Coolant is distilled water and a bottle of Water Wetter.

Rob, in addition to your suggestions I am looking for adding oil cooler as a minimum, possibly different radiator too. I have done several steps towards cooler engine and after 20 minutes of full blast the car still needs to have a break (short shifting and modulating gas for a lap) and then it is fine again.

Maybe IC is heatsoaking and causing slight pinging and thus heating the engine further?

hrk

Is the head gasket swapped?

I don't know how the emagange works- but most engine management will retard timing if air temps get elevated to prevent detonation. That can ultimately cause the combustion cycle to complete post cylinder- overheating the exhaust manifold and turbine. So then you have an extra hot turbo elevating oil (and coolant) temps.

I think your radiator is adequate. It may not have the frontal area but it definitely has the capacity, plus it's cross flow and a true double row.

A datalog would tell wonders when trying to figure out the state of the engine when it's getting hot.

I have a datalog but it mostly records my mistakes, not car events.
Speed, Throttle, AFR, RPM etc are things which I could read from DL-1 log.

I had it on but I have not looked into it yet. AFR info might help a bit.
Emanage should log too, but for some reason I never managed to log anything unless I had pc connected to it.

I am oogling monster radiator just to rule out that side, like this:
http://cgi.ebay.com/ebaymotors/ws/eB...MEWA:IT&ih=017

hrk

that's a very nice double pass rad - that's where your turbo needs it's coolant from, fittings are waiting for it. :D

Logging is preferred, but an oil temp gauge is a minimum if you're running a turbo IMO. Was the head gasket/compression issue from overheating?

Don't know if overheating was the reason for low compression numbers. Car ran ok but warm until redflag, stopping made it overheat despite fan and I presume that is when compression was lost on those two cylinders because it was hard to get started again.

hrk

Quick update.
Compression 160,90,60 and 180. Leakdown showed leakage from cylinders 2 and 3 through exhaust valve, and the leak appeared to occur in valves by each other in the middle of the head.

Pulled the head out and found no crack or nothing visible under first look. Rotated exhaust cam and these two suspectible valves moved slightly sideways just when they were closing, just like if the guides were worn.

Strange co-incidence that guides wore out just at the same time as motor overheated.
Any similar experiences or ideas what to look for once I pull the valves out?
hrk

I have a buddy who had a retainer breack on him on his ca18 recently, he only noticed this after rebuilding his head :rofl: so check those as well.

Colin's original cylinder head that had the greddy on it, had bad guide wear and it got hot too. :dunno: Have you pulled the valves?

Interesting observation.

No, I haven't had a chance to remove the valves yet to confirm whether guides are actually worn.

Assuming my version of coolant rerouting works or the water is not there anymore to cool things down, and the exhaust valve area between 2 and 3 cylinders becomes hottest point, would it be possible that guide would expand thermally and start touching the shaft of valve and have premature wear? Once it is worn enough it might not allow valve to seat perfectly.

hrk

I'd say "yes, that makes sense" - but I'm no engine builder. I don't think there's any denying that excessive heat (whether a little or a lot) is going to accelerate wear. No doubt heat is going to reduce tolerances- usually managed by your high dollar synth oil. But if your guides are getting oiled then you've got other problems. ;) If you don't have any time invested in this head then I'd just swap- being sure to check that on the other head. Unless you have the time to start swapping guides.

We had no idea Colin's guides were in such bad shape until the engine builder showed us the excessive tolerance. That was a 60k head. Half of the mileage was "little old lady", the majority of the rest was greddy miles with a small part (maybe 6 race weekends and two turbo'd track days) being a portion. If the overheating caused the problem, then I'm sure racing on it just continued the wear. The head we ended up using had 160k on it with rare oil changes, yet was mildly driven and the guides were perfect.

I have been plugging away to get better cooling capacity for my 7 to better cope with occasional redflag situation on the track, and this is what I'll try this year:
close front view
http://russmarshall.com/d/19613-1/P3110001.JPG

top view
http://russmarshall.com/d/19620-1/P3110003.JPG

bare intercooler from rear
http://russmarshall.com/d/19628-1/P3110005.JPG

Oil cooler will be on drivers left and intercooler close to intake at drivers right side. I hope I can finish some sort of sidepods to guide air and protect coolers a bit from stones from front tires before the weekend at Road Atlanta. Pod frames are made from electric conduit and will be covered with sheeting aluminum.

New pipes seem to flow better, dyno last weekend showed 192 hp at 5800 rpm with only 7 psi of boost, but AFR was 13:1 and testing was aborted. In previous configuration with smaller intercooler and otherwise similar configuration I had 12.5 AFR:s. It was free baseline only so no adjustments were allowed, I'll see if I get to go there before weekend to verify my 10% adjustment on the fuel.
THe motor is just another junkyard one with supposedly 90 000 miles, I want to sort out the auxiliaries before spending any money to the engine.

hrk

fuck, wrong thread.

I think that's going to work... I don't see how it can't. Of course you'll have some new air to break through now. :D

Well, eventually the rollcage and rear tires would break through the same air so no additional fronta area has been added. More internal resistance and turbulence for sure, but now all coolers have their own inlets and outlets.

hrk

Something that I've seen turbo locosts get away with (overheating-wise) is to mount an intercooler from the sierra or escort coswortch in front of the aeroscreen. It doesnt look very good, but works (the cosworth ic is about 4(d)*4(h)*20(w) inches).
Seems like turbo locosts typically get overheating problems due to fitting rad+oilcooler+ic in that narrow nose cone.

Your sollution with placin the rad in rear sounds even better though, but is a bit more work.

too bad about the valveguides, what coolant reroute do you run?

The coolant 'reroute' in my case is connecting the rear outlet of the head into radiator inlet instead of recirculating hot water back to engine. See
http://russmarshall.com/d/19617-1/P3110002.JPG
And under the temporary location for airfilter, one can see where 3/4" hose connects to metal part of upper radiator hose. At the engine end there is place for mechanical water temp gauge.

hrk