rear main thrust

[Lawrie]

Would any one have the dimensions to the rear main thrust face,maybe from the rear main bolt hole or such,
I want to machine the block for the inserts and three piece thrusts and would like an accurate measurement for them.
I have the info that comes with the three piece thrust washers ,but they just mention the depth and diameter.
Lawrie

[Dave in MN]

Lawrie,

IMO: The dimension from the rear main bolt can change depending on the distance between the thrust faces of your crankshaft. Note on the instructions from the manufacturer that an equal depth counter bore is specified for the front and rear.

When using three thrust washers, I measure the crank, subtract the desired clearance and then have the overall for the thrust surfaces. I try to keep the depth of the counter bores equal. For final adjustment of end clearance, you can always remove a bit of material from the back side of the thrust washers. To decrease crankshaft end play, I have silver soldered the back side of the front thrust washer to build thickness and then removed solder until it was exactly where I wanted it.

If you want to get more accurate in crank position, you would need to take into account the wear on the thrust surfaces of the crank. One would likely need to reference a known original surface on the slinger. Can't use the crank flange to flywheel surface as it may have been surfaced.
Good Day!

[nick c]

I agree with Dave about the numbers. You probably already know this but I will mention it anyway, to line bore the block for inserts the most important dimension is the distance from the center of the camshaft to the center of crankshaft which is 4.155 + or - .001, those that don't use that might have a cam and crank gear that is too tight or too loose.
carry on nick c

[George Miller]

I do mine a little different. If the thrust is not worn real bad on the crank. I use a thrust oil retainer from Snyder's. Then I mike across the block with the thrust in the block. Then subtract the thickness of the thrust washer. now bore the font of block to that depth. Then I put the cap in the lathe and bore flywheel end for a thrust.
Then you do not have to pin the thrust. One thrust is all you need on the front.If you want to use two then you will have to pin them so they do not rotate.

To bore the cap in a lathe I bolt two rear main caps together around a round shaft the size of a crank shaft . It works really good. But you have to have the shaft running dead on or you will have a mess.

[Dave in MN]

Originally Posted by George Miller

I do mine a little different. If the thrust is not worn real bad on the crank. I use a thrust oil retainer from Snyder's. Then I mike across the block with the thrust in the block. Then subtract the thickness of the thrust washer. now bore the font of block to that depth. Then I put the cap in the lathe and bore flywheel end for a thrust.
Then you do not have to pin the thrust. One thrust is all you need on the front.If you want to use two then you will have to pin them so they do not rotate.

To bore the cap in a lathe I bolt two rear main caps together around a round shaft the size of a crank shaft . It works really good. But you have to have the shaft running dead on or you will have a mess.

George, On "A" blocks, I also use the combination seal and thrust.
(I purchase them 20 to 25 at a time from Bert's...Steve has them manufactured.) I follow exactly what you do in your description. I have a mandrel machined to the required housing bore for the inserts and a center cap also bored to the housing bore. After the rear main cap is line bored, I use the described set-up to turn the pocket for the rear thrust. The machined center cap is used with bolts to clamp the line bored rear main cap to the mandrel. I have a dedicated tool post and bit for this operation for quick set-up at my lathe.

For "B" blocks, I do what I explained in my first post. Lawrie is using three thrust washers so he cannot rely on the consistent fitment of the combination thrust and seal.
Good Day!

[Lawrie]

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Thanks , I will be using a new burlington crank,
Lawrie

[nick c]

Dave, is there something special about Berts seal thrust other than they cost less?
thanks

[Dave in MN]

Originally Posted by nick c

Dave, is there something special about Berts seal thrust other than they cost less?
thanks

I think they are exactly the same. Steve, at Bert's, may supply the other vendors. It has been so long since I have purchased them from a source other than Bert's...
Good Day!

[Kohnke Rebabbitting]

We use a C to C of 4.156-50.

Herm.