V8 Coolant Bulk Tank Query

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

Hi
The other differences with my car are that it doesn't have a light bar, so there is uninterrupted airflow to the rad and it has standard cast iron exhaust manifolds that don't radiate as much heat as the tubular types.
But as Dave says it has never run hot, although I don't have a firm reason.
Mine has a 3.38 diff so the engine never rotates that quickly. If you use the revs in intermediate gears you tend to run out of road. I guess if you left it in 2nd it would rev more but would also use a colossal amount of fuel.

I also have a 3.38 diff now so tend to use top in towns rather than 5th which it would pull at 30mph before with the old 3.92 diff! Peter.

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

Does anyone know what diameter the top and bottom hose connections are for the uprated 3 row Marlin radiator? I suspect that they are less than the 38mm size of the Rover V8 engine inlet and outlet but need to know exactly what size they are, before disconnecting the existing system, so I can check what hoses I need to order. The visible part of the rad pipes are not round section, hence my question. Peter.

[dave_kitson]

Re: V8 Coolant Bulk Tank Query

Hi Peter
I can't get at mine to check the size, even though mine are round, but I'm pretty sure they are 34mm. Why they weren't made 38mm is anybodys guess. In any case, the filler adaptor T-piece is 35mm!!! The manual says to use SD1 hoses, cut to suit, which I believe I did, having looked through tons of other hoses to see if I could find anything better. I managed to squash the hoses to fit the connections and haven't had any leaks. It is possible to get sleeves or reducing hoses but you may have fun with the geometry! Try the Europa catalogue - may be expensive, but if it does the job, then its worth it. In any case, SD1 hoses may be expensive - if you can find them - try RPi or Rimmers if you struggle.
Cheers - Dave

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

Hi Peter
I can't get at mine to check the size, even though mine are round, but I'm pretty sure they are 34mm. Why they weren't made 38mm is anybodys guess. In any case, the filler adaptor T-piece is 35mm!!! The manual says to use SD1 hoses, cut to suit, which I believe I did, having looked through tons of other hoses to see if I could find anything better. I managed to squash the hoses to fit the connections and haven't had any leaks. It is possible to get sleeves or reducing hoses but you may have fun with the geometry! Try the Europa catalogue - may be expensive, but if it does the job, then its worth it. In any case, SD1 hoses may be expensive - if you can find them - try RPi or Rimmers if you struggle.
Cheers - Dave

Many thanks for the info Dave. I have been loking at the CBS range of hoses / reducers and other fittings and the two diameters that seem to be used are 38mm and 32mm (or 1 1/2" and 1 1/4" in old money). I guess the Marlin rad may be 32mm then? I will wait to see if anyone else comments on this thread. Peter.

[copperleaves11]

Re: V8 Coolant Bulk Tank Query

Hi Peter.
Like Dave, my top hose filler stub diameter is 35mm which is, from memory the same diameter as the rad stubs. I used 34/35mm silicon hoses and found them a perfect fit, they also stretch over larger diameters much more easily than rubber.David

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

Hi Peter.
Like Dave, my top hose filler stub diameter is 35mm which is, from memory the same diameter as the rad stubs. I used 34/35mm silicon hoses and found them a perfect fit, they also stretch over larger diameters much more easily than rubber.David

Many thanks for the info David, especially the comment about silicone hoses as I have never used those before. Tomorrow I will check the diameter over the hose clips. I guess if I subtract the hose and clip thickness x2 from that it should confirm the bore diameter. I am thinking 4mm per side for a compressed hose plus jubilee clip (x2) will be a good guestimate. Peter.

[mike woodley]

Re: V8 Coolant Bulk Tank Query

Hi Peter,
Have been reading your thread with interest. My Cabrio has a Rover V8 3500 with twin SU carbs. in standard trim. I have the Marlin supplied radiator, with extra cooling louvres punched into the bonnet, two rows each side, see photo. I run a Kenlowe fan set quite high, with a 82c degree standard thermostat . I have covered over 20,000 miles and have never had overheating problems. I live in Okehampton, so not too far away if you want to have a look sometime.
Regards Mike.

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

Hi Mike. That's very interesting.
I also have bonnet louvres, a kenlowe fan and a self-built ram air duct in the nose cone. I think the 3.9 injection engine tends to run hotter than the 3.5 carb version too.

I don't have an oveheating problem in the usual sense i.e no boiling or coolant escape or excessive temperature, just a very busy fan. What I am concerned with is the minimal cooling in reserve with the standard Marlin set up, especially during summer traffic and planned trip to hotter European climes. I have now ordered a custom made rad to go under the front apron and am currently designing some brackets and ducting for when it arrives.

Interesting that you have he same MGF windstop that I have fitted !

Many thanks for the offer to have a look at your Cabrio sometime. Peter.

[djj_engineer]

Re: V8 Coolant Bulk Tank Query

I was reading my MG mag and in it there was a piece about overheating of RV8's
One solution was to fit marine bilge blowers to suck the warm air out of the under-bonnet area.
There may be room to fit one of these on the nearside lower down by the chassis but the off-side looks a bit full with steering and starter etc.
The cabin blower is about 100mm in diameter and 100mm long 12volt supply. It is usually fitted with inlet and outlet hoses so could be fitted some way from the radiator.

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

I was reading my MG mag and in it there was a piece about overheating of RV8's
One solution was to fit marine bilge blowers to suck the warm air out of the under-bonnet area.
There may be room to fit one of these on the nearside lower down by the chassis but the off-side looks a bit full with steering and starter etc.
The cabin blower is about 100mm in diameter and 100mm long 12volt supply. It is usually fitted with inlet and outlet hoses so could be fitted some way from the radiator.

I guess the lack of bonnet louvres and the enclosed engine bay on the RV8 makes this a good idea. That said the rad is larger than the Marlin Cabrio rad. Peter.

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

It occurred to me that as my extra rad may block and / or heat the airflow into the oil cooler, it would be a good idea to know what the oil temp is before I change anything.

Soooooooo! As I already fitted a oil thermostat and temp sender a couple of years ago and bought the gauge, but never fitted it (due to a lack of "round tuits") I decided to fit the gauge while waiting for my extra rad to be made. As the plan was to mount this gauge in an extension to the centre console this is my current project. Hopefully I can finish it soon so I can get on and check some temp readings! Peter.

[Mike]

Re: V8 Coolant Bulk Tank Query

It occurred to me that as my extra rad may block and / or heat the airflow into the oil cooler, it would be a good idea to know what the oil temp is before I change anything.

Soooooooo! As I already fitted a oil thermostat and temp sender a couple of years ago and bought the gauge, but never fitted it (due to a lack of "round tuits") I decided to fit the gauge while waiting for my extra rad to be made. As the plan was to mount this gauge in an extension to the centre console this is my current project. Hopefully I can finish it soon so I can get on and check some temp readings! Peter.

You may wish to calibrate your oil temp sensor/guage with a thermometer and a pan of oil, as you don't want to start problems that may not exist.

How do I know?
- I have very low temps reading off my water sensor/gauge despite callibrating it in a pan of boiling water. I changed the sender and gauge from an old style Smiths regulated 10volt system to a more modern VDO pairing, and still had low readings.

Caerbont (makers of 10v Smiths instruments) have now advised sending my BMW VDO sender back to them with their Smiths VDO gauge, and they will re-callibrate it using an oil bath for temperature source as water apparently is unreliable!

Sounds absurd but I guess holding water at 100C is almost impossible, whereas oil can be taken way beyond in a controlled manner?

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

Thanks for the suggestion Mike. As the gauge (Racetech) and its sender were purchased together they should theoretically match. If my modern is any guide I would expect to see the oil temp approx 10deg C higher than the water temp. Whatever it is reading I am looking for a "before and after new rad" comparison at this time so the exact temp is of less importance than "has it increased?".

The new console was finished today so hopefully wiring it all up tomorrow. Peter.

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

After a few delays I finally fitted the new panel. Although initially designed to house my oil temp gauge. I had also wanted to fit a compass in a less nick-able place than on top of the dashboard!

Once all was assembled I had a slight panic to find the oil pressure gauge was a moving iron type. Compasses don’t like large chunks of magnet next to them and mine threw a fit and said every direction was North East! A quick bit of retro fitting a mild steel shroud around the offending gauge allowed the excellent compensating magnets in the compass to be set up ok. Alas once the whole assembly was fitted in the car the compass again has quite an error.

Next job then is to drive to a nice open space where I can see some landmarks and re-compensate the compass. Apart from that I am fairly pleased with the end result except for the screws in the side panels being too large and too obvious with the foam underlay. Will probably redo those with velcro instead so they match the radio console better. Peter.

Note - Pics resized but still a bit large. Also used to be able to insert captions between the photos but can't seem to do this now! Photos also appear in the reverse order to the ones I selected. Hey ho.