Quick question on the crank bearings. I have a new set that should be here tomorrow. Looking at having my short block assembled over the weekend. Anyway the question...

I had the crank miked... It checks good. I bought standard sized bearings. Is there any reason what so ever to use that string gauge stuff? I can see why if reusing bearings but these bad boys are gonna be brand new. Thanks.

 

Another question... The bearing halves each have a notched side... Do these go together or on opposite sides? Thanks!

 

You still want to use plastiguage when checking new bearings even if it's new. I would...its a fail safe way from having to yank the motor back out if something is a miss.
The tangs face each other when you install. If I had a pic, id post it from my phone, but my Smort-fone doesn't let me.

 

I had a chance to ask a Ford tech... He said the same thing about the plastigauge. The tolerance is supposed to be about 0.002 or 0.003. Can anyone confirm this?

He said the tangs, as you referred to them, should be installed on opposing sides though. Any other opinions on this?

 

It's what you said. After looking at it again, I don't know why I said that. From my understanding, that's a locking feature, to keep the bearing seated and prevent a spun bearing failure. Maybe a wiser member can elaborate on the tang feature.
But, yeah plastigauge all rods and mains. Its so easy now, than later. I had around 0.0015-0.002.

 

I will do this tomorrow but what is the remedy if there are any gaps outside the tolerance?

 

The tangs on the bearing shell half's fit into a matching notches in both the block and main caps. You will also find these on each of the rod bearings.

 

The tangs locate the bearing in the fore-aft direction. Some of the newer production engines use bearings without tangs because they are set in place by a robot. If an engine spins a bearing, it will just wipe out the tang.

 

anyone that uses platigauge instead of a micrometer is a fool..

when you use plastigauge your crushing the bearing and then releasing and recrushing the bearing.

now i know, this was the way of engine building for YEARS... but it's not the best way anymore..

 

The machinist miked the crank and it checked good. He said it shouldnt hurt to plastigauge it but he didnt feel it was needed with new bearings. But a Ford tech and several people here advised that I should do it. Not trying to be a fool but I am getting conflicting advise from credible sources.

 

"Measure twice, cut once". Plastigauge is like $2.75, new bearings, $35-75, uniformity and peace of mind, PRICELESS!!!
Trying to turn engine over with breaker bar and socket and it won't, Low oil pressure, rattling, knocking, grinding noise internally, DEVASTATING.

 

I am gonna gauge it.

 

As far as notches and such for the tangs go, this thing is made pretty much idiot proof to keep people from screwing up the install. The bearings only fit one way unless you install a main cap backwards or something. I will update when I get to the connecting rods tomorrow.

My tolerances on the mains were as follows:

1 - 0.0015
2 - 0.003
3 - 0.0015
4 - 0.00175
5 - 0.002

They are all within limits so on to the next step. A cheap plastic scraper is the best tool for removing the plastigauge without scratching things up.