Talk Morgan Forums Thread Like Summary - Tyre Pressures 2014 Roadster

2014 Roadster - tyre pressures.

Only had the car a few weeks, and I recall the Morgan agent recommending 2.4 front, 2.6 rear, but the manual gives completely different pressures. On the other hand, the manual is a little - erm - idiosyncratic and seems to want to cover a multitude of different models and I'm not sure that I'm reading it correctly.
I'd be very grateful for any advice.
Oh - and whilst I'm here, being a Morgan neophyte a couple of other things:

1. I'm taking it the fuel gauge is also idiosyncratic?
2. The temperature gauge / cooling fan relationship seems very efficient, the fan comes on when you might expect it in these hot weather days, and then cuts out presumably when it's happy. However, there's no movement on the temperature gauge that indicates that it's getting a bit warm and then after the fan has come on you see the temperature drop and then the fan cuts out. Is this the 'normal' type of indication?

Hugely obliged for any feedback.

FWIW I've never seen the temperature gauge move from it's slightly under half scale position once engine of my 3.7 Roadster is warmed up. This remained the case after fitting larger aluminium radiator the only difference being the two speed fan comes on to low speed far more rarely. I did record a peak OBD2 temp whilst on a dyno test of 112°C but didn't have the opportunity to see the gauge then. As Jon suggests the cooling system appears very resilient to all engine demands. Illustrated write up below of same below based on my observations:





The Roadster 3.7 V6 cooling system can be explained with the help of this Mustang engine cutaway image and that of lower inlet manifold. This appears to be moulded from a hard, hopefully non heat conducting, composite and is bolted in the V of the engine to seal with heads. It incorporates on the underside a hot coolant rail (tube) running horizontally down it's middle, mating to water jackets on rear of each cylinder head. Hot coolant flows forwards along the rail protruding to seal via "O" ring to a casting bolted to front face of engine (identified by blue label on cutaway) passing coolant via union to large bore top hose and radiator. The inlet manifold also has a hose union at rear fed from coolant rail to accommodate rubber hose feed to cabin heater matrix inlet (bottom union). In this way the hottest coolant in the engine reaches both the radiator and heater in most expeditious manner without the need for long rubber hoses. The casting provides the narrower bore permanent radiator bypass (part with cast-in text) running down to a mixing chamber below (shown as cutaway) to provide quickest warm up. The bottom hose of rad feeds to the thermostat housing bolted to bottom of casting mixing chamber with the temperature sensing side of enclosed thermostat facing inwards so directly onto bypass flow. This chamber also takes coolant from the return of permanently fed cabin heater circuit (see hose union) via a T piece which accomodates a head of coolant from the lowest point of header tank above.

When engine coolant warms sufficiently the stat begins to open allowing a cooled flow from radiator to be mixed in with the bypass and heater return. The turbulence from various flows into the mixing chamber mitigating the temp of very hot coolant from bypass circuit, the greatest influence being from the radiator cooled flow as the larger bore rad plumbing gives a preferred path for coolant, providing stat is open or partially so. The chamber outlet interfaces directly to pump casting inlet with actual water pump below, then pushing coolant upwards from lower part of engine block waterways. In this way the stat is able to control coolant temperature through a wide range of engine power demands (confirmed by near constant temp gauge) whilst always providing maximum temperature coolant to heater matrix.

The header tank accomodates two very narrow bore bleed/vent hoses from top of rad and top coolant rail with connection to latter seen adjacent to blue label. These assist bleeding and equalise levels throughout the system as coolant expands. The tank has markings for max and min levels with plenty of room above coolant level to allow for expansion as coolant heats when pressure within will rise, hence need for its pressure release filler cap, should system be overfilled. The upper mark should be checked to match top of radiator level since the clear plastic tank is a re-purposed moulding from a Ford Focus installation. Experience suggests coolant level is not critical although overfilling should be avoided.

The radiator, whether OE plastic side tank or conventional design taller after market all aluminium replacement, is further cooled when necessary by a two speed cooling fan. The only difference is it will run far less often with the latter, and when it does is far quieter due to fan assembly being attached directly to radiator without the OE cowling interface. The two fan speeds are ECU triggered by excessive coolant temperature via one of two relays dedicated to each fan speed, with a high wattage Ford resistor being brought into circuit to limit motor current for lower.

It seems likely all the OE radiators leak eventually Ben. The plastic side tank to aluminium core interface being the usual place. Remember also the same radiator was used on the Roadster as lower powered Classics so greater heat stress.



Mulfab are the only remaining company offering all aluminium replacements.

The fuel gauge on all Mogs is notoriously inaccurate, however the selectable little digital bit shows 'range' (distance to empty) and is surprisingly accurate on the 3.7's (note the MPG is in US galls) plus you'll get a ping and dash warning below about 40 miles left

If you look under the dash on the undertray far right, there's a black potentiometer that controls gauge brightness & a little black knob to adjust the time clock

I have 185/70 tyres run at 22 psi for the last 11 years.

For me, it was when I went to remove that plastic drain plug to do a routine coolant change…the cross head and part of the plug broke away leaving the threaded portion stuck inside. Luckily for me, SIFAB was in business then.
Incidentally, I believe Williams may now be trialing a new source for Aluminium rads.