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MG MGB GT V8 Factory Originals Technical - Front & Rear End

I'm starting a restore/V8 conversion for my 1980 MGB. I like the Hoyle Engineering set up for the front and rear, brakes and suspension. Is there any one in states that provide the same type of setup. I don't want to have my mechanic put it together, component by component. I like the idea it is engineered and ready to be installed.

Rich Cohen
ricmgb

Rich, there are a couple of sources for front suspension kits, Bill Guzman at Classic Conversioneering and Fast Cars. Both are sponsors of the British V8 newsletter and have links posted there, http://www.britishv8.org/sponsors.htm
I don't know about rear kits such as the Hoyle here in the US. Bill Guzman is working on a 4 link setup using a live axle. There is someone working on an IRS, but I don't think it's on the market yet. Attached is a photo of the prototype unit I found posted on the MG Experience bulletin board a few months ago. I don't remember who posted the photo or was doing the development.

Bill Young

http://www.fastcarsinc.com/
Go to the MGB IFS page.

Jim
Jim Blackwood

That IRS was done by Todd Budde if I recall correctly. I believe it has gone through a few iterations since that picture was taken, I see the upper shock mount is in single shear, which I know was corrected.

http://www.theneonworks.com
Jake Voelckers

Dose anyone have a concern about the heym joint tie rods on the fast cars front end for regular street use? they look to fragile to me.
M Mallaby

Heim joints are very strong if the right alloys are used, at least as strong as the common ball joints used on most cars. The most common problem for street use is wear, as most Heims don't have provision for lubrication and don't have good dust shields. That said, I'd like to see what the folks at Fast Cars say about maintenance for their setup. They may have experience that shows wear not to be a major problem for many miles.
Bill Young

M Mallaby,

I have had my Fast Cars IFS on my 302 conversion for nearly 3 years. Joints are very strong and hold up to lots of track use and spirited driving on the back roads.
I usually clean and lube the joints with lithium spray grease every 3 months to keep at peak performance.
It's an excellent piece of engineering and I recommend it to all.

Cheers

Pete

Pete Mantell

The pic Bill posted is of my IRS. That pic was from one of the first test fits. Todd Budde built it as noted & final product differs as follows...
- upper shock mounts were modified to put them in double shear & also make the hardware replaceable in the event the threads ever get buggered.
- a battery tray was added to the frame of the IRS because the long curved bars that go to the spring perches interfered with the battery box so I had to remove the battery box. Battery is still accessible through the normal hole in the rear shelf behind the seats.
- brakes, hubs, etc. on mine are chevy parts at my request since my wheels are 5x4.75 lug pattern [Todd normally uses Nissan parts & I believe Fierro for some lug pattern applications]. My set up has a mechanical e-brake function on the caliper as well.
- the IRS was powder coated so it looks way better than the pics :)

I dropped it back out of the car a couple of days ago so i could put the body shell on a rotisserie. if i get a chance this weekend, i'll shoot a couple of pics & post them.

Rob
Rob Ficalora

M Mallaby asked: "Dose anyone have a concern about the heym joint tie rods on the fast cars front end for regular street use? they look to fragile to me."

There's a can of worms! The design may be "safe enough", but it could be safer. The two Heim joints at the rack don't bug me at all, but I don't care for way grade-8 bolts connect the outer Heim joints to the steering links.

Why didn't Fast Cars just use regular tie-rod ends? Grade-8 bolts provide a smaller cross-section than regular tie-rod ends (at the shear plane). If Heim joints were required for sex appeal, mounting the bolts in "double shear" would at least have the effect of doubling their cross-section. (An AN, military-spec bolt would be better than the grade-8 bolt in some respects too. Besides better metallurgy and manufacturing processes, AN bolts are slightly larger in diameter. They fit the Heim joints a little better. Also, they have a longer unthreaded section which would provide more bearing area in the steering arm, and which would have relocated the first thread further from fatigue worries. Grade-8 bolts really aren't designed for shear at all; they're designed for tension, such as when clamping assemblies together.)

Secondly, if you torque that grade-8 bolt to its normal torque spec you'll distort the "ball" of the spherical bearing, which will reduce its life expectancy. Incidentally, all suspension bolts should be torqued right up to spec - they're actually not as strong unless they're torqued and they're also more likely to come loose.

Thirdly, the spherical bearing in any Heim joint will loosen up in the socket over time (and with dirt, and with lack of lube...) This, combined with impact force (e.g. in an accident) could cause the ball to rip out of the socket. If I were installing the Fast Cars IFS, I would place a thick hardened washer (larger than the Heim joint socket's outside diameter) between the bolt head and the Heim joint. However, when you add the hardened washers to the Fast Cars assembly, you may need longer bolts. Consider buying extra long bolts and sawing off the excess threaded section. Be careful at the store, because cheap Chinese "counterfeit" (fake) grade-8 hardware is becoming quite common these days.

All that said, it's still a very, very impressive design overall.
Mark

Rob,

I am very interested to find out more information about this IRS. I have the Hoyle suspension up front, and Doug Jackson's fiberglass springs in the rear.

How does this set up feel.

Thanks,
Shareef
Shareef Hassan

This thread was discussed between 26/09/2007 and 13/10/2007

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