Lotus Elan

Front end overhaul

PostPost by: Bigbaldybloke » Tue Dec 12, 2017 11:53 am

You?re not having much luck are you Jon!
The question is, is the problem with the trunnion or the upright, does the trunnion fit the old upright ok? If so that would confirm your thoughts that the upright is poorly machined. Are you getting the parts in the mail or is the supplier close enough to visit to try other parts to see if it?s a one off machining problem or they are all the same?
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PostPost by: JonB » Tue Dec 12, 2017 12:12 pm

Well first off, both uprights have the machining marks at the start of the thread, right where you absolutely do not want them (or so I read... comments anyone?)

Second - Good point. New trunnion fits the (rusty) old upright perfectly, so I am going to focus on the uprights when I speak to the supplier.
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PostPost by: MarkDa » Tue Dec 12, 2017 12:22 pm

That upright rejected your other trunnion as well didn't it?
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PostPost by: JonB » Tue Dec 12, 2017 12:32 pm

MarkDa wrote:So that's a duff upright then!
A bit disappointing after all the hype they gave you.
An email with that picture should have a replacement and return carriage label in the post today though.


Alas no. The technical guy is not in today, and they have not received the email I sent.
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PostPost by: MarkDa » Tue Dec 12, 2017 12:33 pm

Jon
This may be a silly question but you do have a pair of uprights rather than two of the same?
They've both got the same paint splodge.
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PostPost by: JonB » Tue Dec 12, 2017 12:34 pm

MarkDa wrote:That upright rejected your other trunnion as well didn't it?


Errm, not sure. Yes, maybe. As I sent the other truns back I can't be sure. I do recall the other trunions being lose on the old uprights though.

Yes, they are a matched pair with the threads going in opposite directions. Have no idea what the paint mark means.
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PostPost by: JonB » Tue Dec 12, 2017 12:52 pm

A closeup of the king pin threads of both uprights can be downloaded from this link.

https://drive.google.com/open?id=1E6hoL ... PiMq-Os-Po

The yellow arrows show the chattering marks. Question is, are they unsafe?

To add to the general lack of luck round these parts, Canley are now out of stock!
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PostPost by: 661 » Tue Dec 12, 2017 7:11 pm

I've just done my front end.
I got the uprights and trunnions from TTR.
I was actually there and played with a few different trunnions as there was quite a machining tolerance difference between ones from the same batch. I'm afraid the only reliable method is to manually match a pair.
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PostPost by: JonB » Tue Dec 12, 2017 7:23 pm

That's crazy. Can't be that hard to machine a thread to a 1960's era tolerance. Madness!
Last edited by JonB on Wed Dec 13, 2017 9:00 am, edited 1 time in total.
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PostPost by: Bigbaldybloke » Tue Dec 12, 2017 7:52 pm

I used to inspect and pass or reject gas turbine parts, and that upright would be a reject, no question about it. Sounds like the previous comment about going to a supplier and hand matching trunnions to uprights is going to be the best way forward or at least getting them to confirm they have trial assembled them before dispatching them.
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PostPost by: vincereynard » Tue Dec 12, 2017 10:59 pm

That's a really tough break Jon.
As you say to supply stuff that is not even up to 60's Triumph standard is abysmal.

661 wrote:I've just done my front end.
I got the uprights and trunnions from TTR. I was actually there and played with a few different trunnions as there was quite a machining tolerance difference between ones from the same batch. I'm afraid the only reliable method is to manually match a pair.


Was it the upright or the brass trunnions that varied? So you have to first select a pair of properly machined uprights, then find trunnions that actually fit them!

Anyone on a Triumph forum that shows this is a regular problem?
If that article was correct - " the Triumph upright remains in manufacture today, by Coventry company ESP Ltd using refurbished original tooling." Who makes the " the pressure diecast brass trunnion 266g"? Out of interest Jon weight them.

It worries me a bit as Toad was bought with all new front end fitting by the Peterborough bunch. I doubt there was much quality assurance there.
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PostPost by: JonB » Wed Dec 13, 2017 6:50 am

Two trunnions weigh about 450g, so that seems right. They feel good, with cleanly machines threads (put my finger in there and turned the trunnions round. No burrs or other roughness.) so I am not worried about them.

It's the uprights and those rough markings in the base of the threads. All this I read about microfractures, is it BS or correct?
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PostPost by: alan.barker » Wed Dec 13, 2017 10:08 am

If you reuse the old threaded uprights you need to measure the threads to see if they are parallel and not tapered due to wear. Using thread wires or thread parallels and a micrometer.
The threads may be larger at the bottom and necked at the top :shock: ready to break :shock:
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PostPost by: JonB » Wed Dec 13, 2017 10:10 am

vincereynard wrote:Anyone on a Triumph forum that shows this is a regular problem?


Yes.
http://www.triumphexp.com/phorum/read.php?8,954741
http://club.triumph.org.uk/cgi-bin/foru ... 398778702/

I am sure there are many others. The first thread gets to the point quickly though, and it's the one I first read that alerted me to the problem: "Microscopically if you examine the surface finish of where the thread has been cut, it will demonstrate thousands of micro fissures which are all called stress raisers.

In the part of the thread that breaks it's always close to the top and facing in, so has the maximum loading under cornering.

That's wear the flexion causes the stress raisers to turn into vast crevasses."


vincereynard wrote:If that article was correct - " the Triumph upright remains in manufacture today, by Coventry company ESP Ltd using refurbished original tooling."


That said, they are discussing an upright that was commonly available at the time, made overseas with a "BS" logo cast into it. As you can see from the picture at the top of the thread, the machining is simply dreadful. My uprights only show poor machining at the base of the thread, but that is exactly where it will fail so the fact that the rest of the thread looks good isn't much consolation.

Looking at ESP's Google info, it appears to be a motor factor now, not a manufacturer. I'm not sure they are the maker, although Canley said they are made in Coventry. I called them and sure enough, they're a wholesaler only.

vincereynard wrote:It worries me a bit as Toad was bought with all new front end fitting by the Peterborough bunch. I doubt there was much quality assurance there.


The only way to know is to take the front suspension apart yourself, then clean and examine the kingpin thread for poor machining.
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PostPost by: JonB » Wed Dec 13, 2017 10:12 am

alan.barker wrote:If you reuse the old threaded uprights you need to measure the threads to see if they are parallel and not tapered due to wear. Using thread wires or thread parallels and a micrometer.
The threads may be larger at the bottom and necked at the top :shock: ready to break :shock:
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They don't break at the top, they shear off at the base of the thread.

No way am I reusing the old uprights. The kingpin threads are badly rust pitted from top to bottom (rust pits = stress risers = impending doom). And tapered too, of course. It's a wonder they survived the trip home when I bought the car.
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