Steering, Suspension, & Brakes

tips, technology, tools and techniques related to non-driveline mechanical components

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bsa_m21
Martin Rothman
Vancouver, Canada
(216 posts)

Registered:
01/06/2009 11:41AM

Main British Car:
1980 TR7V8 Rover 3.9L

authors avatar
TR7V8 front end upgrade
Posted by: bsa_m21
Date: April 27, 2010 03:29PM

Over the past year I've been busy building up my "warmed over" 3.9L Rover engine for my TR7 soon to be a V8 and modifying the subframe to take it (1" lower and 1" further back than stock). This spring I decided to upgrade the front suspension and brakes.

I'm using the standard TR7/8 struts, with the hubs modified to accept larger outside bearings (a common mod). I chose a set of Spax adjustable inserts, but decided against using stock or stock like upgraded springs. Instead I went out and bought a couple of cheap 2.5" OD coil over spring sets to play with. I had both single rate

coil1.jpg

and dual rate springs to play with.

coil2.jpg

Currently, I am going with single rate rear springs from a late 90's Honda Prelude. These springs are 2.5" dia, 7.5" long, spring rate about 300 lb/in.

Then I needed to do something about the brakes. I read several articles online here about the MG and TR6 guys using Toyota Cressida 11" rotors with Toyota SR5 Calipers, and figured why not on a TR7? Mistake #1. :). But that's another story....

So, one cold winter evening I got out my trusty Autocad program and began drawing my hub and lower strut leg assembly, to see how to make these parts fit. Mistake #2 - I took the measurements of the parts witout disassembling them first.

I then drew in the disk and calipers, measuring the dimensions from the parts I bought. Mistake #3 - allways measure 20 times and re-verify what you've written down, just to be sure you screw it up..... :)

So. Now I have all my dimensions and it looks like an easy conversion. Out I go and buy the needed aluminum to make the spacers for the disks and schedule a time to go up to a friends place to use his lathe. This is what I made:

spacer1.jpg

So now I needed to drill the holes to mount the spacers to the hubs and the disks to the spacers. I did this with the spacer on the hub, and rotating the spacer to ensure the holes were on a perfect circle.

spacer2.jpg

Boy, it's all been going so smoothly, so far....



Edited 7 time(s). Last edit at 04/29/2010 08:35AM by bsa_m21.


bsa_m21
Martin Rothman
Vancouver, Canada
(216 posts)

Registered:
01/06/2009 11:41AM

Main British Car:
1980 TR7V8 Rover 3.9L

authors avatar
Re: TR7V8 front end upgrade
Posted by: bsa_m21
Date: April 27, 2010 03:43PM

Next I needed to thread the holes.

spacer4.jpg

And, viola! She worked the first time! No mistakes, or so I thought.....

spacer5.jpg

You will note that I've also got a spacer/PCD adaptor to mount a set of 4x100 bolt 16" mags.


bsa_m21
Martin Rothman
Vancouver, Canada
(216 posts)

Registered:
01/06/2009 11:41AM

Main British Car:
1980 TR7V8 Rover 3.9L

authors avatar
Re: TR7V8 front end upgrade
Posted by: bsa_m21
Date: April 27, 2010 03:52PM

So, now I checked to make sure the caliper, disk and hub would all work with the selected rims.

brake1.jpg

Yay! Lots of room to spare...

So, remember I said I drew up everything from measurements I took 20 times....

dwg1.jpg

Well it seems I can't measure very well.

brake2.jpg

The spacer was 3mm too thin and the measurements I made to the caliper mounting lugs on the strut were waaaay off. Grrrr.


bsa_m21
Martin Rothman
Vancouver, Canada
(216 posts)

Registered:
01/06/2009 11:41AM

Main British Car:
1980 TR7V8 Rover 3.9L

authors avatar
Re: TR7V8 front end upgrade
Posted by: bsa_m21
Date: April 27, 2010 04:03PM

So now what to do?

At first I thought I'd just buy a 3mm wheel spacer and stick it between the disk and my spacer, but it wasn't going to work. So finally, after moving the rotors around and around, I decided to build adaptors. Again I measured. Again I checked, double and triple checked. Damn, I'm not going to make the same mistake twice!

So here is what I made:

brake3.jpg

brake4.jpg

And you know what? They worked!!

brake6.jpg

brake5.jpg

Now to finish the engine compartment so I can mount the motor and struts....

Martin



Edited 2 time(s). Last edit at 04/28/2010 08:05PM by bsa_m21.


tr8todd
Todd Kishbach

(381 posts)

Registered:
12/04/2009 07:42AM

Main British Car:


Re: TR7V8 front end upgrade
Posted by: tr8todd
Date: April 27, 2010 09:22PM

When you add coil overs to the TR7 spindles, you have to be real careful on the spring lengths. I always grind off the stock spring perch and install a collar retaining sleeve lower on the tube. I use a 5 or 6 inch threaded sleeve mounted just above the brake hose clip. If you run a 12" 200 # or heavier spring, the tire will hit the bottom of the adjusting perch even if you grind off the old perch. My spring of choice for a road car is a 10" spring somewhere between 250 and 300 pounds mounted on the newly positioned adjusting collars. If you run the collar on top of the old perch, you have to run even shorter stiffer springs. On the TR8 race car, I have run springs as short as 6 inches and as stiff as 600 pounds. I solved all of the problems you addressed by using shortened SD1 struts, adjustable Koni inserts, Jeep cherokee 284mm rotors, and Willwood calipers. I also redrilled the wheel bolt pattern on the hubs to match the Ford posi rear end I installed.(5X4.5") The SD1 uses a larger tube, hubs, and bearings. The only machining was for the caliper bracket, and the drilling of holes in the hubs and rotors.
DSC01352.jpg



Edited 1 time(s). Last edit at 04/28/2010 08:44AM by tr8todd.


bsa_m21
Martin Rothman
Vancouver, Canada
(216 posts)

Registered:
01/06/2009 11:41AM

Main British Car:
1980 TR7V8 Rover 3.9L

authors avatar
Re: TR7V8 front end upgrade
Posted by: bsa_m21
Date: April 28, 2010 09:04AM

Thanks for the feedback Todd.

The car will be used for fast street playing, and my budget is somewhat limited (You can have it built fast, good or cheap ... but you can only pick two of those criteria... :).

I checked the spring rate numbers last nite. The springs are a bit over 7" long, unladen, with a rating of 340 lb/in. I compressed them over an inch to mount, so I figure the static load is a around 400lb. Based on this, I estimated the car will drop about another inch and a bit once it's all mounted. I do have the adjusting sleeves, so can always grind off the old spring perch and mount them if I find I need to play with it.

Still have to clean up the engine bay before I mount it all back together and put it back down on wheels, so it will be a while until I know what adjustments are required. Here is the state of the engine and subframe

100_2919.JPG

Martin


tr8todd
Todd Kishbach

(381 posts)

Registered:
12/04/2009 07:42AM

Main British Car:


Re: TR7V8 front end upgrade
Posted by: tr8todd
Date: April 28, 2010 10:24AM

Front corners should carry about 650 pounds each. Rears about 550. A bone stock TR8 comes in at about 2550 pounds without passengers. Those numbers will vary depending on what you do to the car. Most modded TR8s run around 2350 to 2400 pounds. Based on 650 pounds, your springs should compress about 2" under load. Under heavy breaking with driver, they will compress at least another 1.5 inches. How much spring travel do you have before they coil bind? Those numbers should be in the spec sheet for the springs. Coil bind issues are the biggest reason for trying to run the longest possible springs. Your engine looks sweet sitting there under the car like that. Very cool mounting brackets.



bsa_m21
Martin Rothman
Vancouver, Canada
(216 posts)

Registered:
01/06/2009 11:41AM

Main British Car:
1980 TR7V8 Rover 3.9L

authors avatar
Re: TR7V8 front end upgrade
Posted by: bsa_m21
Date: April 28, 2010 08:04PM

Todd,

The unladened spring length is 8.5"
Mounted is 7.25"
The calculated spring rate is 250 lb/in.
(The 340lb/in value from this morning's post is actually the front springs rating from the kit. Duh!)
The static load is (8.5-7.25)*250 = 320lb
With the springs mounted, there is about 6" of compression to coil bind.

Based on 650 lbs per front corner, the springs should compress by another (650-320)/250 = ~1.5"
This will leave me with ~4.5" of travel to coil bind which is an additional 1100lbs of loading per corner.

If it works out that I have problems, I can always remove the stock spring perches, mount the adjusting sleeves, and add the shorter unused front springs (340 lb/in), kept aligned with the spring union ring in the kit. Then I would have ~14" of springs to play with (8.5" @ 250 lb/in and 5.5" @ 340lb/in). Hmmm. Could be interesting....

brake6.jpg

Which mounting brackets? The subframe or alt & A/C?

engine2.jpg

Tomorrow I start cleaning the engine bay...

Martin


tr8todd
Todd Kishbach

(381 posts)

Registered:
12/04/2009 07:42AM

Main British Car:


Re: TR7V8 front end upgrade
Posted by: tr8todd
Date: April 29, 2010 08:28AM

I like anything home made, and appreciate the efforts that go into making things. I would rather fabricate something that works better and is cheaper than what you may find in a catalog. You wouldn't know by looking at the stuff in the garage, but I am the biggest cheap skate around- and proud of it. I misread your earlier post. I thought the free length on your front spring was only 7 inches. That would be cutting it real close. I just thought of another big advantage to mounting the threaded collar lower. It allows you to turn down the perch to where the spring is unloaded. At that point you can disconnect the shock bolt at the top of the strut tower, lower the shock and replace the spring while everything is still on the car. No need to remove the strut and disassemble off the car. You can perform spring changes in about 5 to 10 minutes per side.


WedgeWorks1
Mike Perkins
Ellicott City, Maryland
(460 posts)

Registered:
07/06/2008 08:07AM

Main British Car:
1980 Triumph TR8 3.5 Litre Rover V8

authors avatar
Re: TR7V8 front end upgrade
Posted by: WedgeWorks1
Date: April 29, 2010 11:55AM

All I have to say is that the set ups Todd and yourself have are soooooo much cheaper than the way I went!

http://i1012.photobucket.com/albums/af242/wedgeworks/Targa%201980%20TR8%20Project/IMG_3001.jpg


bsa_m21
Martin Rothman
Vancouver, Canada
(216 posts)

Registered:
01/06/2009 11:41AM

Main British Car:
1980 TR7V8 Rover 3.9L

authors avatar
Re: TR7V8 front end upgrade
Posted by: bsa_m21
Date: April 29, 2010 01:15PM

Well Mike, like I said before...

You can do fast.

You can do it good.

You can do it cheap.

But you can only pick two of the above.... :)

car&trailer.jpg

Perhaps my next candidate for a V8 & suspension upgrade should be this setup? EH? :)



Edited 1 time(s). Last edit at 04/29/2010 01:17PM by bsa_m21.


Stumpy
Ewen Sutherland
New Zealand
(5 posts)

Registered:
07/25/2010 03:51AM

Main British Car:
1977 TR7 Rover 3.5 V8

authors avatar
Re: TR7V8 front end upgrade
Posted by: Stumpy
Date: January 09, 2011 04:28AM

Hi Martin,
I am currently converting my TR7 to V8 also, I am from New Zealand. I have read with interest your spring conversion set-ups, could you list for me the exact part numbers or names of the springs? I would really appreciate your advice. Did you put roller bearings in the top of your strut to ease up steering or do you have power steer?
My brake conversion is the same as Rimmers from UK, using Vitesse 4 pot calipers, very heavy but i won't be racing the car (maybe?!)
I am also really impressed with your engine mount brackets, what size material and would you share your measurement set out on the K frame? My engine is from the Rover P6b and will be pretty standard until I find a reasonably priced SD1.
work in progress.JPG
engine bay.jpg


Stumpy
Ewen Sutherland
New Zealand
(5 posts)

Registered:
07/25/2010 03:51AM

Main British Car:
1977 TR7 Rover 3.5 V8

authors avatar
Re: TR7V8 front end upgrade
Posted by: Stumpy
Date: January 09, 2011 05:10AM

By the way, my car is not on the floor, it is suspended off the bumper chassis mounts to 2 pieces of 200x50 fixed to my roof trusses giving me a cheap rotisserie. Works great as I have lots of welding to do as you will see.........
P6240021.JPG
P6240024.JPG


roverman
Art Gertz
Winchester, CA.
(3149 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: TR7V8 front end upgrade
Posted by: roverman
Date: January 10, 2011 10:10PM

I haven't compared the Mazda RX 7 front brakes/hubs, struts to TR 7, but maybe ? Light, strong and "dirt cheap".HD brake option,(plentiful), has nice 4 pot alum calipers, strong aluminum hubs,(5 on 4.5"),and forged alum LCA. Maybe Miata ? Good Luck, roverman.


bsa_m21
Martin Rothman
Vancouver, Canada
(216 posts)

Registered:
01/06/2009 11:41AM

Main British Car:
1980 TR7V8 Rover 3.9L

authors avatar
Re: TR7V8 front end upgrade
Posted by: bsa_m21
Date: January 12, 2011 09:04PM

Hi Ewen,

The front springs are from a kit I bought at a swap meet for a 90-97 Honda Prelude (not sure what it might be called in NZ) and is from a company called "Ractive", but was made in China so is probably fairly generic. I used the rear springs from the kit. And yes, I did put put "roller bearings" at the top of of the strut.

For my rear springs I used the front springs from a kit for a 95-99 Mitsubishi Eclipse from a company called Evotion (p/n EV222).

I did a lot of reading and investigating before I decided on what kind of spring rates to use. The below pic shows how I calculated the rates for the springs I bought.

spring rates.jpg

I'm afraid I don't have the original boxes anymore so don't have part numbers and I bought them at a swap meet. You can buy these kits all over the place.

With many kits, spring rates are actually printed on the springs, using either a metric or US code, in the format of “FreeLength.InnerDiameter.SpringRate” For example:

Descr. Length ID Spring Rate

Metric mm mm N/mm
Num of digits xxx yy zz
e.g. 200 64 67

US in in lb/in
Num of digits xxxx yyy zzzz
e.g. 0700 250 0375

So, a spring with a metric 200.64.67 code is the equivalent of a US code 0700.250.0375, making it:
7" (200 mm) Long,
2.5" (64mm) ID,
375 lb/in (67N/mm) Spring Rate

For the sub-frame I used a piece of 1/2" x 2" rectangular tube, with a thick wall (1/8"), and some scrap 1/4" steel plate. I did some measurements from a stock TR8 to try to figure out how to cut and bend my mounts. But finally, with the engine mounted on a stand, I measured and made a wood platform for the sub-frame to sit on, that fit underneath the engine and left about 1/2" of space between the oil pan and the steering rack. I centered this under the motor and started measuring, cutting and tacking the mounts in place. Seems to have worked out just fine.

Using the original TR8 engine brackets and rubber mounts, the stock engine mount location forward/aft is 104mm in front of the centre of the rear mounting holes of the subframe. I made my mounts a further 24mm rearward or 80mm in front of the centre of the rear mounting holes. This also happens to line up with the rear bolt holes for the steering rack mounts.

Vertically, the lower hole where the rubber mount bolts to the subframe, is 138mm above the deck of the stock TR8 subframe. Because I used the TR7 steering rack, I was able to lower mine to 117mm. Here is a pic of the drawing I made:

TR8_subframe.jpg

Hope this info helps you. Good luck with your rebuild. Actually, looks like your body is in better shape than mine was when I started out. :)

Martin



Edited 1 time(s). Last edit at 01/12/2011 09:27PM by bsa_m21.



Stumpy
Ewen Sutherland
New Zealand
(5 posts)

Registered:
07/25/2010 03:51AM

Main British Car:
1977 TR7 Rover 3.5 V8

authors avatar
Re: TR7V8 front end upgrade
Posted by: Stumpy
Date: February 15, 2011 04:22AM

Hi Martin,
Thanks very much for the valued information. Apologies for not replying sooner, I am a builder in my daily life and am currently running a million dollar council project. Not a lot of time to spend on my car!!
Thats some great drawings there, will make life so much easier for me. Happy motoring and thanks again.
Cheers, Ewen.


Addicted
Mike Hagadorn
Warren PA
(132 posts)

Registered:
09/27/2013 03:46PM

Main British Car:
1976 TR7 Victory Edition Ford 302

Re: TR7V8 front end upgrade
Posted by: Addicted
Date: October 30, 2013 05:25AM

Ok guys, I have been working on hub and brake upgrades, and started getting serious about a front suspension upgrade. My question is about strut insert travel vs spring sag.

I have figured I want 4" of static sag. By that, I mean my strut insert has 7" travel, and for the car to sit where I want it, I need it to drop 4" from the fully extended strut position. If I put in a stiff spring (more than 200lb/in?), I won't get that much compression.

So, do I just go with it and let the strut potentially extend to where the springs are fully unloaded and loosing contact with the spring seats? Do I look for shorter strut inserts? Is there a travel limit on SPAX other adjustable strut inserts?

I'm stuck. Let me know what you think.
Thanks
Mike
'76 TR7



Edited 1 time(s). Last edit at 10/30/2013 05:31AM by Addicted.


tr8todd
Todd Kishbach

(381 posts)

Registered:
12/04/2009 07:42AM

Main British Car:


Re: TR7V8 front end upgrade
Posted by: tr8todd
Date: November 02, 2013 04:22PM

I'm not exactly sure what your question is. One of the beauties of coilovers is the fact that you can unload the spring and remove it with the strut housing still on the car, if you make it so the threaded perch extends down onto the tube like on the pictures I posted before. You can lift the car with the front suspension in droop, spin down the perch, remove the top nut and allow the strut shaft to lower. Remove the spring. Install new spring, raise the shaft and secure the top nut, spin the perch back into position. If you simply put a threaded collar above the stock perch, you may or may not be able to remove the spring. That will depend on the spring's free length.


bsa_m21
Martin Rothman
Vancouver, Canada
(216 posts)

Registered:
01/06/2009 11:41AM

Main British Car:
1980 TR7V8 Rover 3.9L

authors avatar
Re: TR7V8 front end upgrade
Posted by: bsa_m21
Date: November 03, 2013 09:38AM

I agree with Todd, cut off the standard spring mounts and weld new mounts low enough to add threaded perch sleeves so you can adjust the ride height.

This is what I ended up doing and am now able to set my front end ride height exactly where I want it.

Now the rear end is a bit more problematic........ :)

M.


Addicted
Mike Hagadorn
Warren PA
(132 posts)

Registered:
09/27/2013 03:46PM

Main British Car:
1976 TR7 Victory Edition Ford 302

Re: TR7V8 front end upgrade
Posted by: Addicted
Date: November 04, 2013 03:45PM

Thanks guys. I've already cut the spring seats off the strut tubes per your recommendations, and I need to order a cheap coil over kit. I'm going to start my own thread with my project info.

This may clear up my question.

http://i302.photobucket.com/albums/nn89/74jawa/TR7/IMG_1135_zps1b51ec7d.jpg



Edited 1 time(s). Last edit at 11/04/2013 03:49PM by Addicted.
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