V8 Coolant Bulk Tank Query

[greyV8pete]

V8 Coolant Bulk Tank Query

My bulk tank (fitted in the heater return line) has started leaking. I suspect it has cracked where the single attachment lug is welded to the tank.

I know that the theoretical idea is that the tank is designed to act as a heat soak but wonder what the effect will be if I bypass it and just run the heater return straight back to the bottom hose?

Does anyone know if the Marlin coolant bulk tank was fitted to all Hunters that had V8 engines or do some manage without it? My tank is fitted on the O/S bulkhead just above the O/S exhaust so I imagine it has been absorbing quite a bit of heat from that.

I know of one Cabrio fitted with an extra rad under the front apron, plumbed into the main coolant circuit, which is my ultimate plan to copy, another has a bus heater matrix in the same position. I have also seen an uprated rad fitted to a sportster which has more room for it than the Cabrio.

I would be interested to know what other Cabrio / V8 owners have fitted to supplement cooling.

Peter.

[dave_kitson]

Re: V8 Coolant Bulk Tank Query

Hi Peter

These V8s are funny beasts! I've done all sorts to get on top of the cooling on mine, yet I know Derek Jones had no trouble at all, although his is in standard tune. I'm not sure if you are referring to my car with a rad under the front apron, but mine was actually plumbed into the heater circuit. Anyway, full details of what I did are in Pitstop feb/mar 2013, along with a list of other measures I had tried. Obviously if you need more info, please get in touch.

I'm not sure how effective the bulk tank is. I tried one on a Pilgrim Hawthorn, and it made little difference, it just took longer to overheat! The extra rads have definitely sorted the overheating on the Cabrio. I eventually put a new cowl over all the louvres which increases the ram-air effect on the move, and I'm now confident enough that I've actually turned the thermostat up from about 90C to 95C (as far as it will go). For good measure I've ditched the HD fan in favour of one which is kinder to the battery and alternator. If you - or anyone else - wants a HD Kenlowe, then it is for sale at a considerable saving to new.

Good luck with whatever you try! Dave

[danny_nelson]

Re: V8 Coolant Bulk Tank Query

Hi Peter, I have been waiting to see if Dave Kitson or any of the other V8 builders came back to you. If you look on Marlin sports cars for sale web site you will see two V8 models (already sold some time back) if you remember I had the grey one? The grey one has the bulk tank fitted but the other does not. Both cars built by Marlin around the same time. I have a V8 built by Marlin 2002 no bulk tank fitted.

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

Hi Dave. That's interesting info thanks. I remember now that the rad under the front was probably on John Mulvaney's car which I saw at Landow track day a long time ago and I think it was in the main rad circuit as the pipes were quite a large diameter I think. I have just finished disconnecting my bulk tank and will road test tomorrow. I tried to remove the tank itself but it won't come off unless the manifold is removed so had to bolt it back in place! As my tank was sitting on top of the O/S exhaust I suspect it's removal won't make any temperature difference except there may be shorter "spikes" in the thermostat controlling temperature gradient. Tomorrow will tell. Peter.

Hi Peter

These V8s are funny beasts! I've done all sorts to get on top of the cooling on mine, yet I know Derek Jones had no trouble at all, although his is in standard tune. I'm not sure if you are referring to my car with a rad under the front apron, but mine was actually plumbed into the heater circuit. Anyway, full details of what I did are in Pitstop feb/mar 2013, along with a list of other measures I had tried. Obviously if you need more info, please get in touch.

I'm not sure how effective the bulk tank is. I tried one on a Pilgrim Hawthorn, and it made little difference, it just took longer to overheat! The extra rads have definitely sorted the overheating on the Cabrio. I eventually put a new cowl over all the louvres which increases the ram-air effect on the move, and I'm now confident enough that I've actually turned the thermostat up from about 90C to 95C (as far as it will go). For good measure I've ditched the HD fan in favour of one which is kinder to the battery and alternator. If you - or anyone else - wants a HD Kenlowe, then it is for sale at a considerable saving to new.

Good luck with whatever you try! Dave

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

Many thanks Danny. I know one Hunter has a bulk tank behind the front chassis cross member but it wasn't a V8 as there isn't room.

Were the V8s that you mention 3.5 or 3.9 engines? My3.9i has a higher T-stat (88deg) opening as O/E standard. Anything lower will make the fuel enrichment kick in so that may be a significant difference between the cars? Peter.

Hi Peter, I have been waiting to see if Dave Kitson or any of the other V8 builders came back to you. If you look on Marlin sports cars for sale web site you will see two V8 models (already sold some time back) if you remember I had the grey one? The grey one has the bulk tank fitted but the other does not. Both cars built by Marlin around the same time. I have a V8 built by Marlin 2002 no bulk tank fitted.

[danny_nelson]

Re: V8 Coolant Bulk Tank Query

Hi Peter the two Hunters were 3.9, my current car is 4500, all serpentine front.
Danny.

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

That's interesting. Were they / is yours, carb or injection? Peter.

Hi Peter the two Hunters were 3.9, my current car is 4500, all serpentine front.
Danny.

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

Hi Peter
.....................I eventually put a new cowl over all the louvres which increases the ram-air effect on the move ...................................... For good measure I've ditched the HD fan in favour of one which is kinder to the battery and alternator. ...................................
Dave

Hi Dave. have just re-read your Pitstop article thanks.

Can you please post a photo of your new cowl. I am planning to fit similar to feed air down "behind" my extra rad "exit duct" to feed the oil cooler that will otherwise have its airflow blocked.

Just wondering if your cowl is fabricated / alloy or glass fibre? Pic will clarify.

I also got rid of my high performance Kenlowe as it was blocking too much of the rad core. I have re-fitted the original skimpy Kenlowe which now works well since I fitted a ram air duct to the Marlin rad. Peter.

[danny_nelson]

Re: V8 Coolant Bulk Tank Query

All injection Peter. Have a look on Marlin sports cars cars for sale the photos are still there and there are engine bay images.
Danny

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

All injection Peter. Have a look on Marlin sports cars cars for sale the photos are still there and there are engine bay images.
Danny

Many thanks again Danny. As a separate thought I fitted the Optimax chip to my 14CUX ECU a long while ago now. I also fitted Lambda sensors in each exhaust with a matching "White" tune resistor.

I guess these other Hunters still have the O/E land Rover disco chip? I wonder if they have Lambda sensors? Peter.

[dave_kitson]

Re: V8 Coolant Bulk Tank Query

Hi Peter
There should be a piccie of the cowl attached if I've done it right! First attempt!
Cheers - Dave

[dave_kitson]

Re: V8 Coolant Bulk Tank Query

Hi Peter
I should have said, it was made from aluminium sheet, painted to match the car. Stainless mesh matches the grill, and trimmed with some chrome/plastic edging. It is held down by 2 self-tappers inside the front corners and 2 at the back, where it tapers down. The other self-tappers you can see hold down the louvre panels; the coachbolts hold the fan under the oil cooler. Looks like it needs a wash!!!
Dave

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

Hi Peter
I should have said, it was made from aluminium sheet, painted to match the car. Stainless mesh matches the grill, and trimmed with some chrome/plastic edging. It is held down by 2 self-tappers inside the front corners and 2 at the back, where it tapers down. The other self-tappers you can see hold down the louvre panels; the coachbolts hold the fan under the oil cooler. Looks like it needs a wash!!!
Dave

Many thanks Dave. That's similar to the idea that I had planned. I will have to do some more development work with my trusty Pizza boxes!

I have been pondering how to support my extra rad which will be at about 30degrees from the horizontal. I had originally intended to bolt dural webs as downward extensions to the two nose cone edge seams, to act as the upper sides of the under bumper scoop and then hang the radiator from those. However after reading your Pitstop article again I am thinking that the front apron may be strong enough to carry the weight directly, via its support brackets. Peter.

[greyV8pete]

Re: V8 Coolant Bulk Tank Query

I went for a run this afternoon for half an hour with the bulk tank bypassed. No noticable difference to running temperature! Possibly the gauge went up a bit more quickly when I did a bit of sustained acceleration but it went down again just as quickly which is what I would expect with less coolant. When parked the cooling fan cut in and controlled the temp as per normal. That was with 12 deg air temperature. During the summer the extra rad will make up for the missing coolant and the extra cooling should help as intended, so plan "A" continues as and when time permits. Peter.

[djj_engineer]

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.