Polishing head chambers. I didn't do it. What can happen?

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cardo0
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Polishing head chambers. I didn't do it. What can happen?

Post by cardo0 » Tue Jun 05, 2018 1:53 pm

I'm having some anxiety over my rough head chambers. Had the heads rebuilt - GEN II LT1 - kinda got the shine on cleaning up the chambers. My fault as I didn't have it written down in the work order. But argh! It's rouger than 60 grit sandpaper.

I wouldn't be able to polish the chambers myself and not hurt the new valve job. Considering taking it to same shop and see what they can do and for how much $$. Heads would need to be recleaned, maybe resurfaced and valve springs set up again.

Am I wasting money for this. Would 1 or 2 margaritas cure my anxiety?

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by Erland Cox » Tue Jun 05, 2018 1:57 pm

I cut chambers with burrs and leave them rough, I wouldn´t bother.

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by Powertrip » Tue Jun 05, 2018 2:42 pm

There are many pro's on here that have shared the benefits of a very rough chamber texture.
On the other hand, one of the japanese OEM's published a paper on the benefits of a polished chamber.

In your case, unless you are looking for that very last horsepower and have a way to verify the differences, don't worry about it. :!:
The price of progress is trouble.

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by statsystems » Tue Jun 05, 2018 3:03 pm

Run it.

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by mag2555 » Tue Jun 05, 2018 3:13 pm

You will have no issues until and if the motor starts to burn enough oil to make heavy enough carbon deposits that glow and then can possible light off the charge before the plug fires, and even then it's most commonly deposits on the spark plug that do the dirty deed!

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by sportsroof » Tue Jun 05, 2018 3:27 pm

Would 1 or 2 margaritas cure my anxiety?
No, but a few stiff whiskeys might. Works for me, just like the rough chamber finish.....Heh
Cheers, Martin

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by ProPower engines » Tue Jun 05, 2018 5:30 pm

Its no worse then a typical CNC chamber blend and that does not affect any performance.
the only thing bad I can see is if its a street warrior and the owner does a ton of slow driving carbon is more likely to hang onto the rough casting of the chamber then a fully polished chamber.

Other then that if the chamber volume is right for the build don't sweat it :D
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Re: Polishing head chambers. I didn't do it. What can happen?

Post by Circlotron » Tue Jun 05, 2018 7:06 pm

Rough chamber will have greater surface area so possibly greater unwanted heat transfer, but may also encourage boundary layer gases to stay put and therefore be a heat insulating layer. :?: :?: :?:

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by David Redszus » Tue Jun 05, 2018 8:16 pm

Circlotron wrote:
Tue Jun 05, 2018 7:06 pm
Rough chamber will have greater surface area so possibly greater unwanted heat transfer, but may also encourage boundary layer gases to stay put and therefore be a heat insulating layer. :?: :?: :?:
Your point is quite valid.
A rough surface has more surface area and will transfer heat at a faster rate than will a smooth surface.

Now the question becomes: do I want to shed combustion heat or retain the heat?
And when the rough surface becomes coated with carbon, what then?

And when the smooth surface becomes coated with carbon, what then?

Carbon sticks to everything.

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by statsystems » Tue Jun 05, 2018 8:17 pm

David Redszus wrote:
Tue Jun 05, 2018 8:16 pm
Circlotron wrote:
Tue Jun 05, 2018 7:06 pm
Rough chamber will have greater surface area so possibly greater unwanted heat transfer, but may also encourage boundary layer gases to stay put and therefore be a heat insulating layer. :?: :?: :?:
Your point is quite valid.
A rough surface has more surface area and will transfer heat at a faster rate than will a smooth surface.

Now the question becomes: do I want to shed combustion heat or retain the heat?
And when the rough surface becomes coated with carbon, what then?

And when the smooth surface becomes coated with carbon, what then?

Carbon sticks to everything.



It's always that damn what then that throws a monkey wrench in everything.

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by groberts101 » Tue Jun 05, 2018 8:19 pm

do an E85 conversion.. it'll stay a lot cleaner. :D

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by modok » Tue Jun 05, 2018 9:49 pm

It'll run better rough.
Why?
I don't really know, but it doesn't bother me. i don't know all kinds of things.
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Re: Polishing head chambers. I didn't do it. What can happen?

Post by cardo0 » Wed Jun 06, 2018 12:01 am

Thx for all the support. I'm mostly worried about detonation as temps get over 110*F here on freeway drives through the desert to work. Well WOT also to pass cars. Then there's midnight madness at the drag strip and we are now four lanes here at LVMS making for all the 1/4 mile passes I can handle. Now that I think of it I really don't have to make every run .

But a smooth chamber has gotta be further from detonation? Or am I thinking about this wrong? Higher compression, higher ambient temperature, and small surface edges to start detonation outside the flame front? Well ya know the stock EFI PCM does pull timing when knick counts get high. So it does self protect somewhat. But still that takes a lot'a power out of the motor and it's not doing what the rebuild is trying to do. Yep leaving some on the table.

Maybe a daily margarita will help.

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by modok » Wed Jun 06, 2018 6:54 am

cardo0 wrote:
Wed Jun 06, 2018 12:01 am


But a smooth chamber has gotta be further from detonation?
I've noted the opposite.
Glen Urban

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Re: Polishing head chambers. I didn't do it. What can happen?

Post by steve316 » Wed Jun 06, 2018 7:30 am

I'm with forget about it and it won't bother you

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