Intermittent engine noise

IvanT28

IvanT28

Junior Member
Just bought a 1928 Model A Special Coupe and I'm a newby to the world of Model A's. I have a noise that comes and goes (more coming than going) from the engine I think. It sounds like a rough bearing. Medium pitched squeal or grating noise. It's not a knock. When its there, it doesn't matter whether standing still or moving, clutch in or out. Seems to change pitch somewhat with rpm's. Changing gear has no effect. I had generator replaced with used alternator when I bought it. Might be a bearing in it. Haven't been able to trouble shoot because of infrequency of noise. Also don't have hardly any clutch free play. Need to adjust that. Could it be that the throw out bearing is occasionally rubbing on the pressure plate? Any suggestions from all you old pro's would be greatly appreciated.
 
Could be the clutch trunion is adjusted too tight. Try backing the trunion bolt up about 1.5 turns as a test. If you have no free-play it is too tight regardless if it is the cause of the squeal or grinding noise.


If you remove the floor boards and then remove the clutch inspection cover, you will be able to see if the throw-out bearing is rubbing. Since you do not know the maintenance history of the car, the throw-out bearing should be checked/greased anyway.

Your "clutch in or out" comment may eliminate the cause as the clutch...you could remove the belt to eliminate the water pump and the alternator as suspects. It's going to be difficult to trace if the noise is not steady.
Good Luck & Good Day!
 
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You really to help us by somewhat isolating the noise. Just where is it coming from?
Its easy to eliminate the alternator, just remove the belt.
If there is any free play in the clutch then the bearing shouldn't be spinning until you take the free play out by lightly stepping on the pedal. Looking in the inspection hole will help.
As Bob said, could be a distributor bushing. There should be a lube cup on the side of the distributor, try adding a couple drops of oil to it.
 
Could be the cam plunger inside the timing cover. I had one with a plugged oil hole in the casting and it would scream then go away then come back. put a stethoscope against the casting bump on the cover and you will be able to hear it.
 
Without seeing or hearing it....sounds like a water pump. Do as Bob said and remove the fan belt and start her up. See if the noise goes away. If it does it's the pump. Don't run the engine for more than a couple minutes. It will overheat. If the noise persists we have to look elsewhere.
 
I agree with checking the easy stuff. Unhook the belt, run the car briefly and if no noise, you have isolated it. I never would have believed it even possible, but I too had an intermittent screaming cam thrust plunger. However dont tear the car apart until you check the easy stuff. As stated a common squeeler is the distributor bushings-first try a few drops of oil in the oiler port.
 
Don'y run it until you fill the distributor oiler to the top, then let it set overnight. Hopefully the passage in the distributor isn't plugged and the oil will be down by morning. If it is, then fill it again and start the engine. You can't over oil the dist.

The cam gear plunger is another very good thought, and I've seen that cause this very symptom. It took several hours of running before it finally went away for good.
 
Hey Ivan: Try isolating the noise using a stethoscope. These are available from auto parts stores. Or you can use a simple wooden dowel (such as a sawed-off broomstick); put one end to your ear and move the other end around the engine but be careful to avoid the fan. Hopefully you'll be able to report back once you've pinpointed the source of the noise.

All ears in Orygun,
Mike
 
Hi Ivan,
You could also use a long screw driver as a stethoscope as Mike above suggested with the broomstick.
Regards
Chris
 
Thanks for all the tips guys. This site is like having an ace mechanic in the closet. Going on vacation tomorrow. Will oil the distributor tonight and maybe by the time I get back the noise will be gone. I'll let ya'll know. Thx again!!! PS.. It's got a new leakless waterpump, but will try the belt trick if noise persists.
 
I had a similar noise. Found out bushings in the distributor (top bushing) was shot due to lack of lubrication, so it had too much play.I am rebuilding it now with a hole on the cam screw and on the side of the shaft for proper lubrication. A fellow member found the problem when he pushed on the distributor body the noise would stop.

Hope this helps,

Henry's 31
 
Maybe my body is put togethe just a bit differently than others but when I use a LONG screw driver to check for noises I don't stick the handle of the screw driver so it directly contacts my ear canal. Instead I let that little bump of skin/cartlige (not the ear lobe) rest between the screw driver head and my ear canal. Seems to filter out the "noise".
Dave
 
1crosscut said:
Maybe my body is put togethe just a bit differently than others but when I use a LONG screw driver to check for noises I don't stick the handle of the screw driver so it directly contacts my ear canal. Instead I let that little bump of skin/cartlige (not the ear lobe) rest between the screw driver head and my ear canal. Seems to filter out the "noise".
Dave
Click to expand...

i do the same thing its called the Tragus ;;; lol
 

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Got back off vacation trip. Oiled the dist again and waited till next morning to fire her up. I've been driving off and on for 3 weeks now and the noise is gone. YAHOOOO. Many thanks guys.
 
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