Fellow vanagon types and so forth mores=

 

    With all the talk = about main bearings color codes I think I can clear the air on this subject. It= has been suggested that the difference in size of the blue verses red is .004= ths. The measurements I have taken show that the difference is .00025 ths. that turns out to be a 1/4 of  .001ths. Why they would bother = to make two different bearings sets with so small a clearance = change baffles me. The clearance for the main bearings is important and = hard to measure I have spent thousands to be able to do this accurately= every time. Plastagauge is nice but not the cure for knowing the clearances of the main and rod bearings and it has let me down = to many times.

    I have never found = the case measurements or the bearing clearances listed for the1.9 or  2.= 1 engines and I am not going to offer them today. what I will say= is that I have found the need to align bore most 1.9 blocks. the reason= is they loose the crush on the bearing over time  In layman's terms the= hole is to big.

As for the 2.1 block some are fine and some need to be align bored and there is only one way to tell. That = one way is with a top of the line bore gauge and a couple of hours to get the block clean at the mating surface and bolted together. I = can say that if the middle bearing web is out of round then it needs to be = align bored the other thing you need to know is that the crush is greater on = the 2.1 main bearings because they are a thinner walled tri metal design bearings.    

 

     The clearance = for the main bearings to the crank on the # 3 and # 4 bearings is= .002 to 004 ths. as taken from the type 2 Bentley book yes its = a different engine but the basic requirements of main bearing = clearances are the same and the journals dimensions are also the same. the # 2 splitshell  bearing is not the same in the = WBX 2.1 engines as the type 4 or the 1.9 engines. the type 2 book says the = min clearance is .0012 ths to .0035 ths. As for the WBX 2.1 I would not = want any less than 0015 ths on this split bearing to be safe. The # 1 = bearing next to the flywheel calls for .0019 to .004 ths I have found most cases with bearings installed to measure close to the high limit of = new spec. the wear limit is .0074 ths. WOW

    As for the rod = bearings I like my rods to have .0015 ths between the rod bearing and the crank journals the type 2 book lists .0008ths to .0027 ths as the new spec= this is for both the 1.6 and the 2.0 air cooled engines.

    I have = recommended not reusing the 2.1 rods over without having the bolts changed and resizing = the big ends of the rods

 

    I just finished and = test drove my 84 westy to the transporterfest in brookline MA.

with a stage 3  2.1 big valve = engine

 I'm really pleased with the = increase in power. I had some concerned about the injection system but the exhaust = gas tests showed everything is a go. I did have to back off the main spring = for the air door in the air flow meter to get the mixture set right. The = mixture adjustment was much more sensitive than any I have seen I think= the big valves are the reason. The flow bench showed a 20% increase in = air flow threw the heads at all valve lifts we tested. 

Because of the past shortage of WBX main= bearings I used a set of used main bearings in this engine with no problems the clearances where right where I wanted them and no oil light at = hot idle  

my new web page with lots of updates and= head flow chart specs for the big valve engines is almost ready and I will = keep you all posted

as always all right reserved

hope this helps

Bob Donalds

Boston Engine Exchange

http://www.bostonengine.com