Lotus Elan

strengthening front covers for sprint DYNAMO mounting

PostPost by: bloodknock » Wed Mar 20, 2019 9:23 pm

Hello folks
Just wondering if anyone has ideas of sources for strengthening brackets for the front covers / timing chain chest, where the Dynamo mounts. I know that such devices exist for the alternator, but am told that its not suitable for a dynamo installation. Years ago, on my S3 the case alloy fractured requiring a welding fix. Just trying to circumvent any issues in this area.
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PostPost by: Frogelan » Thu Mar 21, 2019 2:14 am

Bob

You have raised an important question which anyone creating a FIA GTS car needs to solve (a dynamo is required by the FIA for period F cars).

The steel bracket seems to be made up to spread the forces between the exterior of the chain test and onto the block. Apparently it correctly shown on the photo on the thread "the c40 dynamo and its pulley" by oldelanman:

viewtopic.php?t=32667&p=220048

Could anyone supply a sketch of this obscure NLA part so Bob and I could make one up ?

There were two lower dynamo brackets (either 15,25 cm long (6" for those in the US) or 17.14 cm long (6.75")...Annoyingly I have the wrong length...

Andrew
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PostPost by: 2cams70 » Thu Mar 21, 2019 7:28 am

That bracket is available reproduced by Lotus Marques here in Australia. It doesn't seem to be pictured but it's definitely available.

https://www.lotusmarques.com/parts/cata ... gine-parts
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PostPost by: oldelanman » Thu Mar 21, 2019 7:41 am

Frogelan wrote:The steel bracket seems to be made up to spread the forces between the exterior of the chain test and onto the block. Apparently it correctly shown on the photo on the thread "the c40 dynamo and its pulley" by oldelanman:

viewtopic.php?t=32667&p=220048

Could anyone supply a sketch of this obscure NLA part so Bob and I could make one up ?


The bracket shown in my post is home made and therefore not necessarily entirely "correct". It's basically just a flat plate which spreads the load from the adjuster strap over three front cover bolts instead of the one used originally, there is no additional attachment to the block as you suggest. I thought I had made a sketch when I made mine but unfortunately can't find it now. The only critical dimensions are the spacing of the bolt holes and you can easily make a template from the front cover for that.

The bracket is listed by SJ Sportscars ......
https://www.sjsportscars.com/parts-and- ... 0E0004.htm
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PostPost by: Frogelan » Thu Mar 21, 2019 8:08 am

Thank you Roger! The SJ Sportscars part is for RHD only (my project is LHD), but it gives a very idea of how the brace plate should look.

I think I will make up my own but will ask SJS is they would be kind enough to trace the RHD version for reference.

That is a good start although , but I'm beginning to wonder whether my Dynamo is probably too long for LHD.

I will not be able to check this for a while as my project is coming together rather slowly.

Andrew
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PostPost by: oldelanman » Thu Mar 21, 2019 8:49 am

I can't see how the brace plate would change for LHD as the adjuster strap still mounts on the same front cover bolt doesn't it ? The mounting bracket and possibly the adjuster strap will be different as the alternator is mounted higher (I think) but if you are just adding the brace plate to your dynamo installation I think the RHD design will be fine.
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PostPost by: pharriso » Thu Mar 21, 2019 8:56 am

Frogelan wrote:
Could anyone supply a sketch of this obscure NLA part so Bob and I could make one up ?

There were two lower dynamo brackets (either 15,25 cm long (6" for those in the US) or 17.14 cm long (6.75")...Annoyingly I have the wrong length...

Andrew


Like this?
FrontCover_Reinforcement_Bracket.pdf
(43.59 KiB) Downloaded 143 times
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PostPost by: pharriso » Thu Mar 21, 2019 8:59 am

oldelanman wrote:I can't see how the brace plate would change for LHD as the adjuster strap still mounts on the same front cover bolt doesn't it ? The mounting bracket and possibly the adjuster strap will be different as the alternator is mounted higher (I think) but if you are just adding the brace plate to your dynamo installation I think the RHD design will be fine.


The elan had a different alternator bracket for LHD cars since the steering column ran too close to the larger alterntor. I believe there is no issue for the Generator, so there is only one bracket.
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PostPost by: geni » Thu Mar 21, 2019 9:22 am

Andrew,
je pense encore avoir eu cela dans mon stock de pi?ces ! Me restant a confirmer mes dires Si cela peu t'int?resser je peu y jeter un regards d'ici semaine prochaine car suis encore malade (tr?s grosse grippe) qui ne me l?che plus? avis aux amateurs ?ventuel !
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PostPost by: MarkDa » Thu Mar 21, 2019 1:39 pm

Not something that I knew was missing!
I suspect that if I decide to reinforce the brace I will be making one rather than spending thick end of ?30 buying!

I can see the sense but would have thought that tightening the main bolts after tensioning the belt would be enough to minimise dynamic load on adjustment arm sufficient for normal road use.
Last edited by MarkDa on Thu Mar 21, 2019 6:57 pm, edited 1 time in total.
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PostPost by: elanner » Thu Mar 21, 2019 4:12 pm

Purists look away, but the previous owner of my car must have lost or broken the original Lotus bracket, so he made up a simple alternative that connects to the original Kent engine dynamo top bracket hole (with a piece of angle iron). It has never given me any trouble so I've not bothered to look for a Lotus bracket. Presumably, with this arrangement the timing chest has less stress on it, although I doubt it makes any difference.

It's quite a tight fit so there's little room for a spanner/wrench on the bolt. Next time I fit it I'll probably switch to an Allen head bolt.

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elan_alternatortopbracket.jpg and
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PostPost by: bloodknock » Thu Mar 21, 2019 5:17 pm

For information: I have checked with Steve at SJS who informs me that their plate is for alternator equiped cars only:

Re: SJ050E0004 BRACE PLATE for ALTERNATOR ADJUSTING BRACKET

Hello
Is this strengthening bracket suitable for use with a dynamo equipped Sprint?
Thanks
Bob

No they are only used on cars with Alternators.

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PostPost by: oldelanman » Thu Mar 21, 2019 6:45 pm

bloodknock wrote:For information: I have checked with Steve at SJS who informs me that their plate is for alternator equiped cars only:

Re: SJ050E0004 BRACE PLATE for ALTERNATOR ADJUSTING BRACKET

Hello
Is this strengthening bracket suitable for use with a dynamo equipped Sprint?
Thanks
Bob

No they are only used on cars with Alternators.

Steve


The bracket is certainly sold as part of the alternator installation kit and as far as I know was never specified for use with a dynamo. However, I see no reason why it cannot be used if you wish to reduce the risk of damage to the front cover which you have previously experienced. I have fitted it to my S4 with dynamo without any issues.
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PostPost by: MarkDa » Thu Mar 21, 2019 7:01 pm

Nick
That's a great fix with built in positive tensioning without wrestling with tyres levers etc.
I can't see why you'd ever really need to release the engine end.
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PostPost by: avro » Fri Mar 22, 2019 7:23 pm

Having had the front cover dynamo bracket lug brake off on a rally Twin Cam engine some years ago, it required a quick solution so that the car could continue on its way. The modification was quite a simple one, in so much as we bent the end of the dynamo top mounting bracket 90degrees and attached through the existing hole a rubber buffer.
The rubber buffer was an anti vibration bobbin that was used to mount a Facet electric fuel pump. One end was cut off and the rubber end was radiused in an electric drill with some course emery cloth. 10 minutes later it was fitted into place. Even after the engine had been rebuilt with a new front cover it was decided to retain the modification that worked perfectly well for several seasons of rallying.


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