Bore colour

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CRS
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Bore colour

Post by CRS » Sun Oct 14, 2018 8:02 pm

The photo below is from a wet sleeve V6, large twin turbos, heavily boosted.
overheated bore.png
All bores have colour in them at the top.

I have not seen this before, how common is this?

Coolant temp was stable, I believe the heat couldn't get to the coolant, possibly due to liner thickness.

Thanks for you comments.
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travis
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Re: Bore colour

Post by travis » Sun Oct 14, 2018 8:18 pm

What are you using for fuel?

CRS
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Re: Bore colour

Post by CRS » Sun Oct 14, 2018 8:26 pm

Sorry, the fuel is Methanol.

Tuner
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Re: Bore colour

Post by Tuner » Mon Oct 15, 2018 1:34 am

CRS wrote:
Sun Oct 14, 2018 8:02 pm
The photo below is from a wet sleeve V6, large twin turbos, heavily boosted.

overheated bore.png

All bores have colour in them at the top.

I have not seen this before, how common is this?

Coolant temp was stable, I believe the heat couldn't get to the coolant, possibly due to liner thickness.

Thanks for you comments.
Image
From Wikipedia
Image
Differentially tempered steel. The various colors produced indicate the temperature to which the steel was heated. Light-straw indicates 204 °C (399 °F) and light blue indicates 337 °C (639 °F).[1][2]
Image
https://en.wikipedia.org/wiki/Tempering_(metallurgy)

I've seen an engine color the bore when it was run 15-20 laps or so on a 1/4 mi. oval with no water, the oil cooler was the only radiator, so the oil was the only source of engine cooling. The bore was more or less normal looking were the piston skirts could transfer heat to the oil, but the part of the bore wall that did not have oil film contact with the pistons was straw and blue color. The car was leading the race and got a bull-ring nose bleed on the back of a lapped car and lost the water. The driver is the kind of guy who finishes first and third in a masturbation contest, so he wasn't about to quit just because the temp gauge went up, besides, it came back down (when there was no water left at all).

It may be the water is boiling and forming a vapor barrier on the outside of the sleeves. Is the cooling system sufficiently pressurized to raise the boiling point, 30 PSI pressure cap or ? https://www.speedwaymotors.com/Stant-10 ... gKTSPD_BwE The boiling point will increase by about 3F for each pound of increase in pressure.

mag2555
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Re: Bore colour

Post by mag2555 » Mon Oct 15, 2018 6:23 am

If you are not you should be running Evans brand coolant.

If the coolant your running is boiling in localized area's then no heat transfer is taking place.

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MadBill
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Re: Bore colour

Post by MadBill » Mon Oct 15, 2018 6:16 pm

It's odd that the color is only below the top ring land position... :-k
(Unless the color boundary is at the transition from jacket to deck, which would support Tuner's assessment.)
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

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