[Tom Vaught]

All of the little details: "tricks" helps make a better engine at the end of the day.

If you assume that there will be things wrong with the engine/assembly and double check everything, typically you WILL find stuff that can be made better.
Be it removing the raised spots on the bearings, triple cleaning the oil gallerys with soap and water and then a good flush, Turning the crank after every torque increment on each main cap to make sure all is still turning smoothly.

Tom V.

[hurryinhoosier62]

Originally Posted by ReelFun

No, no align bore or hone on the block.

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OK, then you need to look at the crank and the thrust bearing itself. The crank was ground .010 under, right? When this machining was performed, the crank grinder SHOULD have "bumped" both side of the thrust flanges(unless he was doing a plunge cut) to ensure a ridge was not left in the radius of the journal. If this was NOT done, the thrust bearing is hitting the ridges (zero end play). If there is no ridge in the radius and the thrust flanges have been machined, then insert the thrust bearing half in to thrust flanges on the crank. There should be some play (.003-.005 is the minimum). If there isn't, the bearing is too wide.

[ReelFun]

Thanks everyone for the advice. I haven't had a chance to check some of these things you all have brought up but rest assured , I will be following up. I want to get this done and in the car, but I want it to be right. Keep 'em coming.

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[mgarblik]

Hurryinhoosier62's posts are both what I would do next. If this was the block you were running before the rebuild and the mains were NOT machined, it is safe to assume the block and caps are OK or at least as good as they were for the past 50 years. What has changed is the crankshaft, so that is where you need to look now. If you measured .002 with plastigage, although not the most accurate method, it tells you you have oil clearance and I guess the taper was OK, you didn't say. You have located a zero thrust clearance, so that is likely the problem area. Now is the issue the crankshaft grind or the thrust bearing? Remove the crankshaft, check the clearance between the #4 shell and the crankshaft flange. .003-.005 as stated is good with a feeler gauge. As a double check, reinstall crankshaft with just oil for lube and leave out #4 bearing. If it turns with 1 finger, you have isolated the problem. Good luck.

[ReelFun]

Sounds like some good advice. I will be checking these things as soon as I can. I have a feeling it has something to do with the thrust bearing area. So I think taking it out and reinstalling the crank with 30 weight oil without the thrust bearing will provide some answers hopefully.

[gtofreek]

I wouldn't be a bit surprised if the block main housing bore is out of alignment. The factory has different thickness bearings to deal with the issue, the aftermarket does not. This is why we align hone pretty much everything. I have put many Pontiacs together that were tight to turn, but turned perfectly easy after align hone. The factory align bored them, and they were not always in perfect alignment.

Pulling the crank, and inspecting the bearings, will tell all.

[hurryinhoosier62]

Originally Posted by gtofreek

I wouldn't be a bit surprised if the block main housing bore is out of alignment. The factory has different thickness bearings to deal with the issue, the aftermarket does not. This is why we align hone pretty much everything. I have put many Pontiacs together that were tight to turn, but turned perfectly easy after align hone. The factory align bored them, and they were not always in perfect alignment.

Pulling the crank, and inspecting the bearings, will tell all.

You beat me to it, Paul. That was going to be my next suggestion if the crank still wouldn't turn.

[Tom Vaught]

Couple of questions for the original OP. See below:

1) Where did your get the 389 Engine? (History on the engine).

2) Did you take it out of a vehicle? If so how many miles on the engine?

3) Did you ever spin the engine over with the rods off the old engine before the
crank was cut .010"/.010" ?

4) Was this a "Basket Case" of parts that you are putting together?

Tom V.

[ReelFun]

1) Where did your get the 389 Engine? (History on the engine).

2) Did you take it out of a vehicle? If so how many miles on the engine?

3) Did you ever spin the engine over with the rods off the old engine before the
crank was cut .010"/.010" ?

4) Was this a "Basket Case" of parts that you are putting together?

Tom, in answer to your questions:

1)I bought it from a guy in Charlotte NC. Unknown history. It is a 66 YS block. 093 heads.

2) No, it was already removed and in a garage. It has been rebuilt in the past. Went .30 over on the borethis time. It did have a broken ring on one of the cylinders.

3) No.

4) No, it was together minus the intake when I bought it. I bought it intending to rebuild it.

[lust4speed]

Simplest explanation might also be crap bearings. Every set seems to be just a little worse than the ones purchased before it. I'm probably not the only one experiencing this. Thickness of bearings is all over the place now, and this includes the thrust bearings - one set will drop in and I can slide the bearing around in the saddle, next one might be ok in diameter, but be oversize on the thrust surfaces. Drop in the old bearings and they fit fine.

[steve25]

Broken rings and piston ring lands where common on 389 and 421 motors if the for whatever reason where knocking!

[hurryinhoosier62]

Originally Posted by lust4speed

Simplest explanation might also be crap bearings. Every set seems to be just a little worse than the ones purchased before it. I'm probably not the only one experiencing this. Thickness of bearings is all over the place now, and this includes the thrust bearings - one set will drop in and I can slide the bearing around in the saddle, next one might be ok in diameter, but be oversize on the thrust surfaces. Drop in the old bearings and they fit fine.

Good point, Mick. What everyone needs to remember to do is check EVERY part before beginning assembly. That way, you avoid headaches.

[dataway]

If you pull it back apart .... next time you check for crank rotation do it with only a light oil lube, like motor oil or something. Some assembly lubes can add quite a bit of resistance to rotation ... at least it did on my engine. With just motor oil and no seal I could grab a counterweight and give it a whirl and the crank would spin around more than a full turn. With assembly lube added ... about 1/2 turn. I could turn the crank by hand at the snout with oil fairly easy, with assembly lube in it and rear seal in, could be done, but not easy. Assembled with pistons in and no cam .... think I was getting about 25 ft/lbs to turn.

In all instances the "break-away" torque was easily twice as high as the turning torque.

[ReelFun]

OK, here is an update. I took the crank out and cleaned off the assembly lube from the crank and bearings. I reinstalled the crank minus the thrust bearing using only 30 weuight oil as a lube. Everything turned smoothly and easily. Also had some fore and aft movement on the crank thrust. So I guess the problem lies with the thrust bearing.

The thrust bearing also had some shiny area on the edge. I tried to attach a couple of photos and a video but I was having some trouble with that.

So, should I replace the bearing with another one or try to reinstall the thrust bearing using the oil and see what happens?

[hurryinhoosier62]

Originally Posted by ReelFun

OK, here is an update. I took the crank out and cleaned off the assembly lube from the crank and bearings. I reinstalled the crank minus the thrust bearing using only 30 weuight oil as a lube. Everything turned smoothly and easily. Also had some fore and aft movement on the crank thrust. So I guess the problem lies with the thrust bearing.

The thrust bearing also had some shiny area on the edge. I tried to attach a couple of photos and a video but I was having some trouble with that.

So, should I replace the bearing with another one or try to reinstall the thrust bearing using the oil and see what happens?

If you can, measure the thrust bearing width (installed in the cap and block) compared to the inside width of the thrust flange on the crank. You need a minimum of .003-.005. By "edge", do you mean the inside edge or the outside edge? Personally, I would try a different bearing before attempting to sand one down to fit. Thrust flange finish and bearing finish is critical.

[TedRamAirII]

I think you should put all back in, turn main bolts all in just snug tight, pry crank fore and aft a few times. then torque all bolts. See what happens.

[ReelFun]

It is on the inside surface near the outer edge.

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[wheneaglesfly]

Originally Posted by ReelFun

It is on the inside surface near the outer edge.

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Sounds like the crankshaft thrust Radii was not set correct.
I think Tom mentioned that prior.

[hurryinhoosier62]

Originally Posted by wheneaglesfly

Sounds like the crankshaft thrust Radii was not set correct.
I think Tom mentioned that prior.

Not necessarily. A ridge in the radius would prevent the crank from moving fore and aft, but it should still turn. This is either a clearance or alignment problem.

["QUICK-SILVER"]

Originally Posted by ReelFun

It is on the inside surface near the outer edge.

Is the 'shiny' the same on both upper and lower thrust bearings?

Really need to see the pics. We need a volunteer that the OP can send the pics to and then post them here. Come on Pontiac people.