Thermostats HG's and other woes

[wild bill]

☹️ I've searched Techtalk but need an answer to a couple of questions which i can't satisfy with the search.

 

I need to order a new thermostat (the old one has been discarded) and have been reccomended a 72 degree stat as i am running 1.8 k series with throttlebodies and vhpd head along with emerald ecu.

 

Millwood only do a 82 or 88 so did i mishear the advice or is there a 72 and is it worth fitting .

 

Question 2 relates to my post of a week ago re Broken 7. AA man reckoned that car had got hot due to stuck thermo and then this had caused head gasket issues however i am a bit mystified as

 

a) The headgasket had only recently been replaced with a more robust version than the standard Rover one

b) The guage seemed to work absolutely fine and the car did not go anywhere near the red before i stopped

 

What is the point of the guage if it doesn't prevent these kind of issues don't technically get this

 

Any comments welcome

 

Rob Walker or Paul Jacobs any suggestions gratefully received

[Shaun_E]

There is a 74 degree stat (used on the R500?) and a number of people run with this but personally I think this will make your car run too cool. I am actually having trouble getting my car to run warm enough with an 82 degree stat. I have a 227bhp K series and cooling doesn't seem to be an issue. I think it would be more important to make sure you have a reliable fan switch with manual override or use the Emerald to switch the fan on and off via a relay (which is how mine is set up) . That way on the occasions when you are sat in traffic or the pit lane, the fan operates effectively and keeps the temperature under control.

IMHO the paranoia about K series head gasket failure leads to people trying to make their car run very cool when in reality all you want to do is stop it overheating (by which I mean keep it below 100 degrees or so). I believe that HGF can be caused by local overheating i.e. airlocks so there is perhaps some mileage in overcooling an engine but if you get rid of airlocks and watch your temperature gauge then it won't be overheating that causes HGF. It is my understanding that a lot of HGF is due to incorrect liner heights and the fire rings getting damaged - but I'm no expert on this just read a lot on the subject.

My previous 1.6SS engine regularly got over 100 degrees in traffic and on track and when the engine died it wasn't through HGF (big end bearing failure probably due to blocked dry sump oil pickup).

 

Yellow SL #32

[wild bill]

Thanks Shaun for the info The bit on liner heights is of note as i recall Rob mentioning something of that nature so i'll give him a buzz. Car runs with a manual fan switch and has been fine temp wise until now

[Dave McCulloch]

When I built my 210bhp 1900 K series, I initially fitted a 74 degree stat - but I had trouble getting the engine up to a decent temp, and the air out of the heater (yeah, wimp I know!) wasn't warm enough to keep me warm. So I've reverted to 82 degree and I'm happy again now - and so is the engine - it sits dead on 80.

 

Dave

[old captain slow]

I think most of the issues around blown head gaskets are to do with giving the engine beans before it's warmed up. The thermostat is in the water return rail as a green measure introduced by Rover to get the engine hot quickly as a metro car. If you ask for horses too quickly on a cold engine the small amount of water in the head can boil and Bob's your uncle - blown head gasket.

 

So I have read and it seems plausible.

 

C7 CDW

[MAK]

I too was worried about temps and the potential for K Series to overheat.

 

I fitted the low temp thermostat, which is avialable from Caterham or Minister for R500.

 

I then gave up on the CC temp gauge and sensor and replaced with a dual temp gauge (oil/Water)from SPA and found that in Feb/March the oil temp would not get above 45 deg C. 50 deg C is supposed to be the minimum.

 

I have resorted to standard thermostat and all is well.

 

I think a lot of these Temp problems are more to do with the quality of the instruments which have a very poor resolution (90 deg swept arc full range) and poor sensors.

 

With SPA/ or similar for Temps you may find you have no problem.

 

I would also consider changing the instrument/sensor for Oil pressure- to a mechanical set-up which is avialable from Think Automotive, or use SPA .

 

MAK

 

 

[wild bill]

thanks for all the comments, very much in line with my thoughts having spoken to Rob walker. Im putting an 82 thermostat in and not writing off HG as this was only recently replaced with a competition gasket and very carefully put back together so other options first. Will let you know the results

 

Bill