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I just finished the milling...


olie05

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I just finished doing the milling on the thrust bearing. It needed to be milled 0.0019" according to my micrometer, so I took equal amounts off both sides. I used 320 grit sand paper and sanded in a circular pattern. I got the endplay to almost none at all(my measurements weren't accurate so I wont post them) but I could barely move the crank front to back. It still spun freely. It was much better than if I had sent it back to the machine shop for them to do it.

 

Moderators- I meant for this to be a reply to this post

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you want endplay!

In some cases, if you do not have at least .003" there will not be enough space for adequate oil flow across the face of the bearing, and some galling/wipeout may occur.

Especially withthe "clutch depressed before & during cranking" process used on many cars these days with clutch idiot switches...

 

I miss my old VW. I always started it in Nuetral, and after 98,000+ miles, the thrust bearing looked like new.

 

Tight is not always good...

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I just used the bottom of my micrometer where it has that little thing that comes down to measure different depths.

 

I just measured the endplay again and it was less than .003" but when I took it apart, the thrust bearing surfaces were very well oiled. While the crank was installed I checked thrust-bearing clearance with feeler gauges (first .003" then .002") and neither gauge would fit in either side of the thrust bearing.

 

I'm guessing I have something like .0005" endplay... so I guess I'm going to mill it down .0015" on each thrust bearing face. I'm just scared of having the crank floating around too much... :?

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You'd be shocked no know how much it DOES move/flex..

 

My L28 crank was rediculously polished, shot peened and balanced for 8000rpm redline.

 

Talk about flex....I was dragging the car, and was winding out 3rd and grabbed 4th and ended in 2nd! I floored the gas and nailed the clutch (when I realized what was happening) so as not to blow the engine...

 

It was ok... later on when we opened it up for other repairs, we noticed that I think #3 rod had "walked" forward and rubbed the block journal (not sure on my teminalogy here) anyways my crank had flexed in the middle and allowed one of the rods to move forward on the crank and rub the block....It was ok, but still... all that prep work, and that rod moved quite a bit......

 

Amazing....bullet proof engine that was...well except for the piece of hardend spring steel that got sucked into #5 and spat out the exhaust along with some piston....but that is another story....

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Before you take off much more of the bearing what you really need to do is to make sure the bearing edges are tight against the block. You may be dealing with a situation of the sides of the thrust bearing being bent out slightly. So if you make the bearing fit and then start running the car using the clutch and that stuff, you just may find yourself with to much end play in the crank, and I dont need to go into what that will cause.

If you have a spare crank, install that part and use a block of wood on the end of the crank and tap(hit) it with a hammer to make double sure the bearing is cradeling the block correctly. :D

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If you have a spare crank, install that part and use a block of wood on the end of the crank and tap(hit) it with a hammer to make double sure the bearing is cradeling the block correctly. Very Happy

 

That's what I was doing to get the crank to move front to back. I would just tap it (hit it) on the flywheel flange or the front piece.

 

... If I did this with the thrust bearing in there (along with the other bearings) shouldn't it have "cradled" the bearing against the block? And if that is correct then my feeler gauge tests and micrometer tests should be relatively accurate, right?

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