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Protecting valve seats when porting.

General engine tech -- Drag Racing to Circle Track

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Krooser
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Re: Protecting valve seats when porting.

Post by Krooser »

Well I fired up my electric grinder a couple nights ago and was just going to try a few seconds of grinding to see how tuff porting can be without a speed control.

I installed a 1/4x4" carbide in the chuck, hit the on button and just barely touched a scrap head. The damn thing grabbed the carbide, ripped it off the shaft, bent the shaft 90 degrees and left me holding a seriously out of control grinder!

I'm lucky I still have a hand. Wow.

Got out an air grinder and that was controllable but my hand was so beat up I went to bed.

Speed control is now on my list...
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Re: Protecting valve seats when porting.

Post by mt-engines »

Krooser wrote: Sat Dec 12, 2020 5:36 pm Well I fired up my electric grinder a couple nights ago and was just going to try a few seconds of grinding to see how tuff porting can be without a speed control.

I installed a 1/4x4" carbide in the chuck, hit the on button and just barely touched a scrap head. The damn thing grabbed the carbide, ripped it off the shaft, bent the shaft 90 degrees and left me holding a seriously out of control grinder!

I'm lucky I still have a hand. Wow.

Got out an air grinder and that was controllable but my hand was so beat up I went to bed.

Speed control is now on my list...
Cheap or bent carbides will do that. I use a foot control to vary speed.
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Re: Protecting valve seats when porting.

Post by steve cowan »

Krooser wrote: Sat Dec 12, 2020 5:36 pm Well I fired up my electric grinder a couple nights ago and was just going to try a few seconds of grinding to see how tuff porting can be without a speed control.

I installed a 1/4x4" carbide in the chuck, hit the on button and just barely touched a scrap head. The damn thing grabbed the carbide, ripped it off the shaft, bent the shaft 90 degrees and left me holding a seriously out of control grinder!

I'm lucky I still have a hand. Wow.

Got out an air grinder and that was controllable but my hand was so beat up I went to bed.

Speed control is now on my list...
I learnt fast that burr quality is important as well.
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Re: Protecting valve seats when porting.

Post by FC-Pilot »

mt-engines wrote: Sat Dec 12, 2020 6:03 pm
Krooser wrote: Sat Dec 12, 2020 5:36 pm Well I fired up my electric grinder a couple nights ago and was just going to try a few seconds of grinding to see how tuff porting can be without a speed control.

I installed a 1/4x4" carbide in the chuck, hit the on button and just barely touched a scrap head. The damn thing grabbed the carbide, ripped it off the shaft, bent the shaft 90 degrees and left me holding a seriously out of control grinder!

I'm lucky I still have a hand. Wow.

Got out an air grinder and that was controllable but my hand was so beat up I went to bed.

Speed control is now on my list...
Cheap or bent carbides will do that. I use a foot control to vary speed.
I also use a foot controller to control the speed. It is great for safety as well as control. Now if I only knew what I was doing when I was grinding. 😝

Paul
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Re: Protecting valve seats when porting.

Post by Krooser »

Well I was eyeing the foot contoller ony wifes Kenmore sewing machine until she pulled it out and actually used it for the first time in years....

On to plan B
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Re: Protecting valve seats when porting.

Post by BradH »

Plan B can include an inexpensive light dimmer switch or a Harbor Freight (or equivalent) router motor control. You don't get the simplicity of being able to change the speed w/ your foot, but you can still adjust the speed as necessary to account for different bit styles and materials of heads & intakes being worked on.
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Re: Protecting valve seats when porting.

Post by PRH »

And then...... there’s always “plan c”.

Which is understanding that a novice “head porter”, without any way to verify that whatever grinding thats done on the heads is actually an improvement to what are a set of previously ported heads with a fresh valve job, that are ready to assemble.......may not be worth the risk of screwing them up........ and deciding to run them as is.
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Re: Protecting valve seats when porting.

Post by mt-engines »

Or just buy a Variac like i did when i first started.
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Re: Protecting valve seats when porting.

Post by hoodeng »

Keeping away from the seat with the carbide as others have pointed out is a skill learnt over time and becomes second nature to those that are inside a hole regularly.

One point not raised so far is the lock nuts on the head of the tool sweeping near the seat when working deeper in the port. Once bitten,,,,,,,.

Cheers.
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Re: Protecting valve seats when porting.

Post by steve cowan »

hoodeng wrote: Sun Dec 20, 2020 7:17 pm Keeping away from the seat with the carbide as others have pointed out is a skill learnt over time and becomes second nature to those that are inside a hole regularly.

One point not raised so far is the lock nuts on the head of the tool sweeping near the seat when working deeper in the port. Once bitten,,,,,,,.

Cheers.
Longer burrs :D
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Re: Protecting valve seats when porting.

Post by hoodeng »

That is with a long carbide!
Some of the 4V stuff [V Rod] requires a bit of deep hole work with a runner length of 5.500", paying attention to hand piece location as well as tool location is the norm.

Cheers.
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Re: Protecting valve seats when porting.

Post by cv67 »

Speed control cam really miniumize this..Foredom makes a 40 dollar paedal you can use for this.
Blew through the side of a bowl once not using one...caught the side and went crazy on me..wham! Course it was 90 percent done murhpys law.
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Re: Protecting valve seats when porting.

Post by 6.50camaro »

I bought one of those harbor freight speed controllers . it did show down my milwaukee electric die grinder but not enough for my liking . its still a hand full and need a real sturdy grip and lots of concentration on the job at hand or it still will get away from you. Before my next time I work on my heads I'm going to try a fan speed controller or a foot peddle speed controller not a dimmer switch. A dimmer switch just varies the voltage to the load. Less voltage = more amperage and higher heat. a true speed controller varies Hz frequency slowing the load without higher heat. just my .02 Dan
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Re: Protecting valve seats when porting.

Post by cv67 »

Having a foot control is way more convenient imo. No need to stop what youre doing and adjust it, just the right foot.

I found they dont work with grinders that already have adjustable speed. (mutabo)
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Re: Protecting valve seats when porting.

Post by hoodeng »

Camaro, yes they can bite. I learnt long ago to not tighten the collet chuck to what would be expected for proper tool retention, if it jams it will turn in the collets.

Mind you, i am lucky to only be porting a limited range of heads, anything that can jam or leave more work than i started with has been encountered and accommodated for to the point practices will stay in place ad infinitum.

If the cutting area is closing down or overextending, change tools, dont wait for what you know is coming.

Cheers.
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