Engine Noise

flatheadkev

flatheadkev

Member
I'm looking for possible answers to a noise my engine makes once it warms up. It's newly rebuilt and runs excellent, plenty of power even up hill. It has insert bearings and snyder 5.5 head. The oil pressure reads 6psi when first started. As it warms up I noticed the oil pressure (on the gauge) drops. I have a few pounds of pressure under way but at idle it drops to 0psi. The noise is dull not real loud but consistant, more noticable at idle. "Cloump...Cloump...Cloump...Cloump..." Driving along at 20 mph to 45 mph you can't hear it. I'm not overly concerned that it is something major but thought I would ask the pros.:D
 
Do a search on engine knock on this forum for a few clues, Also purchase les Andrews diagnostic manual
 
I will be talking to him soon at Hershey. I would like to check a few things first. I'd like to readjust the valves if needed, and drop the pan and do a visual first. The rebuild was a short block so I do have some responsibility.
 
flatheadkev said:
I will be talking to him soon at Hershey. I would like to check a few things first. I'd like to readjust the valves if needed, and drop the pan and do a visual first. The rebuild was a short block so I do have some responsibility.
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I would call him first and explain. Bill W.
 
I will record the sound, thats a good idea. I plan on taking it out for a nice ride today and putting some miles on it. It only has about 220 miles on it so far, that is probably not long enough to seat everthing.
 
When cold, it sounds like something up front-like fan belt, water pump, generator bearing---- but warm, I have no idea-better talk to your rebuilder.

If it is up front, you may want to take off your fan belt and see it the noice goes away. If it does go away, then it is one of the things I mentioned above. Good luck.
 
In the first video I can't hear anything but that squeeking *** fan belt. In the second I hear what I believe to be the cam walking because the distributor is about to lock up from lack of lube or the oil pump is dragging or locking up from bushings that are not clearanced correctly. Try the dist first, remove it and make sure it turns easily. If that is not it I would look at the pump. It definitely is not a valve out of adjustment. Does it have plenty of power when running down the road? If it does look at the distributor or oil pump. You can also remove the small cam cover and run the engine when hot to see if the cam is moving forward and backwards.
 
My car had a noise up front,so I removed the side timing cover & cam gear would wiggle about 1/8" as nut hadnt been tightened properly.I put in an aluminum gear & also used Loctite on the threads.I should never have to worry about stripping the cam gear either.
 
James, I put a couple of drops of oil down the dist. cam bolt hole before my ride yesterday. I do remember when I originally installed the distributor there was one spot that bearly hung up my thought at the time was that it would "wear in". I'll bet as things start getting hotter "bearly" hung up becomes "very" hung up. I'll check that first. I could not blame that on anyone but me, since it was my first attempt at rebushing a model A distributor.:o The oil pump is new over the counter it turned freely. I think if the cam gear were loose it would be noisy all the time.
 
The cam is walking, only seems to when the engine is warmed up. I pulled the distributor, it did spin freely. Ran the .500" reemer though bushings and checked shaft dia. and end play, as per Les Andrews. Lubed, reassembled and installed. Went for a test run, Lena runs great more power than I thought a Model A could have. When I returned, temp. at 185, I retarded the spark and still hear the noise. To be 100% sure I pulled the distributor while still hot and it spins with no resistance. I took the cam gear door off and started her up, with a large socket I applied pressure to the back side of the gear I could feel and see that the cam is walking. Next, I will drop the pan and check the pump. The belt was a little tight, I readjusted, no more "squeeky *** fan belt".
 
I pulled the valve cover, visually everything looks good, I removed the drive gear unit and disassembled. The gear spins freely in the sleeve except for one spot that seems a little gritty, there is no discoloration of the shaft or sleeve due to heat. I noticed that the bore, on the gear end of the new bearing/housing is off center. The distance of the bore to the outside machined surface ranged from .237” down to .205”. Depending on where in the rotation it is installed it will be plus or minus .016” off center. Not sure if this could affect the mesh to cam gear. Maybe it is not an issue. To be safe I will be reassembling using the old bearing/housing. Using a long screwdriver through the distributor hole I spun the oil pump, it spins freely. When I’m confident I have removed all the resistance I can, I will check the cam plunger and spring for the right length and tension. I have read about spacing the back side the plunger to decrease the end play. This will keep the cam from walking.
 
I duno what makes the cam walk back and forwards but my A had a hot idle problem for ages ,until I run a bolt in the timing pin hole to just touch the gear,fixed it right up.
So I machined a little spacer under the plunger to just allow about .006 end float on the spring and that fixed it.
I know that it should not need it ,as it wasnt there from new ,but it made it nice and quite.
Lawrie
 
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