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HC Upgrade

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To cut a long story short, due to financial reasons and no free time I've neglected my car and it's been in the garage the past year. With the kids now sold to slavery and no real job for me to go to, I've found myself with a few quid and a bit of spare time to get the Esprit back on the road before complete and utter financial ruin.

I have a nice list of fixes to be getting on with, some of which will mean lifting the engine out. So I started thinking about upgrades I could make at the same time, especially if the engine ends up in pieces. I quite fancy the idea of running a tiny bit more boost - but realise I risk doing serious damage. Is it possible to just switch over to HC liners and pistons, and would that in itself be enough to safely run higher boost?

For the moment I'm trying to keep the car as true to original as I can, so any improvements I can make which would not affect what you see in the engine bay are very welcome - even if there is no performance change but it extends the life of the car I think it could be well worthwhile.

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It's a case of either adapting/ swapping the block to accept ali liners or using iron liners with the HC pistons (not LC liners), you'd really want to swap to the later wastegate, but then I'm sure you can just tune the carbs to suit. Possible, not a 5 minute job, but reasonable.

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I understand that the LC block has to be machined to accept the HC liners...needs to be bored out a trifle. This could work nicely, or the block might distort under the machining load and you end up with less than parallel cylinders. I can be done, but I think you'd want to find someone who has done the job before!


Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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I seem to recall that Ambrose had his motor ruined through this 'upgrade'. You only get one chance to f*** it up and the machinist will never have done it before. Another (cheap!) option is to use aftermarket forged pistons (Venolia) in the LC liners, which is what I do. I also run an HC head with multi angle valve seats. The Wastegate is uprated by around 4mm of aluminium washers in its base. The inlet manifold and is an LC item but opened out (with a file....) to match the HC head. LC carbs actually run a larger choke size than the 45s on an HC, so getting enough air in there is not a problem. I have run like this for maybe 4 years with no issues. Good power and fuel consumption. Significantly better off boost throttle response than the standard LC.

Steve

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It is possible to fit HC pistons in LC liners, its been done before.

The block boring is quite expensive

It is possible to get replacement liners that are designed to do the job in hand but I can't for the life of me remember who it was who was selling them.

If your doing a full rebuild it may be worth weighing up the options between doing it all yourself or giving Gary Kemp a call and see what he'd be looking at for a recon engine or rebuild on yours with your new bits.


Chunky Lover

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Thanks all - so as I feared the block would have to be bored, which naturally I'd only let someone with plenty of experience do! Need to decide if that's the route I should go down, or purely get some forged pistons and an HC head. Just looking around for a head at the moment....

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If you do buy new forged pistons...and new liners....make sure they match. There's a whole world of hurt and disaster a'waiting out there...buying from the same source is no guarantee. The pistons are fine...but the liners vary vastly; I've had it where one liner wasn't big enough for the piston!! Whoever specified them seems to have specified the forged pistons to the largest diameter of the tolerance and the liners to the smallest.....I ended up having to hone some liners myself!! Not ideal. As long as your liners aren't a disaster, I would think you could hone them and fit new pistons to the old liners....but, as ever, no guarantees!!


Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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This was done to my '83 Turbo by the PO, with input/specs from Arnie Johnson. The attached, from an issue of Lotus, Ltd.'s ReMarque (don't know which issue) may be of interest, and is in a huge work binder the PO gave me with the car, but honestly, I can't suss out the notes relating to the HC conversion. If you want, I can put you in touch with him and you can see if he's willing to help out.

HC Upgrage.pdf

Edited by Moxie

1983 "Investor's Special Edition" Turbo Esprit (#43/50) | 2012 Evora S

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With regard to the Ambrose details I remember the thread. He was warned against doing what he did, and then carried on and did it!


Regards

Mat

post-1-0302470001278592957.jpg

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What exactly went wrong for Ambrose then - something at the machining stage, or when it was being given a run in?

Suddenly I'm having second thoughts!

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I seem to recall 'Nip' was not in tolelance, so the machinist's solution was to skim the top of the liners - this then chipped the Nikasil plating. There must be more to it than that, as I also recall the block was scrapped....

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He sold the car on ebay as a project. It was a shame cause its the closest car to mine on the Esprit registry.

Buddsy


 

"Belief is the enemy of knowing" - Crrow777

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Ouch! Well my upgrade plans are to increase longevity of this baby, not do something to instantly end it, so I shall do my best to learn from others lessons. Once I've had a proper look I'll decide if I should get new liners, but I'm hoping to find some forged pistons to fit the existing liners.

If new liners are needed and the block boring, anyone got any ideas who might be up to the job?

Alternatively I could do with a donor car with all the spares I need, then if I f**k anything up then it's no biggy - anyone feeling generous and want to donate to this worthy cause!? I'll throw in a beer!

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When faced with this choice last time I chose new iron liners and original LC pistons on a cost basis Cheapest HC pistons I found find were around £500.

What I hadn't figured on was the wastegate not working and holing a piston( yet to be confirmed) so I will use LC pistons but try to ensure boost is less than 8 psi. I too am not looking to increase performance but to help reliability. Ideally I would like an intercooler but can't justify the cost 

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At that price it probably makes a lot more sense!

I'll do some phoning around next week, as there's a few other bit's and pieces I'll be wanting at the same time.

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