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Rebuilding an existing car


Lostin complexity

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Hi,kjuu ppppa new member and a new owner of a Caterham Super7. I’ve wanted this car since I was 16 (o so many moons ago) and now I have it. Well, that’s not quite correct as I only purchased it on Thursday and it still resides in Massachusetts-2600 miles from here. It was purchased on Bring a Trailer and anyone interested in assisting me in deciding what to do with it can go to that website to learn the details of the car.

Here is the problem ..1300 pounds and 360 horses from a turbo charged 4 cylinder. 2 radiators and lots of plumbing. Not exactly true to Chapman’s ideals. 
it needs a new clutch, any recommendations. Fixed rear axle, should a LSD go in? Should the turbo come out?
what kind of carbs go in?

you get the idea, what is the ideal setup?

I drive my cars a lot. There are no garage queens. No track days but lots of great back roads  

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Hi Jim,

I assume this is your car: https://bringatrailer.com/listing/caterham-super-seven-3/

"The seller notes the current Tilton OT-II 7.25 twin plate clutch is slipping and needs to be replaced."

 

There are many questions to be answered just to replace the clutch with the right assembly. If it cannot be driven conservatively without clutch slippage, and the seller does not have the documentation for the existing clutch the engine and trans will need to come out to determine what needs to be ordered. This is not like a normal, daily driver clutch.

 

If it were my car, I'd limit the boost to about 5 psi, fit a good normal clutch, remove the intercooler, extra radiator, associated plumbing, fit a lower gph fuel pump if it is excessive, cut the leaf spring pads off the axle, and a standard size crank pulley to drive the water pump and alternator at normal ratios to aid cooling and charging. Keep the haltech efi and distributorless ign.

 

Easier just to revert to a standard crossflow with dcoe40s and sell the rest.

 

This may be setup to run of e85 exclusively.

Plenty of zetec efi cats out there you could probably trade for once the clutch is replaced.

 

 

 

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Congratulations MV8,

I was following this one as well, I do hope that the alloy body has a coat of clear so you don't have to polish all that alloy every week.  I just sold a Norton for that reason, lol.

 

Sounds like a bargain to me, enjoy the ride when you get it sorted.

 

Cheers

Dave

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Congratulations on your acquisition.  I thought you got a good buy.  Needs work but price was right.  Looks fantastic.   Its not unusual to have to fettle a seven to get it reliable.  All of mine have seemed to require that - then years of no issue motoring.  

 

First thing, you have a neighbor with a Caterham - calling @kayentaskier to the chat.  I think Jim calls on Josh at Rocky Mountain if he has major issues.  You don't say if you will be doing this or need someone to do it for you.   Jim can advise if there is someone local in St George.  Nice town by the way - I leaked my way through there last year on my road trip.

 

Given everything has to come out to get to the clutch (and you might as well replace any consumables in there at the same time) this is a bigger job that normal.  You won't know what the parts order list is until it is all out. 

 

Ask yourself what your goal in for the car?  Quiet backroads?  Monster straight-line performance?  

 

As it is set up there is 300hp on narrow rear wheels with tire rubber that is better suited to a GT car.  Not a particularly idea formula as 300hp on skinny wheels gives you all the traction of a cat in a wet bathtub.  Not something you want carving a few canyon roads.  But the look of the car is sensational - really well presented in the classic style.  

 

Following on from MPH above in the time honored "if it were my car" theme, I would play on the cars presentation and go for a classic look but upgrade the handling ability and dial the power back since you are backroad focused.  Less is more.  So back to naturally aspirated with Webers on the big valve twin cam.  Drop off the turbo stuff and EFI.  Re rate fuel pump and scale down the oil/water pump flows. Less aggressive clutch.  Definitely LSD.  I would think long and hard about different tires - a top quality performance rubber on the 13 inch wheels but try to preserve the existing snowflake wheels as they are the original for the 80s. Either way you want to stay on 13 inch wheels for the best handling/performance.   Oh and drop some classic looking gauges in the dash instead of the wrong look autometer pro comp ones.  Twin Cam may not require any work but clearly there are open questions on fueling, timing, flows, etc.   

 

7 hours ago, Lostin complexity said:

I drive my cars a lot. There are no garage queens.  

 

Big thumbs up!   More people should take this approach.  

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If you want to keep the existing engine but fit carbs, the actual compression ratio needs to be determined along with measurement of the existing head gasket thickness then raised with an appropriate head gasket and/or piston change. I expect that like the pistons, the cams are specific, custom grinds for the turbo and may need replacement also, plus the crank pulley appears to be undersized, which would slow the water pump (and alternator) for less parasitic loss but making cooling less efficient.

 

I'd be surprised to find an open diff with so much spent on power production.

 

I spy two fuel tanks. I guess the small one is e85.

Edited by MV8
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That is not too much power, as there are more than 2 positions to the footfeed.  I would change the clutch, and for now renew all the rubber while the engine is out for reliability.   Keep the fuel injection in your area as it is far better suited to the altitude changes.  Drive it and then decide what YOU want. A de-tune on the turbo should be easy and as I stated, the foot pedal is your best waste-gate. It is a very pretty car and someone has spent much time and money on it. 

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That sounds like good advice. I always change the fluids with a purchase of a used car and changing the rubber when the engine is out for the clutch would be appropriate. Thoughts on the clutch brand and model?
thoughts on a LSD if it’s fixed now, there seems to be some confusion as to what it has.

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59 minutes ago, Lostin complexity said:

Thoughts on the clutch brand and model?

If only replacing the clutch with no other immediate changes to power output, replace what you have with the same thing. It may need just the discs. They can determine what is installed based on the existing part numbers. The brand is Tilton.

For a good drive-ability compromise with enough capacity for a 5psi system, I would look for a sprung hub, marcel spring if available, ceramic puck clutch disc with a diaphragm pressure plate on a standard weight or slightly lightened steel flywheel.

Hub-Configuration-and-Disc-Pack-Part-System.pdf

Edited by MV8
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As Mike says, I’m close by in Ivins and I use Josh for servicing my 420R. I think there multiple good suggestions in the previous responses regarding possible changes. Once you get the car home, you’ll undoubtedly figure out the best path for your car. BTW, there’s another Caterham owner nearby Washington, I think he has a 420R and has been on this site in the past. 
 

PM me if I can do anything to help. 
Jim

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  • 2 weeks later...

@lostincomplexity I watched that auction with keen interest. There's some good advice here. I say change the clutch with what the Tilton dealer suggests, and try the car as is. Go from there. Congrats on what must be a beast of a 7! Enjoy!

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thanks to everyone for their thoughts and advice. A special “thank you” to Josh in Denver who ran through the project in great detail. The car has arrived from Massachusetts to St. George Utah. As  laid out by the seller, the clutch does need to be replaced. Before seeing it, I was inclined to just replace the clutch and run the car as.   is. After seeing it with hoses running everywhere , a turbo and 2 radiators, I find the complexity of the car to be overwhelming. It has a turbo, 2 radiators (front and back), a dry sump lubrication system and more hoses running in more directions than is imaginable. 
on the plus side, the engine and trans are sound and the car functions as it should. The body  with the unpainted aluminum is stunning. I’m researching ceramic coatings and other products which will allow me to spend more time in the car and less time workin
g with a polisher in my hands. The seats are comfortable and at 6 feet one inch and 185 pounds, I fit in it -barely. 
Im returning the car to its original by stripping out the turbo and related plumbing. I have a 2008 BMW M roadster that has an ESS supercharger and is very simple compared to the turbo. As Colin Chapman said, simplify and add lightness. I’m going to escape this complex build.

I’ll provide more info as the project develops.

jim

 

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  • 3 weeks later...

Ok. Things are proceeding reasonably well  the engine is out and the clutch , flywheel and parts have been ordered from Burtons in the UK 

Tilton did not produce anything but a race clutch in 7.25 inches. 
we are removing the turbo and related parts as the engine runs better without it.  
I need a source for a exhaust manifold and heat shield for the side side pipe. Any ideas 

jim

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Yes, only race clutches in 7.25". A standard size traditional flywheel and clutch are much better since you are eliminating the boost.

It looks like you will need a custom made manifold or reuse all or most of the stainless primary tubes and a custom made slip-on collector to make the side pipe transition. Good custom work usually requires the car to be present as each pipe is fitted to the space available. 

What you have is the Lotus twin cam "big valve" head with a round two bolt port instead of the more common cosworth square two and four bolt configs.

This looks to be the right flange but would not be a side pipe config:   https://www.motorsport-tools.com/simpson-lotus-cortina-exhaust-manifold-twin-cam-2-25-stainless-steel.html

The turbo acted as a muffler so you will probably want to fit a muffler/silencer. You may want to fit a side pipe available for newer models that has everything you want. Whomever is building the exhaust can build the side pipe to fit.
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