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

General engine tech -- Drag Racing to Circle Track

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

Post by 77cruiser » Wed Jun 06, 2018 7:45 am

It's a damned if you do & a damned if you don't, situation then. :o
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Re: Polishing head chambers. I didn't do it. What can happen?

Post by KnightEngines » Wed Jun 06, 2018 9:19 am

modok wrote:
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.
That made my evening. If I was drinking coffee it woulda come out my nose.

Bravo good sir.

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

Post by Erland Cox » Wed Jun 06, 2018 9:45 am

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.
Carbon is a good insulator.
Look at what happens when you first start up with new headers.

Erland

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

Post by DrillDawg » Wed Jun 06, 2018 9:51 am

Back in the day, LOL, I read that the Grump said that his car always ran better after a fresh engine had a good coat of combustion residue on the piston tops and chambers as it retained the heat. If you are worried about carbon buildup just spray some water in the carb and stream clean the chambers.
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Re: Polishing head chambers. I didn't do it. What can happen?

Post by cardo0 » Wed Jun 06, 2018 1:56 pm

Well I know the chamber surface was coated pretty good with carbon before head rebuild but I still got the expected 54cc - 55cc volumes. Thought about trying a spray on thermal barrier coating but the surface would still be like sandpaper anyways. I admit I really don't know but expect the carbon to become something of an ember and create detonation spots also. But with USB endoscopes/cameras cheap as dirt no reason I can take a look once in awhile. But what am I looking for? Carbon? Well it might verify if using water actually works if I get to try it.

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

Post by groberts101 » Wed Jun 06, 2018 5:57 pm

DrillDawg wrote:
Wed Jun 06, 2018 9:51 am
Back in the day, LOL, I read that the Grump said that his car always ran better after a fresh engine had a good coat of combustion residue on the piston tops and chambers as it retained the heat. If you are worried about carbon buildup just spray some water in the carb and stream clean the chambers.
That old mechanics trick work pretty well. Just can't get too crazy with quantity, severely bogging the motor at higher rpms, or you can scuff the bores.

And if the motor is really bad(old oil leakers) then you can start off with an overnight soaking of transmission fluid before the steam cleaning process. Lightly pour the fluid in while keeping rpm up enough to avoid stalling for about 20 seconds.. then raise rpm's to around 2,500 rpm or so pour fast enough to kill the motor and let er' sit overnight. Smoke's like a sum' bitch on startup but works better than I ever anticipated it would cause some of them old timers were well known to be plum full of poopoo! :D

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

Post by DrillDawg » Wed Jun 06, 2018 6:20 pm

If you have seen an engine that had been ran with a blown head gasket you would know it works. And if he would hammer down once in awhile it should clean it's self out. When using the the water just use a high idle and use a spray bottle, spray until the engine once to stumble and let it clear up before spraying more, just like anything else you have to do it right for what you are working on. They use to make a tune up in a can that you would pour in the carb just like you said and it would smoke for awhile.
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Re: Polishing head chambers. I didn't do it. What can happen?

Post by user-30563 » Wed Jun 06, 2018 6:39 pm

Nice! We have a few good men that support the burr finish. Some guy I know is smiling I'm sure.

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

Post by Carnut1 » Wed Jun 06, 2018 8:00 pm

IMG_7595.jpg
Part of DV seminar I was asked to give a very fast (45 min) intake , exhaust, and chamber port with easy to repeat techniques. So no measuring no fancy finishing. This is an EQ Vortec finished with my ancient 1/2" double cut burr driven with DV's Fordom grinder. I was told these were for a 355" hft motor, so they have min metal removed. Blow the pic up and you can see the rough burr finish I prefer on iron. Thanks, Charlie
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Re: Polishing head chambers. I didn't do it. What can happen?

Post by Carnut1 » Wed Jun 06, 2018 8:02 pm

So I am with the rough texture chamber camp.
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Re: Polishing head chambers. I didn't do it. What can happen?

Post by groberts101 » Wed Jun 06, 2018 8:13 pm

portinguy wrote:
Wed Jun 06, 2018 6:39 pm
Nice! We have a few good men that support the burr finish. Some guy I know is smiling I'm sure.
I've seen a few guys smiling around here. Does his name start with an L.. and end with arry?... or does it start with a C.. and end with had? :lol:

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

Post by John Wallace » Wed Jun 06, 2018 8:18 pm

Why not just run the heads and see what they do?
See what it runs at the track.
If not satisfied, then get it polished, and see what it runs.

Quite a few porters/people love the rough surface, makes more HP.

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

Post by groberts101 » Wed Jun 06, 2018 8:19 pm

So I have a question for the guys who prefer burred chambers.

Does this texture remain or maintain the same surface profile over time?

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

Post by statsystems » Wed Jun 06, 2018 8:25 pm

groberts101 wrote:
Wed Jun 06, 2018 8:19 pm
So I have a question for the guys who prefer burred chambers.

Does this texture remain or maintain the same surface profile over time?


I've never left a burr finish in the chamber because I can't do it well enough, so I don't know about the burr finish.

But I can tell you I've seen chambers that were CNC finished and eventual they smooth up.


BTW, there isn't much difference between an as cast chamber and a burr finished chamber. If the OP has an as cast finish in the chamber he should run it. If he has a smooth finish he should run it.

The OP is making a continent out of a flea turd.

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

Post by modok » Wed Jun 06, 2018 9:08 pm

And bead blast the piston tops too.
Glen Urban

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