Lotus Elan

Zetec-R and 5 speed Lotus Box,

PostPost by: pauljones » Tue Jan 03, 2012 8:17 pm

Hi all and a Happy New Year.

As the title suggests,I was thinking of buying a Zetec-R 2ltr from the dreaded flee bay.This would be mated to my Lotus 5 speed box.

So,How easy is this task.I know its been done before and Ive looked at a fair few posts for ideas.I'm thinking about clutch parts and operation as my main concern.

My car is a plus 2,and the reason for doing this the engine is going cheap.Cheaper than a port and polish job on the Twin Cam.I have the box already rebuild,and most importantly,Emerald EFI to be fitted.It makes sense to fit the EFI to the Zetec-R with the 5 speed box.I have to completly rewire the car so im thinking it should be a good move to do this all at the same time.

Id really appreciate any input,ive not used my plus 2 much this year and id really like to get her back on the road and keep her there.

Many thanks,Paul
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PostPost by: Spyder fan » Tue Jan 03, 2012 8:57 pm

Hi Paul,
Are you contemplating a chassis change as part of this conversion? The zetec won't slot straight in to a Lotus folded metal chassis or the standard Spyder chassis without modification to the chassis.

In addition to a modified chassis, you will require modifications to the fuel tank, fuel lines, wiring (for the efi). the drivetrain should ideally be beefed up as well to cope with the power increase, don't try putting 160bhp + through the standard diff output shafts for instance as that will end in tears or worse.

The zetec engine may appear cheap compared to properly rebuilding a twincam, but a proper zetec conversion will cost just as much if not more than restoring a car to standard.

My own +2 zetec conversion cost me £21k of which £6500 was labour (by Spyder) the rest was parts and includes offsetting the sale of parts such as the old twincam and gearbox etc, paint not included as my bodywork was fine and still is. I would be surprised if you could do the job for less than £10,000.

Please don't think I am trying to put you off doing this, zetec conversions work really well and are surprisingly faithful to the original concept of the car. It should only be done if you really want to, not to try and save money.

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PostPost by: CBUEB1771 » Tue Jan 03, 2012 9:23 pm

pauljones915 wrote:As the title suggests,I was thinking of buying a Zetec-R 2ltr from the dreaded flee bay.This would be mated to my Lotus 5 speed box.


I would be very concerned about the Lotus five speed being able to handle much more torque than is produced by a Twin Cam. This gearbox did not survive well when they were used in the early Eclat and Elite with the two liter engine. It was not long before Lotus had to switch to a Getrag gearbox.
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PostPost by: bcmc33 » Tue Jan 03, 2012 10:13 pm

CBUEB1771 wrote:I would be very concerned about the Lotus five speed being able to handle much more torque than is produced by a Twin Cam. This gearbox did not survive well when they were used in the early Eclat and Elite with the two liter engine. It was not long before Lotus had to switch to a Getrag gearbox.

Russ,

You beat me to it - after reading the first sentence in Paul's post, I thought I must tell him to forget that very bad idea for the very reasons you pointed-out.

A modified 1st gear T9 would be my recommendation, or even a 6 speed MX5 box.
Last edited by bcmc33 on Tue Jan 03, 2012 11:44 pm, edited 1 time in total.
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PostPost by: alexblack13 » Tue Jan 03, 2012 10:44 pm

The two of you just beat me to it also.. :roll:

Completely agree guys.. Don't even attempt to use the Lotus 5 speed with that sort of power. It's life will be counted in days (if not minutes!!)

NOT a good idea....BUT ... A good idea, but not with the lotus box


Al' ........... 8)
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PostPost by: Spyder fan » Wed Jan 04, 2012 8:00 am

Paul,
An MT75 gearbox from a Granada/late Sierra is the gearbox of choice for a zetec conversion. The gearlever ends up in approximately the same position as standard and it can take 200bhp + all day long. There are 2 sorts, one with a cable operated clutch that puts the starter underneath the exhaust manifold (not good) and a hydraulic clutch which puts the starter in the more normal position under the inlets. The hydraulic clutch is stronger and some say the gearbox itself is better, but I can't comment on that from personal experience. I have the hydraulic clutch MT75 in both cars although the S4 uses a special version from Mitchell Cotts.(different bellhousing for duratec).

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PostPost by: bcmc33 » Wed Jan 04, 2012 9:53 am

Spyder fan wrote:An MT75 gearbox from a Granada/late Sierra is the gearbox of choice for a zetec conversion.

Alan,
Don't you need the latest level of Spyder frame to fit an MT75?
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PostPost by: Spyder fan » Wed Jan 04, 2012 10:04 am

Hi Brian,
The latest Spyder frame accepts the MT75, but Spyder will alter the earlier frames to suit. The zetec will require the frame to be altered anyway, it's doubtful that Paul has the later frame if he even has a Spyder frame at all. ( Paul can you comment so that we can give some more guidance?).

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PostPost by: pauljones » Wed Jan 04, 2012 7:06 pm

Hi all,

Many thanks for the replies,I did try posting earlier but think batts went off to soon.

Anyway,Yes I do have a Spyder chassis but it is an early example. I was aware it needed a mod for the mt75 gearbox but not for the fitment of the zetec.I will get in touch with them about this,

My main point is my car is a little uprated allready, 3.54 diff, Solid drive shaft from Sue, EFI fuel tank from Andy with JIC-6 fittings.

The quotes Ive had for the head being ported ect and sprint valves fitted is over the £800 for the new Zetec-R engine.Not to sure why the R is there but thats another topic.Anyway,as I have the Emerald to fit,and the car to completley rewire surely what head/engine its attached too doesnt matter.

As for the 5 speed,It was going to go behind the Twink,but as it seems a similar cost to fitting behind a Zetec then I thought Id give it a go.The box has been rebuild by CTS and I was told by a Lotus owner that it being a weak box was a myth and in a light weight Plus 2 wouldnt put much strain on it.How true is this comment?

The Zetec with TB'S should be good for 160bhp,145 on the standard set up.Im not after a track day warrior,just a reliable car I can drive and enjoy.

Im not even going to get the bodywork done,yet....

Paul
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PostPost by: bcmc33 » Wed Jan 04, 2012 7:54 pm

pauljones915 wrote:As for the 5 speed,It was going to go behind the Twink,but as it seems a similar cost to fitting behind a Zetec then I thought Id give it a go.The box has been rebuild by CTS and I was told by a Lotus owner that it being a weak box was a myth and in a light weight Plus 2 wouldnt put much strain on it.How true is this comment?

Paul,

The Lotus 5 speed box is robust for an Elan/+2 with possibly up to 160 BHP & 135 Ibsft torque. But when it was used in the Elite/Eclat with much more torque and body weight, the duty cycle was too great for the box, and hence the upgrade to a Getrag box.
It was the extra torque applied to the weight that made it fail and create the bad reputation - something we don't have with a Twink in an Elan/+2.
As a matter of interest - what is maximum torque from a Zetec?
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PostPost by: pauljones » Wed Jan 04, 2012 8:27 pm

Brian,

Thanks for confirming what I was told,its great to get get a second opinion,and I'm not sure my Dad would like me "borrowing" his Excel box.To answer the question on Torque,The standard R is rated at 130 lbs/ft and 145 BHP.The TB'S raise it by 15 BHP to 160 BHP,ESTIMATED.So I would guess 145 to 150 lbs/ft.

Paul
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PostPost by: bcmc33 » Wed Jan 04, 2012 11:27 pm

pauljones915 wrote:Brian,

Thanks for confirming what I was told,its great to get get a second opinion,and I'm not sure my Dad would like me "borrowing" his Excel box.To answer the question on Torque,The standard R is rated at 130 lbs/ft and 145 BHP.The TB'S raise it by 15 BHP to 160 BHP,ESTIMATED.So I would guess 145 to 150 lbs/ft.

Paul

Paul,

My engine has 125 BHP & 118 lbs ft at the rear wheels, and I have to admit that I use 2nd & 3rd gear in anger when the opportunities arise.
Now how this relates to outputs at the flywheel is often cause for debate. But assuming transmission losses of 20% the power would be 156 BHP & 147 lbs ft at the flywheel. However, I have seen opinions that say 18% and some that say 25% are the transmission losses - I really have no definitive evidence to know what is true, that's why I use the 20% figure we used to use in the good old 60/70's days.

So, maybe we are a bit premature in writing off you using the Lotus 5 speed in your car. Or maybe I'm simply waiting for my box to blow up - even if the car with my fat arse sitting in it only weighs 800Kg :roll:
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PostPost by: rgh0 » Thu Jan 05, 2012 8:41 am

A friend had the Lotus 5 speed box in his Elite for many years and many miles with only one rebuild until he replaced it recently with a Mazda six speed box. So I dont think they were that fragile that it could not be used with any upgraded engine in the 160 hp range in a plus 2 given its use in the Elite with 2 litres and 160 hp and more weight.

Certainly modern synthetic gear lubes should also help the boxes capability as I am not aware of anything of specific weakness breaking in these boxes, just wear in the bearings and syncros mainly that will be helped by modern oils such as Redline.

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PostPost by: pauljones » Thu Jan 05, 2012 1:30 pm

Thanks all for the replies,

So,now it seems the box is ok to use,back to the original question.how easy is it to mate the two together and if any,what special parts do I need?

Paul
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PostPost by: CBUEB1771 » Thu Jan 05, 2012 6:45 pm

I don't want to beat this to death but a neighbor who had an Elite with the Lotus five speed went through two gearboxes in short order and that was the cars death knell. I can't speak to the details of maintenance so I accept there can be quite a range of experience between this and what Rohan has reported. I agree that modern lubricants would likely help quite a bit. Keep in mind the that Lotus five speed uses internals from the Austin Maxi, 1750 cc, 84 or 95 bhp and 2200 lb. I have not found a torque specification for the Maxi but at 95 bhp at about 5500 rpm it is not a big number.
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