that it is something simple and cheap! I can't be much help other than moral support and I want to see how this turns out. What year is it?

[brighton911]

Again, possible timing chain issue. Post your location, maybe there is someone with Porsche engine experience close by that could give you a hand. Hope it turns out to be minor.

[A&F]

Originally Posted by emcon5

Chain tensioner? Do you have pressure fed tensioners?

What year is the car?

Apologies, that info would help.

1985 3.2 911 Coupe.

~130k

[Lapkritis]

Silver Beach is in Michigan.

Could be as simple as a broken rocker/elephants foot. I would start by removing the valve covers and inspecting the rockers first... if all checks well then I would move to the timing covers. Don't bother running it again from this point of course, until you determine what the fix is.

[Gogar]

If the "most recent" change you made was changing spark plugs,

I suggest you work backwards and pull your plugs and get a look.

Did you cross-thread one, did one fall out, etc?

Also, by removing the spark plugs, you will be able to crank the engine by hand and you'll know immediately if something is horribly wrong.

another benefit is to look at the tips of your brand new spark plugs and see if there's anything horribly wrong.

Odds are it's something small. Let's hope, anyway!!

[DRACO A5OG]

Not trying to start an oil debate, so fellas, stay calm.

What brand and oil weight are you using? Did the noise sound liken to a chain rattling in a metal trash can?

[E Sully]

I would put odds on a failed tensioner. When mine failed the chain jumped a couple of teeth, and I had to have a few exhaust valves replaced, along with the valve guides, and timing chains and new pressure fed tensioners. Bottom end and pistons were still good.

[Uncle Enzo]

IDK..any time I have something blow up on the car, I can almost always contribute it to something I had just done. Trace back the steps and stay cool.

[DRACO A5OG]

3.2 came with the pressure fed tensioners.

[A&F]

Originally Posted by DRACO A5OG

Not trying to start an oil debate, so fellas, stay calm.

What brand and oil weight are you using? Did the noise sound liken to a chain rattling in a metal trash can?

The quart I added was 20-50 Valvoline VR1 oil. I figured the high-zinc is a good thing.

I just dug out the receipt from the independent euro shop.... (I save everything)

They charged me for 22 pints of Mobile 1 15w40 and a 93010776401 Oil Filter.

[arry911]

It sounds like when my camshaft went, oil spray bar got blocked so the camshaft got worn out over #6. When you turn the engine by hand as said before you will feel if its catching on anything.

[Scientifik]

No to hi-jack this thread, but I maybe having a similar issue, A&F, view my thread/video and tell me if it sounds like mine.

Engine clattering noise w/video

[Rob 930]

A&F,

Good job in shutting it down. Don't attempt to start it again. It could be something minor, but from your description, it sounds like it may be at least somewhat serious. Trying to run it will only make things worse. The goal is to get your arms around whether you have a serious internal mechanical problem (or just something on the surface that relates to how it runs).

Here's how I would get to the bottom of this quickly. First: remove the oil filter. You don't need to drain the oil to do this. Look carefully at it and at the spigot where it mounts. If you see metal flakes on the end of the filter you just removed or on the console where it mounts), you know that you have damage, likely to the bottom end. This is the worst case scenario. Even if you see no flakes, open the filter, preferably using and oil filter cutter (looks like a giant tubing cutter). Borrow one if you have to or take it to someone to open the filter. Don't use a hacksaw or any cutting tool that creates chips! Look inside for metal flakes. Pull out the accordion-like paper element and inspect. No flakes? Good. Flakes? Engine is toast. (Just kidding, but it will need a complete overhaul). Of course, you can drain the oil and look at it too. But the filter will tell you what you need to know.

If the oil filter is clean, then you may have a top end problem with the valve train. Remove all six spark plugs and look at them. Pay attention to how they feel as you unscrew them. Do they all come out with similar resistance and torque? Look at them to see if any have been contacted (say, from a piston hitting them). Then, slowly rotate the crankshaft clockwise by hand, using a 19 mm wrench on the pulley bolt. See if you can get 720 degrees of rotation easily and with no mechanical resistance. If you meet resistance, stop moving the crank; you'll know that there's something seriously amiss, which is likely from the top end (pistons contacting valves). If no resistance is felt, then perform a leak down test to see if/where there is a loss of sealing in each combustion chamber (to identify a bent valve, for instance). If you don't have a leakdown tester (and you may not), engage someone to help you who has the equipment. Even if you don't meet resistance, you may have a bent valve, so the leakdown test will confirm it.

One other diagnostic tool that is relatively easy is to remove the four valve covers and inspect the rocker arms. If one or more are broken, then you know you have a top end problem and that pistons hit valves. If you see any valves that have excessive clearance, then that would also be a sign of a bent valve.

Any indication of a bent valve is likely caused by a cam chain issue -- as others have indicated. The most likely culprit is the tensioner. But chain guide rails can fail too, and they cause sudden loss of timing. In my experience, chain tensioners fail slowly, and usually cause "rattling" at idle when the engine is warm What you described didn't sound quite like that to me.

Obviously, if you have a top end problem, it's still very serious, but it generally requires less work and expense to fix than if you ate a rod bearing or something went wrong with the bottom end. Then again it could be something a lot less serious than we're all suggesting. But this diagnostic will tell you what you need to know. Basically, if it has metal in the oil, or there's a leakdown problem, the engine is going to have to come out and get fixed.

Good luck and please report back on what you found.

Rob

[DRACO A5OG]

Originally Posted by A&F

The quart I added was 20-50 Valvoline VR1 oil. I figured the high-zinc is a good thing.

I just dug out the receipt from the independent euro shop.... (I save everything)

They charged me for 22 pints of Mobile 1 15w40 and a 93010776401 Oil Filter.

That Mobil 1, was it synthetic or conventional.

Yes, ZDDP in the Valvoline VR1 is very good for our babies. I have not used it but I also read the Kendal Titanium has alot of Zink as well.

[DRACO A5OG]

Does it sound like this?

https://www.youtube.com/watch?v=F-ZgH8YuhU0&feature=youtu.be

[yelcab1]

Originally Posted by DRACO A5OG

Does it sound like this?

https://www.youtube.com/watch?v=F-ZgH8YuhU0&feature=youtu.be

that is bad

[A&F]

Originally Posted by DRACO A5OG

Does it sound like this?

https://www.youtube.com/watch?v=F-ZgH8YuhU0&feature=youtu.be

No it did not. That sounds like engine knock too me.