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RDMG
D R

(43 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
MGB Still Stock (temporarily)

Hoyle IRS parts in the US
Posted by: RDMG
Date: May 26, 2016 08:29PM

Hi folks,

I'm gathering all the donor parts for a Hoyle IRS setup.

Does anyone out there have the essential specs for the proper rear driveshaft flange that bolts to the pinion flange of the differential?

I've had great luck with all the other stuff, but the junkyard Merkur cars I've found have all been missing their driveshafts.

Dave


WernerVC
Werner Van Clapdurp
Lynchburg, Va
(73 posts)

Registered:
09/06/2009 12:56PM

Main British Car:
MGB 1977 Rover 3.5

Re: Hoyle IRS parts in the US
Posted by: WernerVC
Date: May 29, 2016 03:32PM

To RDMG,
I have a differential from a Merkur that I was going to use on my IRS. I have the complete Hoyle front suspension but not installed yet on my B.
I think the shafts from a VW golf have the same dimensions than the Merkur. Not too sure about that.
Where did you buy the Hoyle IRS frame ?
Werner


RDMG
D R

(43 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
MGB Still Stock (temporarily)

Re: Hoyle IRS parts in the US
Posted by: RDMG
Date: May 30, 2016 04:44PM

Hi Werner,

I don't have the Hoyle IRS frame, just the donor parts that bolt onto it.

I bought the rear axle assemblies from a Merkur Scorpio and a Merkur Xr4Ti. The cars are the US-market equivalents of the Euro-market Ford Sierra and Ford Granada, which are the donor vehicles for the Hoyle IRS. I'm 99% sure the US-market parts will fit. The Scorpio has longer half shafts to make a wider overall assembly, otherwise the pieces are generally interchangeable between the two cars. The Scorpio provides 5-lug Jaguar-spec hubs, disc brake hardware, and a 3.34:1 diff ratio, the Xr4ti provides 4-lug hubs that match MGB wheels and a 3.64:1 diff ratio. The half shafts are the Lobro design, I believe common to VW and perhaps some 1970s Porsches. I paid about $400 total for the two assemblies, so I should come out ahead once I decide which parts I'm using and sell the ones I don't need.

Merkur cars were always rare here, and are disappearing from wrecking yards too. On the other hand, Ford explorers with 8.8" aluminum diffs are found in every junkyard you see.

I think Hoyle could make a fortune in the US market if he could adapt his setup to a common US donor vehicle. It would probably only require a modified hub carrier and a bracket for a different differential.


MGBV8
Carl Floyd
Kingsport, TN
(3042 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Hoyle IRS parts in the US
Posted by: MGBV8
Date: May 31, 2016 11:49AM

Try sending a PM to Larry Shimp (302GT). Only person in the USA that I can think of, at the moment, that uses the Hoyle IRS.

[www.britishv8.org]


waterbucket
Philip Waterman
England
(55 posts)

Registered:
07/30/2011 01:08PM

Main British Car:
1978 MGB GT

Re: Hoyle IRS parts in the US
Posted by: waterbucket
Date: May 31, 2016 02:20PM

If anyone is attempting to make their own version of the Hoyle rear end this company (Berrisfords) makes the driveshafts in lengths from 13 inches to 32 inches "off the shelf," in half inch increments. Remember that exports from the UK to the States would be less VAT ie 116 each. They also have a postage calculator to estimate the postage cost to most countries.
[berrisford.co.uk]
Philip


RDMG
D R

(43 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
MGB Still Stock (temporarily)

Re: Hoyle IRS parts in the US
Posted by: RDMG
Date: May 31, 2016 03:43PM

Hi Phillip,

Many thanks for the info-- very helpful. I knew Hoyle offered custom shafts with their IRS kit, but I didn't know they were available elsewhere.

Re my original post above, I think we've found one of the American-English peculiarities here. We in the U.S. call a propshaft a "driveshaft," and we call a driveshaft a "half shaft."

I'm hoping to find the precise specs for the single propshaft flange that attaches directly to the pinion flange of the differential carrier, connecting the transmission to the rear end. (Some in the U.S. call an IRS differential housing a "pig," I guess because it looks a bit like one. Others call it a "ham," I guess to confuse the issue further.)


waterbucket
Philip Waterman
England
(55 posts)

Registered:
07/30/2011 01:08PM

Main British Car:
1978 MGB GT

Re: Hoyle IRS parts in the US
Posted by: waterbucket
Date: May 31, 2016 04:11PM

Hoyle may well buy them from Berrisfords, nothing would be simpler. In the UK a driveshaft is a USA halfshaft and a halfshaft is the shaft in a live or solid axle. There is a lot available in the UK for these Sierra rear axles. I will list a couple that are on Ebay at the moment;
[www.ebay.co.uk]

[www.ebay.co.uk]

You might contact either of these to get the info;
[www.ebay.co.uk]

[www.ebay.co.uk]

Philip



mgb260
Jim Nichols
Sequim,WA
(1728 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Hoyle IRS parts in the US
Posted by: mgb260
Date: May 31, 2016 04:18PM

Dave, Larry Shimp has a article on this site. He used Dutchman custom axles. Does the pinion flange have 4 holes? You may need to redrill, but check out Datsun 240-280Z yoke. Or Ford Ranger.

[www.britishv8.org]



Edited 1 time(s). Last edit at 05/31/2016 04:19PM by mgb260.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5159 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Hoyle IRS parts in the US
Posted by: BlownMGB-V8
Date: June 01, 2016 10:27AM

As I recall, use of the Hoyle limits wheel movement in the upwards direction a bit, compromising either ride height or jounce. This is because it has an upper link (Unlike the Jag IRS) above the half-shaft.

But the real compromise in any IRS under the MGB is the outer rotating joint, whether CV or U-joint because of the large diameter and proximity to the body's frame sections. Compare the diameter of the tube axle to the diameter of the CV or u-joint to see how much travel you will lose, then add the extra room needed by the top link. The MGB has little enough travel as it is.

The solution of moving the hubs outboard of the frame rail requires a substantial fender flare, with the inner fender moved out about 3". But with the Hoyle this provides little or no gain due to the top link. With the Jag it results in 8" of rear suspension movement, however if the lower control arms are to be set to the customary angle (angled slightly down to the outside) the ride height will be greater than stock. With the added 6" of track this really does not compromise cornering ability, though it certainly does improve the ride.

The aluminum 8.8" carrier is bulky and will require removal of battery boxes. It also had reliability problems. The cast iron "hog's head" may fit with minor mods or may not.

Jim


302GT
Larry Shimp

(163 posts)

Registered:
11/17/2007 01:13PM

Main British Car:
1968 MGB GT Ford 302 crate engine

Re: Hoyle IRS parts in the US
Posted by: 302GT
Date: June 01, 2016 02:47PM

Merkur Midwest (in Chicago area) has an adapter from the Merkur pinion flange to a Mustang pattern driveshaft flange (about $230). Hoyle will provide a driveshaft flange ( maybe about $70 with shipping) that will fit the Merkur pinion flange but it is probably impossible to find a driveshaft balancing company in the US that can adapt it to their machine. Chaterham USA uses Merkur differentials and they might have some useful parts.

I have not ever had a problem with the rear suspension (Hoyle) bottoming due to limited travel; I have even changed to 225 pound/inch springs from the kit springs which are 300 pounds/inch. The hub assemblies fit well within the wheel. The only part potentially touching the MGB frame is the upper A-arm but the large MGB bump stop is removed (a stop on the shock absorber is used). So I think that the suspension travel is about the same. But I am sure the Jaguar IRS set up has a longer travel.


RDMG
D R

(43 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
MGB Still Stock (temporarily)

Re: Hoyle IRS parts in the US
Posted by: RDMG
Date: June 01, 2016 05:06PM

Hi Larry,

Thanks for chiming in-- I was planning to reach out to you! I'm very impressed with your MG setup, it's one of my inspirations to take on a conversion project myself.

Thanks for the leads. When you say the Hoyle flange likely won't adapt to a US balancing machine, what do you mean? would the MerkurMidwest custom piece have the same issue?

I have an aluminum mustang shaft that split a weld, that I acquired for pennies. I could have it cut and re-welded to the right length, then balanced with the stock flange, then fit the MerkurMidwest custom flange. I was hoping there's a junkyard flange or an adapter u joint out there, but I guess not.


mgb260
Jim Nichols
Sequim,WA
(1728 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Hoyle IRS parts in the US
Posted by: mgb260
Date: June 01, 2016 06:43PM

The Mustang aluminum driveshaft is way too big in diameter. Most MGB's use 2" to 2.5" I like the Speedway Motors 2" with 1310 U Joint yokes.


302GT
Larry Shimp

(163 posts)

Registered:
11/17/2007 01:13PM

Main British Car:
1968 MGB GT Ford 302 crate engine

Re: Hoyle IRS parts in the US
Posted by: 302GT
Date: June 02, 2016 07:59AM

The bolt pattern on the Merkur flange is very uncommon so a driveshaft that fits the flange will not bolt to a balance machine. The Midwest adapter is bolted to the pinion flange and then a common driveshaft flange (that takes 1310 yokes) is bolted to the adaptor. The shaft is balanced without the adaptor, but the adaptor is round and fully machined so I doubt its effect on balance is significant.

Hoyle can provide a driveshaft flange that fits the Merkur pinion flange and also takes a standard 1310 U joint yoke. Chaterham USA may also have this driveshaft flange.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5159 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Hoyle IRS parts in the US
Posted by: BlownMGB-V8
Date: June 02, 2016 11:51AM

Common differentials have various pinion flanges available. Maybe this would be an option? (On the Dana 44/Jag prices range about $40-$80).

Jim


RDMG
D R

(43 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
MGB Still Stock (temporarily)

Re: Hoyle IRS parts in the US
Posted by: RDMG
Date: March 06, 2017 01:34PM

Just to close the loop on this thread, Hoyle's largest flange is for a 1300 series ujoint, which was a factory size for the Merkur/Sierra donor car. I couldn't find any 1310 combination ujoints in that size, plus the bolt pattern on the diff is very rare, with a 3.540in bolt circle and with the holes spaced rectangularly.

Trying to build a custom shaft at that dimension would have been ridiculously expensive here in the USA, and shortening a U.K.-made shaft would have been similarly difficult.

As it turns out, there's a US company that makes a 1310 sized conversion flange for the Merkur/Sierra diff:

Powertrainindustries.com
Part Number 3102-1409, $130

Only took me 8 months of google research to find it!

Dave



Edited 2 time(s). Last edit at 03/06/2017 05:44PM by RDMG.



MGBV8
Carl Floyd
Kingsport, TN
(3042 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Hoyle IRS parts in the US
Posted by: MGBV8
Date: March 07, 2017 11:15AM

IMO Google makes waaay too much money on their barely adequate search engine.


RDMG
D R

(43 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
MGB Still Stock (temporarily)

Re: Hoyle IRS parts in the US
Posted by: RDMG
Date: March 08, 2017 06:22PM

Agreed on the google thing. Great for finding what everyone else wants to find, not too great otherwise.

I need to retract some of my statements from last year regarding the Merkur parts:

The 4-lug hubs are NOT MGB bolt pattern, and I am not sure about the 5-lug hubs being a Jaguar pattern. Hoyle can provide a custom hub for most common applications, including knockoff wire wheels.

A Merkur Scorpio rear axle assembly provides every salvage piece you need for a complete Hoyle IRS application in a v8 car. The Scorpio provides the disc brake bits, particularly the brake caliper brackets and caliper cores, all 100mm shafts, and a 3.34:1 diff gear ratio in a 7.5" crown & pinion.

I paid $250 for the salvage axle, and just paid a bit over $3k to have the Hoyle kit, custom hubs, and new brake discs shipped to my house. Still need rebuilt calipers, and to resize the halfshafts, but that's it. All in, thanks to brexit's effect on the exchange rate, it's not too far off in price from other hi-end MGB live axle kits available here.

The xr4ti diff at 3.64:1 might be useful for some trans/engine combos, but it's only a 7" dia crown gear, and you'll still need brake caliper brackets from a Scorpio. I think it might be perfect for a supercharged 4cyl MGB with an OD trans, or perhaps a mild 3.5L v8 with a Camaro v8 trans.

Hoyle now sells a version of its IRS kit that takes the larger 108mm Lobro/GKN CV joints, common to many modern high horsepower cars, that is also backward compatible with the 100mm bits from the Scorpio. You can also get an LSD diff with 108mm flanges from the Cosworth racing/rally guys, so there's real potential to upgrade the setup over time.

Now that I found a 1310 adapter flange for the driveshaft, I can have a stock mustang steel driveshaft shortened to fit my mustang T5 trans. Nice savings there.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5159 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Hoyle IRS parts in the US
Posted by: BlownMGB-V8
Date: March 09, 2017 11:41AM

So if not Google then what? Yahoo is junk.

Jim


MGBV8
Carl Floyd
Kingsport, TN
(3042 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Hoyle IRS parts in the US
Posted by: MGBV8
Date: March 10, 2017 10:55AM



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