Source of mystery knock found? Surpises in my L134

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   So my '48 2A was making an obnoxious knocking noise. Nothing about the noise made much sense. The usual issues that come with a loud knock weren't there... Oil pressure exactly to spec at all temps and RPMs, zero metal in oil, etc. The noise would come and go and was much more noticeable at low RPM. Using the dowel as a field expedient stethoscope seemed to indicate that the knock was coming from the front of the engine the towards the top, like it was in the valve train... But that didn't make any sense either. I had kind of thrown my hands up in the air about it and just enjoyed my Jeep. 
Well, the clutch went so the engine was coming out anyway in order to fix that so I decided that since it was already on an engine stand I would re-gasket the whole thing because it was leaking oil out of just about everywhere. I figured while I was in there I would take a close look at everything and see if I could narrow down where that obnoxious knocking sound was coming from. 

There was a bizarre mix of studs and bolts securing the head. Some were 11/16, some 5/8. Nothing too surprising under the head, some carbon, some crusty looking exhaust valves, pistons marked .030 over.  Cylinders with a moderate carbon ring and cylinder walls that were slightly glazed but otherwise pristine. I dropped the oil pan and saw the crank marked in yellow paint .020 x .020. One connecting rod lock nut missing, but not in the pan. I guess they must have lost it during the rebuild and just not replaced it. Everything was extremely tight and rotated smooth. Nothing indicated to me that there was a bearing problem anywhere. (Oddly, the inside of the crankcase was painted red.) 

I was still scratching my head about where this knock could have been coming from until I took off the timing gear cover and immediately noticed that the cam gear screw, lock washer and washer had not been installed! They just weren't there at all. Both gears look pristine which is shocking considering nothing was stopping the cam gear from sliding back and forth on the camshaft. Now I don't KNOW that this was the source of the knocking sound, but it's the only thing that makes sense. What do you guys think?

As an aside, do any of you know a source for the camshaft gear washer? Pretty sure I can source the screw and star washer from a hardware store as I have their dimensions from the parts list, but I only found one vendor listing the washer and they're all the way in Sweden. Everyone else either doesn't list it, or is out of stock.

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w12code3 Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 04 Nov. 2017 Location: Omak, WA Status: Offline Points: 11	Post Options Post Reply Quote w12code3 Report Post Thanks(0) Quote Reply Topic: Source of mystery knock found? Surpises in my L134 Posted: 16 Oct. 2018 at 6:16pm
	So my '48 2A was making an obnoxious knocking noise. Nothing about the noise made much sense. The usual issues that come with a loud knock weren't there... Oil pressure exactly to spec at all temps and RPMs, zero metal in oil, etc. The noise would come and go and was much more noticeable at low RPM. Using the dowel as a field expedient stethoscope seemed to indicate that the knock was coming from the front of the engine the towards the top, like it was in the valve train... But that didn't make any sense either. I had kind of thrown my hands up in the air about it and just enjoyed my Jeep. Well, the clutch went so the engine was coming out anyway in order to fix that so I decided that since it was already on an engine stand I would re-gasket the whole thing because it was leaking oil out of just about everywhere. I figured while I was in there I would take a close look at everything and see if I could narrow down where that obnoxious knocking sound was coming from. There was a bizarre mix of studs and bolts securing the head. Some were 11/16, some 5/8. Nothing too surprising under the head, some carbon, some crusty looking exhaust valves, pistons marked .030 over. Cylinders with a moderate carbon ring and cylinder walls that were slightly glazed but otherwise pristine. I dropped the oil pan and saw the crank marked in yellow paint .020 x .020. One connecting rod lock nut missing, but not in the pan. I guess they must have lost it during the rebuild and just not replaced it. Everything was extremely tight and rotated smooth. Nothing indicated to me that there was a bearing problem anywhere. (Oddly, the inside of the crankcase was painted red.) I was still scratching my head about where this knock could have been coming from until I took off the timing gear cover and immediately noticed that the cam gear screw, lock washer and washer had not been installed! They just weren't there at all. Both gears look pristine which is shocking considering nothing was stopping the cam gear from sliding back and forth on the camshaft. Now I don't KNOW that this was the source of the knocking sound, but it's the only thing that makes sense. What do you guys think? As an aside, do any of you know a source for the camshaft gear washer? Pretty sure I can source the screw and star washer from a hardware store as I have their dimensions from the parts list, but I only found one vendor listing the washer and they're all the way in Sweden. Everyone else either doesn't list it, or is out of stock.
	'48 CJ2A

Mike F Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 12 Aug. 2018 Location: Longview wa Status: Offline Points: 684	Post Options Post Reply Quote Mike F Report Post Thanks(0) Quote Reply Posted: 16 Oct. 2018 at 6:37pm
	I found the same thing when I too my new motor apart for a freshen up. maybe the cam retainer bolt is optional. I got one from willys jeep parts in Yuma AZ. After an extended search.

Rus Curtis Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 25 Mar. 2010 Location: Alabama Status: Offline Points: 1733	Post Options Post Reply Quote Rus Curtis Report Post Thanks(0) Quote Reply Posted: 16 Oct. 2018 at 9:30pm
	Did you check the backside of the cover for scuffing to confirm the gear was making contact? https://www.willysjeepparts.com/Camshaft_And_Timing_Gears_Late_L_4_134.htm https://www.kaiserwillys.com/gear-to-camshaft-hardware-kit-fits-46-53-jeep-willys-with-4-134-l-engine You may also want to check with Harry Sheets for used original. http://www.midwestwillys.com/
	Rus Curtis Alabama 1954 CJ3B Bantam T3-C

w12code3 Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 04 Nov. 2017 Location: Omak, WA Status: Offline Points: 11	Post Options Post Reply Quote w12code3 Report Post Thanks(0) Quote Reply Posted: 16 Oct. 2018 at 11:12pm
	Thanks for the links Rus! Those were vendors I had never heard of before except for Kaiser Willys of course. The problem with their kit is that while it has the bolt and the lock washer it doesn't have the large "washer" that provides the clamping force against the cam gear. They show it in their exploded parts diagram but they don't stock it. Mike F, as far as the cam gear retaining screw and washer being optional, the shop manual says that camshaft end play is set when the thickness of the spacer and the thickness of the thrust plate are correct and the parts "are assembled and drawn tightly together by the gear retaining screw, the end play should come within standard limits." It sounds like camshaft end play is set by the camshaft retaining screw so I would guess that its presence is mandatory. Thankfully for me the only part that appears to have been damaged is the cam gear Woodruff key. The thickness of the thrust plate and spacer that set camshaft end play or within tolerances listed in the manual and there is no major where or galling to any of the services or the keyway in the camshaft gear or the keyway in the camshaft itself. It would appear that the Woodruff key was the softest part in that group of parts. In this photo you can see a distinct shoulder worn into the Woodruff key. In this video, if you look closely, you can see the Woodruff key rocking back and forth in the keyway along with a distinct "clunk" sound. It seems to happen at two specific points per rotation. For reference, here is a video of what the "knock" sounded like when the engine was running. I'm pretty sure that is the cause of the noise. I suppose it's possible that it's not and I put this all back together and it still going to knock. I hope not! But even if it does, at least this problem got fixed before it turned into a major issue. Edited by w12code3 - 16 Oct. 2018 at 11:16pm
	'48 CJ2A

Ol' Unreliable Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 25 Sep. 2016 Location: CO Springs CO Status: Offline Points: 4226	Post Options Post Reply Quote Ol' Unreliable Report Post Thanks(0) Quote Reply Posted: 17 Oct. 2018 at 1:43am
	The direction the crank and cam gears are cut makes it look like the crank gear holds the cam gear on while the engine is running.
	There's a reason it's called Ol' Unreliable

Mike F Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 12 Aug. 2018 Location: Longview wa Status: Offline Points: 684	Post Options Post Reply Quote Mike F Report Post Thanks(0) Quote Reply Posted: 17 Oct. 2018 at 3:14am
	Yea. I didn’t think they were optional. That’s why spent days trying to find one. then all the sudden like the clouds parting I had sourced 3. Yet I now know of 2 motors assembled with out it. I wouldn’t, but 2 other guys did. The fact that it wasn’t there made me look a little deeper. And found / fixed a few other things.

EJs1950 Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 27 Mar. 2018 Location: Fl Status: Offline Points: 22	Post Options Post Reply Quote EJs1950 Report Post Thanks(0) Quote Reply Posted: 25 Dec. 2023 at 4:44pm
	W12Code3. I realize this is an old post. However, my motor has a similar knocking sound. If possible can you post if the knocking problem was solved and what all you found? Thank you.

Flatfender Ben Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 13 July 2014 Location: Nyssa OR Status: Offline Points: 2657	Post Options Post Reply Quote Flatfender Ben Report Post Thanks(0) Quote Reply Posted: 25 Dec. 2023 at 7:54pm
	One of my L-134 sounded just like that and fixing the loose cam gear eliminated my knocking. Mine had run so long that the teeth on cam gear were worn paper thin and the keyway in cam was worn. I installed a good used gear and took a punch to the edges of the keyway and also used bearing/sleeve retainer lock tight. I ran that engine for 6/7 years.
	1946 cj2a desert dog 1946 cj2a bulldog 1948 cj2a blue jeep 1953 cj3b yard dog 1955 willys wagon 1955 willys pickup 1956 willys pickup boomer 1960 fc 170 1968 jeepster commando 1990 Grand wagoneer

IronAge52 Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 22 Aug. 2016 Location: San Diego Status: Offline Points: 257	Post Options Post Reply Quote IronAge52 Report Post Thanks(0) Quote Reply Posted: 25 Dec. 2023 at 8:29pm
	I have a friend with M38 a1 , yes F head . He just did a clutch job and also now has a mystery knock. I would like to help him out but I cant figure it out. not a rod knock or lifter ,some thing else. maybe a flywheel nut came loose. Jerry San Diego
	gearwrencher

dasvis Members Profile Send Private Message Find Members Posts Add to Buddy List Member Sponsor Member Joined: 07 Sep. 2019 Location: Salem, Oregon Status: Offline Points: 1546	Post Options Post Reply Quote dasvis Report Post Thanks(0) Quote Reply Posted: 25 Dec. 2023 at 9:24pm
	Good find. I have seen that before when we had our machine shop. Good thing you caught it when you did, that can get expensive if it goes on too long.
	1947 CJ2A #88659 "Rat Patrol" 1953 CJ3A #453-GB1 11266 "Black Beauty" 1964 Thunderbird convertible ..... & one of them moves under it's own power!!