Thread: Gen I (1969) SBC 350 NEED HELP, TICKING SOUND

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AH but I bought a cheapo stethoscope so when the fan hit my Craftsman screwdriver, I didn't have
a screwdriver in my ear and the word CRAFTSMAN imprinted on my forehead. Or some broom
company's logo. It is interesting that the sound from a stethoscope is different than a broomstick.

its the location of the sound that we're looking for------doesn't matter what it sounds like------its going to be a lifter/cam lobe, rocker, wrist pin, connect rod or main----
when you pin point it you can then determine what it is
but forward of dist on rt side-its lifter/cam lobe cylinder #8

By the way, I have several unique Craftsman screwdrivers:
one that I dropped on a battery and welded itself across the terminals and I pulled off before the battery exploded
one that I got caught in the fan belt when listening for a front alternator bearing
one that I used for a chisel and hammered the shank thru the plastic handle
one that I put a fairly long pipe on to use as a pry bar
one that I had in the flywheel teeth when I forgot and bumped the starter
one that I stirred paint with and forgot to wipe off
and probably a few others I forgot about

Hijack.jpg

CGW3, as you can tell we're a bit bored with the cold weather and low winter post count syndrome, so you're the one who benefits I hope you'll hang in and close the loop with what's happening with your CJ. My '05 TJ is just about due for a Hemi takeout engine package, so I've got an interest in your Jeep

I had one a couple weeks ago that drove me crazy trying to locate it.
Long story short, the spring that holds back the bendix in the starter had broken and the starter drive gear would just sneak out and tap on the flywheel.
The stethascope got me close and after removing the flywheel cover the noise got louder, when turning the flywheel by hand I could hear it... still took me a bit to realize it was the starter drive!

Originally Posted by 34_40

I had one a couple weeks ago that drove me crazy trying to locate it.
Long story short, the spring that holds back the bendix in the starter had broken and the starter drive gear would just sneak out and tap on the flywheel.
The stethascope got me close and after removing the flywheel cover the noise got louder, when turning the flywheel by hand I could hear it... still took me a bit to realize it was the starter drive!

I have thought about this. with my bellhousing off, I was able to look at gap between flywheel and starter drive gear, there is a very small gap, but you can see light between it. Is this something that you were able to see without turning flywheel? or did it only expose itself when you turned? also, was this something that may only hang up right after its been cranked? but spring may work itself back into place as it sits?

Originally Posted by cgw3

I have thought about this. with my bellhousing off, I was able to look at gap between flywheel and starter drive gear, there is a very small gap, but you can see light between it. Is this something that you were able to see without turning flywheel? or did it only expose itself when you turned? also, was this something that may only hang up right after its been cranked? but spring may work itself back into place as it sits?

On mine the starter drive would slide out and the flywheel / flexplate would tap it and push it back into the starter. the running engine vibration would then shake the bendix back out until it was tapped by the flywheel again.. rinse and repeat... I only found it while turning the flywheel/flexplate by hand. And I noticed the clearance disappeared between the two gears.

Thread direction takes a U-turn.....

I'll have to tell a story on myself. Had an old beater pickup, '91 Ford F150 regular cab, longbed. I drove it to Firebird one Friday night to do tech and shut it off as usual. End of the evening, I went to start it and the crank wouldn't turn. I thought maybe I had wadded up a rod bearing, so called my buddy to come get me. We towed it to his 40' x 90' shop and I began pulling the motor for a teardown. Got the motor out and separated from the transmission and all of it laying on the floor. Put the motor on an engine stand and began disassembly. When I pulled the starter motor, what do you think dropped out on the floor? Yep, a bendix tooth that had broken off and wedged between the bendix and the flywheel ring gear.

When the truck wouldn't start, I let the truck roll downhill and dumped the clutch to try to release the crank. All it would do was to skid the rear tires. Had I tried the same thing going backward, the tooth would have fallen out and I would have been able to start the truck with the starter until I could replace the starter later when it would have been more convenient. As it was, it cost me about $1200 to do an engine rebuild because it needed it anyway.

Let this be a lesson to you. Try to push it forward and then backward before you pull the motor.

.

Why do pushrods spin?????

Because------on flat tappet camshafts, the lifter bottoms have a slight curveature to them and the camshaft lobes are ground at a very slight angle------this angle lets the pressure thats transferred to the cam from the valve springs hold the cam back into the block and also control forward/rear slop caused by the angled gear on distributor/oil pump drive----
ALSO----this angle will cauce the lifter to spin on the cam lobe presenting a continuous change in the contact wear pattern that spreads the wear pattern and increases the life of the cam/lifters. If for some reason the lifter can't spin--indicating a worn lobe, the cam will be wiped out within a VERY SHORT time cycle. If the lifters can spin, they will spin the pushrods----so non spinning pushrods will indicate a worn cam

This doesn't happen on roller cams-----------

Here's a diagram illustrating what Jerry is talking about....I think the radius on the lifter crown is about 50 inches and the ramp on the lobe is about 0.004" difference side to side....some fellows will tell you that the lobe difference is 0.0025" on OEM stuff and more like 0.005" on aftermarket stuff....
http://www.crankshaftcoalition.com/w...lobe_angle.jpg

Here's another that shows the point of contact being off center, that's what allows the lobe to spin the lifter....
http://s171.photobucket.com/user/vet...db730.jpg.html

Anyone wanting a flat tappet camshaft to survive should read and heed this tutorial....
http://www.crankshaftcoalition.com/w...ips_and_tricks

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ok guys,still stuck. Here's an update on what all Ive done. Checked starter/flywheel, no issues there. Bought a stethoscope (kind with metal rod) and it amplified the sound but I could not pin it down, pretty much heard it everywhere, with a slight increase in rear of engine from top of distributor all the way around flywheel. When I touch metal stethoscope to block, I can hear bearing (im guessing), but they sound like they are rolling as usual with no odd sounds to make me believe that one could be out. Im assuming that with a stephoscope, you should be able to hear a bearing even if it is lubricated, if touching the location of the bearing. If not, please correct me, and this could be my culprit. Ive done everything but pull the flywheel off, drop my pan, or pull the engine. I want to limit and unnecessary dis-assembly if possible. My only thinking outside of it being a cam bearing, would be somewhere on the distributor-gear on cam-down to oil pump and oil pump itself. The gear on the rear of the cam that turns distributor, does it have a pin through it that could have worked loose, or are there any parts from there down to the oil pump that could fail and should be looked at? If you can suggest any other culprits , please let me know. Thanks Guys

In post #18 you said you were going to look at the pushrods with the engine running, verifying that each one is spinning which is one step to eliminating a wiped cam lobe from the list of gremlins. Did you do that?
If you did then my next step would probably be to adjust the valves to eliminate the lifters from the list.

Originally Posted by rspears

In post #18 you said you were going to look at the pushrods with the engine running, verifying that each one is spinning which is one step to eliminating a wiped cam lobe from the list of gremlins. Did you do that?
If you did then my next step would probably be to adjust the valves to eliminate the lifters from the list.

I did check pushrods and they are all fine.

Originally Posted by cgw3

I did check pushrods and they are all fine.

Just to be sure, you understand that this is to check that the lifters are rotating on the cam lobe, which in turn causes the pushrod to rotate while the engine is running, right? Wiping a cam lobe has become a much more common event in the last twenty years or so due to changes in oils to keep from fouling CAT's ....

I don't think he wants to get his hands dirty