Rear main seal installation and thrust bearing check sequence

[fairlaniac]

I’m about to do my rear main seal and drop the crank in on my 427/484 build. So I’m reading Barry Rabotnick’s book, Steve Christ’s book, Ford shop manual and reading on this forum “The Definitive Guide to Rear Main Installation” http://fepower.net/simplemachinesforum/index.php?topic=758.msg81517#msg81517
So when I drop the crank in it is suggested to install and torque #1, #2 & #4 caps. So I’ll assume the upper half of the seal should be in place prior to this. It looks like some folks smear some TA-31 or other sealant on the outside of the seal half and insert into the block and cap? Also lightly lubricate the seal lip. Then drop the crank in and put the 1, 2 & 4 caps on. Yes, the upper bearing halves are in place at this time. Then you address the #3 thrust bearing and check end play. Is this the first time checking end play? I don’t see in any books you are fully assembling the bearings and caps to check end play and pull apart to then install the main seal. To get sealant on the seal ends and with the crank in place. Are you using a tooth pick to put your dab of sealant on the end of the seal? Seems it could get messy otherwise? Then address the rest of the main seal and #5 cap as published. Does that seem about right? 

Thanks,

[64PI]

When I check for end play I install all the upper bearings, lube, install the crank, torque down the thrust cap with the lower shell in and check end play. Adjust if needed. I will install all other caps and bearings without the seal to make sure the crank spins freely. Then tear it back apart and install the seal.

Fred

[GerryP]

Assemble the crank into the block as this is it...the pans going on after this.  Install the seal and all caps with bearing inserts.  Torque down all caps except the thrust (#3).  Seat #3 and just snug up the cap but do not bring up to torque specs.  Around 10 ft/lb should do it.  Get a deadblow hammer or a regular heavy hammer with a block of wood.  Give the front of the crank a couple of good smacks with the deadblow or, using the wood block to cushion the crank and hammer the wood block.  This aligns the bearing halves.  Now, give the rear of the crank a couple good smacks (or again, using the wood block as a cushion and hammer the wood block).  This seats the thrust in position in the block and cap.  You can use a wedge or a large screwdriver to hold the crank in position while you torque down the cap and measure your thrust with either feeler gauges or a dial indicator.

[blykins]

I try to do the crank thrust check early into the game, because there are lots of times where the end play has to be adjusted by sanding the thrust bearing halves.  The upper thrust bearing can sometimes be a culprit. 

I don't like checking at the end with the cap on because if there is a tight spot or tight clearance, you don't really know which thrust bearing half was responsible for it.  If you check the upper, write your measurement down, then check thrust with the caps on, you can see if or which bearing needs to be adjusted.

With the thrust cap on, you will need to align the thrust bearing halves.   Smack the snout with a dead blow, then walk around and smack the crank in the hind end, tighten the cap, then take your thrust measurement. 

On final assembly, you will need to hold forward against the crank as you torque the caps.  Sometimes you can wedge a screwdriver in between the block and a counterweight to free up an arm. 

[My427stang]

I do it just like Brent

1 - Check all bearing clearances, drop crank in
2 - Check end play with the bottom in
3 - Check with the thrust cap on
4 - Assemble rear main seal last

What I didn't do before, that I do now, is a quick clearance check and torque all 5 before balancing.  I still check at final assembly, but do a quick one before.

I had a SCAT crank that had a poorly machined oil slinger on the rear main.  I had the crank finished, and when I went to put the rear main cap on the engine wouldn't turn. Odd because I measured run out, block was line-honed, and all clearances were spot on.  Head scratcher for a moment, because if the mains are in alignment, clearances are good, and runout is good, what could bind?

Turns out, the crank slinger was hitting the cap at final assembly.  SCAT machined it incorrectly.  It was easy to fix, but it was mine to fix because I had already balanced and polished the crank.

In the end, I try to work as efficiently as I can, but SCAT now convinced me to do a check before balancing, which sometimes is a pain based on timing of other parts being ready.  Not your question of course

In the end though, the rear seal doesn't go in until I am ready to be done with everything associated with the mains