Lotus Elan

If It ain`t .........TTR Grrrrrrrrrrr

PostPost by: jimj » Mon Jun 07, 2010 7:15 pm

Yes, BCthingy is spot on re. the two thirds. You`ve only to look at the two "contributions" from............. you know who !!
Yes again, High Peak Classic Autos lapped in the hubs, drove it round the block then re-torqued, then drove a bit more and torqued again, then I drove the car rather more and re-torqued again, exactly as per instructions. For this reason I can`t imagine how locktite could help.
Jim
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PostPost by: Spyder fan » Mon Jun 07, 2010 8:18 pm

Jim,

TT and myself have had a bit of previous regarding TT knows best, the upshot of which is that he now advertises an "EASYFIT" option for his 26R radiator and swirl pot for +2 owners.

The conversation went like this, it's imprinted in my mind and is almost word for word:

AT: "There's no brackets on this radiator and the swirl pot is far too large and fouls the brake servo, have you sent me the wrong parts?
TT: "What are you talking about I've sold hundreds of these and never had a problem, you are obviously not a competent mechanic"
AT: "The gentleman that is currently servicing my car and attempting to fit your product is a Formula One trained engineer who looks after 6 Boss series cars", I can describe the radiator as a core with 2 hose connections that appear to be in the right place but with absolutely no brackets or plates to fix it to my car and I maintain that the swirl pot is far too large.
TT: " The radiator doesn't need brackets and can be hung from the hoses and any sensible person would remove or re-site the servo as it's obviously in the wrong place, your mechanic is obviously incompetent which is why he no longer works for a major team"
AT: " Mr Thompson, I won't insult my mechanic by repeating any of that and I feel that I will have to return your products as they are obviously not going to fit my car without major alteration to my car or indeed your products; which I would describe as components rather than finished items albeit very nice quality components and it's a shame I can't use them.
TT:" You have obviously just changed your mind about buying these items and want to return them, why don't you say so rather than trying to make out that my products are faulty;
AT: "Your products are not faulty, they are incorrect for the application; therefore in the absence of a set of correct parts I wish to return them for credit, please can we agree this like gentlemen"
TT: "You are obviously not a gentleman therefore that's not possible, but I suppose that you will only get on to VISA and complain and they will chargeback the money"
AT: " That course of action is a last resort, but frankly I feel it's what you deserve at this point; I will ask you again whether you are able to supply the correct products to suit my car, perhaps if I sent you a picture of a +2S engine bay or indeed the Lotus Elan +2 Workshop manual drawing you would see the point I am trying to make. I don't want to return your parts for no good reason, but they are useless to me in their current form.
TT: Okay I will call your bluff and I agree to make a new radiator complete with brackets to your dimensions and sketch drawing and I will also make a new swirlpot to suit the gap between the head and the servo, even though you have obviously got it fitted in the wrong place, I don't suppose you will bother to make a drawing or send me any dimensions and will just call VISA and get this chargebacked so that you don't have to explain to your wife why you spent so much money this month.
AT: " I will ignore the latter part of that and will email & fax the details this afternoon, I think that once you see the pictures and official Lotus drawings of a +2s engine bay you will owe me an apology."
TT: "Ha ha ha, I look forward to that"

How I kept my cool I will never know; perhaps it was just the fact I was so shocked by his attitude.

I never got an apology, but 3 days later a nice shiny 26R style radiator with beautifully welded angle brackets and a custom built swirlpot arrived and the next issue of the club magazine ran his advert with an addendum to the 26R style radiator stating that there was now an easy fit option for the +2.

Rule 1:- TT is always right
Rule 2:- If TT is wrong, please refer to Rule 1

Regards
Kindest regards

Alan Thomas
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PostPost by: elansprint71 » Mon Jun 07, 2010 9:07 pm

With my Toolmaker's hat on I would have to say that in Mechanical Engineering there are two types of taper: locking and locating (these perform those exact functions). The ability to perform these functions depends upon the angle of the taper, locking tapers only work with a very shallow angles, up to a point where the two pieces cannot hold on to each other and no amount of grinding, or lapping will make them stick. I don't have an engineering drawing detailing the angle of the parts in question but I believe that we are approaching the number of degrees where adhesion is becoming less certain.
When operating at the sort of angle we have here it is common practice to fit a drive key, especially if reverses of torque are anticipated. I cannot recall ever having seen the round pin type of key used on any other engineering application, usually a rectangular key with two round ends, or a Woodruff key would be employed, although on relatively small diameter shaft with huge torque reversals when accelerating and braking, the size/depth of the key-way required could lead to failure.
Anyone know any other examples where this type of key is used?
This link show the common types of keys in use:
http://www.engineerskeys.co.uk/details.htm

Apologies to any Engineers reading this, fairly basic stuff but perhaps not to the layman. :)
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PostPost by: elancoupe » Mon Jun 07, 2010 9:46 pm

TTR has both versions of the shafts, keyed and non keyed, available. This was the case in November of last year, when mine (keyed) were purchased.

The shafts for the narrow bearing carriers are not available, you must purchase spacers to make the wide bearing version usable.

Not that anyone reading this thread is likely to be buying them ..... :roll:
Mike
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PostPost by: bcmc33 » Mon Jun 07, 2010 10:02 pm

elansprint71 wrote:With my Toolmaker's hat on I would have to say that in Mechanical Engineering there are two types of taper: locking and locating (these perform those exact functions). The ability to perform these functions depends upon the angle of the taper, locking tapers only work with a very shallow angles, up to a point where the two pieces cannot hold on to each other and no amount of grinding, or lapping will make them stick. I don't have an engineering drawing detailing the angle of the parts in question but I believe that we are approaching the number of degrees where adhesion is becoming less certain.
When operating at the sort of angle we have here it is common practice to fit a drive key, especially if reverses of torque are anticipated. I cannot recall ever having seen the round pin type of key used on any other engineering application, usually a rectangular key with two round ends, or a Woodruff key would be employed, although on relatively small diameter shaft with huge torque reversals when accelerating and braking, the size/depth of the key-way required could lead to failure.
Anyone know any other examples where this type of key is used?
This link show the common types of keys in use:
http://www.engineerskeys.co.uk/details.htm

Apologies to any Engineers reading this, fairly basic stuff but perhaps not to the layman. :)

Pete,

With my out of date toolmaking skills - I measure the inclusive angle at 4°.

I've just remembered that to take the hubs off the old spindles took what I thought was a significant amount of heat on the hubs to get them apart.
I put a similar amount of heat on the hubs to assemble to the new spindles.

With the combination of lapped surfaces on a 4° taper, heat and torque, I would have thought it promoted good retention properties. Even so, I still put the round pin in.
Brian Clarke
(1972 Sprint 5 EFI)

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PostPost by: mark030358 » Tue Jun 08, 2010 9:44 am

JimJ

Did the output shafts actually break or just come loose??

I was considering this option ...

cheers

Mark
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PostPost by: mark030358 » Tue Jun 08, 2010 9:46 am

Does the same apply to the diff output shafts also... is it good practice to replace with stronger ones. My sprint is fitted with the later design

thanks

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PostPost by: elansprint71 » Tue Jun 08, 2010 9:55 am

bcmc33 wrote:With my out of date toolmaking skills - I measure the inclusive angle at 4°.........
.... Even so, I still put the round pin in.


Four degrees is quite a lot for an included angle; the angle for a Morse Taper is around 1.5 degrees.

Of course the question we should really be asking is- if the faces mate perfectly and the Nylok nut is tight, why should things ever work loose? Good thing Lotus did not get around to making aircraft, or submarines. :twisted:
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PostPost by: GrUmPyBoDgEr » Tue Jun 08, 2010 10:16 am

elansprint71 wrote:
bcmc33 wrote:With my out of date toolmaking skills - I measure the inclusive angle at 4°.........
.... Even so, I still put the round pin in.


Four degrees is quite a lot for an included angle; the angle for a Morse Taper is around 1.5 degrees.

Of course the question we should really be asking is- if the faces mate perfectly and the Nylok nut is tight, why should things ever work loose? Good thing Lotus did not get around to making aircraft, or submarines. :twisted:


Ha Ha,
I can imagine Graham Hill giving a Talk now,
"Well I was flying at 10000 Ft and the Propeller fell off"

Back to originator:-
jimj can you please give some more detail of the failure that you had?
Loosening?
Breakage (of what Part)?
Are you absolutely certain that sufficient Lapping in was done?
Mine (new Shafts & existing Hubs) took me several hours for both sides with 3 different grades of grinding Paste.
John
Beware of the Illuminati


Editor: On Sunday morning, February 8th 2015, Derek "John" Pelly AKA GrumpyBodger passed away genuinely peacefully at Weston Hospicecare, Weston Super Mare. He will be missed.
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PostPost by: Davidb » Tue Jan 09, 2018 10:25 pm

Since I have replaced everything in the suspension/drive line except the rear 'spindles' I am now concerned that I should do this-or should I?

What is the current thinking on this?
I have new 26R hubs fitted to original shafts/spindles.
'65 S2 4844
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PostPost by: Chancer » Wed Jan 10, 2018 10:53 am

GrUmPyBoDgEr wrote:Keys or Pins are essentially used as locators or positioners i.e. Front engine Pulley & Timing Marking.
They are not intended to take any form of drive forces.

Cheers
John


Do you really believe that? See how long your front pulley remains on the engine if you remove the key from the keyway.

That said if the pulley bolt comes loose the acceleration deceleration forces each revolution will soon lunch the keyway, ask me how I know :(

In the example you gave both are needed.
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PostPost by: Spyder fan » Wed Jan 10, 2018 11:06 am

Chancer wrote:
GrUmPyBoDgEr wrote:Keys or Pins are essentially used as locators or positioners i.e. Front engine Pulley & Timing Marking.
They are not intended to take any form of drive forces.

Cheers
John


Do you really believe that? See how long your front pulley remains on the engine if you remove the key from the keyway.

That said if the pulley bolt comes loose the acceleration deceleration forces each revolution will soon lunch the keyway, ask me how I know :(

In the example you gave both are needed.


I'm sure that John will give you a reply in good time..... not too soon I hope :D

Editor: On Sunday morning, February 8th 2015, Derek "John" Pelly AKA GrumpyBodger passed away genuinely peacefully at Weston Hospicecare, Weston Super Mare. He will be missed.


When an old topic like this gets "resurrected" it's easy to forget that some contributors no longer use the forums. John was an engineer and a highly respected member of the BMW design team in Dachau before he retired, I tried not to question his technical knowledge in case he made me look sillier than I am :lol:
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PostPost by: Spyder fan » Wed Jan 10, 2018 11:09 am

Davidb wrote:Since I have replaced everything in the suspension/drive line except the rear 'spindles' I am now concerned that I should do this-or should I?

What is the current thinking on this?
I have new 26R hubs fitted to original shafts/spindles.


Perhaps somebody can answer DavidB's question?
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PostPost by: rgh0 » Wed Jan 10, 2018 11:36 am

TTR offer the outer drive shafts both with or without the circular locating pin groove. The end of the groove is a weak point and DB gives a guideline on their manual on how to modify this to avoid the stress raiser. The pin will not stop the hub spinning it it does not lock correctly on the taper ( been their done that and sheared the pin in half ).

Whether it is better to have the pin or not is debatable, lapping in the taper and ensuring it locks is not. I leave the pin and groove there per the oringal Lotus design but do the DB modification rather than eliminate it totally per the TTR option. Other key ways or locating pins in other elements such as the cam sprockets or front pulley are specifically around both correct location as well as aiding torque transmission and preventing fretting with torque reversals.

cheers
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PostPost by: Craven » Wed Jan 10, 2018 11:45 am

Is it preferable to have the hub slip or the shaft snap under excess design loads, I think the wheel staying with the car a better outcome.
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