uprated head gasket

[caterhamnut]

had some really helpful advice from people for questions I have had on where/who/what regarding the fixing of a blown head gasket on our 1.6k supersport, and possible associated nasties. Uprated head gasket has been mentioned a few times. Any opinions? Worth it? (car is used mainly on the road, occasional track day)Where can I order one? What is differance to original equipment gasket?

thanks

[murph7355]

I'm saying nothing.

[oilyhands]

The latest Rover gasket is an improvement over the original although Rover arent specific about the improved areas, the plastic dowels have also been repalced by steel. The two uprated gaskets IU am aware of are the one from Mike Satur (this has a single piece rolled fire ring) which appears to be reliable and is reasonably priced and the multi-layer steel gasket from Raceline which costs around £200. The Raceline gasket being steel will require the liner height above the block to be consistent and around 3-5 thou

 

Oily

[Rob Walker]

Oily, one other improvement I noticed on the Satur gasket is the rubber seals are bonded through the metal. If you hold the gasket up to a light you will see little red spots of light indicating this. The stock Rover has the rubber seals simply bonded to the metal and hence why these seals have been known to move and fail on hot engines.

 

 

 

Rob

[oilyhands]

Thanks Rob, I hadnt spotted that.. it certainly can help the wayward rubber seals from going AWOL.

 

Oily

[Peter Carmichael]

Last time I looked, the Mike Satur ones were cheaper than OE.

 

I don't think there are weaknesses in the head gasket per se, but poor temperature management causes problems. I think Caterham's cooling pack for the k-series is pretty suspect and a lot of it must come down to simple things like the temperature switches in the radiators that don't work and post shutdown heat soak. YMMV

[Jason Plato]

If the repeated failier of k series head gaskets was due to caterham's temperature mangement , then every K caterham would pop its top .

 

Faulty switches can and will occur on any model .

 

Which head gasket did your engine builder install/ reccomend Peter ???

 

I have all my fingers and toes crossed as I write this ....

 

Dave

[Peter Carmichael]

All the k-series head gasket failures that I have witnessed have all been initiated by causes other than the head gasket. When the head has eroded beneath the compression ring, the water jacket pressurises and the rubber bits don't stand a chance - this is typical with track use and a dodgy mix of coolant.

 

On the 250bhp engine I am using a standard head gasket - and Comma Coldstream with a 72 degree thermostat. When I shut down, even after a good slowdown period I can hear the coolant boiling off in the head - very bad news and why I will be arranging an electric water pump purely so I can keep some coolant flow on shutdown.

 

Last year I used a Mike Satur gasket, but I didn't do enough miles to prove anything conclusive about it. It never went on track.

 

The Raceline gasket didn't like the amount of liner protrusion that I had so leaked coolant all around the block. It had to come out to be replaced with the standard gasket.

 

FWIW, I reckon with a decent cooling package the standard gasket will be fine at 250bhp. In choosing to run the standard gasket I have had input from Dave Andrews and Roger King, but really a head gasket that lives for the lifetime of an MGF or Rover 200 does not have a problem. Some of the blame has to lie with the installation and that could have a lot to do with the size, shape and flow resistance of the Caterham radiator. Cooling is a reasonably complex problem to model, with non-linear components such as thermostats. If the radiator cools *too effectively* at low flow rates, the return water will be cold enough to close the thermostat. The k runs a standard thermostat that opens at 88 degrees. That a motorsport tuned R500 engine can hold stable temperatures 15 degrees lower with a 72 degree theremostat shows that the radiator itself has a lot of cooling capability and suggests that with the standard thermostat the temperature is pinned down to the smallest openings of the thermostat. Blanking off some area of the radiator might make a lot of sense even for standard and supersport k's. Kepp blanking it off until the temperature can't be kept in a proper operating range.

 

Oh, and I am seeing *a lot* of higher mileage k-series caterhams with head erosion problems. Hands up Andy Turnbull and Angus&Tessa plus my own supersport engine from a year and a bit ago. 30,000 miles seems to be a lot if you mix in some hard track use.

[MrTrilby]

Peter, I'm interested in your comment "the radiator itself has a lot of cooling capability". Are you talking here about the ali radiator as fitted to a Superlight, or the triple bypass radiator?

 

I'm curious because I've been talking a lot with Andy Turnball about the merits of fitting of a 72 degree stat and triple bypass radiator. My car is used mainly on track.

 

Your comment about temperature stability... I have an 88 degree stat at the moment, and the fan is wired to run continuously since I am bored with replacing thermoswitches. According to my gauge the temperature climbs to "normal temperature" and is then pretty solid with no wobbles, only climbing a bit if I come to rest in a queue after a stretch of hard driving. Is running the fan continously a bad idea in your opinion given your comments on the potential for the radiator return to close the thermostat?

[Jason Plato]

Mr trilby ,

If you are not suffering temperature problems at present then why would you want to uprate the cooling system ?.

Try running with the fan turned off to determine if this has any detrimental effect .

 

All tests should be based upon a 30C day on the track , if this is where the majority of your driving is done .

 

OR , take the thermostat out if one believes this could be staying shut due to water return - of which I have never seen any evidence ?? .

 

Dave

 

 

[MrTrilby]

It depends what you mean by a temperature problem though doesn't it? There's plenty of discussion on Blatchat to suggest that running an 88 degree stat on track days is a problem in itself. I won't know if I have a problem until my head gasket fails, and I'm keen to avoid that conclusion.

 

I've been forced to try running with no thermostat before when it failed coming back from a track day at Anglesey. It's impossible to get the oil and water up to temperature at road speeds, and thermal stability of the engine must be awful with nothing other than airspeed through the radiator controlling water temperature.

 

I really wish the majority of my driving was done at 30C on tracks ;-)

 

 

[Peter Carmichael]

Dave,

 

Running without a thermostat is a *bad idea* unless you can guarantee that the revs are up and the throttle is always open. If you run on the road, the engine will experience quite severe thermal gradients at traffic speeds (~20mph, reasonable airflow, very low heat dump). Remember that you only have one water temperature sender - if you had two, showing the inlet and outlet temperature, you would see quite large differences.

 

Mr Trilby

 

I have run a Supersport engine using both the original small copper radiator and the large race alloy radiator. Both maintain the temperatures very closely pinned to the thermostat opening temperature when running and cope very well when the fan comes on in traffic (if the fan comes on). With 250bhp and a 72 degree thermostat, the large radiator still keeps the temperatures pinned down at the point where the thermostat is just opening - with 16 degrees less temperature difference to ambient, and much more reject heat the radiator copes fine. Therefore the radiator has bucketloads of cooling capability.

 

Cooling is more involved than just keeping your temperatures steady. Cooling is all about the dynamics when different amounts of heat are dumped into the system. I am going to experiment by progressively blocking off the airflow through the radiator until I start to see some temperature rise. Having too much cooling is not a good thing. You have to keep that thermostat open to avoid thermal shocks. A thermostat on the exit side of the engine is a much better idea than the k-series arrangement.

[julians]

How about drilling a small hole in the thermostat so that a small amount of water is always flowing through it, would that not minimise thermal shock.

[Jason Plato]

Peter ,

You could fit a remote Elise thermostat or the adjustable thermostat from Europa spares .

 

Dave

[PAUL MARRIOTT]

Has anybody ever fitted an electric water pump to a k series?

[Peter Carmichael]

Jason Krebs has one on his R500. I am going to be installing one soon, but my installation will be rather different to the Davies Craig EWP recommended installation because I will be retaining the thermostat.

 

The main aim is to arrange some extra cooling after shutdown, but I am also interested in auditing all the cooling system functionality.

[Peter Carmichael]

Holes in thermostats have funny effects that are not always clearly understood by the people who drill holes.

 

Because you now have a bypass, the mixed water temperature will be lower and the thermostat will stay closed longer. Indeed, at any given temperature, the thermostat will be more closed - not necessarily the desired result.