Big problem...

[GRS72GT]

I have read a few threads, but I'm still not very sure of what my issue is. The situation:

I had just made a trip up and down the mountain. It was about 200 miles round trip from my starting point. My GT made it up and down just great, no problems. It was, however, on the flat roads that things turned south.

I was less than 5 miles from home when RPMs started to drop. I didn't hear anything break, but regardless I pulled over to the side of the freeway, when upon taking my foot off the gas, the car promptly died. The oil level was only a little low (probably because it hadn't settled down into the pan completely), coolant was fine. I dropped an extra quart of oil in just to be safe. I noticed smoke of sorts coming from the valve cover cap when I went to put in the oil, but wasn't sure if it was just because of the heat. The temp gauge was reading normal temperature when I started to pull over, and never increased after that.

Anyhoo, after checking all that, I tried to fire it up again. I could get it to fire after cranking it for what seemed like too long. The engine was running VERY rough, making all sorts of hellish noise. It would only stay running with my foot on the gas (at least at 1000 RPM), and I couldn't get it above 2000. I also noticed a steady output of smoke/vapor coming out of my air cleaner.

I decided to at least try and get it off the freeway, so I slowpoked it down the shoulder to the next exit. The noise seemed to get worse from driving it, but at least I was away from cars screaming past at 90 mph. I towed the car home (160 bucks later... ) and looked at it a little bit more this morning. My dad suggested checking out my fuel filters, which did need to be replaced. Checked out the carburetor, and it is clean as a whistle. I still have the same problem though. It will turn over just fine with a wrench, and with the starter, but once it starts, it's really rough, and won't stay running.

I'm pretty sure I didn't throw a rod. I didn't hear anything break, nor is there a hole in my engine block. The thread I read suggested a bent or stuck valve. My valves did make a little bit of a chatter at lower RPMs, but it usually went away at speeds above idle. Would that have had any affect? And I sure as heck don't know how to explain that horrendous noise...

[BMWonly]

I would start with checking your spark plugs, and pulling the valve cover off. I had a cracked rocker arm once, which would explain some of your symptoms. Adjusting your valves might help too.
Others probably have more ideas.

Dieter

[ungermm]

Sounds like you might not be running on all cylinders. Pull each spark plug and check for coolant. Check your spark for each plug. Make sure you don't have a plug wire touching metal and grounding out. Check your compression for each cylinder.

Jerry

[GRS72GT]

Thanks for the suggestions. Ok, I just stepped outside to check the spark plug wires. They are all good, none are shorting out. I haven't got the chance to check the spark plugs themselves. We aren't allowed to do maintenance to our cars at this apartment complex (property manager is a parking lot nazi and is literally out every hour checking for cars w/o permits and other rule-breakers...).

Something odd happened just now. I fired it up again and it seemed like it was running normal... just out of nowhere! I moved my car to a different spot (we aren't allowed to have non-op vehicles on the premises either...) to make it look like I was driving it. After I parked, I threw it in neutral and revved it up a bit to see if it really was behaving. After about 3000 RPM, it made an odd knocking sound and started making the same horrible squelching sound that it had been making before.

I really do appreciate the help, as this is my only mode of vehicular transportation.

[ungermm]

Well, squelching sounds are never good. I guess that's what you meant by hellish noise in your first post.

It could be that once the engine temp increases you're having an issue with a sticky valve. I would pull the valve cover and check to see that the springs and rockers look good and to check the movement of the valves. But, you may have to remove the head in order to find a cause and in order to make repairs.

Then it could even be worse, there is also the possibility that you have a bearing or piston ring seize.

[biglefti]

I not sure how many miles are on your engine, but it may have jumped timing. When the timing chain stretches a lot, it is possible for the timing to jump forward or backward. Hence it may run good for awhile, then jump and start to run bad. Good luck with your issues.

[GRS72GT]

I'm not even really sure how many miles are on the engine. Someone pirated one of the speedometer gears from the transmission, so my odometer hasn't been working since at least 56K. That and I'm not even sure if this is the original motor... Thanks for the input though!

[MICAH1]

Your story seems very similar to what I experienced going to Carlisle in May of this year...... Take a compression check of all four cylinders. I won't guess what it could be, but the compression read should point to or eliminate some internal problems. Keep us posted

[ungermm]

Wish I was there to hear that hellish noise. Can you narrow down the location? Just a thought, but are you sure it's from the engine and not the alternator, AC compressor (probably not since very few GTs had them), or smog pump (again, probably not).

Disconnecting the fan belt while it runs for a few seconds won't hurt it.

I had a squeal last year when I got up to 3500 rpm's. I disconnected the fan belt and rev'd the engine and didn't have the squeal. It wasn't the belt. Turned out to be the bolt head inside the water pump was scraping the water pump impeller.

Also, do a compression check with a cold engine and after it warms and starts to act up.

Another thought...spun bearing. Not sure if this would cause your symptoms though.

[GRS72GT]

Wish I was there to hear that hellish noise. Can you narrow down the location? Just a thought, but are you sure it's from the engine and not the alternator, AC compressor (probably not since very few GTs had them), or smog pump (again, probably not).

Disconnecting the fan belt while it runs for a few seconds won't hurt it.

I had a squeal last year when I got up to 3500 rpm's. I disconnected the fan belt and rev'd the engine and didn't have the squeal. It wasn't the belt. Turned out to be the bolt head inside the water pump was scraping the water pump impeller.

Also, do a compression check with a cold engine and after it warms and starts to act up.

Another thought...spun bearing. Not sure if this would cause your symptoms though.

The noise is actually a combination of things I think. It sounds like there is a knocking sound coming from under the valve cover somewhere. The knock happens intermittently when the car actually manages to idle, which is around 800 RPM. The car used to idle at around 1000... When I rev the engine up a little, the knocking starts up consistently. Sometimes it is regular, as if it were the same cylinder/valve, but sometimes not. It is very hard to hear where the squelch/scraping/rubbing is coming from, but it seems like it is from the cylinder head area as well. I don't hear anything from the water pump area. Other than that, everything seems to run smoothly.

I have also contemplated the spun bearing, but I won't know until I can get a chance to look that far into the engine. The most I would be able to do would be to take the valve cover off, MAYBE the head if I'm lucky. I rebuilt an engine on a different GT about 3 years ago and I don't remember where I put the bit for those bolts...

[MICAH1]

Our problem seem to be the same...... You mentioned in the above post that you did a rebuild on a previous GT, so you have the experience to make the necessary internal corrections.

Sounds like a little person inside your motor with a hammer??

[GRS72GT]

Our problem seem to be the same...... You mentioned in the above post that you did a rebuild on a previous GT, so you have the experience to make the necessary internal corrections.

Sounds like a little person inside your motor with a hammer??

That's exactly what it sounds like, haha.

I will be able to make the repairs myself once I isolate the problem. The only difficulty lies in my current location. I can't work on it in the parking lot of my apartment complex, unless I do it before or after office hours; difficult because it gets dark so early now and we don't have outlets for extension cords...

[neuropel]

...I can't work on it in the parking lot of my apartment complex, unless I do it before or after office hours; difficult because it gets dark so early now and we don't have outlets for extension cords...

Any chance you could rent a storage place somewhere for a week or even a month? Sounds like your current situation is a real hassle...

[ungermm]

My daughter had sent me an email photo of your car at her Apt. complex. Are you living in there too? IIRC, the little mexican restaurant next door has a dumpster behind it with some space. If so, you could ask the manager or owner if he wouldn't mind letting you keep it there for a few days.

Jerry

[GRS72GT]

Yeah, I'm living in that same complex. Strange how small a world it is... haha. I never thought to ask that little restaurant. It's worth a shot if they don't mind me working on my car. There is a little parking area for their employees, and it's never full...

[Gary]

You can use a long screwdriver as a stethoscope to help isolate where the noise is coming from. Grip the screwdriver and place your thumb over the end of the handle. Then put your ear against your thumb. The sound will transmit through the screwdriver.

I had intermittent engine noise problems in my '72 wagon. It sounded like it had no oil pressure then it would clear up. The problem was the rebuilder put 3 overhead valve style lifters in the head (they have a hole in the top for oil to go through the pushrod). The rocker ball wore and would hang up and the engine would lose oil pressure.

[MrGing]

Most of the car problems I've had rarely happen suddenly. Usually there is some clue before a failure (usually). Rotors don't suddenly warp, bearings don't suddenly fail and valves don't suddenly get out of adjustment. They are usually progressive. I say "usually" because sometimes pads do come off plates and overheat rotors, main caps can loosen or break and chains can slip. That being said, I would start looking for simple problems that can make big symptoms. Check to see if the little screw that hold the points down hasn't loosened and messed up your fire. Check the bolt that holds the distributor in place, That would trash your timing. Same with the vacuum advance hose, timing again. Fuel pump and filter (mentioned earlier) won't cause the noise you describe but is a single point failure. Everything mentioned earlier are good suggestions but I tend to stupid little problems first I'd hate to tear into an engine to later find out it was a cracked spark plug.

Hope it's something simple
dan

[tekenaar]

Most of the car problems I've had rarely happen suddenly. Usually there is some clue before a failure (usually). Rotors don't suddenly warp, bearings don't suddenly fail and valves don't suddenly get out of adjustment. They are usually progressive. I say "usually" because sometimes pads do come off plates and overheat rotors, main caps can loosen or break and chains can slip. That being said, I would start looking for simple problems that can make big symptoms. Check to see if the little screw that hold the points down hasn't loosened and messed up your fire. Check the bolt that holds the distributor in place, That would trash your timing. Same with the vacuum advance hose, timing again. Fuel pump and filter (mentioned earlier) won't cause the noise you describe but is a single point failure. Everything mentioned earlier are good suggestions but I tend to stupid little problems first I'd hate to tear into an engine to later find out it was a cracked spark plug.

Hope it's something simple
dan

. . . MrGing, but have to ask . . . still using points? Idling rough, missing, inability to rev above ~3,000 RPM all point to the ignition coil not being properly "charged" between firings which indicates points out of adjustment (too little gap, wear or loose) or a condenser gone bad! While you have the cap off, check the inside for carbon tracking or moisture also . . .

[newman27]

Most of the car problems I've had rarely happen suddenly. Usually there is some clue before a failure (usually)...

Good advice. I've never forgotten my dad telling me to drive the first couple miles and last couple miles each day with the radio off to listen for any early warning signs of a mechanical issue. I still do that today and it has saved me a bundle. My 1999 Olds, for example, had an automatic transmission actuator / solenoid going bad that I caught right away as a result of listening for early warning signs. There was the faintest "clunk" that could be heard on gear shifts during heavy acceleration. The throttle position sensor was also starting to flake out (I learned that later). The dealership indicated that getting it in the shop early probably saved the transmission (and me several thousands of dollars).

[GRS72GT]

Most of the car problems I've had rarely happen suddenly. Usually there is some clue before a failure (usually). Rotors don't suddenly warp, bearings don't suddenly fail and valves don't suddenly get out of adjustment. They are usually progressive. I say "usually" because sometimes pads do come off plates and overheat rotors, main caps can loosen or break and chains can slip. That being said, I would start looking for simple problems that can make big symptoms. Check to see if the little screw that hold the points down hasn't loosened and messed up your fire. Check the bolt that holds the distributor in place, That would trash your timing. Same with the vacuum advance hose, timing again. Fuel pump and filter (mentioned earlier) won't cause the noise you describe but is a single point failure. Everything mentioned earlier are good suggestions but I tend to stupid little problems first I'd hate to tear into an engine to later find out it was a cracked spark plug.

Hope it's something simple
dan

The distributor is down tight, spark plugs are all intact, all vacuum lines are snugly in place. I've already swapped out both of my fuel filters. The inside of the distributor cap is very clean; no moisture or carbon. The points are down tight, and gapped properly. I've checked all the little stuff, and so far everything checks out.

I really do hope it is something simple, but I can't think of anything left to check, except under the valve cover.

tekenaar mentioned the condenser... How would I go about testing that? I know what it is, just not how to tell if it's good or bad...