Cam spring and button

[fredski53]

Had my engine overhauled by a reputable shop. Ever since I installed the engine back in the car, there is a loud knock when you are cruising. One member in our club had his engine redone at the same shop as I did. His engine started making a loud knocking also. The shop owner stated he had a batch of bad cam gears. I changed my cam gear even thou it didn't show any damage. Also installed a new spring and button. The knock is still there! I'm thinking could it be possible the spring isn't strong enough? Has anyone else experience this?

[Patrick L.]

I've shimmed the spring before.

Have you checked the lash ? It should be around .004-.006". Over .010" will make noise.

[fredski53]

I talked to the engine builder about the lash, the said when he rebuilt the engine, he uses a standard crank gear and standard cam gear. When I put the new gear on, he told me to use a standard cam gear.

[J Franklin]

Use the came gear that provides the correct gear lash. Always check with a feeler gauge if you are not certain. A repair of the bearings can make part relations change somewhat. Are you using a metal gear?

[redmodelt]

Have you used a mechanics stethoscope to find where the sound is coming from? Run the engine without fan belt to eliminate the water pump. Did he pour fresh Babbitt in the mains? Mill the head or block too much and pistons are hitting?

[J Franklin]

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Had a large bore and regular gasket once cause a knock when things warmed up.

[fredski53]

I’m using the laminated gear, the builder installed modern bearings, no babbet. High compression head, fs ignition, 12 volt.

[J Franklin]

delete

[Chuck Sea/Tac]

I like the cheap stethoscope from harbor freight. I take the metal end off and use a 3’ length of heater hose. I suppose you could just use the hose. Getting rid of the metal end stops excess metallic noise. You can locate the noise source quite well this way. I actually had a cam with a worn thrust and a weak spring that was knocking on the fly housing instead of on the timing cover. I knew the knock was coming from the rear, but it took a little time to figure out what was causing it.

[KR500]

Does the knock occur when you first start up engine or after it has warmed up. Does it have a higher compression head?

[fredski53]

The knock is there as soon as you start the engine. Cold, warm makes no difference. Yes, high compression head. Right after I had the engine rebuilt, it made the knock, I talked to the rebuilder and he keeps saying too much advance in the timing. I've tried everything I can think of to do. Someone said try a colder spark plug. I'm at the point of just keep running the darn thing, and when something breaks, well, then I'll know what was wrong!

[Jack Shaft]

Ive done two things to cure the issue,one was drill and tap the timing cover and use a set screw inplace of the cam spring.the other was to use a harmonic balancer

[Big hammer]

I just cured an engine noise in the areas that you have. My old distributor had a single shaft instead of the original two piece shaft. I feel the drive gear at the end of the shaft was moving around causing my noise. My noise was at both ends of the cam, front side near the cam gear and at the rear near the exhaust.

[katy]

I’m using the lamented gear

Never heard of them gears. who makes them?

[fredski53]

Snyder sell the laminated cam gear. It's supposed to be better then the macerated one.

[rocket1]

possibly to much forward and aft movement in the crank,something I would check.

[Kurt in NJ]

What about the other guys car--- has that been fixed---- has either of the cars been inspected by the guy that did the work

[fredski53]

I haven't talked to the club member since our last club meeting. Like I said before, I called the guy who did the engine work and he keeps saying its spark knock because of the electronic ignition and high compression head. I remember I had to buy a new lower shaft for the distributor. I was reading the " Red Book" and it said something about the 2 piece shaft connecting slot may need to be filed (opened) slightly to eliminate binding on the shaft. Also if a knocking noise (similar to a timing gear knock) is heard after installing a rebuilt distributor, try loosing the side locking screw to eliminate binding on the shaft.

[katy]

"Lamented", adjective, a conventional way of describing someone who has died or something that has been lost or that has ceased to exist.

[Dick M]

I once saw the same problem. Turns out that the line bore of the crank was slightly off center towards the cam. It made for a very tight fit between the crank and cam gears. I agree you should check the gear lash.