It's going to be hot this week so I got out to the garage at sun up so I could do the cam tower assembly with sealant (Loctite 574 - orange goo) while it is 70 deg F not 90+ deg F.
During mock up I didn't bother to put in the oil return tubes (exhaust side from cam tower to crankcase), but this time it's the real deal so they must be installed. Notice these are the collapsing type tubes and I have installed them into the crankcase on the 1,2,3 side while they are still collapsed for shipping.
It didn't even dawn on me they needed to be expanded until AFTER I applied the sealant to the 1,2,3 bank cam tower - operator error! I corrected that mistake by expanding and locking in place by moving the cir-clip to the upper groove for the 4,5,6 bank.
All I could do was to move forward with getting the cam tower tightened and torqued down to the heads (in expanding / crossing pattern to 18.4 ft-lbs) - repeated the torque sequence 2 more times to make sure I didn't have any "movers", nuts that move a bit before the torque wrench clicks. Then I tightened and torqued down the heads to the cylinders (two steps: 7.4 ft-lbs first in pattern, then 23.5 ft in pattern) - same process, repeated 2 more times at final torque setting only.
Underside of cam tower cleaned with IPA using lint free wipes in the area that has sealant applied.
Sealant applied to the underside of the cam tower and used an acid brush to move the sealant around so it is applied evenly.
Here the cam tower on the 1,2,3 bank is installed on the heads and everything is torqued down.
The oil return tubes? I used a large (24 inch) pair of channel lock pliers to "pull" the upper section of the tubes into the cam tower while I held the lower section in place by hand. Then I moved the cir-clip to the upper most groove to lock the tube length.
Then I repeated the entire process for the 4,5,6 bank. After I got done installing the cam towers, I was rotating the engine on the engine stand and cleaning off excess sealant that had squeezed out from between the cam tower and the heads when I noticed there was something strange about the 1,2,3 bank cam chain.
When I looked at the 1,2,3 chain closely, I saw it was bound up. Then I looked into the crankcase and saw the problem: the chain had come completely off its sprocket on the intermediate shaft and was bound up against the front crankshaft counter weight of cylinder #4!!
I freaked out - and thought if I can't get this chain back on its sprocket, I'm going to have to tear this entire engine apart to fix it.
That episode lasted about 2 minutes, then I thought there has to be a way to fix this. If the chain could fall off the sprocket, then there must be enough clearance around the sprocket that the chain can be moved back onto the sprocket.
So I pulled out a long, thin flat blade screw driver and started poking at the chain in the crankcase. Then it dawned on me that I need to remove the inboard chain ramps to get move maneuvering room - so I removed both the upper and lower chain ramps.
With the chain ramps out of the way, I was able to fiddle with the chain and got it back onto the rear set of teeth on the sprocket - making progress. I continued manipulating the chain and was able to get it back on its sprocket and then I re-installed the inboard chain ramps. What a relief!!
Being thoroughly traumatized, I decided to continue working in the now hot garage and get the chain boxes, camshafts, idler sprockets, outboard chain ramps and mechanical chain tensioners re-installed with the required assembly lube and gasket sealer applied so there would be no chance for the cam chains to come off their intermediate shaft sprockets.
