JowettTalk

I am going to need both a radiator & oil cooler for my Jupiter.
From what I understand fitting a radiator either from Scott Renner in USA or from a company in the UK seems to be the best option for good cooling.
Has anyone got a preference or other idea? Has anyone had an alloy radiator made here in OZ?
The oil cooler also seems to have even more options, the two common ones I have seen are Mini Cooper, & VW.
Anything stamped Mini Cooper seems to be twice the price of anything else (the infamous Cooper Tax ).
Is there some generic cooler some one can recommend?
& to clarify I do not have either part to recondition or modify.
I can probably go to a performance shop & buy a made in cheapo land, however I would need some idea of capacity & fittings need, as I have nothing to copy.
Any help would be much appreciated.

David,
On the topic of oil coolers, the Bowman cooler [https://ej-bowman.com/] that Jowett specified for the Jupiter was 1.75" deep and had a face area of 7.3125 x 3.75" = 27.5 square inches (not including the header tanks), and used ½" BSP pipe fittings. There is specific information on this cooler somewhere on this site.

Something quite similar is available from BAT-Mocal here: https://www.batinc.net/mocal-cooling complete with many accessories and with BSP fittings. Their core appears to be around 2" deep and they offer at least two widths: 12" and 6", but note that this dimension includes what is nominally the header tank so the effective core width is ~0.9" less than this. Thus the most likely substitute for the Bowman cooler is the 10 row 235 matrix cooler that results in a face area of 9" x 3" = 27 square inches. I used one of these on my Javelin for several years. It is likely that these modern coolers are more efficient than the original Bowman design.

I would also strongly recommend using the Mocal OT1 oil thermostat which I also had on the Javelin.

Search for aluminium radiator on JT.
You will see that various members have purchased rads and had them shipped to Aus. Very reasonable.

Search for aluminium radiator on JT.
You will see that various members have purchased rads and had them shipped to Aus. Very reasonable.
https://jowett.net/forum/viewtopic.php? ... tor#p24405

From the last time we compared, the UK rad was the less expensive option when landed in the US. I suspect that has not changed.

The original oil coolers on Jupiters are quite restrictive. Modern ones flow much better. I am a recent convert to the oil thermostat on my Europas and will likely fit them to the Jowetts as well.

What does an oil thermostat do?

An oil thermostat in the lube circuit before the oil cooler bypasses the cooler when the oil is "cold" but directs it through the cooler when it is hot. For several reasons, you want the oil to get up to working temperature as quickly as possible, but then not get too hot under adverse conditions.

A good temperature for the oil is around 90°C but no higher than 100°C, very similar to the engine coolant. Oil is relatively viscous and it takes energy to pump it around the engine, particularly when cold; a hot thinner oil takes less energy to pump and this helps to reduce fuel consumption. At least as important, the hot oil evaporates the water and other impurities that condense into the sump and would otherwise cause corrosion to the bearings and other parts. Oil that gets too hot, perhaps when hill climbing or towing on a hot day, is also not good as this impairs the additive package and results in a requirement for a shorter time between oil changes.

As fitted to my Jup for about 30 years
https://jowett.net/forum/viewtopic.php?p=24739#p24739
also see link in that topic to supplier or search 'Mocal' in JT
You will also see in that picture the extra oil temp sensor and the spin off oil filter conversion that allows you to use filter which takes out smaller particles than the standard . I have 5 temp sensors on the engine which gives me forewarning of anything going amiss and gives me feedback on if I need more or less cooling which can be controlled with a variable pitch mechanical fan, a powerful electric fan and front grill muffs. On the Javelin there is also an additional electric fan on the oil cooler which is fitted in the top of the wheel arch to take heat outside the engine compartment.
In this way the Jup has coped with the Sahara desert , the winter rallies in freezing temps , London traffic and racing. It is just as (if not more) important to get the engine warmed up quickly as stopping it boiling.

Hello David,

You can try Aussie Desert Coolers, who specialise in aluminium radiators and oil coolers. They are mostly involved with the hot-rod market, but during a factory visit recently, Norm (cannot remember his surname) told me that if I could produce a sample, he could make a replica in aluminium. Their workmanship is excellent and they are located in Melbourne's northern suburbs.

I have promised one of their radiators when the Jupiter unit starts leaking.

My oil cooler lurks below the front bumper on rather flexible rubber mountings. Have not hit it yet.

Regards,

Mike A.