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> broken cylinder fin - will it effect cooling ?
jimkelly
post Nov 23 2011, 10:02 AM
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bigkensteele
post Nov 23 2011, 10:16 AM
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Not enough to worry about. If they are new, you could run it on 2 or 4, closest to the fan under the assumption that those get more air flow. Not sure if that is a correct assumption, but someone will surely correct me if I am wrong.
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sean_v8_914
post Nov 23 2011, 10:16 AM
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I would run it. I would measure roundness to ensure that the fin snapping impact did not bother the cylinder.

one could speculate that there could be a modified heat path albeit far too small to measure by conventional means. it would be fun to have access to a lab and all the measuring equipment required to quantify this. I could also speculate that this cylinder would have to be pushed right up to the edge of heat soak to really see a cause and effect. I think DR Porsche estimated about 50hp each was as hard as he would push cast iron safely so maybe if your engine was pushin 250 hp + that fin might matter.
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jimkelly
post Nov 23 2011, 10:18 AM
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#3 runs the most hot - i hear - so - your suggestion makes sense.

thanks
jim
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sean_v8_914
post Nov 23 2011, 10:19 AM
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Jake Raby did data collection on individual cylinder temps with various cooling systems. parameters are too complicated to calc. I would live to read his data
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Jake Raby
post Nov 23 2011, 10:25 AM
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While one fin does make up some surface area loss its not going to be measurable.
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sean_v8_914
post Nov 23 2011, 10:29 AM
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wouldn't you like to have the time and equipment to measure the heat paths?
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Jake Raby
post Nov 23 2011, 10:36 AM
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QUOTE(sean_v8_914 @ Nov 23 2011, 09:29 AM) *

wouldn't you like to have the time and equipment to measure the heat paths?


If it really mattered. At 200HP and even beyond we cool engines with iron cylinders and stock cooling systems without any issues and CHT values COOLER than a stock 2.0 using the same cooling system. Above that output no one has the money to buy the engines; so it really doesn't matter. The crazy ones we do today are just done for fun and these days I am retaining all of those and not even trying to sell them. Its just away to blister the competitors balls.

With the component quality degradation that we have seen in the last two years, it'll be impossible for us to continue building high quality engines at any sane price level after 2015, and it might even occur sooner than that.

My data logging system can measure 32 CHT/OT channels and I have used it to measure CHT and CT on the same engine with 4 sensors on each cylinder. What I learned was critical to the development of engine combinations (that don't generate heat), but not so much critical to the development of cooling systems.
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sean_v8_914
post Nov 23 2011, 10:48 AM
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does the stock type 4 cooling system have a hot cylinder or does it cool fairly even?
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Jake Raby
post Nov 23 2011, 10:53 AM
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QUOTE(sean_v8_914 @ Nov 23 2011, 09:48 AM) *

does the stock type 4 cooling system have a hot cylinder or does it cool fairly even?


An entire hot bank of cylinders, due to the tangential flow of air produced by the clockwise rotating cooling fan. It can be overcome and with the right combination it can be reduced.

This post has been edited by Jake Raby: Nov 23 2011, 10:53 AM
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JDW914
post Nov 23 2011, 01:46 PM
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I glued one on with J-B Weld a couple weeks ago. The engine is still sitting behind the car while we're waiting on other parts so I can't tell you whether the fix worked. It seems to be well attached and the joint is tight.
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LotusJoe
post Nov 23 2011, 02:34 PM
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QUOTE(Jake Raby @ Nov 23 2011, 08:25 AM) *

While one fin does make up some surface area loss its not going to be measurable.

(IMG:style_emoticons/default/agree.gif) It doesn't matter where you put it.
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BajaXJ92
post Nov 23 2011, 05:13 PM
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QUOTE(JDW914 @ Nov 23 2011, 02:46 PM) *

I glued one on with J-B Weld a couple weeks ago. The engine is still sitting behind the car while we're waiting on other parts so I can't tell you whether the fix worked. It seems to be well attached and the joint is tight.


Make sure you register your VIN in the database.

It's really REALLY helpful to future owners.
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jsayre914
post Nov 23 2011, 05:18 PM
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QUOTE(BajaXJ92 @ Nov 23 2011, 06:13 PM) *

QUOTE(JDW914 @ Nov 23 2011, 02:46 PM) *

I glued one on with J-B Weld a couple weeks ago. The engine is still sitting behind the car while we're waiting on other parts so I can't tell you whether the fix worked. It seems to be well attached and the joint is tight.


Make sure you register your VIN in the database.

It's really REALLY helpful to future owners.

(IMG:style_emoticons/default/laugh.gif)
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orange914
post Nov 23 2011, 05:44 PM
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QUOTE(BajaXJ92 @ Nov 23 2011, 03:13 PM) *

QUOTE(JDW914 @ Nov 23 2011, 02:46 PM) *

I glued one on with J-B Weld a couple weeks ago. The engine is still sitting behind the car while we're waiting on other parts so I can't tell you whether the fix worked. It seems to be well attached and the joint is tight.


Make sure you register your VIN in the database.

It's really REALLY helpful to future owners.

JDW914 stands for J D BWELD 914
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