Main bearing clearances too tight - 200tdi

[AceOfHearts]

I'm currently rebuilding a 200tdi for my Landrover and just getting to the point of putting things back together. Crank has been polished but checked out ok at standard sizing. New bearings are standard size quality items.

Bearing clearance spec is 1.2 to 3 thou. Caps 1, 3, 4 and 5 are at (or very close to) 1.5 thou which I am happy with



Cap 2 is at 1 thou though so slightly too tight



I know much worse has probably been left in old Landy engines but I want to do this right and do this once! I have stripped, cleaned and double checked with the same results. I will call the engine shop tomorrow and see what they say (will probably get journal 2 polished slightly more to bring it into spec).

Anyways i know the machine shop has a great reputation and will give good advice, but I just thought it would be interesting to hear what you guys would be doing. I have heard some people take abrasives to the white metal bearings to increase clearance but that definitely doesn't sound right to me!

So what is your vote?

-Leave it
-Crank polished again
-Scrub the bearing

[GreenV8S]

Have you actually measured the crank? If not, do that before you consider any other options. (You seem to be assuming that the crank is oversize but I don't think you have proved that yet.)

[AceOfHearts]

I haven't got a micrometer large enough but the engine shop that polished it said that it was within standard tolerances

[GreenV8S]

Suggest you ignore the plastigauge. If you've got concerns about clearances then measure the parts properly or get them measured properly.

[Boosted LS1]

Bit of a long shot but swop the bolts and then retorque to the same values. Also have a close look at any bearing tangs and champher if they're fouling. Are the shell sitting nicely, are the backs clean. Same for the engine.

[stevieturbo]

Is the crank straight ?

Is the block straight ?

[Mignon]

Obviously there are three intentional things that can affect a bearing clearance. The journal size, the housing size and the shell thickness. Dirt or burrs could of course be non intentional factors but only you can check for those. You really should at least have micrometers of the right size if you intend to do this sort of thing properly and they aren't that expensive, especially the Polish ones that most places sell and well known makes can be found s/h on Ebay. However even without equipment a simple check you can do is swap the bearing shells from another journal and test again with plastiguage. If nothing changes the next step is measure the journals but it's very unlikely just one of these is a different size to the other four.

If the journals also check out ok then it's either housing bore diameter or dirt/burrs. Go over the split lines in the block and cap with a fine engineer's oilstone to deburr them and also wipe over the shell seating surfaces in the same way to remove any high spots.

[CrutyRammers]

You can pick up micrometers for peanuts on ebay - a 25-50mm Moore and Wright on there now for about 6 squid. Gotta be worth a few quid just to be sure...

[one eyed mick]

I will probably get excomunicated for the following If all preceding SENSIBLE advise has been followed I.E. cleanliness ,burrs etc simply wipe out the pair of shells with some Soft! cloth and a little of the thin liquid in an unshaken tin of Brasso lightly ! clean scrupilously ! and re check , may need a couple of wipes !!