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Setting up new Crown Wheel & Pinion - does this look right?


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I have finally got around to installing the new 3.45 CW&P that I obtained yonks ago. My TR3a has got a 2.2 litre engine along with a slightly hotter cam; a TR4a head, manifold and carbs and a Phoenix exhaust. As a result it has always felt undergeared.

 

I have set the pinion to what I think is the right depth using my new pinion depth gauge (thanks Bob Le Brocq) but it's not straightforward because the top of the pinion (which is where I am measuring from) is not absolutely level. It varies by about 2 thou across the pinion, so I have set it somewhere about the middle.

 

Attached are some photos of the mesh pattern. The 'drive' side looks pretty good to me but I wonder if the 'overrun' side looks a bit too deep?

 

Anyone got a view?

 

Rgds Ian

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Very difficult to say from the pictures,

It seems Pic 1 shows the load side

and imprint is a little bit too much to left bottom

of picture what is tip of the tooth.

 

Anyway I mostly found that only the load side must

be correct and the not load side always was a bit

away from perfect. That seems to be normal on

our spare parts.

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I agree that pic 1 shows the load side as being a little bit away from central but my view is that it is not enough for it to be a problem as the vast majority of the tooth is in good contact. On the overrrun side there isn't anything like the same amount of load being transmitted so again in my view I don't see it as a problem.

 

I admit that this is only the third time I have set up a CW&P so my experience is pretty limited, hence I wondered what the assembled wisdom on this site thought before i button everything up and re-install the axle.

 

Rgds Ian

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Is them piks wid a fair bit of load on them

IE, done wid a bigg prybar,or chisel holding the CW whilst the pinnion is turned!!

 

IF its with nee loadings, then it may / could / is, OK

 

if not, then its along way oot

and could cause a noise,or whine

 

A loading will move the contact pattern UP the tooth on drive, an doon on coast

 

{ It all depends on hoo much pree load ye got on yer bearings too,

as too little on the carrier, then it,ll move sideways whenst load is applied,

not so much wid the pin, but it,ll still move sideways , but no so much if they set tight.}

 

 

Some, nee matter wots done just cannot get a good pattern,

the newer thee,s things are, the wus it is i find,!!

 

M

Edited by GT6M
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Thanks Marcus,

 

The photos were take with it pretty much unloaded i.e. I was just holding the crown wheel by hand to provide resistance while I turned the pinion.

 

Here are a couple more in which I have a spanner on the crown wheel bolts providing as much resistance as I can while still allowing me to turn the pinion.

 

I think I'm coming round to the view that I need to take a couple of thou of shims out from under the pinion. Do you agree?

 

Rgds Ian

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Referring to Pic2 I would add a little bit under the pinion, not remove

and give it a little bit more play.

 

The opposite side seems to be much better.

 

As said a proper preload is necessary to keep that setup

under load.

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loading needs to be quite alott

think of yer car putting load thru it,, its moer than what yer hands can apply

 

I wack a chisel between case an CW, so its v v hard to turn wid a 2 foot ratchet

{ note, if its a collapsable spacer type, loadings cant be done as much, as the darn spacer folds up on its sel, grrrrrr }

 

If after a fair bit of loading, its still low on drive, then tek oot a couple of thou,

{ low, tek oot, high, add to pin shim }

bigg movements =little change, yer along way off,

small movements = big channge, yer in the ball park.

 

IF, after a bigg loading, its something like it is in 2, then it looks ok,

but CW may need t,go deeper into mesh

as said, hard t,really tell wid that custard yer useing.

 

CW side to side will alter pin depth as well,

really hard to say for certain, as all seem t,be different im finding

an as said befoer, alot depends on shim pack tightness, esp on CW

 

needs a good ole wak hame wid a copper / hide mallet

and to tek oot, 2 big pry bars on the bolts of the CW, , it,ll come oot easily, but ye can feel the pree loadings

if it comes oot easily, its no got enough pree loading, esp if putting pry bars in the planet area

 

Ohh, really need t,blue up all teeth,{ wots being used, Custard,!! } as alot give diff readings at 3/4/5 diff spots on the CW

also, look into diff, t,see pin patttern

look at yer piks, as they all seem t,be giving diff patterns,

an thats just on a few teeth,!!

and turn quite a few times, can run in a drill t,get a clear pattern first, then add load,

and see the difference a loading meks

 

engineers blue

https://www.ebay.co.uk/sch/i.html?_from=R40&_sacat=0&_nkw=engineers+marking+blue&_sop=2

 

A wee white / shiney spot = a wee bit of metal stikin up, quite common on used,ns

file off wid a fine stone /file, as it / they, can upset yer pattern

but ye,ll never see the white spot / s, wid yer ..custard mix !!

 

good luk

 

M

Edited by GT6M
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Just to complete the story and many thanks to Marcus and Triumph V8, I removed 2 thou from under the pinion bearing and tightened up the pre-load on the diff carrier, which was too low and the following pics are the result. I'm happy with this.

 

Rgds Ian

 

PS Marcus, I already have some engineers blue but I find it difficult to use compared to the 'custard'. The blue is too dark for me. I did however apply less of the custard.

 

 

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