Ok this could be a long thread.

Trying to keep it to specific problems of the parts that Tim Dutton had a hand in creating :angry: - not what subsequent builders owner rebuilders have added along the way.

List of what i have found and gleaned from others - together with remedies which is even better B)

S3/S4

Explanation of the DOC site misses a little bit.

Basically the same chassis - quite different in detail however many detail differences and and without a Locost like plan to refer to its a bit hard to list.

Wider at the base of the screen - a bit more than that. - the body and Bonnet are completely different in may ways - but most sinificantly the S3 has a curve from the screen into the door 'step' and has separate bumper/soilers. and a body line along the side.

Weak points -

Steering rack mounts -

These are 1" strip and they bend allowing the rack to move from side to side - replace strip with 25mm / 3mm angle iron.

Spring hanger mounting behind drivers seat -

The inner mounting is only 1 1/2 strip and this teares the chassis which is only 16swg (1.6mm)

If leaving the same plate the chassis with some 40mm x3mm strip and fix new 40 x3 mm support.

Better to junk the springs and go for 5 link and coilovers

Chassis triangulation

The chassis is quite robust 1 1/2" 16swg box on the whole but it still misses quite a bit of triangulation to assist with torsional stiffness - its quite easy - if you have the expertise to add in quite a bit of extra metal to stiffen up the chassis - In the engine bay between the top and bottom rails diagonals can be fitted and at the rear daiagonas can be added arond the boot area

Uper to lower cross chassi diagonals are a bit harder - these can be installed behind the rear bulhead - 25mm tubing will just fit and in the front in the area of the rad - because of the body construction bracing around the scuttle area is impossible without a great deal of body modifications.

Pedal position

This is a bit of a personal one but I found the pedals way to high when fixed as the build manual says and also to far to the left - much better to have them lower on the bulkhead and over to the right a bit more - this helps the brake master cylinders miss exhausts on pinto installations

Axles

I guess mr Dutton had a whole stack of Weller wheels with an odd offset he wanted to get rid of when he designed the S3 S4 chassis around the Escort becasue without a wheel with a zero or negative offset then if going wider than 5 inch rims and 165 tyres you are going to have problems with the tyres and the chassis rails.

If you can find on the mk1 Capri axle is wider than the Escort as is the Cortina Mk 2 axle so these help the problem a little

Cortina 3/4 are way too wide unless you want to modify the arches as well and go really wide or fit some moden alloys ith FWD offsets.

With escort axles the maximum backspace on the wheels ( measurement from the mounting face to the inner rim is 90mm and the widest rim to fit under the arches and give clearance (just) is 7.5 inch 225 tyres are about as big as you can squeeze in - Diameter wise the arches are huge and you can fit some big wheels in there - However on a personal note anything bigger than 15 " looks a bit out of place on a Phaeton. My personal choice is a wide 185/70/13 or a 205/60/14 - I say wide because some makers mould them wider than others.

Brake master cylinders

Boy what a selection -

Basically - You want to try and get a disc piston pressure of 4000 Pounds pressure
this will give you a decent predal pressure and feel

If using type 16 calipers and the standard pedal box which has a ratio of 4.6 to 1 then a cylinder diameter of .7/.75 is Ok

If using the small type 12 callipers then a cylinder of .625/.7 is ok

As a matter of intrest the difference on the 4.6 pedal ratio on a 100 pound force on the pedal to the line pressure generated by each cylinder is

.625 - 1500psi
.700 - 1197psi
.750 - 1043psi

As you can see a much bigger foot is need on the .75 cylinder

Escort tandem cylinders are 19.05mm - 0.75
Spitfire/Escort single clinders are 0.625

Tandems are usually mounted on a servo wich adds ups the effective pedal ratio to about 7:1 Giving 1585psi - ie back to the 0.625 pressure but the extra volume of the cylinder allows it to run bigger pistons in the callipers with big pad pressures.

The piston pressure on a mk 2 escort is 5600 pounds for a 100lb push on the pedal - one piston remember and you have four on the front.

Dont do what the guy that built my S1 did - fit a rover cylinder with a .8 bore and then fit it with a 3:1 podal ratio

The line pressure is 600psi ( 100 lb push) and the piston pressure is -1680 at the pad - less than useless - however if a solid feeling pedal is what you wnat its great its like standing on a wooded block - however with thats about all it feels like you are pressing on to slow the car!!!.

perhaps this amount on brakes should have been another thread

Oh well please add faults you have found.

Cheers

Andrew

As I am working on my S1 I am coming across a few issues with the build and some things that could be better.

As mine is a little different to the norm these are probably not relevant to all.

Hand brake - seems to be a modified MGB type - when in the "off" position the level fouls the propshaft UJ and makes an alarming noise when they connect - Will probably change/relocate lever to the top of the tunnel - cannot move it forward as it will foul the gearlever.

Front - Rear brake imbalance - with the 3.0L capri axle with the big 9 inch brakes the car is over braked when fitted with the usual 9" Spitfire front discs. The best way is to fit a balance device - these can be made for about £30 using new parts £5 s/h or buy one for about £90. See Dave Walkers RHOC site for detail


Cheers

Andrew

From DOC message board.

Re(2): camber angle
IP: 195.92.67.209
Posted on May 26, 2004 at 05:11:47 PM by Mark Young

The spacers were originally fitted in the Triumph donor car the idea being that the thickness of the shim allowed for adjustment of the camber, and if careful minor adjustment to the caster.
However on Duttons the shims should not be installed as they give too much negative camber. In fact the original build manual clearly states "do not use shims".
However, when the shims are not fitted this means that the only support for the Triumph bracket is on the end of the tube that is brazed into the front chassis leg. Over time due to forces exerted on this tube by the car cornering you get a stress fracture around the perimeter of the braze, this in turn leads to eventual failure and the tube comming free from the main chassis leg. This problem was relatively unherd of 5 years ago but has become more and more common as the relative mileges of the cars since new has gone up. One solution to this would be to thin the shim and cut the tube back so that the bracket is still supproted over the full height of the chassis rail. I have seen a number of early cars with various modifications to over come the problem some solutions being better than others. I prefer cutting the tube back flush on the outer face and strengthening the area this then allows a spacer shim to be made to suit the car and dial out any of Mr Duttons chassis irregularities giving a equal and acceptable amount of camber on both front wheels. Around 1.5 degrees is acceptable for road use on a Dutton. On the back face a reinforceing plate is welded the full depth of the chassis rail and around the tube end to act as a load spreader. There will be an article on how to repair the problem in the next club mag so look out for that

Here's a shot of the usual fitment of the B+ and S1 Panhard rod location - The one on this, my B+ is even worse than normal because for some reason its been cut and bent and then a web reinforcement let in so its effectively no different to a straight bar :blink:

The issue is that its way too high for good geometry.



This shot also highlights how flimsy the stock chassis is. Especially taking into consideration that the bar between the shocker uprights and the round bar diagonal are NOT standard but ones I put in.

Andrew

A couple of comparisons might help with the triangulation weakness:


My Pheaton Series 1




vs Locost Aussie spec



Lots of scope for bulking up the S1 !!

Dry Roads

Barry

It is scary when you see that V8 sitting in between those few tubes.

See my B+ thread for the couple of extra bracing tubes I have felt necessary ;)

Then again I need something to hang the alloy off of.

Cheers

Andrew