operating temp 1.8marina based

[Pierre_Smits]

Hi, I'm still trying to improve my Marlin.
Does anyone know which is the best operating temperature for the 1800 Marina based engine (dual carb)? Probably the engine is from 1975 or even older (kit finished in 1983)
Now on the highway driving over 100km/h (62mph) up to 120 (75mph) increases the watertemp quite a lot: The gauge goes into the red area... my instruments are Smiths and triumph based for as far as I know. (by the way: under 60mph everything is fine!! needle nice in the middle of the temp gauge)
I have an extra fan on the radiator for extra cooling (yes, it's blowing wind in so it's fitted correctly)
I guess I need to upgrade from single core radiator to 3 or 4 core but before I do this I'd like to measure the actual water temp when the gauge reaches the red area. Therefore my question what the temp should be in normal operation (incl highway 75mph)
thanks!

[f.swaans]

Re: operating temp 1.8marina based

Pierre,

Have you checked the thermostat and the senders in a pot with boiled water? When you are in the neighbourhood, I have a multifunctional environment measuring instrument with temperature probe.

[h_m_cumming]

Re: operating temp 1.8marina based

Check also that the system is pressurising. From your description it sounds like you need greater cooling capacity. A 3 or 4 core rad. will do that. Normal temp. is about 90C but remember that's at 15psi pressure.

[Pierre_Smits]

Re: operating temp 1.8marina based

Thanks Hugh! that's a good one! the pressure cap might still be the original from the 70s so I better replace it for a new one. Maybe it will help in the temp issue..
Soon I hope to visit Frans and check out his temperature measuring tool to find out what the actual temperature is and not only the reading of the gauge...

[b_caswell]

Re: operating temp 1.8marina based

Make sure the surround above the radiator is blocked off so that the air flows through the radiator and not over the top. What happens is the air pressure in the engine bay builds up and restricts the flow through the actual radiator.
Also make sure the fuel mix is not too lean/weak and check the timing.

[Sidon]

Re: operating temp 1.8marina based

Hi Pierre,
I had the same problem when I first started using my 1.8TC Marina based Marlin. Does your engine temperature rise when you are in standing traffic as well as when cruising at sustained high revs? Mine did. I went through all the standard checks, changing the rad cap and the thermostat, flushing the system and fitting an electric fan. At the end of the day, though, it was clear that the standard fit Vauxhall Viva rad simply did not have enough cooling capacity. I went to a local independent radiator repair shop and they were very good, allowing me to look through their old stock to find a suitable 3 core replacement. In my case I think the new rad was originally fitted to the Austin Maxi. Bit of bracket bending and pipework and away you go. I've never had a problem since and it's rare that I have to use the fan.

If I were you I would go for the 3 or 4 core rad sooner rather than later (assuming your current rad is the small single core Viva type!). It spoils your enjoyment of driving your Marlin if you are constantly checking your temp gauge.

[Pierre_Smits]

Re: operating temp 1.8marina based

I guess it's indeed an old standard single core Viva rad. The top of the rad is blocked, same as the side, so all the air is forced to go through the rad.
The temperature in slow traffic and standing still are OK, no problems at all. only high revolutions (3500rpm and more continuously) cause trouble.
I think I'll try to find a 3/4 core and that hopfully will solve the problem.
Maybe louvres will help as well? did anybody notice a difference in utilising these?
Thanks!!

[Sidon]

Re: operating temp 1.8marina based

I have louvres along the engine side panels as shown in the photo. I would have thought that these were necessary to allow airflow. Do you mean extra louvres on top of the bonnet?

[Sidon]

Re: operating temp 1.8marina based

Hmmm. They were very clear in Photoshop but the image above is probably too small. Sorry.

[Pierre_Smits]

Re: operating temp 1.8marina based

Hi Simon,
I mean the louvres along the engine side as your car has. At that time it was an extra option for the kit for an extra L15.- or so. Unfortunately the person who built my car did not invest a few pounds more...
I agree that the louvres improve the airflow and might also help in keeping the engine cooler than without louvres...
If anyone still has some left, please let me know :-)
Now I have the bonnet a bit open at the windscreen-side using a small pipe (25mm) on which the bonnet rests. This might help in getting the warm air out...but I'd prefer real louvres.

[bryannewell]

Re: operating temp 1.8marina based

Hi Pierre
My last marlin was a Triumph 6 engined version which ran so hot I suffered fuel vaporisation all the time,I changed the rad for three core and had louvres cut into bonnet,problem solved!!
I am nearing completion of my latest marlin and will definitly be putting louvres in again.
Anyone know where I can get some done in the west country?
Regards
Bryan

[Pierre_Smits]

Re: operating temp 1.8marina based

Last Thursday I went to Frans Swaans to measure the actual water temperature. We found out that the engine indeed becomes too warm. When the needle of the gauge is in the middle it is about 90-95Celsius. As said before, on the highway going about 120km/h the needle moves to the red area which is about 110C and probably even more.
We tested while standing still (idle, about 900rpm) and with the automatic fan cutting in at 75C the temp stabilized at around 80-85C. So, that's good news. However, when rpm goes up so does the temp...
Final conclusion: radiator too small capacity.

My radiator is Chevette or Viva but the core is still original and quite hefty (?don't know the word..) and the lamella have quite a big opening between them. See pictures. It's by the way a dual core as it seems from the pictures.
Frans' Marlin (1800cc) has the same radiator but different lamellla; much smaller and thicker core.

So, I need to find another radiator that will fit or update the core. I got a quote for updating for about €250 ex VAT... not cheap...
I'll start a new subject to see if anyone ever fit a different brand/kind of (newer) radiator.
thanx, Pierre

[greyV8pete]

Re: operating temp 1.8marina based

My Hunter (Rover V8 3.9i) has two rows of louvres along the bonnet as well as the ones in the engine side panels. Have a word with Marlin about their supplier of louvres. They will already know the correct size / have the correct tooling for a Marlin . Louvres would normally be pressed in before painting using a special press tool. Search Google for "bonnet louvres" and you will probably see a first off charge, then a price per louvre. The first charge will almost certainly relate to the tooling set up for the size you require, then the charge "per louvre" will be a time / labour calc. Peter.

[greyV8pete]

Re: operating temp 1.8marina based

Hi Bryan. There is a sheet metal specialist in Marsh Barton Exeter that can put louvres in bonnets. Give me a call on 01392 446928, after 6 pm is best, and I can give you all the details. They made up the rain "gutters" for under the louvres on my Hunter. Peter.

[bryannewell]

Re: operating temp 1.8marina based

Hi Peter
Sorry for the delay,have been away for a few days!
Thanks for the offer to help.
Getting them done tommorrow near crediton!!
Should have checked for replies before!!
Regards
Bryan