The end result of bad cam bearings......

[Dennis Bernth]

Well, they always said 'the wages of sin is death', and now I have some photographic proof of the wages of running with bad cam bearings
If anybody recalls, we were on the way to Nats 2006 when the engine in my 1980 Scout II just quit running. It had been noisy before that, and the gauge would read decent oil pressure, then no oil pressure, then decent oil pressure. I chalked that up to a bad gauge, at least until it died. Today, I was getting a load ready for the scrap yard and I figured I'd strip down that 345 and see if I could see anything wrong. The pics show what I found...
Although I didn't bother taking pics (seen one oil pan with chunks of cam bearing in it, you've seen em all), the oil pan was full of cam bearing. My thoughts now that I've seen this are that the cam bearings went south on me while I was enroute, and fairly early at that as the noise started only about 15 miles from home, but it still had decent oil pressure. I had a fresh oil change in it, and had had no sign of any problems- BUT I had added some 'friction reducing' stuff to the oil that I suspect now might have been a 'chlorinated hydrocarbon', which some people on here have blamed as causing delamination of the cam bearings. Whatever the cause, this engine had made a three hour trip on the highway before I got it and wasn't noisy....so I suspect that I did something to it, and all I can figure is the additive :alien
I think the weird gauge readings were actually right- as the cam bearings spun, they'd open up and let too much oil through, dropping pressure, or they'd tighten up and the pressure would come back up. The gauge was probably right....
Anyway, this is what you can expect if you run your worn out cam bearings a bit too long......
By the way, the silver colored bits you can see in some of the pics are pieces of the cam gear

 

[Jeff Melber]

Holy cow Dennis! If you'd asked I would have said it wasn't possible. Never seen the gears shreaded like that.

Take care,
Jeff

 

[Dennis Bernth]

I've heard of guys saying it's possible if the cam bearings go.....but I haven't seen it either, which is the reason I took the pics. The crank gear is fine, but that poor cam gear....

 

[Carl Howard]

I have a 345 I pulled out of a 1968 Travelall. I bought the truck in Boise Idaho and drove it the 1600 or so miles back to Oklahoma. It ran great during the first 800 miles then lost oil pressure, then lots of lifter noise, then back firing through the carb. . Long story short, I made it home and drove it all the way. The gears on the cam are shred like yours and you can bounce the camshaft up and down about 1/8th inch or so. The oil pan was full of debri from the bearings. I found one pushrod laying in the oil valley and 5 more were bent. but it did still run. I couldn't believe the thing actually made it home.

 

[Erik VanRenselaar]

Did any lifters/lobes get wiped out? I lost one after my cam bearings gave out a few years back.

 

[Dennis Bernth]

Did any lifters/lobes get wiped out? I lost one after my cam bearings gave out a few years back.

I didn't get that far into it, but I kind of suspect not, just because it was still running well and actually was getting about 15mpg pulling a trailer loaded with parts for the swap meet. No rough running or missing or noises in the exhaust like I've learned to expect from flat lobes..... and all the pushrods were in place when I pulled it down.

 

[Erik VanRenselaar]

Well, I'm not *exactly* sure when the lifter/lobe went, but the truck ran quite well right up until the day I pulled the engine out. I had even passed the enhanced CA emission test after the cam bearings went bad.

The first symptom was terrible top-end clacking after driving at freeway speeds for over 30 mins. And this was with an extra qt of oil (20W50) in there. Stopping and idling down for 5-10 mins would make it good for another 30 mins or so.

 

[Dennis Bernth]

Well, I'm not *exactly* sure when the lifter/lobe went, but the truck ran quite well right up until the day I pulled the engine out. I had even passed the enhanced CA emission test after the cam bearings went bad.

The first symptom was terrible top-end clacking after driving at freeway speeds for over 30 mins. And this was with an extra qt of oil (20W50) in there. Stopping and idling down for 5-10 mins would make it good for another 30 mins or so.

I got about 15 miles from home and got the clacking. I debated turning around, but that would have meant going to the IH Nationals with a Dodge Dakota.....no way, it's an IH, it'll make it fine, or so I told my girlfriend. It made it another 125 miles or so before it just quit running. No noise, no commotion, just like you'd turned off the key. I also had the extra quart of oil in it, but I'm thinking it would have needed maybe 7 or 8 more quarts to get enough 'splash lubrication' to prolong it's life any. This might have actually been a rebuildable core, but I didn't need it, and I didn't know if it was worth chancing it for anybody else with all the junk that had obviously circulated through it. The oil had less than 200 miles on it, and it was black and tarry....not a good sign

 

[scoutboy74]

Hey Dennis and others, just resurrecting this old thread. I just dropped the oil pan on my 345 and found a number of quarter-size and smaller chunks of what used to be a cam bearing. I've had this rig for almost seven years and this is the first time I've had the pan off. Who knows how long ago this happened. The oil pressure on my wet guage has always read 40-45 lbs at cold idle and then dropped to between 5-10 lbs at hot idle. It used to make some top end noise at extended freeway speeds. Running an extra quart of 20w-50 helped. The last oil change I switched from a purolator filter to a wix which seemed to improve the pressure reading on the guage by a a few lbs in all situations. I decided I would try rebuilding my oil pump to see if the readout could be improved even more. I stopped for the day when I discovered the chunks. Ignorance was bliss. The engine has always run great. Now the bloom is off the rose. I wasn't surprised to find the chunks, just dissapointed. My plan at this point is to rebuild the pump, button everything back up, and run her 'til she quits I 'spose. Major engine R & R isn't in the budget. I guess when she craps out, I'll just swap in another. Curse you IH engineers for over-building the SV just about everywhere except one critical location.

 

[Tim Potter]

Just out of curiousity, while it's down, why not pull the front off the engine and replace the cam bearings before they spin in their bores? You could even pull the caps and check the mains and rods too. I know it's a lot more work but might be worth it in the long run. That is of course unless you have a fresh one waiting to go in.

 

[Brad T]

So whats the go here... are the cam bearings seizing onto the cam causing it to increase the torque to spin it and strip its timing gear?
Obviously with a stationary cam and rotating engine (when it happens) there is enough valve to piston clearance? Or is that the clunking noise?
Man ive never seen anything like it! The last performance engine i built i fitted steel straight cut timing geardrives. Never strip those puppies

 

[19731110]

Im new to the IH scene. Why do these engines have so many problems with the cam bearings and what do you do to correct it? Thanks!

 

[scoutboy74]

Just out of curiousity, while it's down, why not pull the front off the engine and replace the cam bearings before they spin in their bores? You could even pull the caps and check the mains and rods too. I know it's a lot more work but might be worth it in the long run. That is of course unless you have a fresh one waiting to go in.

That's good advice Tim. No, I don't have a fresh motor waiting in the wings. It would be nice to be able to save this engine before it grenades. This is all uncharted territory for me. For someone who's BTDT, it's no big deal, but the very thought of that procedure has me shakin' in my boots. Once I get through the wallowing in self pity phase, perhaps I'll be able to more clearly see the forest for the trees.

 

[Brad T]

That's good advice Tim. No, I don't have a fresh motor waiting in the wings. It would be nice to be able to save this engine before it grenades. This is all uncharted territory for me. For someone who's BTDT, it's no big deal, but the very thought of that procedure has me shakin' in my boots. Once I get through the wallowing in self pity phase, perhaps I'll be able to more clearly see the forest for the trees.

I would DEFINITELY have your cam bearings checked/replaced if this is a common problem and yours is showing signs!
Dont worry, removing the rockers, pushrods, lifters and then finally the camshaft is quite easy. Its fitting new cam bearings which is the tricky part on most engines! You normally need a tool to fit them so they arent damaged in the process. They are the only bearings i have installed by the engine machinist when i do a rebuild.
As for big ends and main bearings, you are talking taking the crankshaft out now so you may aswell do an entire engine rebuild.... where do you stop?

IMHO, if you arent a competent and set-up mechanic, best thing to do would be to change the cam bearings only. If they are a problem, and yours is showing signs of them being shot, and everything else is fine with your motor, just have them replaced straight up and then she will be reliable for years to come.

What i'd do is remove as much as i could to save labor charges:
- drain engine oil and coolant,
- remove grill, radiator, timing cover(and harmonic balancer if necessary), distributor(if driven by cam), rocker covers, rockers, pushrods, lifters and cam.
- make sure you number every single lifter, pushrod and rocker so it goes back in the exact same position and you have seen or made alignment marks on crank and cam gears.
- tow to an engine builder for new cam bearings
- re fit everything or get them to assemble at least the cam and valve gear.

I think this would be the cheapest way of fixing it properly and you will learn so much from it too.

 

[Dennis Bernth]

LOTSA questions, so I'll give some answers. All are 'IMHO' of course, and worth every penny of what they're costing you....

Q-So whats the go here... are the cam bearings seizing onto the cam causing it to increase the torque to spin it and strip its timing gear?
Obviously with a stationary cam and rotating engine (when it happens) there is enough valve to piston clearance? Or is that the clunking noise?

A- I don't think the cam bearings are seizing on to the cam itself; they're 'delaminating', just basically coming apart in layers. Once you're into the softer inner layers, they wear even quicker and the clearance all the way around opens up. I think as the layers delaminate, they probably spin to some extent, and that might be what caused my oil pressure fluctuations- when the oil hole to that cam bearing was blocked, it raised the oil pressure since all the oil wasn't being pumped out through the wide open cam bearing.

Q-Im new to the IH scene. Why do these engines have so many problems with the cam bearings and what do you do to correct it? Thanks!

A- I don't know that they have any more problems with cam bearings than other engines; you have to remember that we're dealing with old iron here. The cam bearings in the newest Scout engine are at a minimum 27 years old....that's pretty old, and a lot of time for acids and oil contamination to have attacked the metals in them. I'd almost venture to guess that an IH SV engine that has been steadily run for say 10K a year, with regular oil changes with something like Delo or Rotella T, might have better cam bearings than an IH engine that has sat for years before being resurrected and that has only 40K on it total, mainly because the oil changes and the usage will remove more contaminants. When I 'put up' a spare 345 that I have here, I changed the oil and filter, dumped in a bottle of MMO (mainly because it mentioned on the bottle that it 'combats acids in the oil'), ran it to temperature, shut it down and pulled it and put it into storage. That way, everything went to bed with a nice coat of fresh oil on it that hasn't had time to get contaminated wtih blowby, soot, and acids....I hope! Anyway, I think the fact that the rest of the engine is so overengineered just makes the cam bearings one of the things that fail first. Solution is, replace em....simple as that. Find somebody that really knows their stuff, and that you can trust, and let them replace the cam bearings and be happy, the rest of the engine will probably last another 200K.

For Trevor, even though it's more work, you would probably be better off to yank the engine to have the cam bearings replaced. You should be able to do most of the disassembly and assembly up to that point yourself; take the long block, minus cam and valvetrain, timing cover, etc. to your machine shop and have them shove in new cam bearings. It's a lot easier in a shop with good light, and with being able to pull the rear cam cover, than it is to try to line them up and insert them straight while you're working through the grille shell of a Scout. Then put it all back together, new gaskets etc., maybe new freeze plugs at least in the back and a new rear main seal if it's leaking, and slam it back in. Now this is just my opinion, and it might be wrong; but I think it's pretty much a waste rebuilding an oil pump if you find cam bearing bits in your oil pan. The IH oil pump doesn't seem to be one that loses effectiveness over time and age (unlike Frods, standard maintanence on a 351M/400 is rod and main bearings and an oil pump at 100K, and the oil pump makes a HUGE difference in them cause the originals are weak and get weaker). Oil pumps look simple, and they are, but they can be screwed up. I'm a firm beleiver in 'if it ain't broke, don't fix it'. It would suck to do the cam bearings and rebuild the oil pump, and have the oil pump grenade and take out the rest of the engine. BTDT, dunno what I did wrong (on a Frod again!) but it happened, since then unless it really needs it, oil pump goes back in as it was.

 

[scoutboy74]

Brad, I'm definitely not experienced enough to take on this job myself. The other thing is, I'm really can't afford to stick even a moderate amount of money into this engine. I know what you're saying about it being the "right" thing to do and a great learning experience to boot. The long down time for this kind of repair is a major drag too. I know it's the cheapskate, chickenpoop way out, but I really see myself in "run her, but watch her" mode...carefully trying to coax another couple years out of it. On the plus side, it's not my DD. It only sees occasional use, mostly moderate off-road. I really try to limit the extended high-speed trips, and I'll be even more stingy about that from now on. Running SV engines are still fairly plentiful and can be probably be had for much less than what it would cost me to have my current engine fixed properly. That's the sad economic reality of this situation. I'd love to be proved wrong about that, but I don't think I am.

 

[Brad T]

The main thing that wears with oil pumps is the thing thats easiest to fix! The side plate which houses the gears usually wears from the sides of the gears spinning against it. Once it wears, oil bypasses a little and you lose a little ability for it to make full pressure.
Its not hard to wip off the plate and rub it in figure 8s on 1200 wet or dry on a sheet of glass. New gasket and its done!

 

[scoutboy74]

Dennis, good to hear from the grand poohba originator of the thread. Good info and good advice. I've got a lot too chew on and sleep on. If this engine were extra special for some reason, there'd be no question in my mind as to how I'd proceed. The bottom line is, there's nothing special about it. An engine swap can be accomplished in an afternoon. Problem solved...until the bearings go in engine number 2 and the whole process begins anew. That's IH ownership I guess. I've gotten by pretty clean and easy 'til this. Now it's time to pay the piper.

 

[Dennis Bernth]

Trevor, didn't know that you had another engine(s).....but if you do, and you know it's OK, that would be my first choice too. I think the one you have would probably run fine for a couple years- what's different now than from before you pulled the pan, other than you knowing there were cam bearing bits in it? Nothing, so if you hadn't pulled the pan you'd have kept using it as is until the problem got worse.
I'm in the engine swap mode (when the shop gets put back together and I get my replacement tools and stuff bought that is) with the Traveler I bought. It has a 345 that runs OK, but has a knock- probably piston slap, but rather than screw with it, I have a 304 out of another Traveler that runs great. I ran it for a good hour and a half, checking oil pressure cold and hot with a wet gauge, checking vacuum, basically doing everything I could do to make sure it's a good engine. If you've got one that you trust to that extent, that would be the way to go, but for now I think you'd be fine to button yours back up and run it as is, the same way you ran it before.

 

[scoutboy74]

Thanks Dennis. I don't exactly have another engine at the ready, but I know if I really made it a priority to find one I could without too much difficulty. That fact doesn't change the validity of your other remarks. It may not be what 4 out of 5 dentists recommend, but it seems to be the most practical course of action for me at this time. Good luck with your swap. Try not to incinerate the damn thing this time