Ok once again. 1987 dodge d150 slant six 225. It started making a knock noise so I dropped the oil pan down and could move one of the lower rod bearings with finger and another one next to it was loose. Parked it. Checked crank its fine. Problem is got the new bearing in..... Standard size And the same two that were loose before still have some play in them. Not as much but still do.... Would a thicker bearing stop that on them two??? PlS help... About fed up Lol

Check the crank for marking that it was ground undersize. You may have the wrong size bearings. Did you plastigauge the bearings to check clearances?

Are you talking about side-to-side motion along the axis of the crank, or motion perpendicular to the crank? The former is normal and bearings do nothing for that. The latter is definitely a problem.

Best,
Lou

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Home of Slant6-powered fun machines since 1988

Measure, measure & measure again...
The most important measurement is how much out-of-round the journal is.

So you know, the standard size for the connecting rod crankshaft journal(s) is 2.1875 to 2.1865
You want between .0005 to .002 of oil clearance between the bearing & journal. (plasti-gauge can measure that)

All these tolerances limit any out-of-round condition to .001 to .0015 max.
Go beyond that and the journal surface will contact the bearing material and open-up the clearance... making the rod bearings loose again.

So beg, or borrow a 2 - 3 inch micrometer and do some measuring... to make sure your repair is successful.
DD

One moves side to side a little and one moves up and down.

That motor needs to be taken out and gone through or you will forever be chasing a knock until it tosses a rod.

You will probably find a rod big end out of round too.

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Official Cookie and Mater Tormentor.

The crank is wore and has some small gauges in that area. We are just going to get a thicker bearing for now til we get the money saved up to get our old block back and just rebuild it. Our old block had a good crank and everything on it just bad head. It's been a headache we bought this motor was suppose to be a good solid motor and it hasn't been. It is hard on gas for one. Extremely hard. We don't think timing is all the way correct. Got to fix shifting linkage bc it don't want to catch all gears. It was overheating to where the exhaust manifold was glowing Cherry red. Checked the flapper it was good. Took the Cadillac converter off it was clear. So idk. It still has a miss. It's a great solid truck of we could just get the motor worked out. Frames solid no rust on it except for a little surface rust lol. And it don't want to climb hills very well. It loses speed quick.... even if I down shift it struggles.

Manifold glowing is a lean condition. I would suspect a vacuum leak.

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Official Cookie and Mater Tormentor.

Ok I was wrong lol got it to tighten up had to clean cap up. Still going to rebuild a motor but we will see how this hold up. It's all standard bearing

Thanks. I'll check vacuum line again. I thought it was good but I do know before a couple weeks ago it blew the power steering line. The one that goes from the pump to the crap can't think of it but ya.. The pressurized one.. Idk how bc truck was idling. Just still getting bells and whistles worked out I guess lol

Chickabilly:
Over heated exhaust and poor performance & fuel economy are also a signs of retarded timing. Check static timing using a piston stop on number one to determine if harmonic balance has slipped and or is slipping, or wrong timing gage mounted on timing chain cover is incorrect from another year engine, or some other cause.

Once you figure out where top dead center on compression stroke is and if does not match up with timing chain cover gage, make some temporary marks to enable proper timing advance, and see if it runs better and cooler.

The reason retarded timing causes red glowing exhaust plumbing is the air fuel mixture is lit off too late in the compression cycle and is still burning as the exhaust valve opens along with some of the unburned mixture. a lot of that heat of combustion is dumped down the exhaust system and not able to be absorbed by water jacket. This lessens the power or force from the explosion applied to the piston as the burn all happens on the down stroke and some of the up stoke when exhaust valve opens.

Correct advanced timing setting starts the burn before top dead center and as piston reaches TDC said explosion is at peak force pushing piston down all before exhaust valve opens; this allows heat of combustion to converted into mechanical energy (moving piston) and excess heat absorbed by water jacket, transported via coolant to radiator where it is shed to atmosphere, and a lot less heat dumped to exhaust.

Vacuum leak also as Zilla indicated will cause a hotter burn. Depending location of said leak it could compromise just one cylinder due to a local intake gasket problem, or all six cylinders if it were located between carburetor's base and intake manifold, or from a bad power brake booster, other vacuum operated devices with leaks tapping vacuum from below throttle plates (intake manifold).

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Ok we will check that. It's been a project but he mentioned He's actually wanting to sell it. Just not something he's got the money to mess with. I'ts a great truck as we have already put so much money in it. Love old trucks but just don't have the money for it right now and need something reliable and easy on gas.