345 lifter problems

rustyjunk

New member
I have a freshly rebuilt 345 with the lifter rattle syndrome. I have read post about symptoms, do, and don'ts until I cant stand to read anymore. I have yet to find one with the exact symptoms as mine, so I am begging for some one with experience to turn me in the right direction as I know no one in my area with experience with these engines. I have a 73 scout II with the 345 and welded rockers. The engine was fairly sound with no noise and only years of crud from leaks and significant smoke on start up. One night in the garage a friend and I was talking about pulling it for a refresher, only a few hours later was it setting in my floor. I had the only reputable machine shop in my area do the work, 6 months later it was back at my shop ready for drop in. After installing I ran the recommended time to break in the isky cam, everything was great. I ran it for about 200 hundred miles with no issues what so ever. One evening at lower speeds it started to rattle. I immediately shut it off, then after a few minutes restarted and had no issues. After changing the oil I took it for another ride and after about 4-5 miles the "tick" came back. I then added a extra qt after what I have read from other post, but never had to do before the rebuild. The extra qt did not solve anything, but I did narrow the tick down to just the #2 cylinder lifters. Myself being the ignorant person I am decided to order more johnson lifters and change the entire bank. Since the change, a few lifters rattle on start up then quite down until the oil warms up, then the #6 intake lifter is the cause of the noise. I have since changed the lifter again with no difference. With that being said I have also went back and double checked the shaft to make sure it was clean, turned the pump with the rocker shaft on and off to make sure oil was getting where it should, pulled lifters to check oil in the galleries, the one in question doesn't seem to have as good of a stream as others but none the less is oiling. I hope some one can steer me in the right direction. Thanks
 
It sounds to me that your rebuilder omitted the oil gallery plug at the front of th RH bank, in the engine block. Pull the distributor and use a light and mirror or a borescope to verify if it is installed or not.
It sits behind the distributor shaft and is sometimes missed on reassembly. The LH plug is easily seen when the engine is being built up, so it never gets left out.
Let us know what you find.
 
I did do the recommended pre-oil before I installed it in the vehicle to make sure it was oiling, and once again after I had it in the vehicle because it had set a few days before start up. One thing I'm not sure on is the amount of oil that comes out of the rocker shaft when running. I was able to run it with only a few Rags laying on the manifold heat shield to prevent a mess. Also, when I was turning the oil pump with the oil warm it looked like the #4 bearing had oil "pouring" out around it compared to the others. I fear I know the answer, but I just like opinions of others who a experienced before I start pulling it out again. Thanks for all the advice
 
I will double check on the plug by the distributor just to make sure. That's why I love hearing from others just to give me a little bit of hope that I won't have to pull the engine again. One other thing, with the passenger side rockers off, I can almost shoot oil over the fender when turning the pump with a drill. Would a wasted bearing still alow that to happen?
 
I see your concern about the rocker assembly oiling. The oil flow is fairly slow and drippy, not a heavy flow.
On that note I sincerely hope it is a simple fix, but the lifters are fed only from the #5 bearing. It is common to have it installed flush with the rear of the block and not centered on the cam journal. My biggest concern comes from the first 200 miles being nice and quiet. Some significant change in oil to the lifter gallerys occurred.

As mentioned check the gallery plug. It is easy to miss. :icon_4laugh::smilewinkgrin: BTDT.
 
I can't want to start on my travelette, but refuse to until my scout motor is running as it should. With that being said, I bit the bullet and pulled my 318 mile since rebuilt 345 out of the scout last night and started the tear down only to find #2, #3, #4, and #5 cam bearing trashed. From what I can see, the #5 was installed to far back in the block starving the bearing oil supply, and restricting oil to my lifters since the bearing was to close to the rear plate. Thanks to everyone for the tips on what to look for, I was hoping for something simple because I just couldn't believe there bearings would be gone already
 
I hope the shop that did it will warranty a set of cam bearings and the associated work. That sucks.

That's why I did my own cam bearings just to make sure I got it right.
 
I'm sure he would, he is a really nice guy, but after the 8 month wait and the 1hr drive one way numerous times the first time, I have borrowed a install tool and will be doing it myself this time.
 
Make sure when you do the number 5 bearing that you Dremel the oil relief in the bearing to match the block. This helps make sure the oil keeps flowing. I durabond bearings.
 
Dremel where exactly? The supply hole to the bearing, or in the back next to the plate? I have a set of durabond bearings on order.
 
Next to the plate. Even with the bearing hole lined up perfect the path at the back where the cover/ gasket is will be a touched blocked off. If you use a Dremel or rotary bit on the bearing to just cut the bearing to match the block it'll be good for better flow.
 
I've got to call BS here. Not meaning to offend anyone but rather to dismiss wrong internet lore.
This grinding the bearing myth thing has grown out of not understanding how things should look when the rear bearing is installed at the proper location in the block relative to the installed cam location.

1) The correct location for the rear bearing is even with the back face of the cam when the cam is being located by the retainer plate in the front and with the cam gear installed. When you groove the bearing you are actually undercutting the bearing surface where the cam runs. All that should be beyond the rear cam face is any chamfer on the ID of the bearing.
2) The gasket thickness and recessed position of the bearing in the bore give 1/8 +of gap for oil to move from the came diameter to the lifter passages.

3) The direction that the cam bearing journals are polished needs to be such that the grain lays back away from the direction of rotation. The IH gear driven cam turns opposite of the common chain driven cams. IMHO, My witness to many failed cam bearings in short order and the details surrounding them leads me to believe that the cams may have been polished the wrong direction.
4) I recommend test fitting all cams and checking for ease or rotation. I use gear oil or W50 engine oil, never grease for testing and assembly. The cam must turn as if cradled on ice with only finger tip force. Any binding must be inspected and rectified. Tightness indicates 0 oil clearance. This will fail any bearing.
If tightness is felt, turn the cam a number of turns and remove. inspect for witness marks(shinny areas) and fix them. Burnishing the bearing material usually works well. Large localized witness marks may indicate that foreign debris is under the bearing.

Example of proper rear cam bearing location below. This is a first time cracked open SV
 

Attachments

  • Rear-cam-bearingMU.JPG
    Rear-cam-bearingMU.JPG
    76.2 KB · Views: 461
Last edited:
These are my bearings I have removed. I apologize for the poor picture quality, I was trying to show how far off #5 was, and the oil port was closed as the one shown on the #2 bearing in the picture. In you guys opinion, should I worry about other problems, or go with the idea #5 was placed wrong. Should I reuse the cam? It shows no signs of wear, I have put a mic on it, and It is completely true in round. Sorry for all the questions, I just dont want to pull the engine anymore after this.
 

Attachments

  • 0117191905b.jpg
    0117191905b.jpg
    27.8 KB · Views: 383
  • 0117191905a.jpg
    0117191905a.jpg
    31.9 KB · Views: 413
Following the instructions in my post above are best. Your choice on replacing the cam and lifters (I would) and make sure you polish the journals the correct direction.

This cam has to glide when you try to turn it lubed with fingers.
 
Back
Top