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glemon
10-22-2008, 11:27 AM
Dueling Manuals---

The Haynes manual shows a washer underneath the gear that drives the cam and oil pump--it also says the float or play on this gear should be adjusted or it will wear out quickly.

The TRF Factory reprint of the TR250 parts book shows no such washer--nor do the Moss or VB catalogs.

I don't think my motor had one when I took it apart, but I cannot say for sure.

Anybody dealt with this issue or have any thoughts.

I started to assemble the gear and piece that goes over it and had quite a bit of free play, my thought was to take the gear to the hardware store and look for washers of the appropriate size and thickness and fit one, but would defer to any knowledge or experience on the subject that forumites may have, the gear I am referencing is Triumph part number 126785.

I am trying to follow the do it once do it right school in the engine rebuild, but this one has me scratching my head.

TR3driver
10-22-2008, 11:52 AM
Are you sure that illustration with the washer isn't demonstrating how to check the clearance for the gear? You measure the washer, then measure how far it holds up the distributor pedestal. The difference between the two measurements is the clearance (once you remove the washer).

I believe the clearance is adjusted by installing multiple gaskets under the distributor pedestal. If there is too much clearance with only one gasket, then you need to replace the bushing under the gear.

At any rate, there are numerous mistakes in the Haynes manual, so I would ignore it in case of conflicts.

glemon
10-22-2008, 12:05 PM
I'll take another look at the manual, I don't have it with me here, I did get three or four shim gaskets in my gasket set.

But I don't recall seeing any specs for the washer thickness in the Haynes book, don't know how it could be of use to fit and measure without a specified thickness.

Greg

Moseso
10-22-2008, 01:06 PM
I'll take another look at the manual, I don't have it with me here, I did get three or four shim gaskets in my gasket set.

But I don't recall seeing any specs for the washer thickness in the Haynes book, don't know how it could be of use to fit and measure without a specified thickness.

Greg


The specified thickness is what you measure it to be. I used .0625". Then you do the math and set it for the proper clearance.

What they don't tell you how to do is <span style="font-style: italic">decrease</span> the clearance if there's already too much with no shim gaskets. My bushing fit the distributor drive shaft just fine and I didn't want to replace it, so I knocked it out of it's bore, made a .012" shim washer to fit under it and put it back in on top of the shim washer. THEN I could fit a couple of gaskets under the distributor pedestal.

TR3driver
10-22-2008, 01:10 PM
But I don't recall seeing any specs for the washer thickness in the Haynes book, don't know how it could be of use to fit and measure without a specified thickness.
When you use it for checking the clearance, the washer doesn't need to be a particular thickness. Since you subtract the measured thickness at the end, the answer comes out the same.

Say for example, your gear actually has .005" of clearance with no gasket installed. You grab a washer that happens to be .100" thick, do a test assembly with it, and measure .095". .100" minus .095" gives you the clearance of .005".

If you try again with a different washer, that happens to be .150" thick, then you will measure .145" and the difference (clearance) is still .005".

Either way, you take out the washer, then add gaskets as needed to get the specified clearance. So, again for example, if the spec is .015" to .019" (obviously I hope, these are all just made-up numbers, I don't recall the actual specs offhand) and the gaskets are .004" thick, you would need to use three gaskets.

This is a fairly standard technique for this kind of measurement.

glemon
10-22-2008, 04:49 PM
Homer Simpson Dooh! moment, I think I get it, do you measure the clearance from the gear cover to the block with the washer in?

Greg

TR3driver
10-22-2008, 05:13 PM
Yes, exactly.

glemon
10-22-2008, 09:04 PM
OK, I feel slightly less dense, I looked at the Haynes book, it doesn't really outline the measuring procedure at all just shows a pic with the washer I originally asked about, I have an Autopress book and a Brooklands reprint of the shop manual that lay it out much better in the text (using the same pics)

Thanks for the help,

Greg