Lotus Elan

Clean sheet - what would you do for a ‘69 S4 DHC?

PostPost by: tdskip » Wed Sep 18, 2019 6:07 pm

Good day gentlemen. Just doing more planning and thank you in advance for all of the ideas and experiences.

My car is disassembled so I have the luxury of building it back up however makes the most sense. As a 1969 USA car I believe it would have had a dual brake circuit from the factory but those parts are missing in action. With that being the case is there an approach that makes good safety and parts supply sense?

Thanks!
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PostPost by: trw99 » Thu Sep 19, 2019 10:03 am

It would be helpful if you let us know what you plan to do with the car, as that tends to give you the mission from which all else will flow!

Personally I would rebuild to as original specification as you can get. Then use the car. Others will suggest turning it into a mean street car, a track day special or an upgraded tourer. But that decision has to be yours.

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PostPost by: tdskip » Thu Sep 19, 2019 10:59 am

Good morning Tim, sketching out intended use as part of my original post seems obvious now. Sorry.

She will be a fast road street car, not race and not “hard-core”.

I’m not a car show guy nor focused on keeping her exactly as she came from Lotus but I find close to original with sensible (but reversible) upgrades is where I like to be.

Hope that helps. Thanks!
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PostPost by: USA64 » Thu Sep 19, 2019 3:53 pm

My 2 cents:
Whoever came up with "fast road car" should either be given a big bonus or dragged out and shot, I vote for the latter.
It's not going to be that fast by todays standards regardless.
If you beef-up one part you'll have to go round beef up everything else, endlessly.
Try it as designed first, you'll have enough to do with just that.
But please yourself that's what it's for.
We are supposed to be having fun, are we not?
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PostPost by: tdskip » Thu Sep 19, 2019 4:53 pm

Good morning, thanks for the response. I think the “fast road” thing is courtesy of our English friends and denotes a car that will see higher speeds and pressing on. I know that I built my TR6 differently with that in mind that I would have for, oh, say a weekend cruiser.

Anyway - just confirmed this is a single brake line car so that makes the original approach easy. Will do more searching on the merits / issues with a dual line set up.

Thanks!
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PostPost by: nigelrbfurness » Fri Sep 20, 2019 8:13 am

Here's my spec. 1760cc engine, sprint cams or qed 450. 3.9:1 atb diff with solid drive shafts. Adjustable dampers all round, Protech on the front and Spax are fine for the rear. A five-speed gearbox conversion with overdrive top will go well with the 3.9:1 diff and give you crisp acceleration to keep up with those new 1litre turbo Fiestas :-D and maybe even pass a slightly sick one or one driven by your grandad lol. I would be happy with standard brakes fully overhauled an with a servo - but not for track days. Tony Thompson, Voigt and Quaife have all you need. Burtons as well. Have fun!
1970 S4SE/1760cc big valve/SA-AX block, L2s, 45DCOEs, 1978 Jensen GT, 1962 AH Sprite, Alfa-Romeo 159, 1966 Bristol Bus, 1947 AEC Regal bus.
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PostPost by: Spyder fan » Fri Sep 20, 2019 9:45 am

I can thoroughly recommend throttle body fuel injection, I have a Lotus TwinCam sitting in my garage for that eventual retirement project that was built with fuel injection in mind. At the moment I have 2 cars running alternative engines that have throttle bodies, they always start, they always idle, they run smooth throughout the rev range with no flat spots or peakiness and they return more than 40MPG

I know of at least two people who run throttle bodies on Lotus Twin Cams, the benefits are smooth running and increased economy as well as the potential for tuning.

There are well documented DIY versions (megasquirt) or you can buy Jenvey or Weber or Omex systems etc.
Jenvey produce a heritage version that looks like side draught carburettors (expensive upgrade over standard bodies)
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PostPost by: tdskip » Fri Sep 20, 2019 11:26 am

Thanks for the response, some great information and options there. The carb loolk a like FI is very clever.

I was really, for now, asking about the braking system however. Apologies for not being more clear, I mistakenly thought that asking in brake tech section would orient the question and responses. Apologies but great info and something to get saving for!

On the brakes specifically it sounds like a healthy OEM spec single line is up to the job?

Thanks, and sorry again for not being more clear.
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PostPost by: rgh0 » Fri Sep 20, 2019 11:35 am

I would put in an un-boosted dual inline cylinder setup. Early Datsun 1970's 120Y / Sunny cylinders can be fitted. Other options exist, many posts on this if you search the forum. The rest of the standard braking system is fine when fitted with modern high coefficient friction front pads.

cheers
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PostPost by: tdskip » Fri Sep 20, 2019 11:38 am

Good evening Rohan, thanks for the note.

Let me get searching (again).

Cheers.
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PostPost by: Spyder fan » Fri Sep 20, 2019 12:09 pm

tdskip wrote:Thanks for the response, some great information and options there. The carb loolk a like FI is very clever.

I was really, for now, asking about the braking system however. Apologies for not being more clear, I mistakenly thought that asking in brake tech section would orient the question and responses. Apologies but great info and something to get saving for!

On the brakes specifically it sounds like a healthy OEM spec single line is up to the job?

Thanks, and sorry again for not being more clear.


Sorry,
I missed it being in the brakes section, like a lot of users I look at the "new posts" tab and scroll through to see if any of the headings take my interest.

Brakes are pretty good as standard and there are uprate possibilities
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PostPost by: tdskip » Fri Sep 20, 2019 1:14 pm

Please do NOT apologize for your thoughtful and very helpful reply!

It was, and is, appreciated. The cooperative support everyone has offered me here has been fantastic is directly contributing to getting another one back on the road. Thank you.
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PostPost by: Elan45 » Sat Sep 21, 2019 2:00 am

Hello TD,

All S4 Elans even going back to the Super Safety variant of S3 had dual brake circuits and a tandem master cylinder. I suppose your car could have been backdated, but I'll bet you've just overlooked a second brake line.
I don't have my SS close at hand, but seems like the rear brakes connect to the tandem MC through a banjo fitting.

Roger
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PostPost by: nigelrbfurness » Sat Sep 21, 2019 8:20 am

None of the S4s (and its been a few!) I've owned had dual-circuit brakes and tandem master cylinders so I would respectfully suggest that dual-circuit is a federal-only option.
1970 S4SE/1760cc big valve/SA-AX block, L2s, 45DCOEs, 1978 Jensen GT, 1962 AH Sprite, Alfa-Romeo 159, 1966 Bristol Bus, 1947 AEC Regal bus.
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PostPost by: Elan45 » Sun Sep 22, 2019 4:12 pm

Nigel,

Please accept my apology. I don't know why I didn't separate the US Federal spec cars from all others since I have a late '69 home market +2S that only has a single circuit brake system.

But our subject on this thread was a Federal market Ser 4, which should have been originally a dual braked car. Unless, it was imported privately into the US, and was built not to Federal spec in 1969.

Roger
'67 Elan S3 SS DHC
'67 Elan FHC pre-airflow
'67 Elan S3 SE upgrade to 26R by Original owner
'58 Eleven S2 (ex-works)
'62 20/22 FJ (ex-Yamura)
'70 Elan +2S RHD
'61 20 FJ project
'76 Modus M1 F3
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