At the final round a few weeks ago, I was heading back to the pits and overheated the Hooptie. Pegged my temp gauge at 250 rolling up the trailer.

Friday I pulled the thermostat housing and did a spectacular flush of the block and head. Had stuff the consistency of mud coming out for a while. One of the drawbacks of running straight water to appease some tracks. Since Woodburn allows street cars to run antifreeze these days, I'm going to load the car back up with anti-freeze to keep the corrosion down from here on out. The block fill comes up to within two or three inches of the deck. It's been like that since I built it in 2007.

The car is pretty much a track only vehicle, so, since my time slip likes between 150 and 175 degree F starting line temperatures, I opted for a 160 degree F stat. The amount of advance I carry is a bit higher than it was back in the stock configuration. 16 initial, 28 all in. Tip in is at 1400 rpm, and it's all in at 2600 rpm, flash. Stall is 2500.

Our first test was to run the car in Neutral, and heat it, cooling fan off. When the temperature hit 200, I dropped the engine rpm back from 2000 - 3000 to an 800 rpm idle and turned the fan on. The temperature peaked at 205, then slowly dropped back to 200. Cool day sitting on the trailer. It steadfastly refused to drop back under 200. I may need to widen the advance to pull more timing out under 1400 rpm. It's all adjustable with the Mallory Unilite.

I hadn't had temperature problems until the last four or five years, around the time of the Erson 280 cam, and the other lumpier OCG, I'm getting a lot more cylinder fill, so more heat off idle. I need to install a new O2 sensor. The leaded race gas killed the one that's in there. I know I"m lean of peak based on how the ET behaves when ambient temperature goes up. If I can get it a bit closer to stoich, and pull a bit of timing out, off throttle, it should recover more quickly. The stat is flowing full right about 165. I need to source a better electric fan too.

Thoughts? Am I heading down any obvious rabbit holes? This is a stroked long rod, so it loves it some timing.

CJ

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Part of Tyrde-Browne Racing

I didn't see you mention the radiator.
If the block was full of sludge, there's a good chance some of the tubes are clogged as well.
A radiator might still 'flow' okay but be far from peak efficiency with enough internal blockage.
At idle the advance and mixture shouldn't be a big problem, but the pump is turning slowly which means even less flow through the rad.

Sometimes you can spot cool areas on a hot rad using an IR thermometer, but it isn't foolproof.
Depending on what you have in there, maybe it's a good time to upgrade anyway.

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O==\=/==O

"A mechanic is Somebody."
- Jim Preston

I agree with Joe on checking the radiator. I can't see any of the other stuff being enough to give you that trouble. Maybe stuck-closed tstat, but it seems you checked that. Any chance there is water getting in the oil or vice versa?

Lou

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Home of Slant6-powered fun machines

I have a very good OE electric fan that's been taking up space for years. I've been getting down the valley a bit for work so I'll detour to drop by.

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Joshua

Forgot to include, full flow and backflow flush on radiator. It's a happy camper.

Be interested in that fan Josh. I don't know what the fan came off that I'm using, but it's only good for five or so tubes of the drop.

CJ

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Part of Tyrde-Browne Racing