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TR2/3/3A Standard Engine Trust Washer Thickness

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mastaphixa

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The engine I am working on has had previous crankshaft work done as the main bearing shells are identified as being .010" under sized. The installed thrust washers have no markings on them. I have float of about .008". I can't tell if the thrust washer bearing area on the crank has been altered, so my question is, how thick are standard thrust washers? These washers measure between .090" and .094".
Thanks,
Steve Baker
 
What car? There is a tolerance in the tables, I'll look it up.
 
Sorry, TR3. I know the tolerance is .004" to .006". Problem is I am at .008" so I have to do something about it. As stated above, I can't tell if the crank had the thrust washer area machined and oversized thrust washers installed or not.
 
There are sized thrust washers. The shops usually don't mess with the side of the journals. +.001 on each side. Can plane outer side to make exact. Moss? Somebody has had to do a TR3 before, I haven't had to do them on a Triumph. Coming off a Holiday answers may be slow.
 
MOSS Europe has the stock thrush washers listed as 0.0925”. They have +0.005 available, one set might get you to the tolerance you are looking for, or possible just a fresh stock set will do it.
 
You have to take the journal cap off to install the thrust washer. Remove it and check to see ifnthrust washer is installed with oil groove towards the rod journal. Then you can see what has been touched.
 
The Roadster Factory has standard and .005.
 
Just one point--I'm looking at the spec in my TR4 shop manual, and it gives 0.004-0.006 "desirable." I'm not sure what that means, but it seems to say it's not a hard spec. Indeed, it gives a range of 0.0048-0.0117 in manufacturing, with a wear limit of 0.015. I find it amusing that they would spec such a wide range, but specify it to four decimal places. Strange.
 
I find that all the British cars I have rebuilt or worked on have pretty precise measures. More precise than the domestic American cars of that era. Basically, because all the manufacturers in England built race cars after coming down from war when they built fighter planes, bombers, tanks and artillary. My machine shop that does my precision welding was leery of tackling a slider on a gear because "those Brits knew how to harden and measure steel".
 
Your .008" is well within the new tolerance, and unlike the TR6 motor, these motors almost never have trouble with thrust washers.

Rather than go through the hassle of sanding down an insert, I would just put it back together at .008" unless you're going racing or something.
 
No racing here. So at what point would you be concerned with crank end float? I want to make a note in my manual.
 
I ordered the thickest washers and then used a glass plate, 220 wet or dry, and engine oil to sand them to the limit. If it has worried you for the last 11 days...why not do it right? It only took me 10 minutes to get the float spot on.
 
mastaphixa said:
No racing here. So at what point would you be concerned with crank end float? I want to make a note in my manual.
Click to expand...
What I do is buy both standard and .005" sets, then use the combination that comes closest (but not under) the "desirable" .004 to .006" range.

If using +.005" on both sides did not get down to the .0117" spec, I would consider doing something extra (like having the crank cheek welded up and ground down). But it hasn't happened yet.
 
Randall,
Thanks. Where is the .0117" coming from? If it is experience, I certainly respect that, but am I overlooking something in the manual?
 
Still not sold...here's another sales pitch.

The engine is inclined in the chassis, so gravity will tend to move the crank rearward. The crank, therefore, spends most of it's time riding gently on the front thrust bearing. Now you go to engage the clutch. First the free space must be taken up between the clutch forks and throw-out bearing. Then the throw out bearing picks up the crankshaft and must drive it forward until "clunk"...all the thrust play is removed. Now the clutch can be disengaged.


If the thrust clearance is .006". you will never hear the "clunk" engaging the clutch, and the crank will never make an audible knocking from end play. If you approach 1/8" thrust play, then you are significantly affecting the clutch throw available...and you will notice the "clunk" regularly when the clutch is engaged. 1/8" at the clutch is more than all the clutch fork free play available in a well-clearance engine/clutch. Later you my be wondering why the clutch drags, even though all the settings are spot on.

So far we assume everything else is spot on. If you have a cocked rod or piston, the endplay knocking could be constant at idle and low speeds.

If I have to worry about an excessive clearance for more than 10 minutes during an engine build, then that is a sign I need to make it right! If you have been concerned for more than 10 days and you leave the clearance large, then you will always wonder...!?! It's a cheap, readily available bearing. Why give it another minute's thought?
 
mastaphixa said:
Randall,
Thanks. Where is the .0117" coming from? If it is experience, I certainly respect that, but am I overlooking something in the manual?
Click to expand...

?? It's in both the TR3 and TR4 factory workshop manual.
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794pyHW.jpg
 
Randall and John, thanks. I was focused on the .004 - .006 in the remarks column. the .0117" makes sense now. I do have a new set of standard washers that just showed up from BPNW so I will play with those and see if I can tighten it up to the preferred spec. They included a Yorks Peppermint Patty with my order! Do they always do that?
Steve Baker
 
mastaphixa said:
They included a Yorks Peppermint Patty with my order! Do they always do that?
Steve Baker
Click to expand...

Generally BPNW do throw a handful of candy into every order as a thank you. However, they do sometimes forget.
 
On my engine for the Italia, I found 0.008" clearance with Std washers. Thus with the .005" oversize washers on one side, I measured .002-.003. I took the advise of CJD and ground the oversize down about .002. I now measure .004 clearance. As the center cap has some slight movement side to side (actually front to back), I had to fiddle with it a bit to get it even with the washer in the block. But the technique worked fine. I used 120 paper and then finished with 220.
 
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