Lotus Elan

What would you do with the engine out and apart?

PostPost by: tdskip » Tue Apr 16, 2019 12:13 pm

Good morning. Let’s imagine your S4 engine was out of the car and apart and your goal was a reliable road car that balanced performance and civility (not a high strung engine). Let’s further imagine that you didn’t have unlimited money. :D

What would you do to the bottom end? Assuming the crank is OK “just” balance con rods and pistons? Removable front plate for water pump? Standard oil pump or updated? Any updated seals to help keep the engine oil right?

Thanks!
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PostPost by: nmauduit » Tue Apr 16, 2019 3:39 pm

I would take it all apart identifying all parts including the small ones (intake valve 1 2 3 4 etc), clean them up reasonably well and take them (esp. block, crank and head) to a machine shop of good reputation : they should be able to advise of best course of action, taking in account goal and budget, would do some machining if required. Then I would do all the reassembly myself, taking the time it takes and in a clean environment (a couple reading of Miles's book before getting startedmay be advisable, depending on prior LTC experience). This I believe would ensure the most cost efficient approach on a budget.

I don't think valve oil seals are really un plus for these engines, but there are different lines of thoughts.

Then comes the can of worms of "improvements"... lots of stages there... if the above leaves enough for say a grand, moderately enhanced camshafts (like Q420) would be the way to get more performance out of the engine... or as you mention it a removable water pump cassette may be a way to save time on maintenance down the road (but if you do the maintenance you may not count your time ... I have not yet gone that route so far, but am careful not to overtighten the belt)
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PostPost by: tdskip » Tue Apr 16, 2019 4:01 pm

Thanks for the response. In theory the head has been rebuilt professionally leaving me the bottom end to deal with.

I’m sure I will regret saying this-but the bottom end of this engine seems quite conventional and reassembly shouldn’t be that challenging.

To be clear there is absolutely a time and place to spend money on professional help but if the crank and bores / block pass inspection by a machine shop reassembly should be pretty straightforward, yes/no/maybe?
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PostPost by: nmauduit » Tue Apr 16, 2019 4:18 pm

tdskip wrote:Thanks for the response. In theory the head has been rebuilt professionally leaving me the bottom end to deal with.

I’m sure I will regret saying this-but the bottom end of this engine seems quite conventional and reassembly shouldn’t be that challenging.

To be clear there is absolutely a time and place to spend money on professional help but if the crank and bores / block pass inspection by a machine shop reassembly should be pretty straightforward, yes/no/maybe?


you're right, the bottom is easier, totally doable by a careful amateur (borrowing a torque wrench if applicable) - if block and crank pass the inspection the rebuilding cost should be minimal, leaving a tight budget some options...
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PostPost by: tdskip » Tue Apr 16, 2019 7:44 pm

Thanks for the additional response.

Sounds like I need to study this in detail. If I get professional help in checking the block and bores etc think the book is enough of a guide?
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PostPost by: Donels » Tue Apr 16, 2019 9:31 pm

I am doing this right now. Everything is apart and the head is away for professional assessment and overhaul, so just left with the bottom end and I have similar aims to your self, ie a quick but driveable car.

So keeping the D type original cams, in good condition and reusable. They can be changed later if required. Cartridge water pump because existing is corroded and was a PIA to remove. Standard oil pump as high flow, high pressure not necessary for my intended use. New dizzy because old one was u/s. Lightened flywheel as it needs refacing and a new ring gear. The rest will be refurbished depending on condition. For sealants I am following Rohan's advice from this forum. Balancing will depend upon how close the bits are, I’m not building a race engine so mostly normal road revs.

So decide what you’re going to use your car for and spec accordingly.

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PostPost by: tdskip » Wed Apr 17, 2019 2:18 am

Thanks Dave.

Assuming stock compression then too - not decking the head?

I've lightened the flywheel on my TR4a and TR6 (prior to the current one) but those engines are pretty torque oriented. Any concerns with that on an Elan?
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PostPost by: 2cams70 » Wed Apr 17, 2019 6:09 am

For safety's sake do not lighten the standard cast iron flywheel. If you want a light flywheel buy a new aftermarket one or buy an aftermarket steel flywheel and lighten it. Read the Miles
Wilkins book - it's great for the history side of things but not so good as a rebuild guide as a lot of the methods used are out of date and I hate the way he slobbers sealant everywhere!!. Miles Wilkins is optional in my opinion but the original Ford or Lotus workshop manual for the engine is not. You are far better off using no sealant, making sure your surfaces are all true and cutting your own gaskets out of high quality paper rather than using the rubbish typically supplied in gasket kits. I always replace the cheap nitrile seals and "O" rings typically supplied with ones made of Viton. More expensive but it's what all the OEM's use in the modern era. If you are fitting a Burton water pump cartridge there's quite a few tricks to be aware of. I've posted about these previously. Well worth replacing the original cylinder head bolts with ARP bolts (not studs if it's a road engine). Highly recommend having the engine balanced even if it's a road engine - cost is minimal and benefits well worthwhile.
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PostPost by: alan.barker » Wed Apr 17, 2019 6:32 am

Don't forget to replace the Core Plugs in the Block and while they're out give the Waterways a very good clean out
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PostPost by: Donels » Wed Apr 17, 2019 9:10 am

I keep being warned about exploding flywheels so I am a bit nervous even though the lightening is being done by Wilcox Engines. I think I’ll invest in a steel one.

Ref decking. Are you building a race engine or a road engine? I know several people who have built engines as 'projects' to give high power and then been disappointed with on-road driveability. Hence I’m leaving it pretty much standard but for a lightened flywheel (free power) and durability, maintainability, reliability and hopefully leak free upgrades.

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PostPost by: 69S4 » Wed Apr 17, 2019 9:45 am

I had my std flywheel lightened plus a new ring gear fitted when the engine was last overhauled. The engineering co (Oselli iirc) suggested it and I don’t remember being warned about any potential catastrophic consequences from the lightening. So far (quite a few years but not that many thousand miles) it’s still in one piece. I could just be lucky I suppose but should I be worried?
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PostPost by: 2cams70 » Wed Apr 17, 2019 10:52 am

Fitting a lightened flywheel won't give you any more power. It will just improve the throttle response so it "feels" more powerful. The standard Lotus flywheel is already quite light. In fact steel is denser than cast iron so a pattern steel flywheel is likely to be heavier than the standard item unless further metal is removed. If I was just building a standard road engine installing a lightened flywheel would not be particularly high on my priority list. The flywheel may be light but the clutch (which is usually still standard unless it's a full on race engine) is still heavy so they overall effect you can achieve is not all that great. Many people rebuild the engine at the time of lightening the flywheel so I would not be surprised if most of the effect was due to the engine rebuild rather than the lightened flywheel.
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PostPost by: Donels » Wed Apr 17, 2019 11:27 am

Well a lightened flywheel does not actually make the engine produce more power BUT it lowers the rotating mass meaning that more of the power produced by the engine is available for acceleration, hence free power. Depending upon how much weight is removed from the flywheel and at what radius will depend upon how much is gained.

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PostPost by: rgh0 » Wed Apr 17, 2019 1:26 pm

Lots of options and things to consider depending on what exactly is the current engine condition and what is the intended use after the rebuild and how much money do you want to spend now versus spend later.

Are you after more reliability, more power, or both ? Is cost not a barrier or do you have a strict budget.

Some of the key elements have been discussed above beyond that it really needs to focus on your wants and needs from the rebuild. Anything is possible but there is no free lunch

cheers
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PostPost by: tdskip » Wed Apr 17, 2019 2:50 pm

Good morning and excellent question.

Top priorities are reliability, civility (nothing too high strung) and then power. Any sensible upgrades that add to longevity, easy of maintenance and maybe, just maybe, keeping it oil tight.

Budget would be as little as possible to accomplish those goals. :D

Thanks!
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