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Rebuild questions -- feeling a bit nervous

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Stupid kid on the block question again.

How many thrust washers are in my car?
How many should I order?
I have a 1968 TR250 block.

Given there are no Triumph mechanics on island,
I will be replacing the TWs myself. Are special
tools required?

d
 
Dale, I thought you recently measured the crank float, and it was well within specs. Why are you changing the thrust washers?
Jeff
 
Jeff,

Frank and I measured the end float by eye and by feel.
No forward movement "appeared" to the naked eye.

Given that everything else on the car was so totally
buggered up by the junkyard mechanic, what are the odds
DPO Pedro flew in someone from the States to change out
thrust washers?

I think I've got Pedro-ized engine just waiting to blow up.

A new engine I cannot afford.
Thrst washers, I am able to pay for.

d
 
Tinster, when I was reassembling my engine I measured the end float with a DTI guage mounted on a magnetic stand and literally had to move the crank by whacking it on the end with a dead blow hammer. Of course at this point the engine was dissasembled and mounted on the engine stand. tough to feel or visually see a 10 thousands shift in the crank, thus the use of the guage.
If you can use it I wont need it for awhile, so I wouldn't mind sending it to you, just send it back when you are through with it.

Regards, Tinkerman
 
Or you can buy a new dial indicator and magnetic mount, for not a whole lot more than shipping costs back to Tinkerman /bcforum/images/%%GRAEMLIN_URL%%/grin.gif
(under $20 @ Enco)

But my opinion is that, if you couldn't see the movement, then the end float HAS to be just fine. You've already run the engine too far for it to be too tight; and if it was significantly too loose, you'd be able to see the movement easily.

IOW, It ain't broke, so don't fix it !

To answer your original question, your engine would have had two pieces of thrust washer originally (each piece is a half circle). But they come two pieces to a package, so you would normally only need to buy one package. But, you won't know until you get the pan off whether to buy standard or .005" oversize; so some people just buy one package of each size.

Also, there is a common modification to add a third washer. No way to know until it's apart if your engine has that modification.
 
If you do buy new bolts, just be mildly cautious when threading into blind or semi-blind locations. A couple extra mm's of thread on a new bolt can bottom out in a rathole that's not deep enough. Leaving you with a tight bolt that's not doing it's job.
 
Sorry, I nearly forgot my question on this thread.

I thought that I read somewhere that there was a machined approach to modifying the rear of the block and bearing cap for these? Was it a Kastner mod?

Not that this is a bad approach, but while I have it at the machine shop is the time for that work to be done.

And Dale, I agree with Randall. Leave it alone if you can't see any movement.
 
Brosky said:
I thought that I read somewhere that there was a machined approach to modifying the rear of the block and bearing cap for these? Was it a Kastner mod?
Click to expand...
I do not know if the mod originated with Kas; but he does recommend it.
 
Randall,

Do you know what the mod that he recommended is/was? That is what I need to find out.

Thanks,
 
Brosky said:
Do you know what the mod that he recommended is/was?
Click to expand...
Kas is remarkably terse these days, so this is the best write-up I know of :
https://www.tr6web.com/Documents/tr6/mjbtwasherfix.html

In a nutshell, the bearing cap has a groove machined in one side, just the right shape and depth to accept another thrust washer half. This is done only on the rear side of the cap (where the thrust from the clutch is taken up). Then a small hole is drilled through the cap and washer half, and a pin inserted to locate the washer.

If done properly, this doubles the thrust surface area thus halving the pressure. With less pressure, the oil film never gets squeezed out and the bearings last nearly forever (like they did on the TR2-4 engine, which had full circle thrusts from the factory).

Probably the easiest way to deal with it is to ship the cap (I don't think he needs the rest of the block, but ask to be sure) to someone like Greg Solow:
The Engine Room
125 Front Street
Santa Cruz, CA 95060
(831) 429-1800

Don't have one handy to check, but I would guess this is also covered (probably with a diagram) in Triumph Preparation Handbook.
https://www.kaskastner.com/buybooks.html
 
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