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General Tech Rebuilding the Engine

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KVH

KVH

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I'm rebuilding my TR4A engine and I'm trying to recall some basics. It seems I can't check crankshaft end float until after I torque all three of the main bearings and then, if the end float is wrong, I'd need to loosen the center main cap, remove the thrust washers, and repeat it all over again each time I check or recheck. Is that correct? Also, as for plasti-gauge, it seems I'd have to torque all three main bearings and then loosen and repeat all three if I needed a different undersize bearing. Am I recalling things correctly. Finally, what kind of assembly lube do you suggest? Some folks say white lithium grease, some say simple motor oil, and others prefer a professional grade grease "labelled" as an assembly lube.
 
Yes.
Yes.
White Lith will work if the engine will be installed & run in soon after rebuild. It tends to 'dry out' over time.
"Red Line Assembly Lube" would be better short term, but any of the sticky synthetic red grease lubes would work.
 
Yes, that's basically it. If the end float is off, you can get thrust washers of a different size. But they are in 5 mil increments, as I recall, and the spec is 4-6 mils. But in the table on p. 1-104 in the shop manual it says this is "desirable," whatever that means. Just get as close as you can.

You can get bearings in 10-mil increments, but the clearance is specified at 1.5-2.5 mils. If a clearance is off by, say, 1 mil, a different bearing obviously won't fix that. The plastigage is mainly valuable as a check, to be sure all is in order. If you miss the clearance spec, you need to start measuring and see where the problem is.

Hap Waldrop, who hangs out in the Spridgets forum, is a high-end engine builder, and he strongly recommends molybdenum assembly lube. You can get it anywhere; I got mine from Napa. A tube of it will last through several engines.
 
I'm having a problem with what I'm seeing in the rear main seal installation instructions. This is my viton seal after-market one. The statement is very clearly made that after bolting the two halves of the aluminum seal to the block and rear main cap, with the bolts not fully torqued, you are to tap the halves further toward the centering tool to assure proper fit, and then fully torque the halves. The tapping presumably is to adjust fit in case there's some play through the bolt holes or otherwise. After tapping, you torque. This seems to make sense until you actually try it. The two halves are perfectly mated, and tapping one just impacts and moves the other. It sure seems to me that unless you're dealing with something really sloppy in the manufacturing of the seal halves, there's no sense in tapping either half. If they mate together around the centering tool, you should be done. If you tap, rap, or bang, assuming there's some nominal clearance, you're just moving both around for no purpose. Am I missing something? I'm open-minded, just puzzled. (He says while holding his big tapping hammer).
 
It may be a poorly worded instructions.
I seem to remember the centering tool was clamped tight by the main bearing cap. Holding the Seal halves as you tighten should do it but Light taps may help keep the halves in close contact with the centering tool just in case the halves move as you tighten the bolts.

David
 
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