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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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Protecting valve seats when porting.

Post by Krooser »

I'm going to do a bit of bowl cleanup work on the Mopar W-2 heads I have.

They have been ported but not much attention was paid to the bowl area around the valve guides. I never had these disassembled so the original poprting job was mostly a mystery to me. I sent them to my engine machinist for a cleaning and check-up and wound up installing new valves and guides. and a fresh valve job.

They flow 294 on the intakes.

I'm hoping a few layers of duct tape will help protect the seats... I plan to be plenty careful with this whole deal.

Ideas?
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Re: Protecting valve seats when porting.

Post by mt-engines »

Krooser wrote: Sun Dec 06, 2020 11:33 am I'm going to do a bit of bowl cleanup work on the Mopar W-2 heads I have.

They have been ported but not much attention was paid to the bowl area around the valve guides. I never had these disassembled so the original poprting job was mostly a mystery to me. I sent them to my engine machinist for a cleaning and check-up and wound up installing new valves and guides. and a fresh valve job.

They flow 294 on the intakes.

I'm hoping a few layers of duct tape will help protect the seats... I plan to be plenty careful with this whole deal.

Ideas?
The burr should never get close enough to worry about it.. Now chamber blending is another thing, use a valve cut down and margin ground out. Be patient and careful.

You can try hot glue if you are seriously worried.
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Re: Protecting valve seats when porting.

Post by Belgian1979 »

as above. Old valve in the head when porting the chamber.
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Re: Protecting valve seats when porting.

Post by BradH »

Use Dykem or a dark marking pen to provide a clear visual on how close to the seats you're grinding.

If you are like me in that I don't pull out the Makita on any regular basis, go very lightly to get the feel for it again. Using grinding stones on iron heads before hitting them with the carbides could help in that situation by also reducing the amount of material removed to play it safe.

What was mentioned above about using an old valve with the margin cut down for any work on the chamber that approaches the seats is true. Or you can pay to have the seats done twice (or at least touched up) before the heads even get bolted down. Yes, this is the voice of experience on that particular screw-up.

I've used multiple wraps of duct tape to protect crank journals when profiling the throws. Not sure how much you can use to protect the seats before it's simply getting in the way.
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Re: Protecting valve seats when porting.

Post by steve cowan »

I suggest using a air die grinder for better control
Sharpie marker on seat is a good idea,the shank of the burr will mark the seat as well
I to have been in the situation of paying to redo the valve job from a burr mishap,now I do my own valve jobs with stones.
Good luck Krooser, be careful and like the saying goes " we are all only as good as our last stuff up " :D
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Re: Protecting valve seats when porting.

Post by Krooser »

Here is my project.
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Re: Protecting valve seats when porting.

Post by PRH »

My somewhat limited experience with W2’s is that when they get into the 300cfm range, the SSR shape becomes pretty critical.

The bowl pic doesn’t show much detail, but from what I can make out it certainly appears there could be gains to be found by working in the bowl/seat area...... IF..... the SSR will support it.
Somewhat handy with a die grinder.
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Re: Protecting valve seats when porting.

Post by ozyfordman »

I usually scribe a line for the throat diameter by using a valve turned to the right size shoved down past the seat. I grind up to that scribed line and stop to measure often. The shank of the burr can mark the seat so be careful. If you keep the burr parallel to the guide you should be ok.
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Re: Protecting valve seats when porting.

Post by rebelrouser »

Same thing the other guys said, old valve when doing chambers. But the bowl area you just have to be careful. I grind my seats first and do the 60 degree angle below the seat, as a rule, I floe the heads after cleaning to get a base line, then I do the valve job first, then flow the heads again and then start porting. Unless it is a set I have done a lot of and know what needs to be done.
I grind to the 60 degree seat angle, usually using a sanding burr on a slower die grinder when I get close to the seat.
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Re: Protecting valve seats when porting.

Post by ProPower engines »

Just don't do it with out protecting the complete valve seat.

Get a couple of correctly sized valves and cut them to a razor edge to protect the now fresh seat area.
And do any work after the guides are fitted to the valves as they get thinned out in places and some iron heads are very hard to put replacement guides into after the areas in question are butchered by a carbide burr.

It don't matter how steady you think you are use some old cut down valves to project the fresh seats [-o< [-o<
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Re: Protecting valve seats when porting.

Post by Joe-71 »

I use 1/4" teflon tubing from Lowes to slide over the shank of 6" carbide burrs, cartridge roll mandrels, and 1 1/2" short shank burrs, etc. The teflon will cushion the burrs and they peel off if they hit a sharp edge, but do not damage the heads. It takes some getting used to, but works great after you adjust for the extra thickness of the shanks. It will work with electric die grinders if you use a router speed control unit to slow down the grinder speed. I have not experienced any out of balance condition due to the teflon tubing. It protects the valve seats, and combustion chamber edges. Joe-71
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Re: Protecting valve seats when porting.

Post by Geoff2 »

It's very easy to slip with THAT burr...& damage the valve seat. I protect the seats when porting. I machine a ring that looks like a metal O ring, except square section, not round. Sides are about 1/8'" -3/16". OD is slightly smaller the seat & lower face is machined at approx the seat angle [ actual angle is not critical ].
I braze a piece of 1" by 1/8" steel about 3" long onto the side of the o ring. This o ring will protect the int seat so I drill a 3/8" hole in the plate that is inline with the exh valve guide. Using a length of 1/4" threaded rod with spacers between the exh valve guide boss in the exh port & the plate, I position the o ring over the int seat, lightly touching the seat, & tighten the nuts on the threaded rod. Still have complete access to the port for porting purposes & the valve seat is protected.
I make a similar O ring tool to protect the exh seat & bolt it in place through the intake guide.
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Re: Protecting valve seats when porting.

Post by mag2555 »

294, if a accurate number is already 49 Intake cfm over stock for the iron heads .

If true then that's well into the cfm range where without the aid of constant velocity probe checking on a flow bench it gets to be easy to mess up those flow numbers you have already, atleast in terms of new work done on the Intake side of the head.

One thing I can relay to you with certainty is that if you do not have a Intake bowl throat size of atleast 1.82" to 1.83", then you do not have that 294 cfm either!

Here's a picture of how atleast the runner needs to look to hit 315 cfm on a iron W-2 head with a 2.08" 11/16" stem valve .
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Re: Protecting valve seats when porting.

Post by Ron E »

If you have to get close to the seat you might consider a pencil-grinder and do the most dangerous areas with rocks instead of carbides. They work pretty well on iron and are easier to control. Also you can shape the rocks as needed.
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Re: Protecting valve seats when porting.

Post by motormonkey »

Duct tape and lots of it. Use the old style tin foil heater duct tape on the seats (lots of layers), then duct tape over that and the spindle on the grinder. It's worked for me in the past.
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