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Crankshaft oilways
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Posted by alan lindsay (AU)  on Monday, January 11, 2021 at 22:06
Hi all,
well, about half of the T150 basket case has arrived so far. According to it's engine number it was built in November 1969.
it appears to have unified threads, when did Triumph change to Unified?
The bike was purchased as 'pig in a poke' from a mate whose health has failed him so he cannot do the restoration required. Nothing sounds more scary than buying a Trident in bits, sight unseen but so far what I'm discovering in the boxes is very encouraging.
To get things started, a couple of questions: what is the modern thinking on cross drilling the crank and enlarging the oil ways.
I believe the T160 had enlarged oilways as standard, is this true?
Do people nitride the crank?
Any other basic tips for changes to the bottom end before rebuilding starts?
regards
al
Replies   :
Now here's a thing.
I believe that an extra oilway drilling in the crank and enlarged oil feeds into the pump aren't necessary.
But they do no harm and they might improve things.
My understanding is that the extra oilway in the crank was introduced my messrs Pick/Peckett to try to improve the longevity of main bearings in some triples that seemed to get through them within 20K miles - whilst others would see toward 100k.
I think the jury is still out on that one.
Enlarging of the feed was due to cold starts and the pump suction trying to collapse the feed pipe from the oil tank. You only see this in winter and if you warm the bike before riding, then this phenomenon wont manefest itself. Whether it will cause a real issue, the jury is still out.
But both of these concerns can be alleviated by using an oil with a lower winter rating. These weren't available back in the day when the issues were first highlighted.
My suggestion is that whilst you have the thing apart and if you have the money, time and inclination. Then there' is certainly no harm.
But don't loose any sleep over it. There are plenty of high mileage triples without these mods that aren't falling apart.
Steve It is definitely worth enlarging the oil way from oil tank to oil pump from 5/16 to 3/8 diameter but make sure you do the whole pathway, and include the oil pump backplate iitself. You will see a useful increase in oil pressure. T160s were modified at the factory about half way through production but as stu says not consitently, for instance my late T160 had evrything at 3/8 diameter until we looked at the oil pump backing plate which was still at 5/16 (it was the original fitment)!
This Saudi T160 engine I have here is PN068## and that didnt' have the oil pump back plate
enlarged to 5/16" id bore, it was still at the earlier 1/4" id bore, however the oil tank through into
the engine was all the large 5/16" id bore feed. It's has a very late prodution date engraved into the pump body
so it's definitely the original oil pump.
>T160s were modified at the factory about half way through production but as stu says not consitently, for instance my late T160 had evrything at 3/8 diameter until we looked at the oil pump backing plate which was still at 5/16 (it was the original fitment)!
3/8" is the feed spigot OD (the upper one) or at least, that's what it is on my NN067xx T160 which is a reasonably late model.
The ID best as I can measure due to its position is approximately 0.300".
According to the Jack Shemans Service notes (published in Classic Mechanics issue 12, April/May 1986, reproduced in the TR3OC Service Notes, page 7, chapter 7) and which I have quoted the relevant section from, below:
"Jack Shemans:
A useful modification to the oil feedway involves removing the pipe, which has 1/4 inch bore, opening up the hole, right through to the oil pump housing and fitting a pipe with a 5/16 in. bore. This modification, a spin-off from the racing days, helps the oil get round more easily from cold and was incorporated in later models of the T160."
Therefore, 5/16" through to the pump would seem to have been the enlarged size.
Hi Nigel
What is your engine number? Or better yet, do you know when the oil pump inlet was enlarged to 3/8"
Cheers,
Mike K. My engine inumber 067##
and it had definitely never been apart before
Hi Mike,
IIrc, "L.A.B." posted them a while back; find the post with the Forum Search?
Hth.
Regards, A chap down under sent details of what to do and I did them including cross drill to standatd dia. I believe the pump backing plate is drilled as well as the holes in the case that match up the oil tank had to be modded for a larger outlet and inlet to bottom of engine. As well as the the passage from the inlet from the tank at bottom of engine to back of pump.
Im guessing some drill down through the main hoousing with larger drill and inlarge slightly also the hole in the bearings. also I think the feed to the tappets is removed and blanked off. Stuff to mull over have fun be concious of possible F- UP'S Hi Al,
>it appears to have unified threads, when did Triumph change to Unified?
Varies by components but basically doesn't affect triples, they always had Unified threads bar a very few - filler plugs, 2BA on some (but not all) small threads, etc.
>what is the modern thinking on cross drilling the crank and enlarging the oil ways.
>I believe the T160 had enlarged oilways as standard, is this true?
Afaik, no-one's enlarged oilways except from the tank through the pump, not enlarged oilways in the crank.
Later T160's have enlarged oilway from tank to pump; bizarrely, the various components were modified from different engine numbers, not all at the same time ... (!)
Hth.
Regards, |
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