For the last week or so, the engine in my 1926 Tudor as developed an odd noise. I can not remember hearing it any earlier that a week ago. The noise is very simular to a china bell that is muffled. It is chiming rather fast, but I can hear the beats. It is difficult to tell if it follows engine speed, because of the other engine noise. It is not very loud. In fact it is loudest when the engine is cold and is gone when the engine is hot. At first I was unsure if it wasn't a body noise, but now I am quite sure it is in the engine. I can hear the ringing from the top of the engine from either side. I can also hear it while I am driving the car. When laying down under the engine I can not hear it. This leds me to believe the noise is from the top of the engine. I removed the fan belt and the generator and there is no change in the noise. I can not hear the sound by hand cranking the engine.
I have read a lot of old posts on bearing noises, broken valve springs, loose internal oil lines, rod bolts hitting cam bearings and pistons kissing the head.
My engine has a Stipe 280 cam, aluminum non dome pistons and a Z head. I am betting on the pistons hitting the head. Although I checked the piston to head clearance two years ago when I installed the head, I can not remember what the clearance was.
I plan on pulling the head tonight. What do you think I'd see on the piston and/or head, if this is the problem? I expect that maybe a shiny spot where the carbon has been beat off. I also read about poor fitting gaskets and may see a shiny spot on the gasket.
I listened to the engine through a wooden dowel to hear the bearings and this seems OK, at least to me. I used the dowel on the head, but could not hear anything like the ring.
Any ideas, I'll post a picture or two of the head and pistons later tonight after I get them off.
What about grounding each plug in turn to try to isolate it? Might do nothing or could lead to the exact cylinder. (if it is a cylinder/piston/what ever noise. Try to find out what the problem is before starting with the harder stuff.
I tried that and could not hear any difference in the sound. The ringing is not very loud to begin with (you have to remember I have poor hearing in the first place). When my son comes over I ask him to give a listen.
I have had engines that where making noises, ended up being the rods had loosened up from wear and at high rpms the pistons where hitting the Z head. Tightened the rods back up and it was good to go.
How would you describe the sound?
Well.... don't think that the pistons are hitting the head. I try some clay to check the clearance later. Boy is it hot in the garage, 94. How do you southern guys stand the heat.
My Z Head, no shiny spots. The gasket mates with the head and block very well, not like some pictures I've seen on the forum. Looks like #1 isn't firing as well as the rest, but OK.
Number 4
Number 3
Number 2
Number 1
Block and gasket
Block and gasket
I suppose that I could open the inspection cover and check the rods, but I think since I can't hear the ringing from under the engine I don't think it's a rod bearing.
Anyway the next check is to see how much piston to head clearance there is.
well... I think the clearance is OK. I placed some clay and cut up sandwich bag in each cylinder and then squeezed it.
pre squeeze
post squeeze
post squeeze
Number 4 is the smallest about 0.030". This is without the head gasket in place, which is about 0.055". The others are about 0.035". So the clearance is about 0.080", is that enough?
Mike
I have an engine that also has a slight ringing noise and I believe it is coming from the cam gear. That is about the only thing that will ring. Pistons will knock but not ring.
When I removed my generator the drive gear had very sharp teeth and when I feel the cam gear through the generator hole, it's teeth are also sharp. If there is excessive clearance between the crank gear and the cam gear, the cam will not rotate smoothly but rather kind of snap around due to the action of the valves and springs. This is what I think is making the gear ring. I have not yet removed the front cover to check my theory.
You may have something there. I removed the generator a couple weeks ago. Then the ringing started. Maybe that's it. Once I have the head back on, I'll give it a try. Thanks for the idea.
Mike
Make sure the fan isn't close to the front pulley. That gave me a ringing noise at higher speed and against a wind as the vanes deflected the last 1/8 inch to contact the pulley.
I have just checked the valve springs and they are all OK. One thing I found that the crank pin inside of the crank fan pulley is loose and can move back and forth. The crank pulley has a ring to it. Once I get the engine back together I'm going to stuff the pulley full of paper towel to see if that is the ringing. I have to pick up a new head gasket.
I have just checked the valve springs and they are all OK. One thing I found that the crank pin inside of the crank fan pulley is loose and can move back and forth. The crank pulley has a ring to it. Once I get the engine back together I'm going to stuff the pulley full of paper towel to see if that is the ringing. I have to pick up a new head gasket.
If you get that ringing noise when it is pulling hard such as going uphill, it could be gases leaking around the spark plugs. You might need to tighten them or wrap some aluminum foil around the plugs. This noise is more of a chirping rather than a ringing.
Norm
If the crank pin isnt the problem, check the hand crank. The handle on my 13 rings. I know yours is steel, but might be worth checking.
It's your timing gear, as Jeff suggested. Without your generator in place, there is less load on the timing gears and they are then allowed to "play" around in whatever clearance you've got.
I experienced the same thing after installing a Fun Projects voltage regulator. It cut the charge rate and therefore decreased the load that the generator put on the timing gears and I had the same ringing noise. I may put the VR back on after I eventually install some better gears. Do not, in any way, consider this a criticism of the VR. Instead, it's a criticism of my laziness in not pressing on a new crank gear while it was easy to do so.
Well... first I want to thank everyone who gave an opinion. I just spent 4 hours in this blistering hot garage. The temperature has just dipped under 90. Anyway, I think the sound is gone. I think that some times I can hear just a little, but it maybe my imagination. We will see tomorrow in the 4th of July parade. Here's what I did, I pulled out the crank pin and put quite few punch marks in it so that it would stick in the crank better. I added some locktite and reassembled the pin. I had to drive it in. Seems to be holding it's place OK. We will see how hard it is to get out when I have to, some time later. I also re installed the generator. After reading a lot of opinions and the fact that the voltage regulator will unload the generator when the battery is fully charged, I figured why not. So with all this done, the original sound is definitely gone as best and at worst maybe still be there, but very quiet. In my opinion the problem was the crank pin, it was really loose. There may have been some sound from the generator gears. I did try running with the head lights on, putting a load on the generator, but didn't see much change. Hopefully the problem is solved. I find it amazing, this engine is rather noisy, just like most T's, but when a new noise shows I can pick it out as if it was the only one.
Thanks
Mike