Are all Spyder chassis created equal

PostPost by: Alan D. » Fri Oct 13, 2017 7:02 pm

Hello all,
I'm looking to purchase a Plus 2 and from what I have read, I think the only stipulation I would have is that it should have a Spyder chassis. My question is; as this chassis has been produced for a few decades now. Is it still the same or has it been improved or modified over the years?
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PostPost by: LaikaTheDog » Fri Oct 13, 2017 7:32 pm

Personal preference from having both.
An original folded lotus chassis is my choice.
Spider chassis come in two flavours. Folded and spaceframe
Not sure if they still make both.
They also change over the years. Early one have no space for an engine swap. Later are designed to take double rear wishbone and zetec engine.
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PostPost by: vincereynard » Fri Oct 13, 2017 7:33 pm

Far as I know, for the spaceframes, there is a definite Mk1 (twin cam only) and a Mk2 (twin cam + Zetec chassis.)

There are other differences such as the Mk 2 can accept Spyders twin wishbione rear suspenders.

Basically if you want to show get an original, but if drive regularly the Spyder does have many advantages.
And that is from someone who is not exactly their greatest fan!

(Laika beat me to it!)
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PostPost by: Alan D. » Fri Oct 13, 2017 8:07 pm

Thank you both for you explanation, It's a drivers car that I would like. So it sounds like it's the Mk2 chassis for me. It gives the option of fitting a modern engine, but the ability to revert back to "matching numbers". I've done the same with my Elise, remove the standard 118 BHP engine and fitted a 143 BHP VVC engine. I will refresh the original engine and put it into storage.
So how do I identify the Mk2 chassis?
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PostPost by: vincereynard » Fri Oct 13, 2017 8:59 pm

Alan D. wrote:So how do I identify the Mk2 chassis?
Alan D.


Ask Spyder would probably be your best bet.
The early one's can be updated and strengthened in some respects. But, I believe (i.e. don't really know) that only the Mk2 can take a zetec.
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PostPost by: mbell » Fri Oct 13, 2017 10:02 pm

There also changesso that the chassis can take a mt75 gear box. I believe this is a change of cross brace to sheet metal for the rear part of the y.

If getting a new spider space frame you may as well get all the latest greatest features.
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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PostPost by: stugilmour » Sat Oct 14, 2017 3:34 am

Welcome to the forum Alan.

If you want to be able to install a Zetec, the top of the round front crossmember (the piece that acts as the vacuum tank) has to have a half round cutout to accommodate the Zetec harmonic balancer / front pulley. This is in addition to the notch shaped cutout in the back side of the crossmember that accommodates the length of either the Lotus TC or Zetec.

This was not 100% clear to me when I bought my frame several years ago, and I ended up with the Twin Cam only frame. I recently judged it too difficult to modify the frame later to add the notch; probably body removal, steering rack removal, brake line removal before one starts cutting and welding. I have installed an MT75 five speed but I am sticking with a built up Twin Cam due to the chassis.

So, although the guys saying there are the three basic frame types (folded metal like the original, Mk 1 Twin Cam Only, and Mk 2 Zetec) is basically correct, it is a bit confusing. They don?t necessarily make every new frame automatically to accommodate the Zetec, at least in my case they didn?t. And every Mk 2 vintage chassis will not be the same. Basically mine has all the mods except the half round cut out.

For fitment of the MT75 five speed (the transmission Spyder uses for their Zetec conversions) there are two required modifications. There are (from memory) six captive nut / bobbins welded in to the bottom frame rails to accommodate two different transmission mount positions with four bolts each. The other mod is either bending or relieving one of the ladder frame cross bars to accommodate the starter motor for the MT75. This was not done on my frame, and I modified it myself by cutting the crossmember out and replacing it with a bolted in channel.

This picture shows the half round cutout and sort of shows how the right side diagonal member is bent outward for the starter. It doesn?t show the notch cutout very well, it is easy to see looking straight down at the crossmember. Looking over the other features, this frame is set up with the double wishbone rear suspension. I can?t recall if my frame came cut out for the tunnel handbrake, I doubt it.

To take a look at other pictures, try clicking on the photo gallery, change to showing 800 pictures per page, and slowly type in a filtering term like Spyder or Zetec and scroll through the pictures. You have to type slowly as it filters with every key stroke. Not a fast process, but you can see what is out there, as there are certainly other approaches and solutions used.

But for a quick visual check of a candidate Spyder equipped Twin Cam Plus 2 runner, I would look for the half round cutout as it is easy to spot under the bonnet and very difficult to add later if you want to. Or just say to heck with it and look for a nicely built Zetec. :D That would be my preference, but they are not really available our side of the pond.

HTH

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Attachments
666946aa-d426-49b5-84f2-e500f7077726.jpeg and
A picture ripped from the archive to show the required Spyder mods for the Zetec.
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PostPost by: pauljones » Sat Oct 14, 2017 6:53 am

Hi all.

Without trying to confuse matters,

I have an early Spyder chassis, so the twincam only version. It still has the mounts for a rear wishbone suspension.
My understanding was all variants off spaceframe can use the Spyder rear wishbone style suspension but only the latter ones came with ability to fit zetec and mt75.
At one point Spyder were willing to update the older chassis to new spec but no longer offer this service.
My Spyder chassis is atleast 10 years old.

Paul
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PostPost by: gus » Sun Oct 15, 2017 12:04 pm

I think the variations are a continuum.

Rear suspension changed in the late 80s early 90's[dunno if actual chassis change]
more room for transmission
zetec mods
I think more tunnel mods

so in the wild there will be several major variation, mostly getting more mod'able as time goes on
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PostPost by: RichardHawkins » Sun Oct 15, 2017 2:47 pm

Stu,

Looking at th photograph of an MT75 installed in a Spyder chassis, does the gear lever now move further backwards in the chassis?

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PostPost by: stugilmour » Sun Oct 15, 2017 3:11 pm

RichardHawkins wrote:Stu,

Looking at th photograph of an MT75 installed in a Spyder chassis, does the gear lever now move further backwards in the chassis?

Richard Hawkins


My recollection is Spyder says it doesn?t move. Note all the Spyder Zetec cars seem to have the later style consol so it is hard to tell.

In my case it moved rearward slightly; at six feet tall I actually find it more comfortable. I have the original style black plastic consol and use the original Twin Cam engine. Not exactly sure of how much it moved, but I added an appropriately 1? plastic filler to my shift boot hole and fitted a different boot I found at the breakers.

Here are a few more pictures

HTH

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Attachments
0ed417df-b0fa-4433-8bb6-5a97ead2583e.jpeg and
This one shows the shifter mechanism that Spyder provides with the transmission. I recently changed it a bit; Spyder has done a re-design to provide better noise isolation. Haven?t had the car on the road yet since installing the revised linkage.
37f463e7-9bb4-4bd0-ba31-0e6e8eab6362.jpeg and
Apologies for the poor picture. Shows the spacer I added.
717ba56e-0a29-4e40-bd38-81c9f8be3598.jpeg and
This one shows the position of the MT75 shifter in my Plus 2.
4d9f6124-b4d6-4b3e-8b04-3828555ceec5.jpeg and
This is a picture that used to be on the Spyder site, but I can?t find it any more. It was when they brought out the MT75 mod, and shown with a TC. For the original poster, this shows the notched cutout at the back of the crossmember. Note there is no semi circular cutout on the top.
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PostPost by: Spyder fan » Sun Oct 15, 2017 3:28 pm

To answer for Stu, the centre of the gear lever will be approximately 75mm / 3 inches further back than original, this is not as bad as it sounds as the gear lever is now vertical rather than angled towards the rear as before. Consequently your hand touches the ball of the gear lever in roughly the same location. If I can find some photos of mine I will post them up.

My own personal preference is always a Spyder spaceframe over the Gartrac folded metal item, Lotus didn?t make this backbone designed by the brilliant and much missed Ron Hickman, but factored it out to Gartrac who just made what was asked for without any thought to improvement or precision.

Spyder currently offer a spaceframe for the Lotus twin cam that accepts an MT75 gearbox and their own multilink rear suspension system as well as being compatible with all the original Lotus components in addition they offer their Zetec chassis which has a different front crossmember as mentioned by Stu to make clearance for the front pulley on a Zetec engine. There are a few other differences for a Zetec chassis mostly to do with diff bracing, but you can use a Zetec chassis with original stuff as well. Special order you can have a folded metal chassis as per the Gartrac item, the nice thing being you can add your own modifications as required perhaps ask for a bare metal chassis so that you can paint it red lead to look like an original no longer available from Gartrac.

I have lots of details on how to build a Zetec car and Stu and others on here will help you with info as required. Learn from our mistakes as well as our successes.
Kindest regards

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PostPost by: pauljones » Sun Oct 15, 2017 4:33 pm

My MT75 box has a turret and some kind of rose jointed linkage on it. It looks a bit further forward than the example in the pictures. I was told this was to enable it to come out at same place as the origonal. One day ill prove/disprove the idea.
Ill probably have to mod the chassis to fit it tho.
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PostPost by: Alan D. » Sun Oct 15, 2017 10:16 pm

Hello all,
Thank you for the very detailed information, I'm much wiser now. As I read the situation it's the same chassis, but with a few detailed modifications. I can T.I.G weld and fabricate and have good workshop facilities and originally come from an engineering background, so modifications are not impossible. But I will look for a later chassis with the front pulley cut-out.
I was interested in the comments on the MT75 box. I've just purchased a very good MT75 box, with a flywheel which was fitted to a Zetec engine (8000 miler). This was fitted to a Westfield and the owner explained that he changed it for a type 9 with close ratios, because 1st and 2nd gear were too low ( in ratio). So I now think I've purchased the wrong box, but then I see that a few of you are using them. Did you change the diff or is it alright on the Plus 2? I also have a type 9 and bell-housing I think from a Capri. This box was spares or repair, so will need rebuilt.
Thanks again for your help, I can see this is going to be a great forum.
Regards Alan
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PostPost by: stugilmour » Sun Oct 15, 2017 11:50 pm

Alan, there are lots of opinion threads on the MT75 for sure, so searching the archives is worthwhile.

The first gear is quite low, but I like it for creeping in traffic. It is a bit lower than ideal for the track, but I never need first at our home track so really not an issue.

In my Plus 2 I use a 3.54 rear end. The car was available stock typically with 3.78. 3.54 (or 3.55, can?t recall; someone will correct me I am sure) was apparently an option; have never seen one our side of the pond though. Ring and pinions are commonly available for the English Axle, so not a huge deal to change ratio?s. Note the Spyder Zetec?s typically use a different modern diff and 14? wheels, so not sure of the typical ratios that result, but probably pretty close to mine.

There is a very good spreadsheet available on the forum for computing speed in gears, etc. Without going in to a ton of detail here, my Plus 2 with stock sized 165/80/13 tires, 3.54 diff, and the 0.82 overdrive in the MT75 runs 80 mph at 3500 rpm, which is pretty much perfect for modern traffic, but does not offer much acceleration in fifth gear with a stock TC. I understand the Zetecs are similar gearing, but the added grunt of the Zetec makes the car pretty much perfect.

The T9 is apparently considered a better box by a lot of folks because of the wide variety of available ratios, and bell housings are available and can be changed. That said, it is practically more difficult to fit because there is no off the shelf linkage and mounting solution commercially available as a readily available kit. Not saying they haven?t been installed successfully, just saying Spyder uses the MT75 and installing one in their chassis is well trodden ground that may not even require welding equipment if the correct chassis options are ordered (can?t recall why, but I had to slightly modify the rear transmission mount).

The MT75 uses a different clutch setup than stock. Of course, it had an integrated bell housing so perhaps not as easy to connect to the Twin Cam. The slave cylinder is an axial type. A different starter motor is used. A larger flywheel is used (or at least that is what Spyder recommended for my Twin Cam Install). I have never been sure on this detail, but my Twink always seemed sluggish, and I wonder if the flywheel was heavier and robbing a bit of performance? Think I will start another thread to ask about flywheel details.

To add a bit to the confusion, the MT75 comes in a ton of different types. We never really got them over here, or the UK market cars that provide them. Maybe someone else can tell you the exact donor vehicle that they get them from so the starter is on the correct side, the ratios are most suitable,etc.

Anyway, as Alan says, lots of approaches, All the best with your search. If you want the performance of a modified Plus 2, I really would suggest seeing what is out there already built up and mostly sorted. I wouldn?t think it would be terribly practical to ever return a properly built Zetec to stock drivetrain though.

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