Thermostat Location

[Ric H]

I've just been thinking about pitfalls resulting from placing engines designed for FWD cars into mid-mount positions. In particular the potential problem of late thermostat opening as a result of the long cooling pipe runs, or even the opening and then prompt re-closing of the thermostat as it is hit with cold water from the radiator. This is a known problem with the K series in the elise and MGF for example, which can suffer high thermal stress in the engine and blown head gaskets, annealed heads, etc. Rover solved this with a thermostat which opened with pressure as well as temp (i.e. opened at high revs). Does anyone know of any similar problems with the honda K20A? Afterall we have the same layout with the thermostat on the cold return line - great for quick warmup in a front engine layout but not really intended for mid-mount where the "system" coolant capacity is probably a lot higher than the engine capacity.

Discussion of the issue in Rovers here:
http://www.lame-delegation.de/mgf-ne...ystem_Mods.htm

I don't really want to risk screwing up the head so I'm considering working up a remote thermostat arrangement near the head outlet of my honda to replace the existing inlet thermostat. Anyone have any thoughts or done anything similar?

Richard

[craig]

Rich, Honda's dont suffer from this at all and all the honda elises have never suffered from this, but yes it is renowned in the rover k-series.
Not quite sure how you are going to run your car ie marlin black box @400+ which overcomes immobiliser or hondata at only 735 but you can control the fan with the hondata at any temp you want!

I have not tried this yet but John has and tells me that you can change parameters to have fan on all the time if youn choose too!

I have spoke too many honda elise owners and they all tell me that it never gets above about 90c on track or static and they have a much smaller engine bay with guard

If you wish you can search in seloc as it is covered extensively

[Ric H]

Great stuff, thanks Craig. One less thing to worry about!

On further investigation I think it might have something to do with the larger bypass in the k20 than the rover k series. Afterall, the Rover fix (as recommended on e.g freelanders and mgfs) seems to primarily serve to increase the bypass flow.

I am using the K-Pro rather than marlin's box - essentially it seemed like paying £400 for *nothing*, or the extra £350 for a very flexible ECU - plus I save on the fan switch etc as I am using the k-pro for the fan as you mentioned.

Richard

[alackofspeed]

Richard,

It seems CPL are the way to go for Hondata mod - done by return!

The fan control works perfectly, and much to my surprise, the rover fan shifts a surprising amount of air - I thought it'd be a bit limp!

The software seems to work quite well, and if you have the engine running just above idle, most changes are done suficiently quickly that the engine doesn't stop during the upload. The only problem I've had is with the logging being a touch flakey - there is a new version of the software out now though, which isn't on the laptop I was using.

The ability to check all the sensor outputs is quite reassuring, and useful for fault finding.

As for temperature, left running in about 22 C ambient (using the IAT sender for the reading), my engine crests about 90 C when left to idle. Coolant volume for my setup, not including the heater matrix circuit, is about 8 litres.

From my casual browsing of the K20A forum, it seems the K20A2 is a pretty tough unit, and I've not read of any instance of thermostat related issues. I guess with the K-series things aren't helped by the very low coolant jacket volume?

I wonder if you, Jerry, and Craig could get a better deal on the shafts by joining forces? Doubtful, but maybe worth a punt.

Cheers,

John.