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measuring big end journals


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Hi folks


Planning on dropping the Vitesse sump to replace main/big end shells and thrust washers.


I was thinking it would be wise to measure the B E journals for tolerance/ovality if possible.


If a B E cap was removed at bottom of stroke, then conrod/piston pushed up, high enough to measure all around journal with vernier/micrometer.


Conrod could then be pulled back down to mate up.


Would this be a useful/viable proposition do you think, please.


Any help great please.


Cheers, Dave 

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getting the sump off can turn into a right faf getting it past the oil pump  but with engine up as high as you can and much fiddle it drops off 

and probably need to shift the rack forwards . once in desperation we undid the oil pump through the sump gap and let it drop in the sump 

that makes it easy...putting it back ....is back to much tea and cursing  but its  possile how ever you go about it 


yes its possible but  as youre dealing in 0.0001"    

need a micrometer rather than a vernier    

 crank pin is 1.8750" to 1.8755"


checking roundness and ovality is a more complex affair.


the shells will probably tell you a story thats self evident 

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Hello Pete.


Reading between the lines, are you saying that to measure the journals correctly and more easily the crank really needs to be removed ??


And I guess if the shells are not looking as pretty as Day 1 then that is a possible steer for considering further investigation of the crank etc ??





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Another way would be to use Plastiguage. http://plastigauge.co.uk/


It's lengths of special clay-like material, this spread out when you fit the bearing and tighten the cap.

The ultimate width of the spread out stuff shows you the clearance, and you could do it at four (or more) points around the journal.


But whatever you do, it's fine, delicate work.

Changing shells is OK, just, but doing this, lying on your back, under the car, with oil dripping in your eyes?

Rather you than me!



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Cheers, Pete and Richard and John


Hopefully looking to extend the engine life cheaply for a few more years if possible. I don't drive it hard.


Pete. Can the engine raise until the bell housing touches the bulkhead?. Even then problematic?.


Can't imagine how to refit oil pump with sump in semi position.


Thanks, Dave  

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Is there an issue with teh bearings now? Knocking?


If not, have a look at teh old bearings and if the wear pattern is normal (no nasty pitting or other damage apart from wear) then fitting new decent bearings will mean the car has a much improved life ahead of it. I have rebearinged several cars that have been fine for many 10s of thousands of miles. And mine were not driven gently!

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Getting the sump off a 6cyl does have some fight the thing to a standstill many succeed some give up

you cant refit the oil pump from the gap even if your a gynecologist and paint the hall through the letter box. Yes things that restrict lift is the clutch hsg, rad hoses , fan fouling radiator and all things that may get taut,


johns plasti gauges will show some variation in clearances be it wear or ovality,

there were things like Tallyrond that plotted the surface and its concentricity we dont have them in the cupboard

A mic only measures across one axis, it can show a thruppenny bit is round

clives right many an engine gets new life by just fitting decent shells, but its the old utopia or compromise


johns correct goggles and drip tray op head is needed it will drip and dribble for ages


we had to replace the crank in the car ,, it gets worse than bl**dy heavy but you can do it


Dave dont get over anxious about the myths of drain back and a few rumbles when she fires up

you seem to have decent oil pressure, triumph give 40 to 60 psi at 2000rpm

idle low psi switch will show at around 6psi

so if the lights out at idle and you get close to the figures running its in reasonalbe condition




Just drive it

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Hi, and thanks


It has good oil pressure, though a bit of noise on first start of the day and decided not to worry about this.


What's made me worry a bit was.


After moving off one morning it made some noise and after a few miles I had to move off on a gradient twice and knocked a bit.


Twice after just starting after a few of hours it made a bit of noise on same day.


Drove it onto ramps to listen underneath and it made a hell of knocking (high revs and slipping clutch) 


Seems quiet underneath, even using screw driver when idling/some revs.


Only other thing, I fitted a Landy bigger clutch M/C recently and at at around the same time , it makes a bit of a whine from a cold start that disappears with clutch pressure and when warmed up.


Don't want the hassle of this work. Just want to drive it.


Cheers, Dave

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Have you had someone press the clutch and watch the crank pulley float is 0.006 to 0.014"

If its more than that its possible your rattle is an endfloat problem


master cyl changes have no effect on any general noises but you can overstroke the clutch and the throw out makes contact with the cover diaphragm fingers at a full stroke. That's a good racket.



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