Adding Muscle - Now or never

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DavidOliver
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Re: Adding Muscle - Now or never

Post by DavidOliver »

Hi Oldtimer.....like me!
The full description of all the stages of extra muscle is in the Lotusbits document previously mentioned. You can download from Lotusbits. Mike Taylor holds practical experience behind his theories.
In ths Forum you will find an extensive description of gaskets types by Tim Engle, a most necessary document when transforming from an LC engine and you will see a development of thicker gaskets at the expense of compression loss, not the right way to go. I repeat a must read.
For some reason I had assumed you had an automatic, perhaps some other poster.
Therefore flywheel weight reduction is an easy one without needing lower torque. Either by substitution or machining. If you are going to be heavy footed reconsider the clutch quality. Mike Taylor knows, call him not e-mail.
On exhaust manifolds, the main advantage of tubular is the scavenging effect behind the exhaust valves which you do not get with cast iron, and if you heat wrap them, horrible sight which gets more dirty horrible and you cannot re-wrap when fitted, the effect is to increase exhaust gas flow (higher temperature) and improve scavenging again. With tubula I would also provide an off-chassis polished aluminium shield.
If you are not concerned about original appearance, and consider HC cams why not get the cam carriers as well (the red ones) to avoid saddle type gasket frustration, they weep and so do us owners. Be carefull of the cost of changing the timing belt pulleys, all four of them.

Saludos
Dave the cog.

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bash
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Re: Adding Muscle - Now or never

Post by bash »

Personally, I wouldnt wrap them, if you get the usual oil leak you can guess the rest.

Bash
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Lotus-e-Clan
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Re: Adding Muscle - Now or never

Post by Lotus-e-Clan »

bash wrote:
Sun Dec 19, 2021 13:46
Personally, I wouldnt wrap them, if you get the usual oil leak you can guess the rest.

Bash
And another cautionary tale about wrapping.

My CLan's stainless steel manifold rotted underneath the wrap after five years of use on the road all year round in this country (wet salty roads).

Wraps hold moisture too. Wrapping is mainly useful for racers wringing out the last drop of power, not meant for road cars used all year around where wraps tend to stay on the manifold for years at a time.

And I was told that before I used it on the Clan by a rally man, whom I ignored, then learned the hard way.
Last edited by Lotus-e-Clan on Sun Dec 19, 2021 17:34, edited 1 time in total.
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bash
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Re: Adding Muscle - Now or never

Post by bash »

You could get the manifold ceramic coated if you want to empty your wallet.
Bash
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Re: Adding Muscle - Now or never

Post by Oldtimer_Basis »

Okay, an Alumin(- i -)um-Shield, then. We use Wrap all the Time, here, and never had an Issue with it... well, except the aforementioned Uglyness.
Oil, that gets soaked up, will just cook away and add up to the overall Uglyness. Prime Reason we use it is simply to keep the Engine-Bay cooler.
But this is my very first Lotus, so if your Experience with it in these Cars is not that great, a normal Heat-Shield will do the Trick just fine.

Now, please don´t laugh about the next Question :roll:
We don´t do a lot of Stick-Shifters, here, and when, the only Thing is picking Parts, that are beefy enough to cope with the Engine´s Power and that´s it.
So: If I machine down the Weight of the Flywheel, all that happens is that the Engine will behave less tardy, right? I don´t gain or set free any additional Power and the Idle will be more bumpy because of the lower Inertia.

As for the Head: I´m through with the Runners. What do you think about the Bowles? They look okay for me, or could they use a bit more Volume?

I haven´t spent much Time with the Cams, yet. They look very tame and are probably symmetrical. But I have seen that you Guys have posted some Cam-Specs in another Thread, so I can play around with that a bit on the Desktop-Dyno. I think I already know the Answer, but is there a Company, that offers raw Camshaft-Billets for this Engine?

Thanks,
Rafael

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Re: Adding Muscle - Now or never

Post by Marten »

Lotus-e-Clan wrote:
Sun Dec 19, 2021 15:38

And another cautionary tale about wrapping.

My CLan's stainless steel manifold rotted underneath the wrap after five years of use on the road all year round in this country (wet salty roads).

Some countries add magnesium choride to the mix, that can cause stress cracking in higlhy stressed stainless parts (depends also on the grade of steel)

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Re: Adding Muscle - Now or never

Post by Pete Boole »

What is the current volume of your combustion chambers? I have two CNC ported heads that I can measure as a comparison for you if it would help. The main problem with altering the standard cams is the size of the bearings - it leaves very little scope to increase lift - if the cams were held in place with caps it would be much easier! Don't forget that the best head gaskets are also 0.5mm thicker than the originals and reduce static compression ratio by about 0.5, so you don't want to increase the combustion camber volume if this could be an issue. What sort of compression ratio would you like to end up with?

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Re: Adding Muscle - Now or never

Post by Lotus-e-Clan »

Oldtimer_Basis wrote:
Mon Dec 20, 2021 17:47
So: If I machine down the Weight of the Flywheel, all that happens is that the Engine will behave less tardy, right? I don´t gain or set free any additional Power and the Idle will be more bumpy because of the lower Inertia.
The Lotus 912 OE flywheel is a two-part flexiplate. The flexplate softens the take-up through the gearbox by slipping the clutch a little - even if you let the clutch pedal slam shut. The in-built progressive take-up also also wears the clutch plate a little faster too, even if you're the best, most mechanically sympathetic gear-changer on earth.

I definitely wouldn't lighten the OE flywheel given its design.
I (and others) fitted an aftermarket (very) light steel flywheel at the last clutch change (available through Gary Kemp).
Idle isn't lumpy with the light flywheel. I run the idle just over 1000 rpm rather than the std 950 rpm anyhow - it's where it likes be and, because my water pump is electric and responds to coolant temperature (pumps faste rwhen hot), the higher idle does not lead to overheating in traffic. YMMV if you retain the belt-driven water pump, especially if the pump has lost efficiency at idle due to corroded vanes.

What you will notice with the light flywheel is greater engine braking when you take your foot off the gas, or switch off (it stops immediately given the 10.9:1 compression ratio of the SE!). I can't claim the engine produces more torque, but subjectively it responds to the throttle like it's got loads more torgue...revs rise much more rapidly and fast gear changes are a pleasure. The clutch feels lighter with the solid flywheel but you have to adapt to the sudden take up (which is soon mastered) - The OE flexiplate flywheel adds spring weight to the pedal action as you have to overcome the flex in the plate as well as the springs in the clutch release diaphragm.

Oldtimer_Basis wrote:
Mon Dec 20, 2021 17:47
As for the Head: I´m through with the Runners. What do you think about the Bowles? They look okay for me, or could they use a bit more Volume?
Not sure what you mean by the Bowles? If you mean combustion chamber volume, then you should volume the combustion chamber to acheive a static compression ratio (SCR) that works best with the cam's inlet closing after bottom dead centre in order to maintain a decent dynamic compression ratio (DCR) when off-cam. For the SE inlet cam the SCR is 10.9:1 to maintain the DCR just above 9:1. Any less than this WILL give you a lumpy idle and worse driveabilty when off-cam in the lower rev range (engine will feel 'cammy').
Peter K

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Re: Adding Muscle - Now or never

Post by Oldtimer_Basis »

Sorry, I meant "Bowls" - that Part of the Runners, in which the Valves are in...

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Re: Adding Muscle - Now or never

Post by DavidOliver »

I now realise you are across the water. Not many Excel´s over there, Are you in a hot/dry area?
I am not used to the terms Runners or Bowls, now realise they refer to Inlet track and Combustion chamber.
Personally I would not modify Bowl volumes, only balance, and porting the inlet tracks OK and to ensure mating of manifold to head by dowels.
Lotus did most of this work, we are starting off with a pretty good top end.
For access to parts in the USA contact Tim Engle, he is on this Forum and truly knows the 9XX engine in all stages of tune.

The main reason for lighteming the flywheel is to reduce the kinetic energy needed to either accelerate or decelerate the engine. A more resposive engine.
My 84MY LC engine has a solid flywheel, perhaps the SE engine is flexiplate, do not know. The solid flywheel is machineable, not more than 2kg. but get advice.
Any mods to the flywheel will require full balancing of crank, flywheel, clutch assembly.
With the pistons out it is worth measuring weights and balancing conrod end to end weights, a bit laborious. Worth doing even on new units. Balance to under 1gm. For the piston take the weight out of the Gudgeon (Thrust) pins as opposed to skirts or crowns.
While at it, with the water pump out to check condition, inspect the flow channels in the block, earlier engines I have found can have restrictions by casting burrs, so easy to smooth out and up to 30% better flow.

Saludos
Dave the cog.

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Re: Adding Muscle - Now or never

Post by Oldtimer_Basis »

LOL :lol: No, I´m a German and my Shop is in a sleepy Town called Grevenbroich, between Duesseldorf and Koeln (Cologne). So, between us is just a little bit of Water :)
We mostly work on american Cars from the 50ies to 70ies, so I adapted the american Terms. I already realized that there are more Differences between american and british English than Elevator and Aluminum, for Example: You say Engine, they say Motor. But I wasn´t aware that there are so many Differences.
With Bowls I mean the End of the Inlet Track, not the Combustion Chamber itself. This is the Area, where the Air/Fuel-Mixture can "wait" until the Valve opens. A big "Bowl" can prevent a temporarily Raise of Pressure or even a short Stop of the Flow in the Track, so it ensures a continuous Flow.
But they already look okay as they are...
I have to rebalance the whole Rotating Assembly? Naaaah, I´m too lazy for that :mrgreen:
Especially, because I really like what I see under the Oil-Pan. Everything looks pretty tough, built for Strength and Rigidity, not so much for ultra high rpm´s. Now I can also see, that someone already overhauled the Engine, because it´s got Liners in the Cylinders. I read "whilé" on the Pistons. Never heard of that Brand. Does anyone know that Manufacturer?

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Re: Adding Muscle - Now or never

Post by Lotus-e-Clan »

Oldtimer_Basis wrote:
Tue Dec 21, 2021 14:42

Especially, because I really like what I see under the Oil-Pan. Everything looks pretty tough, built for Strength and Rigidity, not so much for ultra high rpm´s. Now I can also see, that someone already overhauled the Engine, because it´s got Liners in the Cylinders. I read "whilé" on the Pistons. Never heard of that Brand. Does anyone know that Manufacturer?
No, liners are standard fitment. Cast iron liners in the low compression engines and Nicosil aluminium liners in the high compression SE engine.

Liners are a push fit and move if the engine is rotated with the head off - Use temporary larger washers to retain liners when re-building or rotating - or make shaped retainers yourself if you need the clearance.
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Re: Adding Muscle - Now or never

Post by AndyC »

Do you have an image of the liners in the cylinders? I ask because I've not seen that before. SE which are a High Compression engine normally have aluminium liners with a Nikosil coating, the coating can give the appearance of there being two metals concentric to the bore.

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Re: Adding Muscle - Now or never

Post by Oldtimer_Basis »

They... move? :shock:
Is that normal with Aluminium-Blocks? The only Alu-Block I know is the old Buick V8, and there the Liners are anchored by a wierd Wave-Pattern outside of the Liners.
Good Thing, I haven´t rotated the Crank, yet. Man, that´s a different Horse to ride... :?
...and I thought: Hey, that´s just half a V8 - how difficult can that be? :lol:
Sorry Andy, I still have to install one of those Cloud-Things on my PC... I´m running an old Windows-Version, which hasn´t got this One-Drive (I think).
But I can tell you: The Liners are standing more or less free down in the Block - I cannot really see, where they rest. I mean, if they are simply pushed into Place from above, they have to have a Rest somewhere down there...

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Re: Adding Muscle - Now or never

Post by AndyC »

The liners get sealed in place, note I didn't say glued.
When building the block you need to have liner clamps to stop them moving, once the sealant has set well you can generally get away without them but Lotus still recommend them. The sealant keeps coolant from the oil pan & crank.
To remove the liners it's just a wooden drift (and I don't mean a solid bit of oak, I mean a sift bit of pine), or a proper puller which puts metal across the base of the liner and has threaded rod run up to the deck and then stands proud of the deck to the tightening pulls the liner away from the casting.

https://www.thelotusforums.com/forums/u ... 2fe7b6.jpg

People have been known to install liners, install pistons etc, turn engine and the friction from the rings is enough to push the liner out of its new sealant. On an engine that's been run I'd not expect that. In fact if turning it moved a liner it would be a sign the sealant had failed and needed re-doing.

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