TCS/Zetec/NG3 Conversion

[andy harwood]

Small update.
Received new axles, stub axles, and 2 100mm VW bus CV joints.
New axles are stock 15 1/4 long, have about 2 inches of splines, permitting use of either type 1 or 2 CV joint
Axles installed have about 3/8th in. end play at full axle droop, and have end play when level, so not in a bind there.
New stub axles for Bus type CV joint fit. being shorter it appears end of stub axle will not protrude past wheel center cap.
Hubs in photo are type 3, I turned the diameter down enough to fit the Honda rotors, and turned in a seating ring for the rotor.
Will play around with spacers to back space stub axle to have enough room for lower link bracket. It appears the stub axle will be the correct length, as there is almost room to insert cotter pin, with axle not being tightened, using 2 spacers on back side.
Appx. parts cost so far, about $750-800. not including parts purchased but not used, lol
2nd photo shows with short spacer, 3rd w/ full spacer.
Thanks to a post on the yahoo group today about problems installing a NG3 with Banks twin link kit, I saw where I've been wrong in measuring this.
Lower links - I was thinking of using 6061 aluminum 7/8" rod for the link body and 1/2"heim joints - good, bad, so-so?

[BDA]

That looks nice! I would have preferred to have two CV joints rather than a U-joint and a CV joint which is how Richard's twin link rear suspension was set up back when I go it. But I can't say I could tell the difference.

[andy harwood]

Thanks BDA.
Reading my posts, I'm sure most realize I'm learning as I go on this project. Reading a post on the YH group yesterday, made me realize something I hadn't thought about - that the output shaft width is different between a 365 & NG3 transaxle. I had not thought about that.
After quizzing some real machinists, I think I will scrap the type 3 hubs that I turned down. Reason being because of existing lug holes and the way the back side of hub is cast, it will put new lugs between the webs cast in the back, which is a thinner part of the hub.
I had ordered 2 blank  rear rotors, but the hat of the rotor is so tall, it appears to be unusable. Was going to send them back, but with return shipping, well... thought I was going to have some door stops.
So, today I will look into cutting the rotor off and using the center hub.

[jbcollier]

Custom work is always like this.  My problem is that I think best with my hands.  Some people can "prototype" in their heads.  Not me, I work and rework pieces to fit and solve my issues and then I remake them again in a cleaner, more elegant design. The cast-off bin can fill rather quickly some days.

[andy harwood]

Custom work is always like this.  My problem is that I think best with my hands.  Some people can "prototype" in their heads.  Not me, I work and rework pieces to fit and solve my issues and then I remake them again in a cleaner, more elegant design. The cast-off bin can fill rather quickly some days.

I'd hate to say how much time I spent on the first set of engine mounts, and then chunked them. If I had hired me to do this job, I would have fired myself before lunch on the first day.
Out to look at brake rotors and scratch my head a bit!

[SwiftDB4]

Andy, keep us posted on the type 3 hubs. That's been my stumbling block. Cast hub looks too thin as you say. Jamar makes hubs that look like they could be redrilled. ISP West also has type 3, occasionally blank, but pricey.

[andy harwood]

Today's playtime.
Undrilled VW IRS rear disc hub.
The hat depth (3") seemed to make it undesirable to use for the conversion.
Splines are 2" deep, Lotus hub splines are about 1 3/4" deep, and VW type 3 hub about 2.25" (from memory, so beware)
So today, I kinda made more than one piece out of a one piece rotor.
Anyhows,
German mfg. type 3 hub thickness, between the webs - .4
Brazil mfg. type 3 hub thickness, between the casting webs - .390
EMPI VW beetle rear hub, disc thickness - .545
I just skimmed the back side to smooth it up. It is not turned down to correct diameter.
These hubs were about $80.ea, shipped. (you don't want to return, priced mailing via USPS was $75. only reason I still had them. Even I get lucky on occasion!)
It appears having shorter splines, will offer more options in spacing, will investigate tomorrow.  Wifey has told me I had enough fun for today.
Pics show rotor/hub, and cut off hub, photographed from back side.

[EuropaTC]

Hi Andy,

If you're looking for discs for the conversion, perhaps these two pdf files will help. They don't show every detail such as bolt spacing and hole arrangements but they do have the basics of diameter, thickness and top hat heights. I've split into 2 parts because the complete file is slightly over the 1mb limit.

I used this file and a UK website when searching for discs.  http://brakeparts.co.uk/#!/shop

The website was good because not only were they one of the cheapest around over here (yeah, cheapskate, I know    ) but they also have pictures of the disc with hole dimensions in most cases.

Keep posting, although I'm not contributing this is a really interesting thread and the learning curve you're on is going to be great for those that follow.

Brian

[andy harwood]

Thanks Brian.
When I started this, it was going to be rebuilding the TC engine and adding rear disc brakes. I don't know how I got to where I am today!
The plans on the YH group are the ones I have been following, using Miata calipers, Honda rotors that have been turned down in diameter and redrilled for bolt spacing.
I'll look at the files, as you can see - I'm not afraid to buy parts, modify, then not use.
Speaking of braking -
The Lotus hub has a 'centering ring' (I don't know the correct term) for the brake drum to center on, even though it also centers on the wheel stud shoulder. In the photo, Lotus hub on left, VW type 3 hubs, center and right. The VW hubs had a centering ring, a larger diameter that had to be turned down for the Honda rotor to fit hub.
I guess my question is - is this 'centering ring' machined into the hub necessary? The rotor will center on the wheel stud shoulders anyhows, and machining the hub face down will reduce the thickness of the hub.
Also found that the center mount for the lower links, modified by Banks when purchasing the NG3 will not allow the lower link bolts to be completely inserted as the 1/2" hole is about 1/4" out of alignment. Appears it will be as easy to make another as to modify this one.

[andy harwood]

SwiftDB4, Can you tell me or do you have photos of this? Is it the stock mechanism, or a modified one for the NG3?

"Used Banks side shifter to left side on the NG3. Works well with very little play."

Thanking you in advance

[BDA]

I guess my question is - is this 'centering ring' machined into the hub necessary

I would think not. I think the centering is required for drum brakes because centering on wheel studs would not be accurate enough. If the drum is even a little off, you would have a problem with vibration, but if a brake disc is off a little, it won't matter.

[jbcollier]

Unless the rotor/drum is being held on by a tapered fitting, thus guaranteeing centring, keep the centring ring.  Small amounts of run out may make wheel balancing a nightmare.

[EuropaTC]

I guess my question is - is this 'centering ring' machined into the hub necessary? The rotor will center on the wheel stud shoulders anyhows, and machining the hub face down will reduce the thickness of the hub.

I think I'm with BDA and the centering ring is more to do with drums and getting the shoes aligned.  As for imbalance I think it's down to how accurately you measure and for anyone who is confident and capable of doing this sort of conversion my personal take is that you'll be fine.

My first set of rear discs were MGF 240mm ones which had a centre bore of  66mm, a very sloppy fit but it aligned itself on the studs because it has exactly the same PCD as the Lotus. With the disc alone bolted on (no wheel) and a dial gauge resting on the edges & sides I can't say I noticed any significant movement, a the needle moved up and down but nothing that made me worry.  Admittedly I was more concerned with run-out than centering, but deflection was minor all round. I can't remember what it was but I was aiming at 0.004" total run-out and it didn't get close.  And more to the point. there didn't seem to be any wheel balance problems either.

The second set of discs were Mini rear, 259mm and a 64mm centre bore. This was a much neater fit and like the MGF discs showed minimal run-out and no balance problems.

In conclusion I don't think you need a centering boss but you do need some accuracy in hole drilling ! If you're 1 or 2mm out then I would be cautious but presumably you'll be marking the honda (or whatever) discs better than that.

Brian

[SwiftDB4]

SwiftDB4, Can you tell me or do you have photos of this? Is it the stock mechanism, or a modified one for the NG3?

"Used Banks side shifter to left side on the NG3. Works well with very little play."

Thanking you in advance

I bought this from Banks 10 years ago to change NG3 shifter to left side, assume he still sells this?

[andy harwood]

Thanks Swift.
I got the crank with my NG3, it was laying loose in the box, not welded to the shaft. Gotta do some more research on this.

On another note in this journey - and you'll probably like this -
I unboxed the 2nd disc rotor to cut the hat off, and it's a bit of 'same same but different' than the first.
(I never really understood the "same same, but different" bit in Thailand, but it seemed to fit here)

Guess I should have looked at both discs in the beginning, didn't, but that's just how I roll.
Anyhows -
2nd rotor thickness -
between the casting webs - .580
web -                                 . 830!

So, Swift, we were both looking for more metal in the hub, there it is!
These came from Chirco. (pic is backside of both rotors)