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Need advice on 1972 TR6 thrust bearings and main bearing

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RacingDreamz Avatar
RacingDreamz Ben Jones
Mountain City, Tennessee, USA   USA
This is a follow up on the issue with my clutch fork problem. Turns out, the clutch fork pin had been altered with a grade 8 bolt and is secure. So my mechanic tried to do a measurement on the crankshaft. He couldnt get a good reading so he took out the thrust bearings. They are measured at .09. He also said the main bearing 'cap'(?) looked worn and ask if I heard any 'slap' or knocking in the engine and how the oil pressure was. I told him I had never heard noises like that and the oil pressure was always real good. So my main question is, should I order the two sizes up for the thrust bearings, just in case, and the main bearing cap? Is the Roadster Factory the best place to order this from? Any other questions I need to ask my mechanic before I do order? Any advise will greatly be appreciated. smiling smiley

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poolboy Avatar
poolboy Ken D
Sandy Hook, Mississippi, USA   USA
Find out more about the main bearing cap and what exactly is worn ?
And the way to know in advance what size new TW's need to be is to measure the crankshaft end float with the old TW's still in place....then remove the old TW's; measure them to 3 decimal places...not just 2 decimal places and use that measurement to determine how much thicker than the old TW's the new TW's need to be to make the endfloat .006 to .008"
Just some accurate measurements and a little math...no guess work involved.



Edited 1 time(s). Last edit at 2017-10-25 03:43 PM by poolboy.

RacingDreamz Avatar
RacingDreamz Ben Jones
Mountain City, Tennessee, USA   USA
I just called him back with your questions. He tried to get his micrometer on the crank but with the engine still in the car, transmission out, it was too hard to get an accurate measurement. But the main bearing is 'worn'. So I'm going to go ahead and order all three sizes of TW's and a main bearing, just in case. I appreciate the input. It helped. smiling smiley

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poolboy Avatar
poolboy Ken D
Sandy Hook, Mississippi, USA   USA
He just doesn't want to or know how to do it correctly, because I assure you there's a whole lot of us shade tree mechanics that have measured endfloat with the engine still sitting in the car..

RacingDreamz Avatar
RacingDreamz Ben Jones
Mountain City, Tennessee, USA   USA
Well, I trust him but he's never worked on a TR6(didnt know what it was) so I'm sure he doesnt know how the best way to measure. What advice can I give him on how to measure the end float with the engine in the car?

poolboy Avatar
poolboy Ken D
Sandy Hook, Mississippi, USA   USA
Tell him to try feeler gauges....but the old TW's have to be put back into place and I bet he's not going to want to....too much trouble.
http://www.6-pack.org/j15/index.php/forum/15-mechanical-repair-maintenance-a-restoration/161183-end-float-09-both-thrust-washers-measure-092-is-this-right?start=45#161612

RacingDreamz Avatar
RacingDreamz Ben Jones
Mountain City, Tennessee, USA   USA
GOT IT!!! Thanks I'll save all this, print out the pictures and information and give to him tomorrow. I really appreciate all the help. smiling smiley

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Tonyfixit Avatar
Tonyfixit Tony M
Duncan, British Columbia, Canada   CAN
Check this out:

http://www.customthrustwashers.com/

Personally (being mathmatically challenged) when I am replacing TW's I put in a stock pair, then measure the gap with a feeler gauge to decide what oversize.

If your bearing cap is damaged I would VERY MUCH consider getting it machined to accept a full circle TW (see above site) and be done with the issue once and for all.

RacingDreamz Avatar
RacingDreamz Ben Jones
Mountain City, Tennessee, USA   USA
Thanks, Tony. I'll relay this to the mechanic. smiling smiley

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j007 Avatar
j007 Joseph M
Madison, Ohio, USA   USA
Our we talking about the main bearing being worn or the side of the bearing cap being worn?



Joe
73 Triumph TR6

RacingDreamz Avatar
RacingDreamz Ben Jones
Mountain City, Tennessee, USA   USA
Joe, I went by the shop today to look at the bearing cap he took off. It's just the side of the bearing cap. Worn down to the brass. Didnt look like too much wear, but some. There was some sludge in bottom of oil pan. Oil was very clean, but pan was sludge. No metal bits at all was found either. So that's good.

JimmyBb Avatar
JimmyBb Jim B
Verona, Wisconsin, USA   USA
Ben
Reading your post my first reaction was to tell your mechanic that since the sump is removed there are many places to set a dial indicator against and get an accurate measure. Since excessive endfloat manifested itself with with an investigation of your clutch we know the crank movement is large. If there is actual wear on the main bearing cap, that means that at some point the thrust washers were not in place. When wear gets excessive the thrust bearings can fall into the sump and leave metal to metal contact between the cast metal of the engine and bearing cap. It may be bad enough that new thrust washers will not stay in place. The best solution is with a machine shop. Even if you buy new bearing caps, the journals should be bored to be sure everything is perfect enough for the crank. Gets expensive. If you don’t want to spend that kind of money, there is a company out there that make solid bronze thrust bearing of any thickness you need. They will also machine your bearing cap and attach by screws a custom thrust washer that has been know to fix your problem. I’ve lost track of the company but it was not hard to find on line. Worh talking to the company owner. Think his name is Scott

poolboy Avatar
poolboy Ken D
Sandy Hook, Mississippi, USA   USA
The link to Scott Helms custom TW's is right up there in Post #8 by Tonyfixit.

RacingDreamz Avatar
RacingDreamz Ben Jones
Mountain City, Tennessee, USA   USA
Thanks, Jim and Ken. I gave the info on Custom Thrust Washers to my mechanic today. I'll talk with him again tomorrow and 'highly' recommend that he call Scott Helms also.

But again, a lot of what he told me is over my head as I'm not a mechanic in any shape or form. I dont even know what a main bearing or thrust washer does or it's use. So may be putting too much into this here. I dont know. But I am very appreciative for all the advice and help. I do relay all this info to him. Basically, I dont know how bad anything is really worn. I do know that NO metal shards or anything like that was in the oil when drain and in pan. I do know that the engine ran fine, quiet, no slap or knocks. Good oil pressure and good power. This is all I know. So if I seem ignorant to a lot of this, I am. smiling smiley Please excuse me for that. smiling smiley But I'll have him call Scott tomorrow. smiling smiley Thanks again.

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