Changing crankshaft bearings with the engine in the car.

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Max1196 said:
What about the cam bearings? They're just as old/ wore as the crank bearings.
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I bet the cam bearing wear is half as much or less since it turns at half crank speed, and has a constant load.

Crank bearings do much more work than cam bearings.

You'll be fine doing it in the car, old bearings come out easily. Change the oil pump while you are in there with a new standard volume pump.
 
junkyardhero said:
the gargantuan pain in all nine assholes of laying on the ground with **** dripping and dropping on your face while cussing and fussing on this job aside... what happens when you're done and (insert sing-songy voice) the oil pressure's still low?

while it's likely just the bearings are beat down, the possibility does exist that the crank could be pooched as well.

or maybe the oil pump is waxed ***...

i say throw some 50 weight at 'er and let it rip, see what time it is.

but if i'm doing mains, i'm doing rods-- in for a penny, in for a pound. what's another few hrs to yoink a motor at that point for the ease of working standing up.
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I would be doing it standing up.

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Max1196 said:
What about the cam bearings? They're just as old/ wore as the crank bearings.
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Cam bearings don't see reciprocating wear, they see rotational. It has been my experience that crank bearings see far more wear than cam bearings.

RustyRatRod said:
Also, consider what some have said. If the bearings and or crank need help, what about the cam bearings? What about the camshaft itself? The lifters? How sloppy is the timing chain? What about the rings? If this is a car you're gonna sell, then shyster it up and unload it. If you plan to keep it, you might want to rethink it.
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When I sell something and I want top dollar, I do NOT want it coming back to haunt me. I make the car as mechanically sound as I can just to protect myself from looking like a liar and a cheat.
The camshaft is probably fine. all the rocker arms are secure with no play. The engine idles and runs great.
I will change the oil and try another oil pressure gauge first.
Thanks!
 
IF this is a "I wonder what this would do" experiment, pull one bearing out of the cap. If std. size, get a set of .001" oversize. or plastigauge and see what clearance is.
please disregard, just typing with out thinking.
 
Inertia said:
I would bend up a cotter pin to slip into the oil hole, funny angle thing and just rotate the crank.
The cotter pin "flukes" laying across the bearing surface would just push the shell around till it'd pretty much fall out when nearly all the way around.
Just lay the new shell on the clean/lubed crank surface, finger pressure to get it started, the cotter pin/rotate shaft till you can engage the "tab".

Not my favorite job, hoist helps.
@Kern Dog

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That's the exact same method I used, twice, on some old trucks, about 30 years ago or so. Maybe we learned about this from the same source! (Hot Rod mag, perhaps?)

Regardless, I know the OP has a hoist, but I hate working over my head, so if thicker oil isn't an option, if it were up to me I'd pull 'er.
 
I bought the lift in 2015. I built the shop in 2006 with the intention of installing a car lift.
I am still fully capable of "flat back" work but this is so much better. I lose perspective of what is the left and what is the right when I'm laying down. Standing while working is a lot easier.
 
Kern Dog said:
I bought the lift in 2015. I built the shop in 2006 with the intention of installing a car lift.
I am still fully capable of "flat back" work but this is so much better. I lose perspective of what is the left and what is the right when I'm laying down. Standing while working is a lot easier.
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i was just goofin' about the lift. i have one too, and while it's sooo much nicer to work standing up, it seems like i've always got a car on it and one underneath torn apart and unmoveable and two parked up land locking evertything. which, now as i type that out sounds more of a "me" problem than i'd care to admit.

pro tip: if you put your hands out in front of you, the one that makes an L with your index finger and thumb is not your right.
 
Of all the engines that I have torn down to rebuild, very few had cam bearings worn much. The ones above didn't wear, they rotted from contamination. Bearings don't flake and chip apart from wear.
 
Brooks James said:
I have heard/read that magnum cam bearings wear more than anticipated ??
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i mean, think about what they came in: trucks (mostly) and what gets abused more than work trucks? more likely to neglect OCI and maintenance? (*coughs* besides rental equipment *coughs*)

the "flaking" of cam bearings has also been (loosely) linked to the acid/acid by products in modern motor oils, namely synthetics-- which again, goes to extended, missed or ignored OCI's.

so, little wonder the cam bearings are pooched in a lot of magnums.
 
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ProjectBazza said:
That's the exact same method I used, twice, on some old trucks, about 30 years ago or so. Maybe we learned about this from the same source! (Hot Rod mag, perhaps?)
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Very well could have been, I used that method before my apprenticeship.
We gained mosta our early knowledge from the monthly magazines, and adapted that to whatever make we were working on.

Personally, I'd run 20/50 like I do my high mileage Jeeps. 300k, 3 of em, - knock like hell for a coupla seconds every morning , - for years.
Cheers
 
The nearby dump has a recycling facility where people can take stuff that others “recycle”. Sometimes it is spray paint, bug killer or cleaners.
Sometimes it is oil still in unopened containers. There will be some that suggest that you don’t use old oil but my thought is… for a stock vintage engine not built for high performance, it will be fine. It is coming from a sealed container and it was made with less detergents and likely has some zinc in it.
Look at modern oil:

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I don’t have the info right in front of me but I read an article that laid out a timeline for when the detergent packages were ramped up and zinc was phased out. See where the blue bottle has an API rating of SN plus? That is the highest rating so this oil is great for newer cars but not so much for the classics. That article stated something about the SJ series still having some zinc but less detergent. Lower alphabet letters indicate older oil with less detergents and more zinc.
I got 10 bottles of classic Castrol.

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See the API rating?

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This stuff is much better for classic engines. Get ready for one better!

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Remember that stuff? I remember the TV ads for it back in the 80s. Someone had 6 unopened bottles at their place for years before it was brought to the dump. Check out the API.

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Backing up a bit, here are two bottles of Castrol. Old on left, new on right.

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Remember, the old stuff was API SF.

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Again, fine for newer engines but no zinc for us classic car guys.

4 1/2 quarts of vintage ARCO Graphite and….

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55 PSI at cold fast idle. 20 at hot idle in gear. That is plenty good enough to forego a bearing swap. The old oil looked clean but drained out like water even with the engine still sort of cold. I only ran it long enough to move it to the other room.
Score!
 
Garrett Ellison said:
I haven’t heard a lot about the cam bearings, but I do know that a considerable number of the cams produced weren’t adequately heat treated. I have seen an early 5.9 magnum before that had the cam bearings pretty well chewed up in it before. The cam was showing signs of delaminating on the lobes, so it may have had something to do with it.
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never had a cam with laminations on the lobes either ...
 
413 said:
I bet the cam bearing wear is half as much or less since it turns at half crank speed, and has a constant load.

Crank bearings do much more work than cam bearings.

You'll be fine doing it in the car, old bearings come out easily. Change the oil pump while you are in there with a new standard volume pump.
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Tom Hoover once said , in a Chrysler drag seminar in OKC , that cam bearings can look like hell and never give a problem . I suspect there are a lot of them replaced that don't really need it , I have never worried about them unless the block has been vated ...
 
Kern Dog said:
I would be doing it standing up.

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Cam bearings don't see reciprocating wear, they see rotational. It has been my experience that crank bearings see far more wear than cam bearings.



When I sell something and I want top dollar, I do NOT want it coming back to haunt me. I make the car as mechanically sound as I can just to protect myself from looking like a liar and a cheat.
The camshaft is probably fine. all the rocker arms are secure with no play. The engine idles and runs great.
I will change the oil and try another oil pressure gauge first.
Thanks!
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agree, I turned down $36,000 on my barracuda , because it needed wiring ...had it rewired due to a health issue at that time .
 
Max1196 said:
Ok.
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Those look just like the cam bearings in the Hemi Charger Dad gave me (back in 1983) after he dropped a valve and drove it for five miles, embedding the valve head in the piston and knocking a hole in the head.

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Cam was fine. So were the crank and rods. Don't know if the condition of the cam bearings had anything to do with the dropped valve, but I suspect they were already bad, I'm thinking from being damaged by some yahoo who installed the cam in one of the two earlier rebuilds. I've never seen cam bearings like this in any of the other engines I've had apart (maybe a dozen or so).
 
came across a picture that showed them using a tongue depressor to drive the upper main bearing out of the block.
 
If you're hearing rattling down low it's more likely rod bearings than mains, so if you're in there change both. It can be done in car and it's fun!.....well, minus the fun part. Regardless, 20W-50 should improve the issues without turning a wrench :)
 
TheRacerDave said:
If you're hearing rattling down low it's more likely rod bearings than mains, so if you're in there change both. It can be done in car and it's fun!.....well, minus the fun part. Regardless, 20W-50 should improve the issues without turning a wrench :)
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Rod bearing and main bearing noises distinctly different .
 
Kern Dog said:
Who has done this?
I've replaced rod bearings with engines still in cars but I don't think that I've replaced a full set of main bearings before. Rods are easy, pushing the rod UP a slight amount allows adequate clearance to slip the top shell out.
The mains though...it isn't as if you can pull the crank away from the block to give the upper shells room to move.
20+ Years ago I did replace a few bearings in a Honda 1.5 4 cylinder but that was a LONG time ago.
I've changed rear main seals in LA and Big blocks. That upper section just rotates around when you push it with something soft enough to not scratch the crank should it slip.
I'm thinking that a firm plastic stick could be used to clock the bearing shell a bit, then a pick could be pressed on the back side of the bearing that sticks out, slowly rotating it until it slips out.

This car.....

View attachment 1716305152

Looks like crap but is a fun dirt road drift car. It has a fairly stock mid 70s 360 with a stock bottom end, a 280/474 Mopar cam, #308 heads, a Weiand intake and Holley 600 carb. It runs strong but the oil pressure is low. The cheapo aftermarket gauge actually reads zero at idle. During a cold start, my 440 Power Wagon reads 70 psi. Another car reads 50. This was at 25 at fast idle. That is simply too low.
I'm hearing some rattling inside. I pulled a valve cover and let it run. The rocker arms are somewhat quiet. It seems like it is down low. I thought maybe the oil is just tired and maybe thin but it is clean. It does have a little smell of gasoline but I can't be sure. It has literally been YEARS since i changed the oil. The car sits until I decide to bash around dirt trails, then I park it for months. I might change the oil and see if that increases the pressure and eliminates the knock/rattle. If not, I can pull the pan and check the condition of the crank bearings.
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That car is hot
 
I could be totally wrong about this, but with my car, I think I could have the engine out sooner than if I had to pull the pan out of the way...........I think.

Not to mention, that thing will drip drip drip for days! Doesn't sound very,,, "joyful",,, to me.:BangHead:
 
I've done it on a slant six. I have the official service tool (for bearing removal) that inserts into the oil hole, but the cotter pin idea above looks like it would work also. You can also get plastigauge and check for proper clearance with the new bearings. If the clearance is still a little too big, you may be able to find bearings that are for undersize crankshafts. The hardest part (besides getting on/off the floor 100 times) is finding room to use a beam torque wrench in the limited confines under the vehicle.
 
Max1196 said:
Ok.
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I didn't take pictures, but I have seen this on 80's small blocks. '82 Ramcharger 318, '84 Diplomat 318, '87 Truck 360. Changed cam bearings in the vehicle except for the back one which always looked good. Position #1-3 always looked terrible. It was side work on Saturdays and never thought anything about recording it.
 
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