Maiden Voyage of my 61T - Oh No!!!!

[KULTULZ]

Yes, as long as you are able to drop the pan. You will have to pull the cylinder head and remove the piston/rod from the top.

Ask which method is cheaper (labor).

[simplyconnected]

...Is it possible that the PO installed a high pressure/flow oil pump?...

It is possible that someone replaced the pressure relief valve spring with one that is too stiff.

Oil pumps come in gallons per minute (GPM) of flow.
There are two common choices; OEM and 'high volume' which really means, higher flow.

Pressure IS resistance to flow. Turn on your garden hose and it has no pressure but falls out the end .5 meters. Cover the end with your thumb and it shoots out many meters because you raised the pressure by restricting the flow.

Since liquids cannot compress, the pressure relief valve dumps any pressure (back to the oil pan) that overcomes the preset spring tension. Oil filters usually bypass at around 33-psi, which means much of your oil will not be filtered at idle speeds. - Dave

[KULTULZ]

It is possible that someone replaced the pressure relief valve spring with one that is too stiff.

Oil pumps come in gallons per minute (GPM) of flow.
There are two common choices; OEM and 'high volume' which really means, higher flow.

Pressure IS resistance to flow. Turn on your garden hose and it has no pressure but falls out the end .5 meters. Cover the end with your thumb and it shoots out many meters because you raised the pressure by restricting the flow.

Since liquids cannot compress, the pressure relief valve dumps any pressure (back to the oil pan) that overcomes the preset spring tension.

Oil filters usually bypass at around 33-psi, which means much of your oil will not be filtered at idle speeds.

- Dave

In some instances, someone may have either jacked the pressure (relief spring) or added a HIGH VOLUME and/or HIGH PRESSURE PUMP to mask a problem. Regardless, that pump has to go.

[KULTULZ]

The noise is only present on idle when the motor is hot.The mechanic said that he thinks the problem could be a gudgeon (wrist) pin but he is not certain.

The mechanic also said he could find nothing to indicate that my motor will let me down. He suggested that I have two alternatives: put another 500 kms on the car and see if the noise gets worse or dismantle the engine to look for the problem.

Looks like I will be up for some pretty expensive repairs.

Mark

This is a fresh engine?

If there is no variance in oil pressure (needle bouncing or dropping however slightly), I might just take the gamble and see if the noise worsens if the tech cannot isolate the noise. If the noise gets worse, a tear down will be necessary.

[Guest]

I can source an oil pump easily enough. I take it that the pressure relief valve is part of the pump?

[simplyconnected]

Section 66 of your Illustrations Catalog shows an FE oil pump:



When oil pressure over comes the spring tension (6670), it forces the piston (6674) open, causing the excess pressure to dump back in the oil pan.

[Guest]

I finally got a retired mechanic friend to look at my car. He lives out of town and so it has taken a while to arrange it. Unfortunately he is not well and so he's not able to work on the car himself.

We removed each of the plug leads in turn to see if it affected the noise. As expected the motor ran rough and the idling dropped with the removal of a lead. This made no difference to the noise HOWEVER, removing the lead to the back left hand cylinder (8) made no difference to the idling or the noise.

The motor had always run rough at idle and no one could work out why. So the symptoms are:

Noise on idle when the motor is hot
Rough idling
Very fumey both from the engine pipe and the oil filler
Removing the lead to cylinder 8 makes no difference

Are we getting somewhere?

My mechanic mate said that we could check out the cylinder using a flexible camera but the left side head probably needs to come off to see what is going on.

Mark

[KULTULZ]

I finally got a retired mechanic friend to look at my car. He lives out of town and so it has taken a while to arrange it. Unfortunately he is not well and so he's not able to work on the car himself.

We removed each of the plug leads in turn to see if it affected the noise. As expected the motor ran rough and the idling dropped with the removal of a lead.

This made no difference to the noise

HOWEVER, removing the lead to the back left hand cylinder (8) made no difference to the idling or the noise.

The motor had always run rough at idle and no one could work out why. So the symptoms are:

Noise on idle when the motor is hot
Rough idling
Very fumey both from the engine pipe and the oil filler
Removing the lead to cylinder 8 makes no difference

Are we getting somewhere?

My mechanic mate said that we could check out the cylinder using a flexible camera but the left side head probably needs to come off to see what is going on.

Mark

#8 cylinder is not firing for whatever reason. There is your rough idle.

Excessive fumes out of the oil filler pipe suggested the Road Draft System is not functioning properly (or possibly poor oil control @ the piston rings/valve seals). Plug reading will ID poor oil control.

There is an excellent TECH ARTICLE here on updating early engines to PCV. Also consider PERTRONIX II to increase spark voltage (to keep plugs clean).

Just how objectionable is the noise?

ADDED-

#7 and #8 cylinders fire consecutively and therefore the plug wires should be separated from the cap to the plug(s). If run along together, there is a possibility of cross-fire, especially @ HI-RPM and/or if bad or cheap plug wires.

[KULTULZ]

Before I left the car had a couple of issues that needed to be sorted. There was a light knocking noise at idle that the mechanic thought was a stuck lifter. He suggested adding some lifter clear to the oil and taking the car for a run.

Anyway, the car went very well. However, some of the TBird guru mechanics had a listen to the engine noise. It only becomes apparent when the motor is hot and it tends to fade in and out. It can be quite loud although you don't hear it when driving or when the engine is revved. So after much listening with long screwdrivers (no one had a stethoscope) the noise appears to be emanating from the timing chain area. Another mechanic said it also could be a gudgeon pin (wrist pin) - hopefully not.

Noise from under the timing cover may indicate timing chain problems or a defective fuel pump.

If a bad pin, it should have subsided with the plug lead removed as this will take a lot of pressure off the piston/rod assembly.

Did we ever find out the mileage on this engine?

[Guest]

The motor has done about 2500 miles since a full rebuild 6 years ago. Pulling the lead off cylinder 8 made no difference to the idling. Maybe it's only running on 7 cylinders?

[KULTULZ]

It's taken my a while to find a mechanic I trust and I took the car down on Monday. The mechanic organised another mechanic who is an engine builder to also come and listen to the noise. He seemed to know his stuff and went over the engine for about 15 minutes with an electronic stethoscope. He said the the knock appeared to be coming from the centre of the engine at the bottom.

He also noticed that the dip stick tube had been pushed about 10mm out of the block. I thought the oil level was low but it seems that the motor may have the wrong dipstick. The motor is very fumy considering it is a rebuild.

Anyway, he pulled the pan off the bottom of the motor and here is what he found:

The motor has been rebuilt with everything clean and tight

One side of the thrust bearing was worn a bit differently from the other but this would not make the noise.

Mark

OK, that answers the engine condition.

The highlighted text worries me.

[Guest]

The mechanic said that the engine wasn't run in yet and not to worry too much about the thrust bearing yet. The noise is quite obvious but varies in volume.

[KULTULZ]

Well, I hope he is right, but a fresh engine should make no noise or smoke. If it does there is something wrong.

Wish you well with it...

[bird 60]

Engine Noise

Hey Mark, why don't you send a vid with the engine running so some of the guys on the Forum can listen to it & give their five cents worth. You might get the feedback you want & hopefully the right one.

Chris.....From OZ.

[jopizz]

Before you take anything apart you should do a compression test on each cylinder to compare the number 8 to all the others. Did he put a vacuum gauge on. That's one of the best tools for diagnosing engine problems and should be the first thing a mechanic does when troubleshooting a problem like this. Once again any mechanic who wants to take the head off for a misfiring cylinder before doing basic troubleshooting doesn't have a clue what he's doing. It's truly amazing to me how hard it is for you to find a competent mechanic. As mentioned the number 7 & 8 spark plug wires should be kept as far apart as possible. Is there spark on the number 8 wire? What does the spark plug look like? What does the inside of the distributor cap look like? Did he test the plug wire with an OHM meter? All these things should be done before you even think about taking the head off.

John