Rover V8 Thermostat

[Chassis 33]

If I'm removing the thermostat from a RV8, what size restrictor should I use to ensure the whole engine is cooled. I know engines like the A-series have lots of problems with headgaskets and the like if the thermostat is removed and no restrictor plate added, is the RV8 the same?

Regards
Iain

[350Matt]

why remove it?

in any case you need a 25mm hole

Matt

[GreenV8S]

The thermostat you replace it with should provide the necessary restriction.

[trackcar]

Ive never understood the thermostat removal thing .. why would anyone deliberately prolong the warm-up period of their engine, and once warmed up (if ever) would they then not want to regulate that temperature properly? Makes no sense at all to me.

GreenV8S made me chuckle.

[blitzracing]

We have problems on the Ginetta's (RV8)with the temparature fluctuating between 85-95'. Im told this is due to steam pockets developing in the top of the head, that does not cause the thermostat to open untill the cooler water lower down gets warm enough to open the stat itself. The cure is to drill a 4-6mm hole in the very top of the 'stat to allow any steam to escape, so the water level on the stat is always as high as possible. Dont know if this is technically correct, but it solves the problem for sure. It may just be a problem on the Ginettas as the header tank is only just above the heads.

[spend]

trackcar said:

Ive never understood the thermostat removal thing .. why would anyone deliberately prolong the warm-up period of their engine, and once warmed up (if ever) would they then not want to regulate that temperature properly? Makes no sense at all to me.

GreenV8S made me chuckle.

You should think twice about where Peters stat is

Later RV8 arrangement with a nice flowing bypass (PRVT?) seems a much better idea to me

Dave

[trackcar]

blitzracing said:

We have problems on the Ginetta's (RV8)with the temparature fluctuating between 85-95'. Im told this is due to steam pockets developing in the top of the head, that does not cause the thermostat to open untill the cooler water lower down gets warm enough to open the stat itself. The cure is to drill a 4-6mm hole in the very top of the 'stat to allow any steam to escape, so the water level on the stat is always as high as possible. Dont know if this is technically correct, but it solves the problem for sure. It may just be a problem on the Ginettas as the header tank is only just above the heads.

I like the drilling holes idea .. I only drill a 3mm hole in the top of the RV8 stats though on road cars because if you go too big you cna run into overcooling in winter, it's surprising how little coolant flow is required to keep an engine temp down in winter on light cruise, also the hole provides an air-lock escape route to aid filling the system and also (i think) gives a more progressive first opening of the stat as you're bleding through warm water before the true stat operating temp is reached, so you eliminate the hot/cold/hot swing.

[GreenV8S]

Total stab in the dark, but are you thinking of doing something dodgy with an EWP? That's the only reason I can think of for removing the stat (and it's not a good one IMO).

[That Daddy]

trackcar said:

blitzracing said:

We have problems on the Ginetta's (RV8)with the temparature fluctuating between 85-95'. Im told this is due to steam pockets developing in the top of the head, that does not cause the thermostat to open untill the cooler water lower down gets warm enough to open the stat itself. The cure is to drill a 4-6mm hole in the very top of the 'stat to allow any steam to escape, so the water level on the stat is always as high as possible. Dont know if this is technically correct, but it solves the problem for sure. It may just be a problem on the Ginettas as the header tank is only just above the heads.

I like the drilling holes idea .. I only drill a 3mm hole in the top of the RV8 stats though on road cars because if you go too big you cna run into overcooling in winter, it's surprising how little coolant flow is required to keep an engine temp down in winter on light cruise, also the hole provides an air-lock escape route to aid filling the system and also (i think) gives a more progressive first opening of the stat as you're bleding through warm water before the true stat operating temp is reached, so you eliminate the hot/cold/hot swing.

Good point Trackcar,have been modding stats like this for years,works wonders for the Rover K series,that can be a bugger to bleed,your def right about that hole size 3mm seems a ideal compromise

[GreenV8S]

What would be ideal, of course, would be an entry stat with a full flow bypass. How on earth would you arrange that on an RV8 though?

[v8 racing]

On all our personal race cars we have run we have found the best arangement is to use a normal type stat then cut the centre out, with a standard stat in there even when open the stat does restrict high rpm water flow for sustained rpm, the only bummer was it took longer for the temperature to come up in the pits but worth it

[GreenV8S]

v8 racing said:

On all our personal race cars we have run we have found the best arangement is to use a normal type stat then cut the centre out, with a standard stat in there even when open the stat does restrict high rpm water flow for sustained rpm, the only bummer was it took longer for the temperature to come up in the pits but worth it

I'm very surprised to hear that from you. Wouldn't you prefer to have your engine temperatures stabilised and controlled? If you still have an unregulated bypass you're compromising the radiator flow too.

[v8 racing]

GreenV8S said:

v8 racing said:

On all our personal race cars we have run we have found the best arangement is to use a normal type stat then cut the centre out, with a standard stat in there even when open the stat does restrict high rpm water flow for sustained rpm, the only bummer was it took longer for the temperature to come up in the pits but worth it

I'm very surprised to hear that from you. Wouldn't you prefer to have your engine temperatures stabilised and controlled? If you still have an unregulated bypass you're compromising the radiator flow too.

Hi pete i totally agree with what you are saying about contolling and stabizing the temps, the problem is though most stats are designed for road cars not race cars, the problem was i wanted to run my water temps no higher than 75 deg for optimum performance, as it turned out it worked out very well, once the temps are around the 75 deg area they cant really plummet in a race car and i just controlled it on the fans, i am not saying it is right or to go and do this as it was a bit of a paine keeping your eyes on the gauges but it definetly worked, even when we ran the 74 stats the temp whilst racing we couldnt get below around 82 deg so the stat even when open is definetly a hinderance.

[trackcar]

v8 racing said:

GreenV8S said:

v8 racing said:

On all our personal race cars we have run we have found the best arangement is to use a normal type stat then cut the centre out, with a standard stat in there even when open the stat does restrict high rpm water flow for sustained rpm, the only bummer was it took longer for the temperature to come up in the pits but worth it

I'm very surprised to hear that from you. Wouldn't you prefer to have your engine temperatures stabilised and controlled? If you still have an unregulated bypass you're compromising the radiator flow too.

Hi pete i totally agree with what you are saying about contolling and stabizing the temps, the problem is though most stats are designed for road cars not race cars, the problem was i wanted to run my water temps no higher than 75 deg for optimum performance, as it turned out it worked out very well, once the temps are around the 75 deg area they cant really plummet in a race car and i just controlled it on the fans, i am not saying it is right or to go and do this as it was a bit of a paine keeping your eyes on the gauges but it definetly worked, even when we ran the 74 stats the temp whilst racing we couldnt get below around 82 deg so the stat even when open is definetly a hinderance.

I'm guessing that the outright coolant flow is also important in a race engine .. you could potentially control the temp on a 74deg stat if you have a massive radiator capable of getting rid of the heat, but if you're struggling with coolant flow rates through a small stat you may end up with an adverse temperature gradient through the engine from areas of high flow to areas of low flow typically around the back of cylinder heads ..

on a race engine keeping a high coolant flow rate to reduce that thermal gradient through the engine may be more benficial .. to that end I woud probably go with an very high flow external thermostat .. you could even machine a housing to take two thermostats side by side to double the flow through the controlling mechanism and still have a nominally 74degree operating temperature ?

[GreenV8S]

trackcar said:

on a race engine keeping a high coolant flow rate to reduce that thermal gradient through the engine may be more benficial .. to that end I woud probably go with an very high flow external thermostat

Hell, yes.

Land Rover PEM101020 does the job very well indeed, it's got a full flow bypass so oversizing the radiator doesn't kill the engine, the bypass shuts off when the stat opens so you get maximum possible flow through the rad when you need it, it has ample flow capacity and it just works. It's got quite a high opening temperature, but lower temperature versions are available including ones which have a significant ambient bias (control to a cooler temperature in hot conditions).

[Else]

[quote=trackcar
I like the drilling holes idea .. I only drill a 3mm hole in the top of the RV8 stats though on road cars because if you go too big you cna run into overcooling in winter, it's surprising how little coolant flow is required to keep an engine temp down in winter on light cruise, also the hole provides an air-lock escape route to aid filling the system and also (i think) gives a more progressive first opening of the stat as you're bleding through warm water before the true stat operating temp is reached, so you eliminate the hot/cold/hot swing.
[/quote]

Joo,
I have an 82 degree stat with a 3mm hole positioned at the top but the temp cycles from 70 to 90 on the guage with the heater on cold but stays at 80 with the heater on hot. I have never really worried about it, it doesn't seem cause any problems.
Am i right in saying that the heater circuit is acting as a bypass when open therefore smoothing out the hot/cold/hot swing that you mentioned above.
Should i be looking to fit a small bore pipe in parralel with the heater circut to cure the swing when the heater is off (on cold).

Andy

[Else]

Bumped back up to hopefully get Joo's attention

[trackcar]

I would have thought that was a good idea Andy, indeed teh ewedges had just such a by-pass for the heater circuit as std .. however i'm assuming that in realy hot weather when you need full flow through the rad you'd be diverting some of that through your heater bypass circuit so not gettting full cooling effect which may be more important of a large capacity engine like youve got .. GreenV8S has mentioned the land rover stat above which sounds like the perfect solution for all track orientated RV8 cars?

[Else]

Thanks Joo, i,ve Googled the part number and found several interesting articles on what it is and how it works.

http://wiki.seloc.org/a/Pressure_Relief_Remote_The...

http://www.mgfcar.de/epc/1166.htm

I'm going to be pulling the engine out over christmas for Rob to work some more magic on, i'll install one when its back in.

I'll be looking for another session on your rollers again, see if we can push old girl a bit higher

Andy

[GreenV8S]

Else said:

I'm going to be pulling the engine out over christmas for Rob to work some more magic on, i'll install one when its back in.

Thoroughly recommended. Which front cover are you using, and what bypass? In case you're interested, my installation has been given Bill's stamp of approval and is working well. Happy to talk it through with you if you want nearer the time.