Main-rod bearing dry film coating ?

[135sohc]

How much clearance does the film coating take away ? The crankshaft for my engine was in good condition and according to the shop only required a 'polish' to give it a fresh surface. How exactly much of a 'polish' this was I dont know but they said it was still well within the standard spec and with fresh standard bearings it would be fine. But I dont know how much I want to believe that...

[turbovanman²]

Coatings on the bearings are so thin you can't really measure it per say so it won't change your clearance.

[22mopar]

Microns. clearance have a tolerance because if stacking tolerances. measure you clearance and if it's good then run it. I intentionally over clearance my rod bearing since I turn over 7500 rpm and use 15-40 high zinc oil. my pressures maintain 50-60 psi full hot at idle

[turbovanman²]

That's the word I was searching for, microns,

[Directconnection]

That's the word I was searching for, microns,

More like "tenths of a thousand" (ie: .0001")

We use bearings from Calico and even though I don't do final assembly, I do see that coated bearings do make a difference in your sizes... but I forget typically by how much (doh!) ( I think .0005" total)

I will add, that you should measure your crank before doing anything else. Measure it in 3 spots: left, right and middle, then measure again at 90 degrees to that to check for "out of round" If they are a really good shop, then maybe they did a decent job of polishing it. If not... then it's REAL easy to put taper and make it barrell shaped. You want your journals to measure the same all across the journal, with no more than a few "tenths" difference (a few of these: .0001")

If your journals were polished to the point that they are a bit undersized, but show almost no taper or barrel shape (typically, this happens where the sanding "belt" overlaps if using a sanding belt prior to a polishing belt) then you can use a set of "ones" These are bearings that are .001" smaller in ID for reasons like this. Sometimes, to get our clearances right even if the rod's housing bores are right on the tightest side of the spec, we'll use only one of the .001 bearing halves combined with one bearing half from a standard set. Sounds odd, but we've done it in a pinch many times on extreme high performance V-8's. Not sure if you can get "ones" for a 2.2 or not....

[trannybuster]

^^What sucks is that I USE to be able to get clevites in .001-.005 or something like that but I cant find them anymore. Had know that was going to happened Id ordered two set of all....err

[thedon809]

I just bought some clevite main bearings in .001. I got my crank polished. The mains needed .001 undersized and rods standard.

---------- Post added at 09:49 PM ---------- Previous post was at 09:47 PM ----------

Here you go. Rod and main bearings in .001 for cheap. http://www.northernautoparts.com/ECa...ubmit=Continue

[135sohc]

Thanks!

Yeah I'm really not sure if I consider this shop good for anything but excuses on why my engine isnt done... I will be double checking everything and not just going on their word.

[22mopar]

if I had your motor it would not only be done by now, it would be blueprinted also. On all my motors, I use a deck plate when I bore/hone cylinders, I line hone the mains, recondition rods, ARP rod bolts, balance both ends of the rods, grind/polish/balance crank, chamfer oil holes, use file fit rings.

[Directconnection]

if I had your motor it would not only be done by now, it would be blueprinted also. On all my motors, I use a deck plate when I bore/hone cylinders, I line hone the mains, recondition rods, ARP rod bolts, balance both ends of the rods, grind/polish/balance crank, chamfer oil holes, use file fit rings.

Standard procedure of the "good" shops.

You left out "check rods for total straightness on Sunnen rod straightness fixture"

Mike, you'd be surprised at how many "shops" never check rod straightness, as that's real important to better ring seal (and bearing wear) I can tell when another shop (inferior) has done prior work to a motor. Rod housing bore mating surfaces aren't chamfered, oil holes in the pin bushings and piston pin bosses aren't chamfered, clearances off, taper honed into the housing bores, improper grinding/balancing of rods, etc...

I'd say a huge majority of the cost effective shops never run a mandrel through the mainline, as that costs money to do so on both ends (customer and shop) Some shops never polish the crank (whenever a groove or scratch happens in a journal, that material has to be displaced somewhere's, and it often leaves a slight raised edge on the left and right sides of said groove, so installing new bearings w/out a polish means it will scratch up the new bearings the 1st turn of the crank) Most shops never check the crank for straightness....

How do I also know this? Because a lot of customers that own their own rebuilding shops come to us for their machine work, and they often "cheap out" on these things.

We got one shop called AMS, and they do horrible work. customers go to them because they are the cheapest. We know why we can't compete, because they skip over 50% of the things we always make sure to do (and why some people think we cost too much.) They were rebuilding a stock 302 Ford and somehow torqued the rod down with the bearing shell overlapped. They initially brought the rods to us with ARP bolts just installed, but they never even re-sized or even checked the housing bores. My job was to press off the old pistons and hotbox on the new. They come back the next day with the housing bore torn out from the bolt hole. I had to take a ball peen hammer and shape it back into form and resize it then even after I told them it was junk. They came back the following day a frigged up the crank to block fitment, in which we again... had to fix.