Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Air Intake improvements

Your cardboard experiment will be interesting.

I don’t know the detail of the Sigma so can only attempt an explanation on the Duratec.

Below is a pic of the Duratec showing the coolant paths and how they mix at the stat housing. Also a pic of my old 90deg stat. Note the stat is a double valve arrangement. The primary valve is pretty standard. The secondary valve is the plunger at the end that seals against a seat in the block. When the primary valve opens to let the rad coolant into the block the secondary valve closes off the hot by-pass coolant.

As said before it looks like it is dependent on a precarious temperature balance between the hot and cooled coolants that might hold the answer. Just a wacky theory……

FWIW the coolant bypass whether it's integrated into the block or an external pipe, is always a narrower bore than main rad cooling circuit.

This is the case with conventional cylinder head or rad return thermostat location.

When I replaced broken radiator with a Mulfab alluminium one, I noticed a drop in the cooling water temperature. This must be because the Mulfab one being made from alluminium and being larger. As I did not like the esthetics of the new radiator sticking out from below the front, I got a stubby valance from Wolff Engineering, to cover it up as well as to get some extra protection. Result is that the running temperature is slightly up again.
In order to lower the under bonnet temperature, I installed bonnet extenders from John Taylor. This also provides some extra free volume around the itg air filter, which should help breathing. An additional bennefit is the increased sound level from the air intake.

I wonder if closing the gap at the bottom between radiator and front of engine (as mentioned earlier in this discussion) would be of additional help to help both air intake temperature and flow (given the bonnet extenders).
Cheers,
Bert

It's not a difficult job Bert, because you can start with a flat sheet of aluminium, and improvise. I've done it on each of mine. Of course it's impossible to really evaluate the outcome, but none of mine have run hot, even last summer.

I had a good run today and I'd say the new deflector plate made no difference whatsoever. Still gives an indicated 96 once fully warmed up at 40 to 50 and got up to 102 at 70 on a long gentle hill, just about 100 at 70. The fan didn't come on as far as I could tell. I will leave the plate there to see what happens in the summer.
It seems like the thermostat is controlling the inlet temperature to the engine and the dashboard water temperature gauge is reporting the outlet i.e. 88 deg inlet constant but the more the load the higher the outlet temperature.

Inspired by Jon's much earlier posts relating to getting more cooler air into the 3.7 Roadster's air box, I've also cut a 4" hole in the box but then used a ducting elbow that came from Screwfix to help draw cool air from the side vents in the bonnet.
A quick spray of matt black and I think it looks quite tidy.




I've left the original hole in the base of the box open, but I'm hoping that this - very cheap! - addition may improve things.

Only a proper dyno test will confirm one way or the other whether there's any difference in performance, as I must say I can't notice any, but I just feel that anything's got to be better than the standard arrangement.

Sid, looks a good idea

My MK2 version now has a scoop fitted above the rad which feeds air via a duct direct into the front airbox hole

The engine deffo runs cooler as the fan cuts in a lot less

Sid, photos of Mk2 upgrade



Intake scoop mounted on top of rad

Neat job Jon. I feel if I was to do the same I would need to start with an unbutchered airbox as that is what the MMC mod is IMO.

Do you happen to know the source of (intact) airbox?

My investigations revealed there were two 3.7 V6 Mustang airbox variants, and the OE slab filter (replaced with K&N) on mine matches the 2011-2014 one with straight not angled outlet. Even then it would have had a hole at the front to accept the rectangular cold air inlet pipe (see my photo further up this thread) which would be sited just behind left hand bank on Morgan, so maybe yet another Ford airbox variant.

Nice idea, Jon. Interesting to hear that the car now runs cooler, too.
Maybe your design restricts some of the airflow that would normally have by-passed the radiator, but is now forcing more air to go through it?

Anyway, you've now prompted me to experiment with installing a blanking plate above the rad, as the cooling fan certainly kicks in a lot more than it ever did on my old +4.

So thanks for that, as it's given me more excuses to disappear into the garage for some more tinkering...!