Good question,
We were advised to by the technical adviser of CMI, who strongly recommended fitting the late type axle.
We're keeping the original rear track by using new minilites (keeping the old minilites on the front) on the rear, with enough positive offset to keep the tyres in the same place. Actually, the track increases by half an inch per side, because they were stock for escort mexico, and thus about 300 pounds cheaper than getting custom minilites made.
We never had marcos alloys, and the minilites fitted are early magnesium ones, with virtually no offset (mounting flange in centreline of wheel rim). Modern minilites with +ve offset ET+20 move the rims inward, down the axle, by 1.5 inches per side to counterat a 2 inch widening of the axle each side. We now have two different PCDs, which is daft, but not really, because even with the same PCD, a front would not fit on the rear and vice versa.
I will look into the TR7 parking brake mechanism right now, but I suspect it will be irrelevant, as I have ford backplates.
what drive ratio is your cortina axle? We fitted the late capri axle on the instruction that the corsair axle had a 3.7 drive ratio which was undesirable, and that improving that ratio was hard, although I now see that an early capri axle would also house a 3.09 drive ratio and would have the narrow track and a marcos-friendly handbrake linkage.
Additionally, we are also having to have a new propshaft made up, as the new diff is longer and has a different drive flange. All in all, I think the we were foolish to follow the advice, and should have kept the original axle and improved the drive ratio if possible.
tom
On 1 Apr 2008, at 0112, Donny Lang wrote:
Mr. Berriman,
Can I ask why you are replacing the axle assembly?
The extra width of the Capri axle really alters the look of the rear of the car, and the Mantula rear fenders incorporated large rear flares to help cover the extra width. I looked into this option and whet another direction.
I am also replacing my whole assembly on my early steel-chassied Marcos (#5514) with a custom narrowed unit from a Triumph TR8/Rover SD1. I am doing this to effectively change the axle ratio to match my new engine/trans combo. I am retaining the 3 3/4" bolt circle pattern so that I can still use the original Marcos alloys and will be within 1/4" of my original width. I will be using the TR7/8 parking brake mechanism, though am using 2" wide by 9" drums from Triumph Stag for more rear brake performance.
I have a good take-out complete ORIGINAL (Cortina?) axle assembly with the dual pattern axles that could be available if this helps your project. Mine should be the exact axle that originally came in your car.
-Donny
----- Original Message -----
Sent: Monday, March 31, 2008 10:37 AM
Subject: [MarcosManiacs] Axles, Handbrakes, and Panhard Rods
I'm currently rebuilding 1969 wood chassis Essex engine (bought off
neil calder in dec. 2007). It's going well, and we've flown through
the chassis and body rebuild in our few weekends' work.
However, we've hit a biggy:
The axle is replaced with a Mk 3 capri unit, on the advice of Mike
Andrews, although this has now necessitated new wheels (offset to
restore old track) new propshaft (shortened and with new diff flange)
and has stumped us as to how to actuate the handbrake with the
panhard rod in situ. The ford linkage sits exactly where the panhard
rod wants to sit, and requires removal in order to fit.
Mike's solution is to replace with original (corsair) brake
backplates and just extend the original marcos linkageto the wider
axle, although this would necessitate extracting the halfshafts off
both axles, and junking the already-rebuilt brakes from the Mk 3 axle
and rebuilding the corsair axle brakes (undesirable).
SO:
I know some mantulas use the Mk 3 axle, and presumably have an axle
located by panhard rod. How are their handbrakes actuated? How does
anyone else actuate a Mk 3 handbrake on a marcos?
All hints/answers GREATLY appreciated: I've got a few ideas, but I
don't like 'em.
Tom
PS: Has anyone else fitted replacement sills from Rory? Anyone else
find they don't fit??
