Upper and lower rod bearings.
Thread Starter
10 Second Club
Joined: Jan 2010
Posts: 2,317
Likes: 20
From: Hurley, VA
Upper and lower rod bearings. Ok it's late and I was doing some reading while half asleep. I just dropped my 408 in today but I'm having a OCD fit because I can't remember if I had the upper and lowers in the right spot. I've either got them all right or all wrong. The bearings looked identical and I actually had the rods in and out of the motor twice and the engine was turned with them installed several times by hand but I had to remove them all because the machine shop messed up the cam bearings. Everything turned free and they were no marks on the crank at all I'm just kinda panicking last minute because I can't remember. Would it really make a difference? If they were backwards would it have been noticeable ( marks on crank, binding etc) ? It's a tsp crank with clevite h series bearings? Do I need to pull the oil pan and make sure before I start it?
Staging Lane
Joined: Jun 2013
Posts: 90
Likes: 39
If you have correct rod side clearances then bearings are probably in the right places. If you don't, then you have problems. The rod bearings have a chamfer that must face the fillet on the crankshaft which is why they have a upper and a lower. If you have them on backwards or wrong with most aftermarket cranks the side clearance will be tighter than normal which on aftermarket rods is usually around .020-.025 or so.
Thread Starter
10 Second Club
Joined: Jan 2010
Posts: 2,317
Likes: 20
From: Hurley, VA
The machine shop set the clearances honing the rods and line boring the block. We just did the assembly. I'm pretty confident they're in right now after thinking about everything. Wouldn't I have noticed it being tight when turning it if they were in wrong?
I'm pretty sure that the Tangs are offset on the top and bottom rod ends to avoid this problem. You would have seen them poking out one side the rod, and likely wouldn't have been able to install both rods on one journal.
