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View Full Version : New Lotus Owner...and some questions



DJThom
10-19-2004, 01:42 PM
I have just purchased a Lotus Elan S2 roadster. Paint and body are done, mechanicals are done, but it needs assembly. This is my first Lotus, and joins a MGB in my garage that I rebuilt with my dad 10 years ago when I was in highschool, and a XKE and AH 3000 in the family.

I have one short and one long question.
Short: What tire sizes fit on the Elan with standard (non flared) fenders. The car has been fitted with the later knock off wheels.
Long: I'm reading all these articles and web pages stating power ratings on the twin cam engine up to 185 hp. What are recommended modifications (boring, pistons, cams, headers etc.) that can be done for street cars to get more power but without spending a fortune or doing anything too crazy.

Thanks
DJThom

Jon12
10-20-2004, 01:48 AM
Just saw one of these driving around locally, I was going to stop and say hello but the owner circled the block. Very good looking cars in person.

Dan_Morrison
10-21-2004, 02:41 AM
Short: Not much else will fit. I think original tire size was 145-13. Maybe 165/70-13? Maybe.

Long: 185 BHP would be race engine territory and not streetable, plus many $$$$. The usual performance mods are just about the same for any engine, but on the Lotus nothing is going to be cheap.

DJThom
10-21-2004, 09:16 AM
Exerpts from some other responses I've received offline from others more experienced than myself...

For better performance a good choice is the Bridgestone RE92 in a 165/70 x 13 size. This is as big as you can go. A 175 tire will not fit in the wheel wells of an S1, S2, or and S3. S4's with their larger wheel wells can usually squeeze in a 175 tire.

and...

Pirelli P-1000 155/ 80 R 13 ‘s. It is important not to go low profile for road use since the taller tires are more comfortable with camber changes – and they have more compliance –better ride , - bigger isn’t better with the Elan since Chapman’s whole concept was around low unsprung weight.

TypeRboy
10-22-2004, 01:32 AM
Hey good choice for a LBC! I'm still running 145 sr 13 Michelins on my car, and there is not much room left as it is... A 165 70 13 would fit. ( my tires are very old stock, and quite hard and slippery, but complete the stock look of the car very well..).

You probably will find that you don't need a lot more power out of the car as it is stock. Use a set of sprint cams, balance the motor, get a lighter steel flywheel if you can, match the int and ext ports, put a header on it with a larger bore exhaust ( not an easy fit, and watch those speed bumps..)cc the head and degree the cams ( the cams and gears can be wildly out of spec from the ideal..).

Lastly you might consider using a set of Del'Orto carbs. They start and run better, and have a smoother progression from part to full throttle. There is no power difference, but a big driveability and part throttle performance difference. I have run them on other motors and currently am running them on my Cortina, and loving it.

Take an Elan out for a drive if you can find one. You need to see the kind of power band that you are trying to play with. These motors have a very flat torque curve, and never really " come on cam " like most other motors. They pull steady and strong right up to redline and beyond ( hence the rev limiter rotor supplied stock in every Elan )

Building the motor for higher performance won't change these characteristics much, these are definately not motorcycle engines. If you want more power the best way is more displacement. You can build a stock block 1600 cheater motor, or build a tall block 1650 to 1700 torque monster. I chose the torque monster, and it works very well indeed. I would guess my power at about 135 hp, but I can drift the car around long sweeping corners quite easily in second gear ( haven't tried it in third, that's way too fast for me.)

I would advise against drastic gearing changes, like 411's or limited slips. On the street.

Well anyway you won't find that you have a problem with spinning just one wheel, in fact you will have trouble keeping the car pointed in the right direction as it is.

Enough said.. I'm not an expert on these cars, having only restored one and helped on another. I don't race mine ( or anything for that matter ) so maybe you should seek counsel from some people who actually have gone whole hog on their cars. I will say that the returns you get for the money that it will cost you to bump your HP up even just 20% should make you stop and think hard about it. ( just a used steel crank can cost you $1500.00 ) Been there, not doing that again thanks /ubbthreads/images/graemlins/nonono.gif

DJThom
10-26-2004, 02:19 PM
Thanks for the suggestions! By tall block I assume you mean the Cortina block? What did you do at the front where the stock cover is a bit too short? Also, I heard that you can get more power just using the cortina crank in the stock Elan engine (with shorter pistons obviously). True?

Did you do bench airflow on your head? Where did you get it done, and how much better did it get?

Thanks
Darren

TypeRboy
10-27-2004, 04:17 AM
Yes the tall block is the 1600 kent block. The space between the timing cover and the head is filled with an aluminum plate the same shape as the tiny cork gasket, then two gaskets are used. The timing chain is a bit longer with 122 links as well as the external oil return hose is a bit longer. There is also a minor mod that can be made to the timing chain tensioner to align it better, but the thing works fine as it is. There is also a longer timing chain rubbing block to be used as well ( I think, it's been a long time since I put this motor together..). Yes the 1600 crank in the stock block is also a good way to go, and a better fit in the car as well.

My head is not bench flowed, but just cleaned up and the ports matched, and the sprint big valves installed ( they are not much different, but you might as well use them for whatever gain you can get, the price is the same..)

The thing i hate about this motor is the way oil collects in the tappet boxes and bleeds into the valve stem. If you leave the car for a few days, it throws a cloud of blue until you burn off the oil that seeped into the combustion chamber. I could have put valve seals in there, but I figured the lubrication might be necessary, so I left it stock. Now I'm not so sure. I have another motor and I might put seals into it and see what happens. I don't have a car for that yet, but if a Super 7 sort of car comes up cheap enough, then I would add it to my stable.

I will probably be selling the Elan pretty soon anyway, i have too many expensive toys hanging around. If all my motors blew up at once, between the Type R, the BDA and the two lotus motors, it could cost me $30k just to fix em... /ubbthreads/images/graemlins/eek.gif

Super 7
10-28-2004, 01:47 PM
Type R, I had Ive build me a 1680cc Crossflow, and it Dynoed at 135 hp. Its a street engine, and is not at all fussy.

Your Twink should be more powerful than that.

What block did you use for your High Deck conversion?

TypeRboy
10-28-2004, 07:26 PM
The block is one of the nos AVO 1600 replacement blocks that were available from Ford Motorsport ( still stamped 711..)I'don't think they are still available, but they were up to about 6 years ago. It came from kelvon ( I can never remember how to get their name right ) lotus parts in the UK. ( about $2000. 00 landed in the driveway ) The block has very thick casting so I could run a thick wall 1750, which I am. Motor runs very cool, and like yours is not fussy at all.

My motor is basically stock, just with the displacement bump, so I would doubt that I have much more than 130 hp, but really I am just guessing. I should dyno it and at least get a rear wheel figure, but I hate bad news ( sorry to say sir, but she makes a whopping 76 hp to the wheels! )

/ubbthreads/images/graemlins/cryin.gif