Do Cyl Head Bolts need lube/grease when Installing? + Change only rod shells of Rod/main bearings reusing old Cap shells?

[JohnelP]

two separate questions, but I do not want to create two threads
Do Cyl Head Bolts need lube/grease when Installing? - Reason for asking: manual says to have the head bolt hole/bore totally clean without any oil, as torqueing the head bold with oil in the bore pushes oil to damage the cyl head. And make sense. However, i see some opinions mentioning the threads of head bolts should be greased.
Right or wrong?
Same question for the connecting rod bolts.

2nd Question - This is a "what if" question. Can you change only rod shells of rod bearings, reusing old Cap shells?
I know the logical right way is to change both shells, and i agree with that.
However, as a philosophical question, given the cap shells wear much less than the rod shell - as power stroke forces more rod shell, and less the cap shell, if one decides to change only the upper shells, and reuse the lower-cap- shells, would that be an "OK"/"so be it", or is it a No No.
Assume crankshaft / journals are OK and the hybrid plastic-gauge measurement remains within specs.

I am thinking the concern would be that there are -even if tiny - differences in the thickness of the shells, and the joint of the shells may not be smooth - but a tiny step - that would create trouble to the oil film and may scratch the journals. But I guess this is valid if both bearings are new, as you cannot have perfect equal dimensions.

OK or NoNo?

 

[Crates]

Im assuming you are talking about factory parts vs aftermarket, which often have their own unique requirements.

In general the factory head and rod bolts only call for a light coat of engine oil to the threads and under the head of the bolt prior to installation. I’m not aware of any OE requirement for grease. My plant builds the 3.5 ecoboost for the Ford GT, the 5.0L Coyote crate engines and most of GM’s LS based crate engines. We only use engine oil except where required otherwise (i.e. aftermarket rods). Follow the factory service procedure for torque/angle requirements explicitly.

Regarding rod bearings, always replace them in pairs. Pay attention, some are unique to the rod and cap ends. Generally they are stamped as such (upper/lower).

 

[JohnelP]

Thanks.
Bit of follow up on main bearings. When checking the main bearing play, practically you have to put plastic gauge on all main bearing journals "at once" - including thrust bearing ??? - and later, after haven placed all plasticgauges on all main journals tighten all main bearing caps in the same "spiral" sequence - similar to head bolts tighten sequence. You cannot measure the main bearing play by tightening only one main bearing at a time (like rod bearings), right?

When measuring the longitudinal play for thrust bearing, the main bearings must all be installed, right? Some folks measure the axial play when crankshaft is just placed in the block, without tightening the main caps. Right or wrong?

 

[Crates]

Thanks.
Bit of follow up on main bearings. When checking the main bearing play, practically you have to put plastic gauge on all main bearing journals "at once" - including thrust bearing ??? - and later, after haven placed all plasticgauges on all main journals tighten all main bearing caps in the same "spiral" sequence - similar to head bolts tighten sequence. You cannot measure the main bearing play by tightening only one main bearing at a time (like rod bearings), right?

When measuring the longitudinal play for thrust bearing, the main bearings must all be installed, right? Some folks measure the axial play when crankshaft is just placed in the block, without tightening the main caps. Right or wrong?

The main bearings are select fit based on the letter grades that are stamped on the block and crank. There is a table with all the corresponding grades - you use the factory grade info to select which bearings are required for each journal. On some engines this is also done for the rod bearings, but most are one size. If your crank, block and rods are all original and not damaged I would recommend using the factory method of determining which bearings you need.

The thrust is a bit more involved since the main cap is not doweled and must be set correctly before its torqued. We use a special fixture that pulls the cap rear ward while thrusting the crank forward. I would suggest getting the repair manual and following the recommended service procedure that is outlined for setting the thrust. This is very important since the torque converter applies forward axial load to the crank and it’s important that the load is shared equally by both the upper and lower thrust bearings. Crank endplay is checked after you set the thrust and torque the main caps.

The crank thrust is checked by mounting a dial indicator to the front of the block and indicating off the front nose of the crank (you could also mount it at the back if that is easier). You can use a screwdriver in between either side of the cap and the crank counterweights to move the crank fore and aft.