strengthening front covers for sprint DYNAMO mounting

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.
Regards
Bob

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

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

lotusmarques.com/parts/cata … gine-parts

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 …
sjsportscars.com/parts-and- … 0E0004.htm

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

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.

Like this?
FrontCover_Reinforcement_Bracket.pdf (43.6 KB)

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.

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 !

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.

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.

Nick

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.

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.

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.

Nick


Hi Bob. Not sure this adds anything to the previous advice. I had a few made up some years ago
and may still have one or two available. If your in UK, could possibly drop one in the mail to you
for a small fee + postage. (Well, smaller than SMS are charging…) You will need longer bolts thru the timing case at the 3-Bolt positions that its fitted to.
Weather it fits a LHD car, I can’t confirm.

This one fitted to my Sprint.

Yes Roger, I could not see why it shouldnt be used with dynamo, I just assumed I was missing something!

Rose joint adjuster rods are readily available, see eBay. Although they make adjustment easy they do little else as far as support goes as they are effectively a radius rod. When using one, virtually all of the rigidity is supplied by the lower pivot point. Looks to be using a small Denso here and going by the one I have, use a single lower mount, Although it’s quite beefy it’s only about 1" wide. Make sure the bolt is good and tight after you have adjusted the belt as this will doing most of the support work. Dynamo owners will know how easy the mounting holes in the end plates go oval with time if the pivot bolts aren’t kept tight. Unfortunately, they are often hard to get at when you have to use 2 spanners and can suffer from “good enough” when tightening.
The mount with the buffer reminds me of a conversion to a Volvo B18 engine in a car I bought that used a large Lucas alternator. The initial service included a new belt. Found that the adjuster arm was just jammed against the block and it just dropped out. It worked OK but I changed back to a dynamo.

Make sure the lower front mounting bolt securing the alternator or dynamo is properly tightened too. If it isn’t a greater portion of the belt force will be transferred to the upper bolt and hence through the adjusting strap to the front cover. On Escorts the Ford factory bracket for alternator mounting was a very substantial affair with three point mounting to the block. Same bracket was used for LTC and standard crossflows. Never had problems with things breaking with that arrangement. I believe the same bracket can be used on RHD Elans but not LHD ones.

This one ?